The patient presented with abdominal pain and fevers which was initially diagnosed as a urinary tract infection. He is an older man with a prosthetic aortic valve and prostatic cancer who had a Foley catheter for several weeks leading up to a prostatectomy. Antibiotics relieved his abdominal pain. Echocardiogram revealed aortic valve vegetations. A CT scan revealed a mycotic mesenteric aneurysm and vascular surgery was consulted.
Examination revealed moderate cachexia and a soft abdomen. He was taken to the operating room for resection of aneurysm. Laparotomy revealed a mass in the small bowel mesentery root. The aneurysm had moderate but not excessive amounts of inflammation.
The CTA had shown the superior mesenteric artery to be patent above and below what was likely an embolized vegetation (see white arrows in all images).
The treatment goal was aneurysm resection with an intraoperative determination of need for revascularization. His thighs were prepped for possible saphenous vein harvest and cryopreserved artery was available.
Resection revealed the artery to be infected. There was good backbleeding from the distal SMA.
The handheld Doppler signals in the distal segment of SMA were excellent, corresponding to the viable bowel, but the patient’s cachexia and relative inanition concerned me for future bowel ischemia complicating his planned redo aortic valve replacement and subsequent prostatectomy.
But before I embarked on vein harvest, a simple maneuver determined my next step. I brought the distal SMA to the proximal SMA and found there was enough laxity to simply anastomose both to each other.
The flows were now excellent in the SMA. The patient recovered uneventfully, requiring no subsequent bowel resection. He then had his redo-aortic valve replacement from which he recovered well from and ultimately soon after had his prostatectomy.
Treatment with antibiotics without resection is not a good option as the majority of these rare aneurysm go on to rupture if left unresected. A frequently cited article by Drs. DeBakey and Cooley from 1953 (ref 1) and other subsequent articles show success with simple resection. While cryografts and saphenous vein grafts are subject to infection, they can be used safely in this setting, but the best conduit using no conduit. Often, aneurysms start at a small nidus and not only expand but elongate, given an opportunity to repair aneurysms primarily.
Reference
DeBakey ME, Cooley DA: Successful resection of mycotic aneurysm of superior mesenteric artery: case report and review of literature. Am Surg 1953;19:202-212.
Type B aortic dissections (TBAD) are frequently seen here at the Clinic as we serve as a regional referral center. As a trainee, I read the chapters discussing all the classifications and discussions of the biomechanics and felt quite intimidated by the all the moving parts involved in an aortic dissection, and I missed the main point about TBAD. Aside from the rupture risk due to the attenuation of the adventitia and hypertension, the acute TBAD is a rapidly developing stenosis of the aorta due to the inflation of a wind sock balloon created by the dissection flap. You can assume any flow that occurs in the false lumen is limited by the area of the proximal tear which is always smaller than the area of the aortic lumen. The true lumen is still perfusing the lower half of the body, and because of the volume filling effect of the flap, flow is restricted. The equivalent physiology is seen in aortic coarctation. Long term, the false lumen behaves like a pseudoaneurysm and may thrombose, continue to grow, or both.
Our group looked at CT’scans on 80 consecutive patients and found that the true lumen to false lumen ratio of less than 0.37 is predictive of the need for intervention.
This makes hemodynamic sense as it approximates the 70% critical stenosis borderline for other arteries. It explains why closing the opening of the dissection, the opening of the wind sock, and expanding the true lumen effectively treats malperfusion.
This patient whose CTA is shown above was transferred with increasing abdominal pain, inability to control blood pressure, and worsening lactic acidosis.
There was nearly complete obliteration of the true lumen throughout the aorta and occlusion of the left renal artery and dissection into the celiac and superior mesenteric arteries.
Aortography showed the dissection, and absence of visceral vessels from the injection which was from the aortic root. True lumen position was confirmed with IVUS.
A thoracic stent graft was delivered across the left subclavian artery origin up to the innominate artery origin -the patient had a bovine arch. Immediately, there was filling of the visceral vessels with re-establishment of true lumen flow.
The renal occlusion appeared improved but there was still a stenosis due to deflated dissection flap and this was stented (panel right above).
