AAA

When both iliac systems are occluded below an abdominal aortic aneurysm: hybrid techniques on the cutting edge

Posted on April 2, 2017April 2, 2017 by docpark

preop CTA EVAR-ENDORE.jpg — AAA with iliac arterial occlusion -arrows point to right external iliac and left common iliac arterial occlusions

The patient is an 70 year old man referred for evaluation of claudication that occurred at under a block of walking. He reported no rest pain or tissue loss. He smoked heavily up to a pack a day, with congestive heart failure with an ejection fraction of 40%, prior history of myocardial infarction treated with PTCA, and pacemaker, and moderate dyspnea on exertion.

On examination, patient had a flaccid abdomen through which the AAA could be palpated, and he had no palpable femoral artery pulse bilaterally, nor anything below. He had a cardiac murmur and moderate bilateral edema. Preoperative risk evaluation placed him in the high risk category because of his heart failure, coronary artery disease, and his mild to moderate pulmonary disease.
CTA (pictured above and below) showed a 5.1cm infrarenal AAA with an hourglass shaped neck with moderate atherosclerosis in the neck, an occluded left common iliac artery with external iliac artery reconstitution via internal iliac artery collaterals, and a right external iliac artery occlusion with common femoral artery reconstitution. There was calcified right common femoral artery plaque.

Preop left and right centerlines EVAR-ENDORE.jpg

Treatment options included open surgical aortobifemoral bypass with exclusion of the AAA, total endovascular repair with some form of endo-conduit revascularization of the occluded segments of iliac artery, or a hybrid repair.

Open aortic repair in patients with heart failure and moderate COPD can be performed safely (ref 1). Dr. Hollier et al, in the golden age of open repair, reported a 5.7% mortality rate operating on 106 patients with severe category of heart, lung, kidney, or liver disease.

Typically, the hybrid repair involves sewing in a conduit to deliver the main body of a bifurcated or unibody stent graft when endovascular access is not possible. Despite techniques to stay minimally invasive -largely by staying retroperitoneal, this is not a benign procedure (ref 2). Nzara et al reviewed 15,082 patients from the NSQIP database breaking out 1% of patients who had conduit or direct puncture access.

Matched analyses of comorbidities revealed that patients requiring [conduit or direct access] had higher perioperative mortality (6.8% vs. 2.3%, P = 0.008), cardiac (4.8% vs. 1%, P = 0.004), pulmonary (8.8% vs. 3.4%, P = 0.006), and bleeding complications (10.2% vs. 4.6%, P = 0.016).

Despite these risks, I have performed AUI-FEM-FEM with good results with the modification of deploying the terminus of the stent graft across an end to end anastomosis of the conduit graft to the iliac artery (below), resulting in seal and avoiding the problems of bleeding from the usually heavily diseased artery

AUI fem fem.jpg — Aorto-uni-iliac stent graft across end to end conduit anastomosis to fem-fem bypass

The iliac limbs of some stent graft systems will have proximal flares and can be used in a telescoping manner to create an aorto-uni-iliac (AUI) configuration in occlusive disease. The Cook RENU converter has a 22mm tall sealing zone designed for deployment inside another stent graft and would conform poorly to this kind of neck as a primary AUI endograft which this was not designed to act as. The Endurant II AUI converter has a suprarenal stent which I preferred to avoid in this patient as the juxtarenal neck likely was aneurysmal and might require future interventions

I chose to perform a right sided common femoral cutdown and from that exposure, perform an iliofemoral remote endarterectomy of the right external iliac to common femoral artery. This in my experience is a well tolerated and highly durable procedure (personal data). Kavanagh et al (ref 3) presented their experience with iliofemoral EndoRE and shared their techniques. This would create the lumenal diameter necessary to pass an 18F sheath to deliver an endograft. I chose the Gore Excluder which would achieve seal in the hourglass shaped neck and allow for future visceral segment intervention if necessary without having a suprarenal stent in the way. I planned on managing the left common iliac artery via a percutaneous recanalization.

