Category: aortoiliac occlusive disease (AIOD)

Removing failed aortoiliac stents: an aortoiliac endarterectomy to engineer a lasting hemodynamic solution

Post author By Docpark
Post date 6 Jan 2023
1 Comment on Removing failed aortoiliac stents: an aortoiliac endarterectomy to engineer a lasting hemodynamic solution

The patient is a woman in her forties who works hard and smokes cigarettes to find stress relief. The year prior to presentation, she began to get cramps in her calves while she walked the halls of the building she cleaned, and this became unbearable. A consultation at our hospital revealed moderate to severe diffuse atherosclerosis without a dominant lesion but notable small distal aorta and iliac arteries with a 50% stenosis of the left iliac origin. Recommendations were to quit smoking and exercise. She found this difficult to achieve and went to another hospital nearby.

There, 6 months prior to presentation, she began complaining of painful cyanosis of her toes which was described as blue toe syndrome. These outside studies were not available. She was taken to the OR and her common iliac arteries were stented. This gave her relief, but the soon pain returned three months later -her stents had occluded. This was treated with more stents, extending them proximally into the aorta and distally in the case of the right across the iliac bifurcation. This afforded her relief for three more months until one weekend she found herself unable to walk again for more than minimal distances, and she took herself to my hospital, University Hospital, Cleveland Medical Center.

On examination, she was a large woman with no femoral pulses, but signals could be obtained in her popliteal and tibial arteries. Her PVR’s showed inflow disease and poor flow at the feet.

Her baseline CTA in workup of her claudication the year prior to getting stented shows the aorta and iliacs, while open, are small, with aortic lumen diameter reaching 10mm and common iliac lumen diameter at 6mm with diffuse atherosclerosis (below).

Aorta scanned winter prior to index intervention showing small aorta diameter of 10mm and diffuse narrowing of common iliac artery, 50% stenosis left CIA orgiin. Intervention was not scheduled. Patient went elsewhere and underwent intervention .

The CTA on presentation shows bilateral stent occlusion. A closer look shows the second set of stents extending the original stents both proximally into the aorta (raising the bifurcation) and distally into the external iliac and across the internal iliac origins (white arrows). The internal iliac arteries, despite the stents and on the right thrombus in the stent, supply flow to the external iliac arteries which have not thrombosed.

The treatment options were

Exercise and risk factor modification
Reintervention
Axillo-bifemoral bypass
Aortobifemoral bypass
Aortoiliac endarterectomy and patch angioplasty, stent removal

Although exercise and risk factor modification should be part of the treatment regimen, the best time to institute this was before her first intervention. With the long segment occlusion of her stents, coverage of the right internal iliac artery and occlusion, and acuity of her symptoms, this is no longer feasible.

It reveals a certain kind of bias when we prescribe walking exercise to those who can’t afford gyms or equipment, and whose neighborhoods are unwalkable.

Reintervention, having failed once, will not be durable. Even with anticoagulation, any recanalization -thrombolysis, thrombectomy, balloon angioplasty, atherectomy, lasering, and restenting, would not be durable.

It is likely the patient is frequently vasoconstricted and this is exacerbated by smoking. While never diagnosed with Raynaud’s, she did give a history of easily have numb, cold fingers and toes in the chilly winters in Cleveland. Even normal spectral Doppler signals will show pauses in flow in the peripheral arteries. Combined with any hypercoagulability and injured lumenal surfaces from interventions, and stents will go down.

An Aside on Small Aorta Syndrome in Women

One of the advantages of being a village elder is you remember forgotten concepts that guided treatment “back in the day.” The small aorta syndrome defined as having an aorta smaller than 12mm in diameter is one of those. Best described as not having enough pipe -imagine a small caliber fuel line throttling an engine. For all the muscles involved in standing and walking, there is a minimal diameter necessary for function.

Small aorta syndrome stands up to objective testing. A patient with a small aorta but otherwise patent lower extremity arteries, can present with claudication and demonstrate drops in ABI with exercise. These are typically female smokers with elevated BMI. Along with their small aortas, their external iliac arteries will be small, and I used to wonder if some critical period of inactivity in their early years failed to grow these arteries, or if this process of normal growth and remodeling is retarded by smoking.

Small aorta was a common indication for aortobifemoral bypass (ref). Unlike some abandoned indications for operation like “4.5cm AAA” and “asymptomatic 60% internal carotid artery stenois,” it had a testable finding of drop in ABI with exercise, but its acceptance has waned in the advent of the endovascular era. In a purely open era, I think there was greater emphasis and awareness on engineering the hemodynamics. While endovascular interventions simplify treatment, just stenting a small arteries usually doesn’t fix the problem as illustrated in this case. That is because there is a maximum size that the arteries receiving the stents will allow.

The iliac artery and aortic bifurcation will only tolerate so much upsizing with stents before rupturing. The interventions are constrained by the size of the adventitia. What is also ignored is the concept of elasticity -the 7mm lumen through a reopened and restented artery provides more resistance to flow than a 7mm artery restored via endarterectomy. All stents decrease elasticity of the circuit and decreases flow in a pulsatile circuit because of the increased impedance. Bovine pericardial patches on the other hand add elasticity. Endarterectomy restores elasticity. .

Enough Pipe

In the early 2000’s, I used to live in an pre-war apartment in Riverdale down the hill from Drs. Takao Ohki and Frank Veith. The apartments above and below me all shared this same feature -poor water pressure, because during a restoration twenty years before, the owner used the wrong, smaller size of pipe for this line of apartments. The taps would run, but if more than one apartment ran the shower or dishwasher, the taps would drip. The apartments would claudicate. The pipes were all patent, but inadequate. Not enough pipe. This patient endowed with small vessels, grew a large body, and smoked, and her muscles needed more pipe to support the added load. Not enough pipe.

So is the solution an aortobifemoral bypass? It is the board answer and a durable one, but it shares with axillobifemoral bypasses the risk of groin infections, particularly with a large body habits (below). The outflow arteries, all patent, are small and likely subject to vasoconstriction. My choice of ABF graft in this patient is a 14x7mm bifurcate which is on the small side, but I would be afraid that a 16x8mm graft would be too large on both the aortic and iliac side, resulting in mural thrombus formation.

A vertical groin incision will create a 3 inch deep canyon in the fat to get to the CFA

Axillo femoral bypasses, aside from the groin issues, suffer from poor long term durability and is not a great choice for a 40 year old. Her axillary artery was 6mm and sourcing flow to the lower torso from that is never great. Also, supplying a long 8 or 10mm graft would recapitulate the original problem of a small aorta. Not enough pipe.

For me, the best option would be to remove the stents and restore the distal aorta and iliac arteries to their original elasticity and slightly larger than original diameter. I would then be able to reopen flow to the occluded right internal iliac artery. Not just enough lumen, but enough and correct pipe.

Technique: Exposure

Exposure is predicated on the planned extent of the endarterectomy, place for clamping, and plans for aortobifemoral bypass if the endarterectomy results in poor adventitia. In a woman, the iliac bifurcations are easier to reach. A midline laparotomy is the incision of choice here. Let me digress here about the laparotomy. Over the three decades since the launch of laparoscopic surgery and subsequently endovascular surgery, the midline laparotomy has gotten an undeserved bad rap. Laparotomies are well tolerated and should not be viewed as a rare bailout or outright failure of laparoscopic therapy. Rather, it is still the gold standard exposure.

The infrarenal aorta to the right external iliac artery is exposed as well as the common iliac. In this patient the sigmoid mesentery was fatty and did not readily expose the iliac bifurcation so a separate exposure of the distal left common iliac artery was performed by mobilizing the left colon.

The aorta above the bifurcation was prepared for clamping. This involves circumferential exposure as I prefer a transverse aortic cross clamp. The lumbar arteries are clamped with bulldogs or aneurysm clips. The right external iliac well beyond the stent is controlled and the internal iliac is exposed and controlled. On the left the internal and external iliac arteries are expose and controlled.

The patient is heparinized clamps applied, and I make the arteriotomy with a 15 blade cutting down to the stent. The aorta is cut to a point about a centimeter below the clamp. The external iliac is cut to where there is patency of the artery and the plaque is mild. The endarterectomy is performed in the same way one does a carotid or femoral, with care to find the correct endarterectomy plane outside the plaque and good end points where the plaque adheres well. The internal iliac plaque on the right was chronically occluded but was successfully removed via eversion resulting in back bleeding. I sound the artery with a dilator to make sure a dissected plaque isn’t occluding it then reclamp.

The left common iliac artery is opened via a separate arteriotomy as I find tailoring a Y-shaped patch laborious. The arteriotomy is extended under the sigmoid mesentery and then moving the left colon medially the arteriotomy is finished slightly beyond the external iliac origin. The endarterectomy is finished short of the iliac bifurcation and any narrowing at the bifurcation is treated with the patch.