His abdominal pain remitted and his lactate normalized. His creatinine stabilized and has since normalized.
Lactate
Again, if the true-lumen is compressed, the aorta is stenotic because there is a wind sock inflated in it. TEVAR offers a minimally invasive option, frequently percutaneous, for treating this.
The patient presented with complaints of leg and foot pain with sitting and short distance calf claudication, being unable to walk more than 100 feet. This is unusual because sitting usually relieves ischemic rest pain. He is in late middle age and developed claudication a year prior to presentation that was treated with stent grafting of his superficial femoral artery from its origin to Hunter’s canal at his local hospital. This relieved his claudication only briefly, but when the pain recurred a few months after treatment, it was far worse than what he had originally. Now, when he sat at his desk, his foot would go numb very quickly and he would have to lie down to relieve his pain.
On examination, the patient was moderately obese with overhanging belly. He had a palpable right femoral pulse, but nothing below was palpable. He had multiphasic signals in the dorsalis pedis and posterior tibial arteries. The left leg had a normal arterial exam. Pulse volume recording and segmental pressures were measured:
These are taken with the patient lying down which was the position that relieved his pain, and the PVR’s show some diminishment of inflow. It would be easy at this point to declare the patient’s pain to be due to neuropathy or spinal stenosis, but because of his inability to walk more than a hundred feet and because of his severe pain with sitting, I went ahead and obtained a CTA.
The CTA showed he had an occluded superficial femoral artery (SFA) with patent profunda femoral artery (PFA) with reconstitution of an above knee popliteal artery with multivessel runoff. The 3DVR image showed his inguinal crease to be right over the femoral bifurcation which is not an unsual finding, but his stent graft was partially occluding his profunda femoral artery.
I decided to take him to the operating room to relieve his PFA of this obstruction. My plan was to remove the stent graft at the origin of the SFA and at the same time, remove the plaque and occluded stent graft from his SFA to restore it to patency.
In the OR, on exposing his SFA, I discovered that because of his overhanging belly, his inguinal ligament had sagged and was compressing his femoral bifurcation.
This explained his presentation. The stent graft really had no chance as when he sat, the belly and ligament compressed it at the origin, and because it partially occluded the origin of the PFA, sitting probably pinched off flow completely. The 3dVR image shows the mid segment of PFA to have little contrast density -this is not because of thrombus, but because of the obstruction, the PFA was getting collateral flow from the hypogastric artery.
The stent graft was removed at its origin via a longitudinal arteriotomy after remote endarterectomy of the distal graft.
In this case, the Multitool (LeMaitre) was useful in dissecting the plaque and stent graft because of its relatively stiff shaft compared to the standard Vollmer rings. The technique of EndoRE has been described in prior posts (link).
The stent graft came out in a single segment -they come out easier than bare stents.
The patient regained palpable pulses in his right foot and recovered well, being discharged home after a 4 day stay.
While one could argue that just taking out the short piece of occlusive stent graft over the PFA was all that was necessary, I feel that there is no added harm in sending down a dissector around the stent, and in this patient there was restoration of his SFA patency which was the intent of the original procedure.
Unlike PTFE bypasses that sometimes fail with thromboembolism, SFA EndoRE fails with development of focal stenoses. From a conversation I had with Dr. Frans Moll at the VEITH meeting, I found that he has had good experience with using drug coated balloons in the treatment of these recurrent stenoses.
At the time of discharge, the patient was relieved of his rest pain, and was no longer claudicating. The common femoral artery, its bifurcation, and the profunda femoral artery remain resistent to attempts at endovascular treatment, and remain in the domain of open surgery. And in retrospect, the history and physical examination had all the clues to the eventual answer to the oddities of the patient’s complaints. The combination of inguinal crease, abdominal pannus, and low hanging inguinal ligament meant these structures acted to crush the stent graft and femoral bifurcation.