The patient’s right common femoral artery was exposed in the usual manner. Wire access across the occluded external iliac artery was achieved from a puncture of the common femoral artery. Remote endarterectomy (EndoRE) was performed over a wire from the common femoral artery to the external iliac artery origin (pictures below).

File Mar 31, 13 41 31.jpeg — External iliac to common femoral artery plaque removed with Moll ring cutter (LeMaitre Vascular) over a wire

The 18F sheath went up with minimal resistance, and the EVAR was performed in the usual manner. The left common iliac artery occlusion was managed percutaneously from a left brachial access. The stent graft on the left was terminated above the iliac bifurcation and a self expanding stent was used to extend across the iliac bifurcation which had a persistent stenosis after recanalization.

The patient recovered well and was sent home several days postprocedure. He returned a month later with healed wounds and palpable peripheral pulses. He no longer had claudication and CTA showed the aneurysm sac to have no endoleak (figures below).

post CTA EVAR-ENDORE

postop centerline EVAR-ENDORE — Composite imaging showing normal appearing right iliofemoral segment (EIA + CFA) and patent left common iliac artery.

Discussion
I have previously posted on using EndoRE (remote endarterectomy) for both occlusive disease and as an adjunct in EVAR. Iliofemoral EndoRE has excellent patency in the short and midterm, and in my experience has superior patency compared to the femoropopliteal segment where EndoRE is traditionally used. This case illustrates both scenarios. While the common iliac artery occlusions can be expected to have acceptable patencies with percutaneous interventions, the external iliac lesions typically fail when managed percutaneously especially when the stents are extended across the inguinal ligament. The external iliac artery is quite mobile and biologically, in my opinon, behaves much as the popliteal artery and not like the common iliac. Also, the common femoral arterial plaque is contiguous with the external iliac plaque, making in my mind, imperative to clear out all the plaque rather than what can just be seen through a groin exposure.

On microscopy, the external iliac artery is restored to a normal patent artery -I have sent arterial biopsies several months after endarterectomy and the artery felt and sewed like a normal artery and had normal structure on pathology. This implies that the external iliac can be restored to a near normal status and patients that are turned down for living related donor transplantation of kidneys can become excellent recipients. In this case, this hybrid approach effectively treated his claudication but also sealed off his moderate sized AAA while not precluding future visceral segment surgery or intervention with a large suprarenal stent.

Reference

Hollier LH et al. J Vasc Surg 1986; 3:712-7.
Nzara R et al. Ann Vasc Surg. 2015 Nov;29(8):1548-53
Kavanagh CM et al. J Vasc Surg 2016;64:1327-34

Avoiding Aortic Exoleaks: principles of the proximal aortic anastomosis

Posted on April 30, 2016May 1, 2016 by docpark

The proximal anastomosis is the most critical portion of an open aortic aneurysm repair. Several concepts are central to creating an anastomosis that doesn’t bleed at unclamping: managing narrow spaces, overcoming distortion, and using just enough tackle.

Narrow Spaces

The transabdominal exposure is a narrow space. The work is done under the overhanging left renal vein, the transverse colonic mesentery, the liver, the rib cage. Extra lateral space can be made by eviscerating the bowel, but at the cost of higher rates of ileus, and doesn’t solve the first problem. The standard DeBakey aortic clamp and straight Fogarty clamps stand nearly straight up, limiting the space above the incision at the aortic neck. My goto clamp is the Cherry Supra Celiac Aortic Clamp, designed by my mentor Ken Cherry. 1606988_10203082426724504_324421715_n

It hugs the contour of the mesentery and liver overhang, and the handles stay out of the way above the wound. It will also tilt up the aorta because of the weight balance. The other option is to apply a transverse clamp, which I will discuss in a later post. The transverse clamp leaves the suprarenal space free of clamp, but can be difficult if not hazardous to apply. The clamp has to be hemostatic and this can be challenging with atherosclerotic plaque -preoperative planning must include planning for safe clamp sites. A suprarenal clamp may be limited by the presence of the terminal insertions of the diaphragmatic crurae. I have recently found that dividing these crurae with a Maryland tipped Ligasure, a laparoscopic instrument I use to dissect the retroperitoneum, makes short order of what can sometimes be an awkward exposure in this tight space. Finally, endarterectomy of the neck should be done carefully to let needles pass without difficulty.