The specimen shows that the adventitia remains separated from the stents by the plaque. I rarely use tacking sutures as I feel a properly performed endarterectomy results in no plaque or well adherent mild plaque.

The patch needs to be thoughtfully applied. An overly large one will billow, and at worse case, create an artificial aneurysm. For example, for a 7mm iliac artery, the circumference is 22mm. Adding an 8mm patch with 1mm suture bites results in a 26mm circumference and an 8.3mm end diameter. Narrower is okay, but much larger will result in size mismatch that the body compensates for by laying mural thrombus. A long 8mm wide patch can be cut from a large swatch of bovine pericardium, remembering to add a slight angulation onto the iliac artery.

This operation avoids the groins with exposure or access into a small artery with a large sheath. A 4mm artery with 12.6mm circumference receiving an 8F sheath receives a 2.6mm hole, a 40% defect across the anterior hemicircumference of 6.3mm. This is not trivial, particularly because the arteries are often atretic after prolonged occlusion, may tear with a closure device, most of which are off IFU for such a small vessel. Avoiding the groins altogether is a great benefit to this type of procedure.

A postoperative CTA showed wide patency of the restored aorta and iliac arteries.

At followup several months after the procedure, the patient was walking well without claudicating and was ready to return to work. PVRs showed excellent flows down to the toes.

Hemodynamic Engineering

A surgical trainee has to develop a sense for flow. Looking at a circuit, she has to ask “how does blood get from point A to point B?” Merely providing a pipe does not mean a cure. For example, replacing a blocked artery with a steel pipe would provide flow but it has a hemodynamic impact that is different from the native vessel. Flow stoppages during the cardiac cycle that is modulated in a normal artery by the elasticity of its wall. While we don’t deliver steel pipes, we do something similar in ballooning heavily calcified arteries, or stenting them. ABF with prosthetic bypass offers a safe, broadly available method of treating this, but is fraught with problems for patient who develop groin infections or occlude a bypass for the reasons previously mentioned. Endarterectomy and patching with bovine pericardium allows for more precise restoration which would be a laudable goal in a young patient.

And my final point is this. This patient can yet undergo aortobifemoral bypass. Ironically, even larger stents may be safely placed than was previously possible. One of the principles laid out by Dr. Jack Wylie in his peerless surgical atlases was of leaving a patient in a condition to allow for future necessary operations. For a forty year old patient with many decades left, this is a critical concept.

This case represents the second aortoiliac endarterectomy I performed to remove failed stents. The third just happened today with resection of failed CERAB stents which I did with my chair and fellow Mayo Alum, Dr. Jae Cho. I think that there is a room for this operation which should not remain in the history books.

For a video presentation from Dr. Pat O’Hara: https://vascsurg.me/2022/10/15/aortoiliac-endarterectomy-removing-occluded-stents-is-possible/

References

Cronenwett, JL, Davis JT, et al. Aortoiliac occlusive disease in women. Surgery 1980; 88:775-84.

Tags #vascsurg

AIOD aortoiliac occlusive disease (AIOD) clti hybrid technique techniques

hybrid AUI-Fem-Fem technique

Post author By Docpark
Post date 16 Oct 2022
2 Comments on hybrid AUI-Fem-Fem technique

I had posted the above picture from over 15 years ago during my time in Iowa of my hybrid AUI-Fem-Fem (under unclampable 2, link). This technique came back to me as I was strategizing the upcoming aortic revascularization of a patient with iliac occlusions with the added complexity of an ileal conduit in the right abdomen. He had multiple failed prior iliac stents and failed femorofemoral bypasses -his right CIA and EIA were occluded while the left EIA had become occluded resulting in ischemic rest pain. While the picture alone is sufficient for me, it was brought to my attention by Dr. Joedd Biggs, fellow alum of the Mayo Clinic, on faculty at University of Kansas Hospital, that more detail was needed. So while resting my tired dogs, I got on my tablet and drew it out. Joedd, I present you my technique for a hybrid AUI-Fem-Fem bypass of the aorta.

This technique is made easier if one of the iliac arteries are patent. It is not a necessary condition.

The image above shows the necessary incisions for the femorofemoral bypass and the retroperitoneal pelvic (transplant) exposure of the left iliac bifurcation. I nearly always make oblique rather than vertical skin incisions in the groin to avoid wound complications from incising the inguinal crease orthagonally.

The transplant exposure facilitates a retropubic tunneling of the femorofemoral bypass which is performed first.

A left lower quadrant retroperitoneal exposure of the pelvis is performed -this is a standard renal “transplant exposure.” The two groin incisions are made and the common femoral arteries are exposed. Endarterectomy may be performed, although if the orifices of the SFA and PFA are patent, I don’t. The bypass graft is tunneled retropublicly and this is facilitated by the transplant incision. I generally use a 7mm ringed PTFE graft. Once done, the common iliac artery is divided above its bifurcation and the bifurcation is oversewn or stapled. A 12mm bypass graft is then sewn end to end to the common iliac artery (below).

The secret sauce in this technique is the end-to-end anastomosis of a 12mm bypass graft to the common iliac artery.

Through the conduit, a suitably chosen iliac limb of an EVAR system is brought through to the aorta and deployed with its end across the anastomosis into the conduit. A Gore Excluder 12mm ending iliac limb is ideal as its proximal end is appropriately sized for the diseased abdominal aorta. The limb is then aggressively ballooned to profile, particularly in the 12mm graft (below).

The Excluder 12mm limb works nicely and will seal against the 12mm bypass graft with sufficient overlap. It is then aggressively ballooned to profile from inflow to end.

The 12mm conduit graft is then sewn end to side to the femorofemoral bypass (below), completing the AUI-Fem-Fem.

I believe there are hemodynamic advantages to this over reintervening on native aortoiliac segment. First, size does matter, and until a suitable aortoiliac occlusive disease stent graft system is engineered, this represents an optimum. The Gore excluder graft limb is 16mm proximally and this is usually more than enough to diameter for the diseased abdominal aorta. The end diameter of 12 or 14.5mm will seal nicely in a 12mm conduit. I have not used a 16mm conduit only because I prefer not rupturing the aortic bifurcation with the “aggressive ballooning” mentioned above. The 12mm diameter is the boundary above the “small aorta syndrome” diameter of 10mm.

If the iliac is occluded, a wire can be driven through it from above and the conduit sewn over it. The iliac limb can be delivered after some pre-dilatation then followed by the “aggressive ballooning” of the iliac limb. The deployment into the conduit creates a stable “endo-anastomosis.”

Patients like my upcoming patient usually fail intervention due to the lumen size issues. An 8mm fem-fem bypass fed by a diseased series of iliac stents with at most 7mm lumen diameter is a recipe for the development of mural thrombosis and occlusion. The lower half of the body are fed by the diseased conduit of the donor EIA. This way, true aortic inflow is created.

AIOD aortoiliac occlusive disease (AIOD) techniques

Aortoiliac Endarterectomy: Removing Occluded Stents Is Possible

Post author By Docpark
Post date 15 Oct 2022
1 Comment on Aortoiliac Endarterectomy: Removing Occluded Stents Is Possible

I recently had lunch with Dr. PJ O’Hara, emeritus professor, and former partner of mine from the Cleveland Clinic. We hadn’t met since 2018 at the VAM in Boston, while I was still in Abu Dhabi. It was a recent case I did that caused me to reach out. I won’t be posting that recent case in detail today -it was a patient who had had multiple aortoiliac interventions for aortic bifurcation disease, but who closed up their stents within a few months of intervention. Rather than subject that patient to another round of interventions, I chose aortoiliac endarterectomy because the prior interventions failed to address the basic problem of the undersized aorta and iliac arteries.

The last case that Dr. O’Hara did before retiring was an aortoiliac endarterectomy which I assisted with, nearly a decade ago. During that case, Dr. O’Hara mentioned a video he had put together for an SVS meeting. He was kind enough to give me a copy share.

Aortoiliac endarterectomy -forget thee not!

The modern application of this technique is in the removal of occluded aortoiliac stents. The aorta and iliac arteries are restored, and yes, stents can go back in if needed.

A quick survey of some of my contacts at major centers reveals that this technique is rapidly becoming forgotten as its practitioner retire or revert to teaching the technically easier aortobifemoral bypass (ABF) graft. I hope to revive this because I know there are many patients who have challenging anatomy for ABF but potentially could undergo plaque and stent removal and restoration of their aorta and iliac arteries.