The patient was referred to me after having undergone an intervention for chronic mesenteric ischemia. She is over 70 years of age and had lost over thirty pounds in 3 months due to severe abdominal pain with eating. A month prior to seeing me, she had undergone arteriography at an outside hospital and was found to have occlusion of her celiac axis (CA) and superior mesenteric artery (SMA) with a small but patent inferior mesenteric artery. Attempt at recanalization, done from left brachial access, of the SMA was abandoned after the patient started having pain, and the inferior mesenteric artery was accessed and stented with a balloon expandable stent. Despite the stent, the pain persisted. On examination, she was cachectic, weighing about a hundred pounds, and had moderate to severe pain with abdominal palpation. CT angiography (shown above) showed a chronically occluded CA and SMA and a patent stent to the IMA.
After discussion with the patient about the possibility of a bypass, we decided to proceed with diagnostic arteriography and an attempt at recanalization. When planning these, I always try to come from the groin first as most of the time I am able to revascularize from below. I try to avoid 6F sheaths in the arms of thin cachectic patients -women especially where the brachial artery is likely the same diameter as a 6F sheath. The only downside about coming from below is that it is technically challenging and the stent comes off at a higher angle than the SMA typically has in situ.
The image below shows the procedure:
The series of images shows the initial aortogram and access. The superior mesenteric artery has a stenosis at the origin, with an area of post stenotic dilatation or small aneurysm, which occludes beyond the first three branches of the SMA. The IMA fails to feed the bowel -the later phases not shown shows filling from the SMA segment to the CA and ileal branches.
The key step to this procedure is in getting “deep” access with a wire -in this case a floppy Glidewire, which I used to cross the occluded SMA. There is feedback from the tip which occurs if you spin it without a torque device. The wire has the quality, a feature really, of being tacky when dry, allowing for a great deal of coaxial spin with your first two fingers and your thumb. The tip transmits information about what it is crossing as you spin it -this is something that is hard to teach at first, but is gained largely through experience, but I learned it from Dan Clair over a decade ago when he barked at me to get rid of the torque device (“a tool for babies!”). The tip will go where it should if you spin, not push.
Once the wire is buried, a suitable catheter that tracks well is brought across the occlusion. Again, while there are many catheters that can do this, the Glide Catheter is suitable again from spinning across an occlusion over the wire that would push out the lowest profile and equally hyrdophillic catheters. Once the catheter is buried, a suitably stiff wire (in this case a Rosen wire) should be brought across -this widens the arc created by the wire as it goes up and over the SMA origin and allows for delivery balloons and stents. Using the balloon-piton technique (a requisite for FEVAR), the sheath is brought into the SMA, securing access into it.
The occlusion in the mid-SMA ballooned nicely and did not require a stent -a nonocclusive dissection is seen but I chose not to treat this as placing a stent is likely to cause as many problems as solve and the dissection is in line with flow. The origin was stented with a balloon expandable stent -having the patient awake is useful in determining if the stent is “big enough.” Final arteriography in two planes is shows below.
Gratifyingly, the entire mesenteric system in the CA (foregut) and SMA (midgut) lit up. I admitted her for observation as I have seen patients develop bowel infarction with reperfusion which may be due to embolization but I think just as likely due to edema. Food needs to be reintroduced slowly as there maybe metabolic consequences to rapid refeeding. Her baseline lactate was 2.6mMol/L but came down to 0.8mMol/L the next day. Her other labs were normal. Her pain remitted and she was able to tolerate a regular diet by postoperative day 2.
Discussion:
Mesenteric ischemia is a particularly morbid condition. When it presents acutely, there is a high mortality rate (ref 1). Revascularization in good risk individuals is still bypass surgery (ref 2,3). The inferior mesenteric artery offers a dismal revascularization target for this reason -while the artery will remodel and dilated in the setting of mesenteric ischemia, its orifice from the aorta does not and is usually no more than 1-2mm from birth to adulthood. Also, while the large bowel will get perfusion from the IMA, and the foregut may get collateral flow from collaterals fed from the middle colic via the Arc of Riolan, the midgut does not get sufficient flow from from the IMA because it requires the longest path to fill the ileal and jejunal branches. The development of atherosclerosis in the aorta further complicates attempts at stenting. Despite this, it is still attempted (ref 4) and in 4 patients was successful at relieving pain for short periods of time, with one patient requiring eventual bypass despite characterization as “high risk.” It is a reflection of how poorly this vessel does with intervention that this 4 case series is the largest in the literature.