Distortion

The proximal anastomosis is ideally just another end to end anastomosis -attaching a circle to a circle, but clamping narrows and distorts the circular aortic neck (top illustration). To envision this, imagine the aortic neck being a clock face:

FullSizeRender

Lets say the suture should be applied at each of the hours and half hours. You get ready to sew your first aortic neck and after endarterectomizing some plaque, you get this:

The important point is that you still have to apply the original plan of applying sutures evenly and at an appropriate frequency (about 3mm apart), to avoid gathers and gaps, especially on the posterior wall. One way is to apply outward tension with a Wheatlander retractor in the aortic sac.

The posterior wall of the aorta should be distracted to avoid distortions that create uneven gaps between passes of the needle.

The bites on the aorta should be generous, on the graft, less so. As long as the gaps between the sutures is the same on both aorta and graft, you shouldn’t get leaks. The other principle to guide you is the needles should pass pointing to the center of the clock -this is challenging in the Dali clock, but if you pivot your shoulder, your suturing won’t be bullied by the distortions and the narrow space.

The Right Tackle

You don’t go after panfish with a deep sea tackle. Pictured below are a spinning lure for trolling with a large hook and a small dry fly with narrow guage hook for comparison.

Which hook creates the larger hole in the fish’s mouth? In fact, both lures can be used to catch the same large trout, but in different situations.

OLYMPUS DIGITAL CAMERA — On a lake, large hook, on a stream, small hook for same fish.

One of the techniques which I have borrowed from our partners in cardiac surgery here at the clinic is using smaller guage monofilament and needles. I once co-scrubbed an aortic arch case with Eric Roselli, and was bemused to see him sew graft to the fearsome ascending aorta with 5-0 monofilament suture. Then I saw no needle hole bleeding and was sold. Up to then, I had switched from my 3-0 on SH needles to 2-0 on MH needles -basically the largest vascular needle, and saw posterior aortic wall break down from the needle trauma. Unfortunately, 5-0 suture doesn’t come long enough, the CV needles aren’t big enough to sew posterior wall. I now use 4-0 on SH with 48cm length suture. Ideally, we’d have a 5-0 monofilament on a 60cm suture with a SH shaped and sized needle with the narrow guage of the CV needle.

Also, because the needles are finer and I favor supersized Castro needle holders. The needle holes which represent rents in the aortic wall are far easier to deal with using a smaller needle. Right tackle.

Moneyballing a Type II Thoracoabdominal Aortic Aneurysm

Posted on April 5, 2016April 5, 2016 by docpark

The innovation of sabremetrics in baseball management and finance as described in Michael Lewis’ wonderful book Moneyball wasn’t just the ability to quantify skill to predict outcomes, it was the ability to assemble that skill without overpaying. For a baseball team on a budget, spending all your payroll on a superstar makes no sense when you can get equivalent quants of skill in a statistical aggregate of no-name players with proven metrics. Rather than pay for an A-Rod, you can recruit, and pay for, 5 players that in aggregate, statistically achieve what you would get with a healthy A-Rod, so the thinking goes. How does this translate into vascular surgery? Can we arbitrage complication rates?

The open repair of type II thoracoabdominal aortic aneurysms is a heroic endeavor, putatively best done by surgeons wearing cowboy boots, and classically comes with sobering complication rates that exceed 20% for death and paralysis. Is it possible to reduce this risk by subdividing this most enormous of cardiovascular operations into component parts?