Tags #vascsurg, #vascularsurgery

AIOD aortoiliac occlusive disease (AIOD) bypass hybrid technique Practice techniques

Good Surgeons Copy, Great Surgeons Adapt: Cribbing the Open Hybrid Renal Artery Angioplasty and Stenting During Aortic Reconstruction

Post author By Docpark
Post date 2 Jun 2022
2 Comments on Good Surgeons Copy, Great Surgeons Adapt: Cribbing the Open Hybrid Renal Artery Angioplasty and Stenting During Aortic Reconstruction

Steve Jobs is credited with popularizing the saying credited to Pablo Picasso, “good artists copy, great artists steal.” While its provenance may be apocryphal, it makes an excellent point about how we learn. Even in the lack of understanding, it is still possible to learn by copying. Toddlers do this. We, as land mammals, are hard wired to copy.

Take for example this patient below with Leriche syndrome with a triad of smoking, claudication, and impotence.

Aortoiliac occlusive disease with history of smoking, claudication, and impotence in a middle aged man = Leriche Syndrome

Because of his relative youth, being his 50’s, I felt the most appropriate procedure was an aortobifemoral bypass.

I frequently use these diagrams to illustrate for the patient.

The only real complexity to manage was the severe stenosis he had in his left renal artery.

The options included

renal endarterectomy as part of aortic thromboendarterectomy
renal artery bypass from the aortic graft
reimplantation of renal artery
something else

Something Else: The complexity of renal revascularization creates risk. An antegrade endarterectomy of the renal artery would be done below a suprarenal clamp, adding to clamp time. A bypass would require the kidney to bide its time during the proximal aortic anastomosis, and the anastomosis for a jump graft, then the anastomosis to the left renal artery. This renal ischemia time can be extended by cooling the kidneys with cold (5 degree) LR, but why risk it? A renal endarterectomy can devolve into a visceral segment endarterectomy. After an hour, a nephrectomy.

That’s where this whole copying concept comes into play. Back in 2012, I worked with Dr. Jeanwan Kang, who had just come out of training with Dr. Richard Cambria. We were doing a type IV thoracoabdominal aortic aneurysm, and the right renal artery had a ostial stenosis. While I was figuring out the best way to manage this, Dr. Kang asked for a 6x18mm renal stent and an insufflator. She stuck the stent into the renal orifice and deployed the stent, opening the orifice. I had to find my jaw which had dropped to the floor.

Now, ten years on, that’s how I managed this patient’s ostial renal artery stenosis.

The patient’s thrombotic plaque went up to the renal origins and needed to be endarterectomized, but embarking on a renal endarterectomy adds potentially harmful renal ischemia time. Therefore, through the vertical aortotomy, I was able to get a clean end point to the aortic thromboendarterectomy and position a stent in the renal orifice and deploy it.

After thromboendarterectomy of the aortic plaque, the left renal ostium is treated with a balloon expandable stent. The aorta then is partially closed primarily to move the clamp below the renal arteries

Once the stent was deployed, the aorta was partially closed primarily to allow the clamp to be moved below the renal arteries. This all took less than ten minutes of ischemia time. The aortic graft was then sewn end to side to the remaining aortotomy.

The patient recovered and was discharged on POD#6 with normal renal function. In followup, his CTA showed excellent graft and stent patency.

A followup CTA shows a patent 14x7mm aortobifemoral bypass. I choose the bypass based on avoiding excess size mismatching distally as I find that patients who get 20x10mm grafts run into problem with mural thrombus because of limited flows into smaller femoral vessels. The renal stent is patent.

The centerline view of the renal stent shows it to be widely patent.

Patent stent with avoidance of the pitfalls of a renal endarterectomy

The patient is walking well without limitations and has improved blood pressure control, achieving normotensions at times.

If you are curious about the results from MGH, I refer you to their paper on 67 patients treated with open hybrid revascularization of the renal artery during complex aortic reconstructions (reference). At a mean followup of a year, they reported a 98% stent patency.

There is a comfort in sticking to what you know. The extreme example of this is the practitioner who graduates with a skill set from training and never expands on it. Yet there is an opportunity cost to blind devotion to sticking what you know and that is never growing. I recall this in the panel discussions during the VEITH Symposia I used to sneak into as a resident in the 90’s where great authorities pooh-poohed or condemned anything endovascular.

It’s a sign of a nimble mind that Dr. Cambria, after learning endovascular techniques mid-career, adapted these skills to his open surgical toolkit. His trainee, Dr. Kang, soon after, taught me.

Or was I just looking over her shoulders taking notes?

Reference:

Patel R, Conrad MF, Paruchuri V, Kwolek CJ, Cambria RP. Balloon expandable stents facilitate right renal artery reconstruction during complex open aortic aneurysm repair. J Vasc Surg. 2010 Feb;51(2):310-5. doi: 10.1016/j.jvs.2009.04.079. Epub 2009 Oct 22. PMID: 19853403.

Tags aortobifemoral bypass, renal angioplasty

aortoiliac occlusive disease (AIOD) bypass chronic limb threatening ischemia Practice techniques

Durability is the Gift that Keeps Giving

Post author By Docpark
Post date 1 Feb 2022
No Comments on Durability is the Gift that Keeps Giving

The patient was a 50 something year old man who I took care of in 2016 before I left for Abu Dhabi. He had a background of hypertension, hypercholesterolemia, and IDDM with chronic immunosuppression for rheumatoid arthritis. For several weeks he had rest pain in his feet and impending gangrene of his left great toe. More worrisome was the development of punched out ulcers on his groin crease resulting in weeping wounds after a bout of cellulitis. He had no palpable femoral pulses. Pulse volume recordings showed flat lines from the thigh to the feet.

CTA of the abdomen and pelvis with runoff showed aortic occlusion due to heavily calcified plaque with reconstitution of the external iliac arteries via the internal iliac arteries. The common femoral arteries were only mildly diseased and there was patent runoff.

Centerline up right femoral into aorta shows occluded aorto-iliac segment and diseased external iliac artery.

Centerline up left femoral into aorta shows mirror image of disease on left side

He was one of the rare instances of chronic limb threatening ischemia due to aortoiliac occlusive disease, AKA Leriche syndrome. The added background of autoimmunity made him vulnerable to the ulcers in the groin crease, and the infections there made access challenging.

The choices were endovascular versus open surgical repair. The groins were a problem with recent cellulitis, immunosuppression and open wounds, but with careful prep, and coverage with Ioban, access was possible, even for stent grafting. The problem was the aortic bifurcation was heavily calcified, and manipulating this likely thrombotic material with an end stump of aorta can cause renal embolism. There was a small risk of rupture at the bifurcation and of renal failure.

Standard aortobifemoral bypass graft was out of the question because of the lack of a safely clampable aorta -there was circumferential aortic plaque below and above the renal arteries and the infections in the groins would jeopardize any prosthetic graft. You have to respect unclampable aortas but like anything else, there are ways around it (link).

Regarding the groins, during fellowship, Dr. Thomas Bower used to take the distal anastomoses to the external iliac arteries which could be exposed via short lower abdominal incisions if not through the midline incision itself, avoiding groin incisions in hazardous groins.

I performed an aorto-bi-iliac bypass using the balloon in the infrarenal technique after obtaining supraceliac control described in my technical post (link).

A small aortotomy can be controlled with a finger and a foley easily slipped in -just remember to clamp it

This typically provides adequate hemostasis and space to perform a proximal anastomosis

I was able to endarterectomize a nice segment of aorta and anastomose end to side -always end to side as it preserves endovascular options. The distal anastomoses was to the external iliac arteries. He did well in the immediate postoperative period but I soon left for Abu Dhabi.

In the five years since the operation, he has needed an SMA stent and has devloped worsening CKD and autoimmune diseases. But one of the gratifying things is he healed his wounds on this groins and thighs and the left hallux, and pain has never recurred. He had a contrast CT at the 5 year point (figure) showing a widely patent graft, and he sought me out when he heard that I was back in Cleveland.

His PVRs remain normal (figure).

The PVRs and ABI’s remain robustly normal even after 5 years

I’m not saying that iliac stents from the iliac bifurcation to the renal arteries was a bad option, but there is a particular sadness and weariness when I have to take care of occluded stents. As an engineer, what is worse than ballooning an occluded stent and placing another stent inside? Knowing what I know about cell biology, what is worse than lasering, drilling, cutting, that cicatricial scar tissue that is neointimal hyperplasia in terms of what you leave behind. This man still has decades left to live and he will have his bypass graft far longer than any stent. This durability, a byproduct of the technique, is a worthy virtue.

When I operated, he was in his mid fifties and despite his comorbidities, was able to undergo a big operation. Now he is in his sixties and his autoimmune issues have progressed to where he is suffering from stiff person syndrome with difficulty walking. His renal function is poor and overall he is a terrible open surgical candidate. If I had done interventions at that time, which I was tempted to, he could today be facing amputations in the setting of cytotoxic immunosuppression having run out of endovascular options.

We have lost too much to innovation. The fact is, aortic surgery for critical limb ischemia was once and it still is a thing, because it works.