The analogy to IMA stenting in the legs is stenting of a heavily diseased profunda femoral artery in the setting of critical limb ischemia with femoropopliteal occlusive disease. It is occasionally successful in the short term, but will only delay the inevitable operation. There are no low risk patients with severe weight loss due to mesenteric ischemia. Aggressive intervention offers a path of survival for these patients, and but long term results are only possible with bypass.
Park WM, Cherry KJ, Jr, Chua HK, Clark RC, Jenkins G, Harmsen WS, et al. Current results of open revascularization for chronic mesenteric ischemia: a standard for comparison. J Vasc Surg. 2002;35(5):853–859.
Kasirajan K, O’Hara PJ, Gray BH, Hertzer NR, Clair DG, Greenberg RK, et al. Chronic mesenteric ischemia: open surgery versus percutaneous angioplasty and stenting. J Vasc Surg. 2001;33:63–71.
Wohlauer M, Kobeiter H, Desgranges P, Becquemin JP, Cochennec F. Inferior Mesenteric Artery Stenting as a Novel Treatment for Chronic Mesenteric Ischemia in Patients with an Occluded Superior Mesenteric Artery and Celiac Trunk. Eur J Vasc Endovasc Surg. 2014;27(3):e21-e23.
The patient had undergone EVAR for bilateral common iliac artery aneurysm with the original Gore Excluder stent graft a dozen years before with coil embolization and extension to the external iliac on the larger side and femoral to internal iliac artery bypass on the other side. A coagulopathy, one of the clotting factor deficiencies, had made him high risk for bleeding with major open surgery. His aneurysms never shrank but remained stable and without visible endoleak by CT for a long time resulting in ever longer intervals between followup.
2013
Between 2009 and 2013, there was subtle enlargement on the embolized side without a type I or type III leak, and the patient was brought back a year and a half later, with further growth of the sac.
2015
This was a relatively rare type IV endoleak that was causing sac enlargement due to excessive graft porosity of the original Excluder’s graft material. Its treatment is either explantation or relining. We chose to reline the graft with an Excluder aortic cuff at the top and two Excluder iliac limbs.
This was done percutaneously and in short followup, there has been stabilization and even some reduction in the aneurysm circumference.
It was long known that a certain percentage of PTFE grafts “back in the day” would sweat ultrafiltrated plasma. The relative porosity of the grafts allowed for transudation of a protein rich fluid.
Tanski W, Fillinger M. J Vasc Surg 2007;45(2):243-249.
This results in a hygroma formation. I remember seeing this in AV graft fistulae back in the 90’s -after flow was introduced, the grafts would start sweating! The newer grafts are lower porosity and this is seen very infrequently. Drs. Morasch and Makaroun published a paper in 2006 comparing parallel series of patients who received the original Gore Excluder (OGE), the currently available Excluder Low-Permeability Device (ELPD), and the Zenith device (ZEN). Sac enlargement occurred in equal measure between OGE and ZEN but zero was reported for the ELPD.
Haider S et al. J Vasc Surg 2006;44(4):694-700.
The ELPD had higher rates of sac shrinkage than the OGE, and equal rates of sac shrinkage compared to ZEN.
Haider S et al. J Vasc Surg 2006;44(4):694-700.
The diagnosis in my patient’s case came about through serial followup through a decade. While I doubt that the aneurysm would have ruptured in the same way as in a Type I, II, or III endoleak, I am sure it would have progressed to developing symptoms from aneurysmal distension or local pelvic compression.
Is it possible to visualize this kind of endoleak at the time it is suspected? I came across a case series from the Netherlands using Gadofosveset trisodium which takes longer to clear than the usual Gd-based MR contrasts and they successfully visualized transudative leaks in 3 serial patients with the original Excluder graft.
Cornelissen SA et al. J Vasc Surg 2008;47(4):861-864.