The patient is a middle aged man in his 50’s who presented with a type B aortic dissection. His dissection flap spanned from his left subclavian artery to the infrarenal aorta. He was a long time smoker and had hypertension that was difficult to control, made much worse after his dissection. He had a moderate dilatation of his thoracic aorta, maximally 36mm and tapering to 35mm in visceral segment. There was a 4.9cm infrarenal AAA where the dissection terminated.

CTA at presentation

His chest pain resolved with blood pressure control and he was discharged, but in followup his thoracic aortic segment grew and his blood pressure worsened, never getting below a 150mmHg systolic despite multiple agents. CTA two months after presentation, showed growth of his TAA to 44mm from 36mm in two months and the visceral segment showed that his dissection flap impinged on flow to the right renal artery. His AAA remained the same. He continued to have bouts of chest pain related to hypertension.

CTA at 2mo post presentation

Twenty years ago, the board answer would have been to replace the whole aorta. In young, otherwise healthy man who had been working in road construction up to the dissection, he would have been considered a candidate for a direct open repair of the type II thoracoabdominal aortic aneurysm. From the landmark paper out of Houston by Dr. Svensson in 1993, open type II TAAA repair was associated with about a 10% death rate and 30 percent paralysis rate. Waiting a few months for the aneurysms to grow further in this patient, in the 90’s this patient would probably have ended up with an open TAAA repair. Good thing we have better options.

The goals of modern therapy are to treat the urgent indication while holding off repair of less critical segments of the aorta, and to do so in a way that each operation builds on the previous one.

This patient needed a left subclavian artery debranching and then TEVAR of his dissecting thoracic aortic aneurysm, and intervention on his right renal artery. We did this in one setting performing first a left carotid subclavian artery transposition and then percutaneous TEVAR from the left common carotid artery origin to the supraceliac abdominal aorta.

TEVAR with carotid SCA transposition

completion TEVAR.png

The completion aortography showed good deployment of the CTAG device from the left common carotid artery origin to the celiac axis origin. The false lumen was no longer visualized. The right renal artery which was narrowed was treated with a balloon expandable stent.

The distal thoracic aorta, the true lumen was constrained by a chronic dissection flap. It is here I gently dilate the distal thoracic stent graft with the hopes of eliminating the distal false lumen. This is different from the acute dissection where I rarely balloon.

The TEVAR was done percutaneously, minimizing the overall time in the operating room. The technical details of the transposition can be found in the excellent paper by Dr. Mark Morasch.

renal PTAS

When I do this procedure for acute dissection, I quote the patient a general risk of stroke, paralysis of about 2-5% and death of 1-2 percent for someone with low cardiopulmonary risk like this patient had. He recovered rapidly and went home post op day 5.

Followup post TEVAR

He at 6 month post TEVAR followup, CTA showed stablility in his thoracic aorta. in infrarenal AAA grew from 5.0 to 5.7cm between the 1 month CT and the 6 month CT.

6 month CTA imaging

The terminus of the stent graft excluded the false lumen in the thoracic aorta but also resulted in filling and pressurization of the false lumen beyond and can be seen as a 44mm lateral dilation of the visceral segment of the aorta which had developed in the 6 month interval since the TEVAR.
The infrarenal neck continued the dissection and had dilated to about 36mm, but was parallel for a good length above the AAA. I decided to treat the inrarenal aorta with direct transabdominal repair. This would allow me to fenestrate the aorta, and possibly prevent further growth of the viseral segment while reserving the retroperitoneum for the visceral segment repair if it came to it. The neck diameter was 36mm.

His operation was performed via an anterior approach with the patient supine. A tube graft repair was performed expeditiously and included resecting the dissection flap up to the clamp. Care was taken to avoid injury to the renal stent. The proximal anastomosis went well – the dilated aorta yet had strong tissue strength. A felt strip was used to buttress the aortic side of the anastomosis. The estimated risk of paralysis was less than 1% and risk of death was less than 2%. The patient recovered uneventfully and went home on POD 5.