Tags #medtwitter, #vascsurg, #vasctwitter

AIOD aortoiliac occlusive disease (AIOD) Commentary humor opinion PAD

Perfectly Compulsive, Perfectly Smart

Post author By Docpark
Post date 15 Dec 2021
1 Comment on Perfectly Compulsive, Perfectly Smart

Recently, in clinic, my nurse handed me the patient sheet with the comment, “this is for iliac stents.” This caught my attention as “iliac stents” does not make sense as a chief complaint. The patient had been sent with a vascular lab report. It was a duplex scan documenting peak systolic velocities over 300cm/s in the common iliac arteries, appropriately diagnosing 50-99% stenoses. The patient had hip and thigh pain with walking short distances. I could have been excused for just cancelling the visit and booking an angiogram, except that would make me just a technician responding to a request. So I talked to the patient.

The patient was a nice lady over 70 years of age with recent onset of hip and thigh pain with walking 50-100 feet. This was incapacitating her as she was used to living an active and independent lifestyle. Her pulse examination was normal, not an uncommon finding with aortoiliac occlusive disease which manifests as a hemodynamic phenomena best explained as “small pipes.” Except she had never smoked, and had only hypertension and mild hypercholesterolemia. The review of systems was notable for fatigue and arm and shoulder pain. While she had not lost weight, strangely, her jaws hurt when chewing food.

I do not claim any kind of magic skills when it comes to diagnostics, but these other complaints did not fit. And it is not uncommon for someone to have several common conditions. Maybe she had TMJ, shoulder arthritis, early heart failure, and aortoiliac occlusive disease, to fit all of her complaints. Why was I wasting my time diving into nonvascular ephemera when I could be sending her to be scheduled for an aortogram and iliac angioplasty and stent?

I’ve carried with me this notion that all physicians can be mapped on x-y axes with one axis representing degrees of intelligence peaking at perfectly smart. Perfectly smart doctors have seemingly magical skills. While they are not rolling back their eyes while waving their hands over the patient, the handful of perfectly smart physicians I have worked with can quietly listen and digest a case and come up with the diagnosis, no matter how obscure and rare. On the other axis is compulsion, with the perfectly compulsive marching their patients through every test and algorithm to rule out every diagnosis on a exhaustively long differential list.

Intelligence and Compulsion, Written with a Doctor’s Penmanship

Those striving to be perfectly smart hope to bring efficiency to the clinical process -such as for this patient, it would have made sense for efficiency’s sake to move forward with an exercise treadmill ABI test and booking for an aortogram. Those stuck in perfect compulsion never quite reach a diagnosis, even after ordering batteries of tests, but rarely make mistakes, which is the point of perfect compulsion, because if you carpet bomb the diagnostic possibilities, something will hit. They are especially bulletproof to malpractice, particularly when patients choose not to have any more tests out of exhaustion. Their patients are rarely happy having to go through a myriad of tests to paint away the rule-outs while never quite identifying the disease. Those who play around with being perfectly smart get burned by that which are unknown and unfamiliar. They get blindsided. You want to revert to compulsion when you are tired and overloaded. You want to be smart, all the time.

The point of training, which never ends, is you have strive to be both perfectly smart and selectively compulsive, but it’s better to be lucky than good. It was my luck that I recently reviewed temporal arteritis. Every few weeks, I get asked to remove temporal arteries, and choosing not to be just a technician (although admittedly in the workup of TA, we kind of are), I plowed into UpToDate and Pubmed, seeing if there was a way out of doing these procedures -there really is not, except in the requests for temporal artery biopsy in younger patients -go read it yourself. It was here that I refreshed myself on polymyalgia rheumatica, which has as its symptom complex, muscle pain, lethargy, and jaw claudication. Out of duty, and compulsion, I ordered a CTA, because I knew that the patient had risk for atherosclerosis and arteries stiffened by calcium can have elevated velocities without critical stenoses. Out of curiosity, and after a quick call to one of the Clinic’s rheumatologists who order these temporal artery biopsies, I ordered an ESR and CRP.

The CTA came back with calcium at the aortic bifurcation and origins of the common iliac arteries where the outside duplex showed elevated velocities, but only revealed mild disease on the CTA. Both ESR and CRP came back very elevated. I referred the patient to our rheumatologist, and with steroid therapy, all of her symptoms resolved. Without an aortogram or stents.

I sat and thought about this for a while before posting. The patient was quite happy to give her permission. I cannot fault the outside vascular lab for their diagnosis of iliac stenosis because the diagnostic criteria are basically the same as our labs. It has made me think that approaching this case as a revenue opportunity as increasingly happens would not necessarily have been in error if I had performed an aortogram as long as I did not place stents. I can’t imagine the pressures put upon physicians who have put themselves into situations where they are paying for costly angio suites or their own 90th percentile salaries and lifestyles from not over-calling a stenosis and deploying stents, particularly when there is no oversight.

41 percent of my patients with median arcuate ligament syndrome present missing their gallbladders because biliary colic was the diagnosis that was both familiar and vaguely fit the complaints (reference 1). Not much harm can come from taking out a gallbladder, no? We know that a minority of operators harvest a significant share of the Medicare pie when it comes to peripheral interventions (link to terrific OPED, reference 2). Oh, I am sure each of these cases can be “justified.” Pleading justification from limits of knowledge means I proceed to treat what I am familiar and comfortable with -vascular disease, rather than an unfamiliar disease (at least to vascular surgeons) like polymyalgia rheumatica. If I can fail to recognize my ignorance, who can fault the perfectly compulsive? Like a broken clock that can be correct twice a day, someone of poor intelligence but perfect compulsion can be more effective than a greedy hack seeking to be perfectly smart and efficient.

Dunning and Kruger found that those with lower competence overestimate their ability, and those with higher competence underestimate their ability. Medicine is a perfect laboratory of Dunning Kruger. To be effective, you have to be correct and assertive. The problem is you are trained to project that confidence in the early stages of training and career when you are not ready. What patient would seek an unconfident physician? What person truly knows what they don’t know? The hardest step in medicine is both admitting what we don’t know but also applying hard-gained knowledge and experience with audacity. True humility comes from self knowledge and awareness. False modesty is externally directed, but true humility is internally focused. I don’t have a pat answer, but to become perfectly smart, you have to be perfectly compulsive about filling your knowledge and experience base. You have to submit your complications for peer review, you have seek and collaborate with sound partners, and you have to avoid financial traps that bias you to bad behavior. Above all, you have to stay curious.

References

Weber JM, Boules M, Fong K, Abraham B, Bena J, El-Hayek K, Kroh M, Park WM. Median Arcuate Ligament Syndrome Is Not a Vascular Disease. Ann Vasc Surg. 2016 Jan;30:22-7. doi: 10.1016/j.avsg.2015.07.013. Epub 2015 Sep 10. PMID: 26365109.
Sheaffer WW, Davila VJ, Money SR, Soh IY, Breite MD, Stone WM, Meltzer AJ. Practice Patterns of Vascular Surgery’s “1%”. Ann Vasc Surg. 2021 Jan;70:20-26. doi: 10.1016/j.avsg.2020.07.010. Epub 2020 Jul 29. PMID: 32736025.

Tags medtwitter, vascsurg, vasctwitter

AIOD aortoiliac occlusive disease (AIOD) bypass complications cost innovation graft infection techniques

The Story Should Fit: Repair of a Stent Graft Infection with Aortoiliac Endarterectomy and Bovine Pericardial Graft

Post author By Docpark
Post date 21 Nov 2021
1 Comment on The Story Should Fit: Repair of a Stent Graft Infection with Aortoiliac Endarterectomy and Bovine Pericardial Graft

One of the greatest surgical texts, Cope’s Early Diagnosis of the Acute Abdomen, is something every surgical resident, vascular or general, should read. The mid-century edition which I owned during my residency, has since been updated, but the central message of the book is this: every complaint or pain the patient has comes from a nerve, either peripheral or visceral, and understanding the nature of the pain, you narrow the diagnosis to only a few possibilities. Irritation of the psoas muscle results in a characteristic pain that years of diagnosing appendicitis the old fashioned way -by exam, then operation, makes it easy to recognize, like Marilyn Manson showing up as your substitute teacher (I would have said Alice Cooper, but that completely dates me). When the psoas muscle is irritated, by a hematoma, injury, inflammation, or abscess, the muscle relays intense pain localized to the retroperitoneum. Stretching the muscle worsens the pain, and the patient is often seen with the ipsilateral hip flexed. The genitofemoral nerve which rides on top of the psoas, is triggered and there is pain referred to the groin and proximal anterior thigh. Seeing this, and fitting the story allows for a diagnosis, before imaging. Without this insight, there is no swift vector to treatment and resolution.