The problem is that Gd-based contrasts have toxicity, especially for patients with poor renal function. The protocol is time consuming. And I suspect that ten years out, a lot of grafts will have positive findings, especially cloth based grafts that are sutured to their supporting stents, without clinical basis for treatment as their sacs size are likely stable on a year to year basis.
That said, as we are well into the second decade of commercially available stent grafts, it is even more important than ever to continue lifelong followup even for what is assumed stable, patent grafts and anatomy.
Sketch of Dr. Gilbert Upchurch’s hybrid treatment of TAAA, at least as I understood it.
The VEITH Symposium has been my favorite meeting since I was a junior resident back in the 90’s. This year is no different. I finally figured out why I like it so. VEITH is organized like the Iowa State Fair with all the charms and chaos that makes that fair one of the top 10 things to do in the US. There is the location at the Hilton Midtown which puts it in the center of all the commercial and tourist chaos that makes NY amazing. It is a high end version of the midway at the Iowa State Fair on East Side night, but instead of fried Snickers and bad teeth, you have perfectly crafted international foods and people from everywhere. Like the Iowa State Fair, everything is happening at the same time and you have to plan out your day in great detail. And there are the must sees like the debates between the giants of the field and the 20 surgeon panels sitting on stage no different from the 1000 pound pig and the handsomest cow. Then there is industry, but rather than tractors in green or blue flavors, we get seven different kinds of stent grafts at my last count. You learn how to pick out the signal from the noise, not always by counting the N of individual papers, but in the trends of the numbers of presentations that generally agree, like the hot new Fair food that catches and gets easier to buy every subsequent year. A true free market of ideas. And finally, like you can run into friends who moved to Dubuque, you run into people who were important on your life path, Jedi and Sith masters and padawans, and you have large unhealthy dinners together. What’s not to like? Next year, at VEITH!
Why perform such an extensive endarterectomy when just a few stents will do? This is a valid question, given the relative safety of interventions and the durability of bypasses. There are three reasons why ilio-femoral-popliteal endarterectomy works well in my practice.
Minimally invasive
Restore elasticity and collaterals
Move the inflow point from the groin to the knee
The procedure is minimally invasive. Take for example this patient whose plaque is shown above. He had a common femoral occlusion for which a common femoral endarterectomy was aborted when the prior surgeon ran into excessive bleeding. Workup for coagulopathy was negative and the patient came to me with rest pain. Pedal level pulses were not palpable, and the signals were barely there.
CTA showed that he had a CFA occlusion as well as SFA occlusion.
Because the common femoral plaque is contiguous with the external iliac plaque, it is often simpler to complete a remote endarterectomy over wire up to the external iliac origin than to try to get a satisfactory end point at the inguinal ligament -I do not like stenting across the ligament into the patch which is the usual bailout if the end point causes a stenosis. It is far simpler to apply a stent at the external iliac origin.
The popliteal end point was chosen where the visible plaque was no longer apparent in the patent artery. The goal is to cut across thin intima, and frequently no distal stent is required because a secure end point is achieved much like the “feathered endpoint” seen in carotid endarterectomies.
My intention was to endarterectomize the atherosclerotic plaque from the external iliac origin to popliteal artery via the groin incision marked in orange.
3DVR allows for planning the operation in great detail
The video shows the setup and motion in dissecting the plaque.
The plaque came out easily (first image, top).The proximal and distal end points required stents.
Before and after
The patient regained palpable dorsalis pedis and posterior tibial artery pulses. Total OR time was less than 2 hours. An ilioinguinal field block allowed for good pain control and the patient was discharged the next morning, having to heal only a 10cm wound. There is no good endovascular option for common femoral disease, and while stenting the whole SFA can be done, on more than a few occasions I have had to treat occluded “full metal jacket” SFA stents, usually by removing them. EndoRE has been shown to be superior to PTFE and almost as good as vein in the REVAS Trial when compared to fem-AK POP bypass. Going home the next day after such an extensive revascularization is not a stunt -it’s the direct result of limiting the incision and blood loss and OR time.