He did well in subsequent followup, having successfully quit smoking. He retired early on disability and was becoming more active, but the visceral segment dilatation was concerning. At 6 months post infrarenal AAA repair, he underwent CTA and it showed patent thoracic stent graft and infrarenal abdominal graft. The intervening visceral segment continued to enlarge and was now 46mm. The decision was to wait another interval 9 months to see if this would stabilize. The segment grew some more and was 49mm. He wanted to give it another 6 months and at that time, CTA showed further growth over 5cm, and he had developed some abdominal discomfort. He was taken to the operating room.

A four branch repair of the visceral segment thoracoabdominal aortic aneurysm was performed. The diaphragm was taken down and the stent graft was clamped as was the infrarenal tube graft. A premade Coselli graft was used to bypass to the right renal, SMA, celiac, and left renal in those order. The patient had a CSF drain for the case which was removed on postoperative day 2. He recovered rapidly and went home on postoperative day 6. His estimated risk of paralysis was about 2-5%, mitigated by a protocol centered on CSF drainage and blood pressure control. His risk of death was 5%. Telephone followup reveals the he is pain free at a month out and functional nearly at baseline.

This illustrates the notion that three smaller operations in an aggregate over three years achieved the equivalent of the single big open type II TAAA repair.

equivalence — Illustration on left from Svensson et al.

The idea is to make each step achievable -like coming down a mountain taking three days on well marked paths rather than base jumping off the summit.

Clearly, the patient was younger and a fast healer, and credit must also be given to the anesthesia/critical care team who see high acuity cases in volume every day and not every patient can expect to have such short stays and excellent outcome, but these are far more likely if operations are planned out in such a manner.

Reference

Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Experience with 1509 patients undergoing thoracoabdominal aortic operations. J Vasc Surg 1993;17(2):357-36.

If the odds are against the patient, who is for the patient?

Posted on January 7, 2016January 8, 2016 by docpark

The first patient, a man in his late 70’s, ruptured in the emergency room at around four in the afternoon on a weekday, which was fortuitous, as the hospital was fully staffed, fully armed. The patient had arrived only a bit earlier with the complaint of severe abdominal pain, and soon after getting his CT, arrested. CPR commenced as I arrived by Dr. Timothy Ryan, our chief resident at that time.

Ruptured CIAA with CPR 1 -_1 — a rupture

The patient was wheeled upstairs with ongoing chest compressions. The anesthesia and operating room staff started a bucket brigade of blood -there was enough staff to start a symposium. Within 5 minutes of hitting the operating, I poured betadine on the chest and belly and took a blade and cut open the abdomen. Blood poured out onto our scrubs and to the floor and our shoes. I pushed my hand into the retroperitoneum, gently sweeping aside the torn tissues and blood clot to feel the hill of the aneurysm. I walked over the slope of the aneurysm and tweedled my fingers around the aorta above the aneurysm. The cross clamp rode my fingers into position around the aorta. The patient, so very dead minutes before in the ED, came back as I began to feel a pulse above the clamp. The patient lived through the operation and the night where grim data -pH of 6.8, lactates in the double digits, four figure LFT’s, kidney failure all predicted a bad outcome. And yet he survived, and a few days later, a second operation to washout and close his belly which had been left opened and packed occurred, and he recovered. We still talk about that day now three years out, and while he thanks me, I thank the whole hospital because I don’t remember speaking very much -the right things just happened around me as we worked, the whole hospital and me.

More recently, while I was finishing up two urgent cases, I got a call that the patient with the leaking aneurysm had arrived from across town and was becoming hypotensive.

Gratefully, one of my partners, Dr. Christopher Smolock, was rounding that Saturday and stepped in to finish up the last of the two cases while I ran down to the patient, a man in his late sixties, who had arrived in our acute aortic syndrome unit.

We conversed, the patient and I, and he understood what laid ahead. We rolled him up to the OR, and while we were prepping and draping, my fellow, Dr. Francisco Vargas, looked to me gravely and said with certitude, “I think he’s dead.”