Patient with inability to straighten left hip after iliac stent placement

The patient, a middle aged man, had undergone a redo-iliac angioplasty and stent for left iliac in-stent restenosis. He relayed that on the table, he felt immediate left lower quadrant abdominal pain and the desire to flex his left hip. He was restrained, sedated, and the procedure finished -a covered stent had been placed. When he came to my office a month after his initial procedure done elsewhere, he was in wheel chair, unable to straighten his leg. He claimed before coming to see me, he had gone to another hospital, where he had a CT scan and was told nothing was wrong (will have to confirm). He was having subjective fevers at home.

On examination, he sat on the exam table with left hip flexed. His pedal pulses were easily palpable. He had furuncles in his groins which he relayed he had had all of his life. I sent him for CTA and subsequently admitted him for surgery.

The CT showed a large collection around the left iliac artery and stents and on the psoas muscle, an abscess. The blood cultures on admission were positive for Staphylococcus lugadensis sensitive to penicillin.

Putting the story together after the fact is much easier than when you are in the moment, but being aware of the location and type of pain should give you a clue. Very likely, he had a brief rupture on the angiosuite table resulting in his sudden pain, drowned out by the sedatives typically given in response to a patient moving when a stent is deployed. Inflating a balloon in an artery typically causes some discomfort -as the vessels are lined with visceral nerve fibers which are quite sensitive but less localizable than say a pin poking on the index finger. If you ever had bloating with gas, that general discomfort localizable to the mid abdomen, that nausea and discomfort is from stretched visceral pain fibers. If you have ever had dull aching pain of distended spider veins, that is visceral pain. It’s there, but you would not be able to pinpoint it exactly. That is not what this patient had when he flexed his hip on the angio suite table. While the covered stent was deploying, he likely briefly ruptured causing both somatic and visceral pain around his left common iliac artery and iliopsoas muscle. Additionally, if the sheath had been entered through an area of a skin abscess, likely the sheath, wires, and gloves were contaminated. Any handling of the balloon expandable stent graft, which I highly discourage, would have contaminated it, resulting in a device infection, which was made more likely due to his diabetes. As the hematoma got infected, it resulted in the worsening symptoms he was having of left lower quadrant abdominal pain, groin pain, thigh pain, and inability to straighten his hip without pain.

I took him to the operating room and drained his abscess, assisted by Dr. Andrew Tang, chief resident headed to CT Surgery fellowship here at the Clinic, and Dr. Jenny Chang, PGY 2 Surgery. I gave Dr. Chang a copy of Cope’s with the admonition to read it soon and pass it on, as most of the current generation claim no knowledge of this important text. While I am not against interventional drainage, it takes time to drain the collection through a tube whereas sticking your hand in, sampling the collection, observing the injury, and breaking up collections and washing out with brown-bubbly -a mix of betadine/peroxide diluted in saline, I believe speeds the recovery from the infection. His drainage was done through a retroperitoneal approach from the left side and notably, his psoas muscle while viable, did not retract to cautery energy, suggesting some degree of rhabdomyolysis. The iliac artery was an indurated, thickened, and hard from the calcium and plaque that was the original problem affecting his distal aorta and iliac arteries (see left arteriogram centerline). I placed a pair of JP drains, removed one that wasn’t draining much on POD #3, and the other about a week after discharge on POD#5. His WBC elevation which was never high promptly resolved. I kept him on oxacillin with consultation from ID, and waited. After 3 weeks, I repeated his CTA.

His right iliac centerline showed patent stent with diffuse plaque and calcium starting in mid infrarenal aorta.

His abscess had significantly resolved and his pain was gone. He was ambulating again.

The choices at this point were the following

Continue treatment of patient with supressing antibiotics for life
Resection of left iliac stent graft which is presumed to be infected

If resection chosen, the options for repair that I considered included:

NAIS (ref 1). Neoaortoiliac System graft using femoral vein
Aortoiliac homograft
Rifampin soaked gelatin coated graft (ref 2)
Extra-anatomic bypass with axillofemoral bypass or femorofemoral bypass.
Aortoiliac endarterectomy and repair with bovine pericardial patch and graft

The choice of replacement is becoming clearer in that while rifampin soaked grafts offer immediacy and expedience, all grafts seem to be prone to reinfection at a higher rate than autologous material (ref 3). The NAIS bypass is a great option, but is hampered by the addition of several hours invested in harvest of the femoral veins. While it can be staged with mobilization done one day and harvest another, those added hours add complications. We often forget that the simple metric of procedure time is the most important determinant of complication rate. Any operation going over 2 hours risks wound infection for example simply from ambient colonization of the open wounds from the rain of dead skin from the surgeon’s face, aerosolized fecal flora from flatii (prohibited in my ORs). The microenvironment of the open wound is also room temperature and not 37, having an impact on organ function and hemostasis. The homograft is the original aortic graft -before Arthur Voorhees invented the cloth vascular graft as a resident at Columbia P&S (my medical school alma mater, ref 4), major hospitals had tissue banks of aortic homografts harvested from the recently deceased. Having homografts is now an outsourced function, but does require having proper refrigeration for the cyropreserved grafts and generally can’t be ordered with short notice.

Rifampin soaked grafts work well, especially wrapped in omental flap, in the short and medium term but suffer a reinfection rate that is higher than seen with autologous tissues, and prosthetic grafts without rifampin, such as PTFE for extraanatomic bypass, have the highest rates of reinfection (3), despite being the board answer decades ago.

Endarterectomy allows for use of native tissues for repair. The adventitia around plaque and stents, while thin, can support physiologic pressures, even when they have been occluded for years. And while practice of aortoiliac endarterectomy is a bit of a lost art, it has both a long history stretching back nearly a century and a modern track record with carotid and femoral endarterectomy. It is merely a matter of scale. Pinch and zoom in on a femoral endarterectomy at the bifurcation and you have the same case as with an aortic one.

The question is, is bovine pericardium more autologous than prosthetic? It is a decellularized sheet of collagen from a cow’s pericardium, used in heart valves and vascular patches, but only recently applied as a graft (ref 5-7). I have long used bovine pericardium as a patch with some caution, but the rule of thumb is are there well vascularized tissues around it? A layer of Scarpa’s fascia and fat in a groin wound are not sufficient to protect a bovine patch, but a sartorius flap is. For me, once the infected stent graft is out, knowing if the surrounding tissues bleeds well is an important one.

I chose to do aortoiliac endarterectomy. The patch and graft would be made with bovine pericardium, unless I found the left iliac segment to be devitalized and foul with anaerobic vapors, then, I would close and go NAIS or extra-anatomic. The key point is that choices have to be on the table and constantly rearranged during the conduct of the operation.

The patient was preoperatively vein mapped and had suitable deep femoral vein for bypass conduit, having robust duplicated systems that would impact the patient minimally. The patient was placed in a supine position and via a midline laparotomy, the infrarenal aorta and the common iliac arteries beyond the short iliac stents exposed. I chose this limited exposure as any further into the phlegmon on the left risk injury to ureter and vein. The aorta had a palpable demarcation between plaque and mildly diseased proximal segment, predicted by the CTA to be at the IMA. A longitudinal arteriotomy was created on the right side from mid aorta to mid right iliac, and the left side had a separate arteriotomy to release the stent. The plaque came out in a single specimen (image).

The exposed stent is the left iliac stent holding within a stent graft.

The left iliac artery was destroyed by the infection but the tissues around it bled avidly and were not foul or infected. I avoided excess debridement here as the iliac vein was intimate with the phlegmon. There was a 3cm gap. Again, I thought briefly about taking femoral vein, but proceeded to make a graft from the bovine pericardium. This was sewn around the rod portion of a renal vein retractor from the OMNI set. The finished product resembled Voorhees’ graft. It was sewn into the orifice of the iliac from inside the aorta and end to end to the freshened iliac stump. Unfortunately, the omentum was atropic across the transverse colon, but the tissues around the resected artery and stent graft bled well, indicating good penetration of antibiotic. The retroperitoneum was closed after hemostasis obtained. Dr. Shashank Sharma, our chief resident headed to a vascular surgery fellowship at the renown Houston Methodist next year got to see what is unfortunately a rare occurrence -an aortoiliac endarterectomy, which through me puts him three degrees of separation from Cid Dos Santos (ref 8). Dr. D’Andre Williams, PGY-2 Vascular Surgery Resident, got important lessons on sewing the aorta. She’s part of a fortunate cohort that get exposed to open aortic surgery at our main campus which is unfortunately rare throughout the world.

The pericardium was soaked in rifampin, but probably did not bond to the collagen.

The final graphic shows the operative end result.

The patient recovered well and was discharged within the week with another month of IV antibiotics planned.