2. Restore Elasticity and Collaterals -Arterial Restoration
One of the components of arterial flow that is lost with atherosclerotic disease is arterial elasticity. That is the stretchiness of the artery in response to pressure. Elastic distension and recoil account for significant portions of forward flow during diastole which is lost with atherosclerotic plaque. As plaque builds up, and the artery becomes stiffer. The artery that goes through remote endarterectomy regains this elasticity. Ultrastructure from a recanalized external iliac artery sampled from a punch arteriotomy for a cross ilio-femoral bypass showed that three months after endarterectomy, the external iliac artery was ultrastructurally normal per pathology report.
Also, collaterals that were previously occluded are seen to be restored to patency. This has an important impact on patency and any future failures. The endarterectomized arteries fail due to the presence of isolated, random fragments of medial smooth muscle which cause focal TASC A restenoses. These are easily amenable to balloon angioplasty. If the revascularization fails, there is no catastrophic thromboembolism that is typical of PTFE thromboses -rather the collaterals keep segments open and it is straightforward to thrombectomize or lyse the artery and intervene as necessary.
3. Moving the inflow point from groin to the knee.
This is an important concept. One of the principles of inflow restoration is delivering large flow and pressure directly from the aortic source to the leg. Recanalizing from the external iliac to the below knee popliteal artery creates this situation below the knee, allowing for very short bypasses to be performed from the popltieal artery to tibial targets -a very useful circumstance when vein is limited. This next patient is a presented with gangrene of his fifth toe after esophagectomy for cancer, and had severe diabetes.
He had useful saphenous vein in his thigh only, some of it having been harvested in the proximal thigh for a common femoral endarterectomy. CTA showed a dilated common femoral and profunda femoral artery, severely calcified SFA and popliteal artery which were occluded, and only a patent peroneal artery as runoff.
The plan was to harvest the short segment of vein then through the same incisions, below the knee and in the mid thigh, expose the below knee popliteal artery and tibial origins, and the mid SFA. I intended to avoid the groin. The plaque was removed from the tibioperoneal trunk to the SFA origin, and the origin was stented.
This reestablished a normal inflow at the level of the below knee popliteal artery. I also did an eversion endarterectomy of the anterior tibial artery which resulted in significant back bleeding -a good sign. A short bypass was performed from the below knee popliteal artery to the peroneal artery.
This resulted in a palpable dorsalis pedis artery pulse and excellent peroneal and posterior tibial artery signal.
The ABI improved and the waveforms predicted healing for his 5th ray amp.
This last case illustrates the point that once the conceptual inflow point is moved to the below knee popliteal artery, bypasses can become short, and durable tibial revascularizations become feasible. By avoiding a redo groin, avoiding multisegment arm vein bypass, and keeping the procedure time under 5 hours, the operation remains less invasive.
The dictum that better is the enemy of good is one of the old chestnuts carried around surgery training forever. It is an admonition against an unhealthy perfectionism that arises from either vanity or self doubt, and in the worse cases, both. The typical scenario is a surgeon trying to make a textbook picture perfect result and finding the patient’s tissues lacking, will take down their work to make it better, and repeat this process while the patient and everyone else in the room lingers.
Trying to avoid this, many surgeons will try to avoid any difficulties -the bad patch of scar tissue, irradiated body parts, areas of prior infection. But the mental contortions involved in avoiding “perfect” can result in actual physical contortions that in the end don’t pay off in good enough. I have not been immune to this, and I don’t think any physician or surgeon can honestly say they haven’t experienced some variation on this.
This patient is a younger middle aged man who in his youth experienced a posterior dislocation of his left knee, resulting in an arterial transection. This was repaired with an in-situ graft. Subsequently, he had complications of osteomyelitis and had his knee fused after resection of his joint. He did well with this bypass for several decades, but it finally failed several years ago, and a new one was created (image above).
Rather than directing the graft in line as in the previous one, this was was taken from a medial exposure of the femoral artery and tunneled superficially around the fused knee to coil lateral, ending in the anterior tibial artery.
This graft in turn thrombosed and was lysed by the outside surgeons and underwent serial interventions of proximal and distal stenoses at the anastomoses. The patient, when I met him, was contemplating an above knee amputation as a path to returning to work as a nurse in a rural hospital.
While there should be no reason long bypasses should do any less better than short bypasses, I do have to say these things about this patient’s bypass:
No vein is perfect and the longer your bypass, the more chances you will have that a segment of bad vein will end up in your bypass
Turning flow sharply can cause harsh turbulence. Turbulence can cause transition of potential energy into kinetic energy which acts to damage intimal, resulting in intimal hyperplasia.
Thrombosis is a sure sign that your graft is disadvantaged, and the longer the period of thrombosis, the longer the intima “cooks” in the inflammatory response that accompanies thrombosis, making the vein graft even more vulnerable to subsequent intimal hyperplasia, thrombosis, or stricture.
A high flow, small diameter vein graft entering a larger, disease free bed results in more turbulence but also Bernoulli effects that cause the graft to close intermittently, vibrating like one of those party favors that make a Bronx Cheer (a Heimlich valve). This is the cause I think of the distal long segment narrowing on this graft.
This patient was decided on amputation when our service was consulted, and after reviewing his CTA, I offered balloon angioplasty as his symptoms were primarily of paresthesia and neuropathic pain. I used cutting balloons and got angiographically satisfactory results.
The patient, although he admitted to feeling much better, was sad. He relayed that he had felt this way several times before, only to have his life interrupted by pain and weakness signaling a restenosis.
A direct graft would require about 10 centimeters of vein
It was only a month later when I heard the patient had returned with the same symptoms. He wasn’t angry nor full of any “I told you so” that frankly I was muttering to myself. Reviewing his CTA, he had restenosed to a pinhole. The vein, to use a scientific term, was “no good.”
The other interesting finding was that he had an abundance of very good vein. Following surgical dictum, his original and subsequent surgeons had used his vein from his contralateral saphenous vein. His right leg, fused at the knee, lacked a good calf muscle pump action. While there were no varicose veins, the greater and lesser saphenous veins were large and generous conduits, at least by 3DVR imagery, confirmed on duplex (image below, white arrows).
3DVR showing presence of potential conduit
The extant arteries were smooth and plaque-free. I decided to harvest his lesser saphenous vein and through the same incision expose his distal superficial femoral artery and tibioperoneal trunk. While I anticipated some scarring, I was confident that the sections of artery I wanted to expose were easy to access because of some distance from the fused knee.
On left short saphenous vein was harvested then same exposure used to expose TP Trunk
The picture shows the exposure and reversed vein graft in-situ, using the segment of lesser saphenous vein. As in prior experience in redo surgery, you can never know if a dissection will be easy or hard simply based on fear or concern for breaking something. It’s not until you start bushwacking –carving through scar and dealing with extraneous bleeding will you learn whether it was easy or hard. You can only be certain it was necessary. The only hitch was the femoral artery while well exposed, was buried in scar, and I chose not to get circumferential control as I was fairly deep, and had avid backbleeding from a posteriorly oriented collateral that required a mass clamp of the deep tissues.
Will this work better? Don’t know but it has a good chance, and I think a better chance. It is a large vein oriented in a straight path over a short distance going from good artery to good artery. This is better theoretically than a long meandering bypass with smaller vein.
The patient, a younger middle aged woman, was referred for treatment of a large, growing infrarenal AAA over 8cm in size complicating a severe pancreatitis. The pancreatitis occurred about a month prior to presentation and resulted in a substantial pancreatic leak. At the time of that presentation, her AAA was found incidentally and was about 7cm. In the interval, her pain resolved and she was asymptomatic. On examination, her abdomen was soft, and a large aortic aneurysm was easily palpable.
Pancreatitis with surrounding retroperitoneal fluid leak
CT scan was performed showing an enlarging AAA over 8am and abundant retroperitoneal pancreatic fluid without abscess or infection. The AAA was infrarenal but complicated by a severely tortuous, short infrarenal neck with 90 degrees of angulation and about 8mm in length. As the pancreatic leak was yet early in the process, no pseudo aneurysms had formed. MRCP showed no active leak.