Conclusion: The operation was started at 8 in the morning and was done by lunch time. For aortic cases, this is a crucial metric, as when the clock winds past the surgeon’s comfort, the patient suffers even more. Adding the femoral vein for a NAIS may have been the textbook thing to do, but we don’t do extra-anatomic bypasses that much either. I don’t believe that adding two more hours for retrieving the femoral vein would have enhanced the procedure, and would have served to add potential areas for complication. Technically, the aorta closes much as with a carotid or femoral endarterectomy, but the adventia is thin and really should be sewn with 5-0 or 6-0 Prolene. The larger needles such as the SH size creates unnecessary bleeding unless sewn with a line of felt which could become infected. Despite the thinness, it will hold pressure if it is not infected. Clamps that bend out of the “airspace” above the laparotomy, such as the Cherry Supraceliac Clamp and Wiley Hypogastric Clamp, prevent limiting the operative space with long clamps such as aortic Fogarty or DeBakey clamps, while being stronger than the Zenker.

A final comment for Staphyloccocus lugudensis. This is the second major vascular graft infection with this organism I encountered this year. The other was an infected aortic stent graft. Lugudensis means from Lyons. I do not know why that is, but it is so far not the nasty player that is S. aureus. I am sure it will share some plasmids, and become resistant one day, but in the earlier case in Abu Dhabi and now this, it is sensitive to penicillin, and came from the skin at the femoral puncture site, and for this we are fortunate. Major vascular infections are one of the few areas that still demand open surgical skills, and we foresake them at great peril. It’s critical to remember all the collective memory of surgery from the past, or we will become mere technicians fixing whatever comes out of the radiologist’s report with whatever knowledge obtained from a Zoom meeting for the latest, greatest device.

Acknowledgement

Gratefully, the patient gave his permission, as with all patient, for use of his case for educational purposes.

References

Chung J, Clagett GP. Neoaortoiliac System (NAIS) procedure for the treatment of the infected aortic graft. Semin Vasc Surg. 2011 Dec;24(4):220-6. doi: 10.1053/j.semvascsurg.2011.10.012. PMID: 22230677.
Oderich GS, Bower TC, Hofer J, Kalra M, Duncan AA, Wilson JW, Cha S, Gloviczki P. In situ rifampin-soaked grafts with omental coverage and antibiotic suppression are durable with low reinfection rates in patients with aortic graft enteric erosion or fistula. J Vasc Surg. 2011 Jan;53(1):99-106, 107.e1-7; discussion 106-7. doi: 10.1016/j.jvs.2010.08.018. PMID: 21184932.
Smeds MR, Duncan AA, Harlander-Locke MP, Lawrence PF, Lyden S, Fatima J, Eskandari MK; Vascular Low-Frequency Disease Consortium. Treatment and outcomes of aortic endograft infection. J Vasc Surg. 2016 Feb;63(2):332-40. doi: 10.1016/j.jvs.2015.08.113. PMID: 26804214.
Smith RB 3rd. Arthur B. Voorhees, Jr.: pioneer vascular surgeon. J Vasc Surg. 1993 Sep;18(3):341-8. PMID: 8377227.
Almási-Sperling V, Heger D, Meyer A, Lang W, Rother U. Treatment of aortic and peripheral prosthetic graft infections with bovine pericardium. J Vasc Surg. 2020 Feb;71(2):592-598. doi: 10.1016/j.jvs.2019.04.485. Epub 2019 Jul 18. PMID: 31327614.
Lutz B, Reeps C, Biro G, Knappich C, Zimmermann A, Eckstein HH. Bovine Pericardium as New Technical Option for In Situ Reconstruction of Aortic Graft Infection. Ann Vasc Surg. 2017 May;41:118-126. doi: 10.1016/j.avsg.2016.07.098. Epub 2016 Nov 27. PMID: 27903471.
Belkorissat RA, Sadoul C, Bouziane Z, Saba C, Salomon C, Malikov S, Settembre N. Tubular Reconstruction with Bovine Pericardium Xenografts to Treat Native Aortic Infections. Ann Vasc Surg. 2020 Apr;64:27-32. doi: 10.1016/j.avsg.2019.10.104. Epub 2020 Jan 10. PMID: 31931127.
Barker WF. A history of endarterectomy. Perspectives in Vascular and Endovascular Therapy. 1991;4(1)1-12. doi:10.1177/153100359100400102

Tags #medtwitter, #vascsurg, bovine pericardial graft, endovascular stent infection, stent graft infection, vasctwitter

acute limb ischemia aortoiliac occlusive disease (AIOD) innovation limb salvage PAD skunk works techniques ultrasound

The shunt as temporary bypass -a modest proposal

Post author By Docpark
Post date 3 Aug 2019
No Comments on The shunt as temporary bypass -a modest proposal

The rise of cardiopulmonary bypass life support has also given a rise to the need to keep large, obstructive cannulas in femoral arteries. ECMO cannulas are often kept in for days, and it is not uncommon to discover limb ischemia and infarction relatively late. This can be avoided by placing a distal perfusion cannula to shunt blood to the leg early in the ECMO process. The ECMO cannulas have a convenient side port to send a little flow to a 6F sheath placed in the femoral or popliteal artery. This is an established technique (reference 1, sketch below), and it works despite the modest flows achieved because it does not take much to keep the leg alive. These patients are not walking, nor are they need to heal leg wounds, so just enough blood flow means something just a little more than what they get when the common femoral artery is completely occluded by the life support cannulas. What is fascinating to me is that these shunts can pptentially help to save limbs when used as temporary extracorporeal bypasses when definitive vascular surgical care is not immediately available.

brachial to femoral shunt sketch

When I was a medical student, I took on a research project after my first year where I had a Langendorff preparation of a rat heart (below).

an isolated, perfused, beating rat heart placed in a superconducting magnet for NMR spectra acquisition

My project was to take a rat heart and keep it alive, beating, and even working, through a perfusion apparatus and place this inside a superconductive magnet to obtain Phosphorus nuclear magnetic resonance spectra -intracellular metabolism data including concentration of ATP, intracellular pH, and ATP/ADP ratio. While the project was successful -I am quite proud to have been the only person at Columbia to have successfully acquired NMR-S data with living beating heart, I moved on to other interests and took away this concept: with oxygenated, glucose enriched, isoosmolar fluid perfused at arterial pressure, any organ can be kept alive, possibly indefinitely, including a brain which only recently others have found possible (reference 2) in reputable scientific circles, but the the Nature publishing Yalies were scooped by the Simpsons decades ago (below), and maybe Mary Shelley centuries before,

simpsons head

This is the simple idea. Revascularization is keeping the target vascular bed alive by delivering oxygenated blood. With a shunt, it could be little, it could be a lot, but it certainly is better than zero, and even a little can buy you time.

The breakthrough that I had was several years ago, a patient arrived from another hospital with an Impella pump which did not have a side port like an ECMO cannula. It is a large catheter that augments cardiac output and in the patient that I was asked to see this patient as their leg was cold and pulseless. Their cardiac output was very poor, and they were sustaining an augmented systolic pressure in the 90’s. There was no way to get this patient to the operating room for a revascularization of any sort. It did strike me that the patient had the misfortune of having catastrophic heart failure in the absence of significant athersclerosis and had normal brachial arteries. After discussing the ramifications with the ICU and family, I placed a brachial artery 5F cannula, and connected it to a 5F sheath I placed in the superficial femoral artery below the occlusive common femoral sheath (figure below). A doppler on the tubing connecting the two cannulas confirmed flow and the patient’s left hand maintained a pulsatile oximetry waveform. The leg pinked up and eventually there was a signal in the foot. This managed to perfuse the leg which did better than the patient who succumbed to multiorgan failure from heart failure. The leg did great.

Which leads me to these thoughts. Most hospitals are good at diagnosing large vessel occlusion via CTA. Most hospitals have doctors who can place arterial lines with ultrasound guidance. In the instance of aortoiliac occlusion or femoral occlusion from thromboemboliem, time is a critical limiting factor to limb salvage. Many hospitals do not have vascular surgeons. Many hospitals transfer these patients with a heparin drip but in the ischemic condition. Transfer arrangements may take hours. Why not ameliorate this situation by having an appropriate physician -an anesthesiologist, an intensivist, an EM physician, place an ultrasound guided radial or brachial arterial line, connect to arterial line tubing to a dorsalis pedis arterial line. Tape it all down on the patient after confirming flow (crude sketch below). This would be better than the three extra hours of ischemia the patient gets hit with on transfer. No one would transport a donor kidney without adequate perfusion and protection, but dying legs get transferred all the time with established warm ischemia. If done well, it might turn an emergency procedure into an urgent, semi-elective one. Have the vascular surgeon video conference in to confirm the absence of blood flow and appropriateness of temporary shunting.

radial artery to dorsalis pedis artery shunt

If we are to live in a world with less vascular surgeons, then the radius of survival has to be extended with use of technology and simple ideas such as this. Comments are welcome.