Short neckGreater than 90 degree neck angulation
Other than the pancreatitis, the patient, who was in her 50’s, was an otherwise good risk patient.
The treatment options were:
1. Wait until pancreatic fluid resolution or pseudo aneurysm formation, then standard open repair of the large aortoiliac arterial aneurysm. Not desirable because of the relatively rapid aneurysm growth and current size.
2. EVAR -This is outside the IFU for any of the available devices because of the highly tortuous neck anatomy. While note shown, the external iliac arteries were 5mm in diameter, but in the absence of plaque, was possibly due to spasm. The Nellix device is yet on trial, but there are limits on how much you can straighten this neck. The devices with suprarenal stents end up straightening out the graft with deployment of the graft in an ellipse. This also means loss of seal zone length which decreases with oblique deployment. FEVAR is not possible because of this neck tortuosity as well but was considered briefly.
3. Homograft repair or Rifampin soaked graft repair -The former is costly and still susceptible to infection from a virulent organism as is the latter, but both are likely safe with likely foregut flora.
4. Neo-Aorta reconstruction (NAS) with deep femoral vein. This could work, but is time consuming and relatively morbid. The tactic of mobilizing the vein and then repairing the aneurysm in a separate, staged fashion the following day or two is reported to shorten the overall operative time. This patient would require both femoral veins to be harvested.
5. Aneurysm exclusion and extra-anatomic bypass with axillofemoral bypass. Offered to complete this list, this is the least desirable option given the poor long term behavior of axillofemoral bypasses in younger patients.
When faced with this kind of challenge, it makes sense and should be standard practice to get the opinion of the group. I happen to have excellent partners to run this kind of cases. The consensus was this: EVAR with accepting a short term result to temporize until definitive repair could be done. I found this acceptable. I chose to use the Excluder device because it allows for redos of the proximal deployment (C3 Delivery system) and the 23mm and 26mm devices used 16F access. A detailed discussion with the patient and the intention to eventually definitively repair open was discussed and patient was agreeable to proceeding. Plan B’s of Rifampin soaked graft replacement and NAS was also discussed.
I tried two things that was different. I felt that a stiff wire would result in horizontal orientation of the top of the graft, and so I placed a bend in the wire. Prior experience with unintended bends in wires have taught me that passing these wires is largely tolerated as long as it is done through catheters and sheaths. The other thing I did was bend the top of the delivery system -this was done with some care as I did not want to detach the contraining mechanism.
The wire and delivery system modification did tilt the top of the graft away from the left side of the aorta. It had the unintended effect of keeping the wall grabbing anchors away from the near wall while constrained.
It didn’t tilt the graft as much as I would have liked, but the graft deployed in a left to right fashion that allowed for controlled delivery across all of the available neck. Gratifyingly there was seal (below). I flared the right, while excluding the left iliac bifurcation because of the larger iliac aneurysm.
As this was done percutaneously, the patient recovered rapidly and was discharged a day later. The question philosophically for me is if the seal remains intact, would there ever be a need for explantation? The patient only received perioperative antibiotics, and I felt long term antibiotics was not indicated. Standard followup was arranged.
There is no question there is a need for devices designed for this kind of neck anatomy. These devices need to bend over to angles at least 90 degrees and unbend based on delivery system design. They need to be low profile as this facilitated repair in this patient with small access vessels.
update:
After she recovered, her interesting case was published as a case report in BMJ:
Karam PA, Moslim MA, Park WM, Morris-Stiff G. Abdominal aortic aneurysm in the setting of Clostridium perfringens pancreatitis. BMJ Case Rep. 2017 Aug 7;2017:bcr2016218549. doi: 10.1136/bcr-2016-218549. PMID: 28790092; PMCID: PMC5612546.
The flows were now excellent in the SMA. The patient recovered uneventfully, requiring no subsequent bowel resection. He then had his redo-aortic valve replacement from which he recovered well from and ultimately soon after had his prostatectomy.
The patient regained palpable pulses in his right foot and recovered well, being discharged home after a 4 day stay.
A Surgeon's Notes 