Reference
1. Foltan M, Philipp A, Göbölös L, Holzamer A,
Schneckenpointner R, Lehle K, Kornilov I, Schmid C, Lunz D. Quantitative assessment of peripheral limb perfusion using a modified distal arterial cannula in venoarterial ECMO settings. Perfusion. 2019 Mar 13:267659118816934. doi: 10.1177/0267659118816934.

2. Vrselja, Z., Daniele, S. G., Silbereis, J., Talpo, F., Morozov, Y. M., Sousa, A. M. Mario, S., Mihovil, P., Navjot, K., Zhuan, Z. W., Liu, Z., Alkawadri, R., Sinusas, A. J., Latham, S.R., Waxman, S. G., & Sestan, N. (2019). Restoration of brain circulation and cellular functions hours post-mortem. Nature, 568(7752), 336–343.

Tags acute limb ischemia, temporary shunts

amputation aortoiliac occlusive disease (AIOD) BKA graft infection limb salvage PAD tibial revascularization

Never say never

If you work long enough, you will not only see everything, but you may end up doing something that you say you would never do. You will be confronted with a scenario that would test not just your skills but also your boundaries. The adage, never say never is a warning that all of us may face a choice -to remain rigidly consistent with some earlier proclamation or to excuse a little hypocrisy for the sake of the patient.

At one point in recent years, I saw a patient who had an axillary artery to anterior tibial artery bypass with PTFE (figure above). That was a kind of marvel to me, but my initial response was a bit of a sneer.

“Who does this?” I thought.

Giving it some thought, the rationale could have been to spare the patient from a hip disarticulation as the patient had had failed revascularizations and was occluded from the infrarenal aorta to the anterior tibial artery on that side. If you see such a thing, it sparks wonder as it feels both wrong and splendid at the same time because some surgeon had the audacity to pull it off. By the time I saw it, the patient had avulsed the proximal anastomosis, infarcted their leg to their thigh, and was headed for a hip disarticulation, four years after the creation of the bypass. Four years of patency!

It was no wonder I remembered this case when this middle aged man presented to our clinic with a gangrenous right third toe. He had diabetes, hypertension, CAD with prior PTCA, prior acute mesenteric ischemia with bowel resection with an SMA stent, CHF with moderately reduced EF, CKD, and aortoiliac occlusive disease treated in past with aorto-bi-iliac bypass, left to right fem-fem bypass complicated by graft infection requiring resection of the fem-fem bypass, with subsequent development of rest pain on left leg and gangrene on right leg. He had been told at his home institution that he required eventual bilateral hip disarticulations. At the time of consultation, he was minimally ambulatory, limited by severe pain. He had been this way for over a year.

On examination, he had heavy scarring in both groins from prior open incisions healed by secondary intention, a midline laparotomy incision. He had weak bilateral axillary and brachial artery pulses. He had no pulses in either leg. The right foot had gangrene of the distal phalanx of the third toe. The both feet were anemic and painful -the left foot had more dependent rubor. Pulse volume recordings were flat in both legs. TCPO2 was in the 20-40mmHg range at the thighs bilaterally suggesting reduced potential for healing an above knee amputation. Vein mapping showed no suitable saphenous vein in either leg. CTA (figure below) showed both external iliac arteries to be occluded or absent and the common femoral arteries to be occluded or missing bilaterally.

AngioRunOff 1.0 B20f

The left femoral bifurcation was preserved and the left SFA was patent into small underfilled tibial vessels. On the right, there was an isolated segment of profunda femoral artery that reconstituted from pelvic collaterals. The right below knee popliteal artery reconstituted and had underfilled but patent three vessel runoff (figure below).

posterior view of right popliteal reconstitution

The patient was admitted for workup and treatment. Heparin drip was started. In the setting of rest pain, I find that heparin drip improves circulation and symptoms even though it shouldn’t. I don’t have a great explanation for this, but it does, and I would welcome comments. To better assess how much operation the patient could tolerate, a cardiac risk assessment was performed. He was deemed a moderate to severely elevated risk due to his EF of 35% but had a normal nuclear stress test.

The options I presented to the patient were
1. Hip disarticulations
2. Bilateral above knee amputations with a wait and see approach to hip disrticulation
3. Sympathectomy
4. Axillo-profunda or popliteal bypass on right and Axillo femoral bypass on left
5. Ilio-right popliteal and left femoral bypass.
6. Thoracic or supraceliac aorta to right profunda and left femoral bypass

Hip disarticulation is the bogeyman of leg amputations done for peripheral vascular disease. When done for trauma or cancer in young people, the ability to rehab and walk again is excellent. When done for tissue loss in elderly, non-ambulatory patients, the reported mortality of the operation rises to above 50%. It is usually posed as a lead in to comfort measures. The above knee amputations were not likely to heal despite the neither here nor there findings of the TCPO2 which is only good when the results or normal or dismally low. Sympathectomy is an option for those without options, but this patient still had options, I felt.

Any revascularization relies on the choice of inflow, outlow, and conduit. In endovascular revascularizations, the conduit is the previously occluded vessels, but in this instance, because of the infected grafts, there was neither continuity, nor a good option even if there was as the common femoral artery is a terrible recipient of endovascular therapy. The options then devolve to choosing an inflow. The axillary arteries are technically easiest to access and manage and form the basis of treatment of high risk patients requiring limb salvage who have no endovascular options. The axillofemoral bypass is given a bad reputation of having a poor patency, but the key is the quality of the vessels and the number of potential tension, compression, and kink points. I think the reason why the axillary to anterior tibial bypass lasted for four years in the first patient had to do with his immobility, and the pristine nature of the anterior tibial artery -the only patent vessel below his umbilicus. Here to, the inflow disease appears to have spared his right popliteal artery and his left superficial femoral artery.

The only compromise with an axillary artery inflow is the amount of potential flow. In a patient with a 6-7mm axillary artery, the amount of flow going to both an arm and a leg, and a lower torso, would greatly exceed the flow capacity of that vessel. The infrarenal aorta on this man is graft and is relatively inaccessible due to the prior laparotomy for acute mesenteric ischemia, signalling the high likelihood of adhesions. The supraceliac aorta is an excellent inflow source and I have had good results dissecting it out laparoscopically as it is often deep and narrow an exposure to try to dissect open -While the retroperitoneal tunneling can be tricky, it is not insurmountable and good bypasses can result (link).

My eye focused on the left iliac graft which perfused the internal iliac artery on that side. The graft was generous, and likely a dilated 8mm graft, and could be exposed via a left lower quadrant retroperitoneal exposure (the transplant exposure). This would allow me to to then tunnel to avoid the terribly scarred groins. On the right side, the obdurator canal could be traversed into the postioer compartment of the thigh -a graft could be sent to the below knee popliteal artery with a side graft to the tiny profunda femoral artery. On the left, the graft could be tunneled laterally near the insertion of the sartorius muscle and onto the superficial femoral artery. All of the incisions would be made in virgin skin, the only redo dissection being digging out the left iliac graft while avoiding injury to the ureter.

So I proposed a ilio-popliteal bypass. Not quite an axillo-tibial bypass, but almost there. There was some karmic balance being restored by my taking decision. It would be with PTFE all around. I quoted a 5-15% risk of major morbidity and mortality, lifelong anticoagulation, and right third toe amputation. The patient agreed.

sketch of iliopopliteal and iliofemoral bypassrs

The operation was done in a hybrid suite, as should all limb salvage cases. The retroperitoneal dissection was challenging because of the heavy scar tissue around the well incorporated iliac bypass, but with patience, a clampable 3cm segment was achieved. I am a big fan of Wylie hypogastric clamps because they stay out of the way when placed in a tight narrow spot, and for that same reason, I prefer the Cherry supraceliac aortic clamp. They were designed by my mentor, Ken Cherry, and his mentor, Jack Wylie for this kind of operation. A few venous bleeders were easily handled with my ring compressors (below), and I hope to continue this chain of innovation, but I digress.

a Park clamp

The bladder was dissected off the pubis to allow the graft to be tunneled to the right pelvis. A counter incision in the right lower quadrant abdomen and a mid thigh incision mobilizins the anterior compartment muscles to the posterior compartment allowed me to tunnel across the obturator foramen. The obdurator vessels need to be avoided or there will be bleeding. this mid thigh incision allowed exposure of the profunda femoral artery more proximally and allowe the graft to be tunneled anatomically to the below knee popliteal artery for anastomosis. A jump graft was taken off this graft on the thigh to the profunda femoral artery which was small and diseased -no more than 2mm in size. An axillary bypass to this profunda would be doomed to the compromised patency rate published for ax-fem bypasses giving them a bad name. The left superficial femoral artery was exposed and provided outflow to the left iliofemoral bypass which was tunneled far laterally under the inguinal ligament to avoid the scar tissue where the common femoral artery was.

There was immediately multiphasic signal in both feet on release of clamps. After closure of all the incisions and dressings, the right middle toe was amputated.

The patient recently came back for an 8 month followup. His grafts remained patent and he was walking without limitations. Given the high quality of the inflow (large iliac graft), and the amount of decent outflow -the right popliteal and profunda, the left superficial femoral and retrograde to the profunda, gives the patients some surety of longevity for his grafts. These grafts will need lifelong surveillance.

I have since opened my mind a bit about that axillary artery to anterior tibial artery bypass. When given the choice between comfort measures for an otherwise nonambulatory but alert patient and hip disarticulation with its attendant high risk, a bypass from a large axillary artery to a large, relatively disease free anterior tibial artery is not the worst thing that could happen. For that patient, it gave them 4 more years with their family, which in any measure, is priceless. To that patient’s family, that surgeon was a savior.

Tags axillo-femoral bypass, extra-anatomic bypass

AIOD aortoiliac occlusive disease (AIOD) bypass Commentary EndoRE opinion ultrasound

Arterial Restoration in CLTI with Remote Endarterectomy (EndoRE).

Post author By Docpark
Post date 12 Jun 2019
3 Comments on Arterial Restoration in CLTI with Remote Endarterectomy (EndoRE).

preop PVR

The patient is a man over 70 years of age who came to the hospital with severe pain of his right foot and leg with walking short distances and at night while recumbent. He had a history of hypertension, diabetes, and coronary artery disease, and several years ago had his left common iliac artery stented. On examination, he had no lesions of his foot, and his pulses were only palpable (barely) in the femoral arteries only. He did have strong monophasic signals in the anterior tibial arteries bilaterally.

Initial vascular lab testing showed only mildly depressed ankle brachial (above), with dampened waveforms consistent with inflow and femoropopliteal disease on the right. He underwent arteriography by our vascular medicine specialist and cardiologist Dr. Faisal Hasan, and it showed bilateral common iliac stenoses, a severely calcified and nearly occlusive plaque in the right common femoral artery, and a long segment occlusion in the superficial femoral artery with diffuse calcified plaque extending into the popliteal artery. There was diseased but patent 3 vessel tibial runoff.

aortogram

R SFA arteriogram

To Act As A Unit are the Cleveland Clinic’s words and it shows the Clinic’s roots as an US Army field hospital on the vasty fields of World War I France a little over a century ago, and we take it seriously. It may come as a surprise to some that a cardiologist referred me this patient after mutually deciding that the common femoral disease and the TASC D SFA occlusive disease, but we both decided that a surgical approach was the best one. The question then is how much more flow?

I ordered a CTA (CT angiogram) particularly for endarterectomies as I find it imperative to know the actual end point of plaque. Arteriography only hints at it, and while a 5mm lumen may look large and patent, it may be a channel in a 10mm wide plaque that when a stent terminates within it, breaks and becomes biologically active as intimal hyperplasia at best or embolizes at worst. CTA shown below revealed the plaque where contrast angio showed only the lumena of the vessels.

The 3D reconstruction function also allowed me to see and plan the operative approach and predict the lack of saphenous vein confirmed on duplex ultrasound.

For the students reading this, ischemic rest pain is often simpler to treat because it requires only a little more blood flow. There is a neurologic ischemia component that is not well studied, particularly in diabetics, as ischemia may result in anesthesia in someone who has underlying diabetic neuropathy, but that is not an indication for revascularization while rest pain is, and someone should investigate this. This little more blood flow in the form of treating inflow disease only may be sufficient in relieving rest pain while avoiding interventions on the superficial femoral, popliteal and tibial arteries which have limited longevity.

The common femoral artery on the other hand is the throttle of inflow and as a principle, inflow can be considered as the infrarenal aorta to profunda femoral artery, and repairing the common femoral necessitates an operation. There is no durable or laudable endovascular procedure for occlusive disease of the common femoral artery, a feature shared with the subclavian artery at the thoracic outlet and the celiac axis at the median arcuate ligament. All three are externally compressed by hard structures and revascularization must be ever mindful of the inguinal ligament, the thoracic outlet, and median arcuate ligament. The only exception to the “you must operate” rule of the CFA is calcified atherosclerotic disease in high risk individuals, and I make careful exception here with rotational atherectomy devices.

Claudication is another thing entirely. Claudication limits lifestyle and can be corrected by changing lifestyle -either with more exercise or limiting exercise. The thing is, when a patient has reached a certain age, that lifestyle may be walking slowly from chair to commode, and if that activity is limited, no amount of haranguing may be able to induce that person to embark on an ambitious exercise program. Sometimes, you have to be realistic about telling a frail old man to go for a 60 minute walk. But if that person has difficulty getting to the bathroom because of leg cramps, then either they have to get assistance or more bloodflow, and ironically, a little more blood flow represented by improving inflow, may not be enough.

That was what I was thinking when I was planning this operation. Improve the inflow with stents to the common iliacs and a right CFA endarterectomy, but use the opportunity of surgical exposure to extend the endarterectomy to the distal external iliac and through the entire SFA.

My fondness of remote endarterectomy is well known from my many blog posts on it (link). It is a modern update on a very old procedure -the ring endarterectomy, done since the middle of the last century when bypass grafts were unavailable. The occlusive plaque is removed, and an end-point reached and cut with a scissor like device (available from LeMaitre). It is the ultimate hybrid operation (below) requiring open and endovascular skills. I tell prospective trainees to judge training programs by how facile are the surgeons and how many are the procedures with and involving a hybrid approach, because any program can have few (getting fewer) old surgeons doing only open surgery and a lot of young surgeons doing only endovascular procedures, but a rare few will do a lot of hybrid procedures.

I chose to add femoral EndoRE. This would bring the extra blood flow needed to kickstart any walking program, barring cardiopulmonary limitations.

The patient was brought to our hybrid operating theatre and prepped from nipples to toes. The right common femoral artery was exposed for endarterectomy, and accessed then with a sheath along with a left femoral sheath for kissing balloon angioplasty and stenting of the common iliac artery stenoses (below).

preintervention post kissing stents

Afterword, the CFA was opened and endarterectomized, and the SFA was remote endarterectomized (below).

EndoRE setup EndoRE

The endpoint was chosen in the above knee popliteal artery to avoid having to stent the dissected end point plaque well into the popliteal artery. If I wanted to go all the way to the below knee popliteal artery, I would have to open it to manage the plaque and artery at the so-called trifurcation, typically with a patch angioplasty. The plaque came out in one piece (below):

EndoRE plaque plaque in toto

The terminus of the plaque in the POP where it was cut has to be managed with a stent, unless you open and complete the endarterectomy and patch the artery. I was able to cross the dissection (no small feat) and plaque a stent. The artery was widely patent and even the small branches off the previously occluded SFA were now reopened.

Endpoint management before and after endoRE

His pulse volume recording done after intervention reflects the improved flows (below).

PVR before and after

His rest pain resolved, but more gratifyingly, he has regained the confidence to walk and exercise, which he now does without limitation up to 45 minutes a day. In two month followup, we performed a duplex which showed his right SFA to be basically normal (below), including an intimal stripe and media. This is not an anomaly. When I took a punch out of restored artery to perform an anastomosis (from this case link), I sent it. Previously it had been an artery that was obstructed for nearly a decade, but after EndoRE, had become an elastic, compliant vessel. The pathology returned as “normal artery.”

postop duplex at 2 months

When these fail, they typically do so a random points on the endarterectomized vessel and on the stent. While stent grafting may have better outcomes with regard to restenosis, doing so covers collateral vessels and PTFE grafts behave poorly by embolizing while clotting off, and PTFE stent grafts are no different. Data from over a decade ago suggests that EndoRE of the SFA while inferior in patency to vein grafts, are equivalent to PTFE [reference 1] and superior to endovascular revascularization [reference 2] in terms of primary patency. When they occlude, they achieve a “soft landing” without the furious acute ischemia and embolization seen with PTFE bypasses.

I think these handful of cases I performed here in the UAE represent the first in the region. The main difference here is that the arteries tend to be smaller by about 20%, and in one instance, the smallest Vollmer ring was too large for the vessel in a case where I abandoned the SFA revascularization -the profunda and inflow revascularization proved sufficient in reversing rest pain. The intriguing property of endarterectomy is something that we all try to do with surgery but rarely achieve -a restoration to an earlier time. I believe this patient’s right femoral artery is now back to a youthful state.

References:

Eur J Vasc Endovasc Surg 2009;37: 68-76
J Vasc Surg 2012;56:1598-605.

Tags arterial restoration, claudication, femoral endarterectomy, remote endarterectomy, rest pain

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