Chest compressions commenced and again, knife in hand, I cut him open from sterum to pubis and got the clamp on. It took 15 minutes of CPR to get a pulse back. I was very pessimistic as during the case, ridiculously bad lab data came back like a pH of 6.9, lactate above 10, no urine.

The blood bank sent down coolers like the kind you take to tailgates, only filled with blood and plasma. The aneurysm had grown like a rotten apple on a stick and the graft we needed to repair it was surprisingly short. He too made it to the ICU, and after a long recovery which included dialysis, a tracheostomy, and a reboot of the brain -the brain takes a while to recover from the anoxia, but his went “bonnnnng” like a waking Mac after days of spinning beach balls, and he started to follow commands. The morning before he transferred to rehab, we talked about what he could have done to prevent the rupture. Not knowing about it, not much, I replied. People traditionally lived to about 20-30 years of age, I said, before dying of disease, violence, or predation. Longevity has meant wear and tear on irreplaceable parts. We agreed it was good to be alive.

Ruptured aortic aneurysms are the sine qua non of vascular surgical practice. As a junior resident back in the antedeluvian 90’s, I remember one of my chiefs, Dr. Eric Toschlog, now a trauma surgeon out East, running a patient upstairs from the ER with a rupture, and before the attending arrived by taxi, had the graft in. When it became my turn, as a fellow working on a patient who had been helicoptered in from the frozen wastes of Minnesota, I remember playing a trick with my mind -that the patient was proportionally the same size as the rabbits I was working with in the research lab, that I was really big and the patient’s aneurysm very small. This works to calm the heart, steady the hand. Nowadays, my mind is blank, and my hands working reflexively.

There has been a series of papers that create scores that allow prediction of odds for survival, and both of these patients, particularly with their prolonged CPR, have greater than 90% predicted mortality on these measures. In this month’s JVS, Broos et al, in the aptly named paper, “A ruptured abdominal aortic aneurysm that requires preoperative cardiopulmonary resuscitation is not necessarily lethal” describe a 38.5% survival rate among their series of patients with rupture who had CPR (ref 1).

Practically speaking, no one I know would use these scores to decide to not operate. While many series show better survival for emergency EVAR compared to open repair, several randomized control trial failed to show better results when these methods were directly compared. A retroperitoneal approach is preferred by some in our group, but having tried both closed chest CPR with the patient in right lateral decubitus position and open cardiac massage -(both died), I prefer supine.

There is no survival if there is no attempt.

Reference

J Vasc Surg 2016;63:49-54.

The Interrupted Natural History of Aortic and Iliac Artery Aneurysms

Posted on January 5, 2016January 5, 2016 by docpark

The patient, now in his 90’s, found out about his aortic and iliac artery aneurysms in his early 80’s, had been offered repair, but had refused. Several years ago, one of my partners emergently repaired his ruptured AAA (abdominal aortic aneurysm) via a retroperitoneal approach using a tube graft. At the time of the repair of the AAA, the common iliac artery aneurysms (CIAA’s) were not ruptured and would have added risky time to the repair. He survived and had a postop CT done about two years ago which showed his CIAA’s.

The patient chose not to pursue repair of these aneurysms, I assume figuring that at his age, he’d again take the chance that he would pass on without the hassle of another procedure.

He was recently admitted for treatment of another condition, when his physicians noted a large visible pulsatile mass on his lower abdomen.

CIAA

A CT scan was performed. It showed a 13 cm left common iliac artery aneurysm which was responsible for the visible puslatile mass and a large right common iliac artery aneurysm. The left internal iliac artery was thrombosed. His right common iliac artery aneurysm was over 5cm in size.

CT 13cm L CIAA preop

My partner, Dr. Ezequiel Parodi, was consulted for this case. He performed a percutaneous EVAR. The procedure was made difficult by tortuosity in iliac artery and the tube graft in the aorta requiring a secondary access from the arm to straighten out and advance the stent graft (aka body floss).

In followup, the aneurysms decreased in size and showed no endoleak around a patent stent graft.

CT postop L CIAA (1)

Common iliac artery aneurysms expand at a rate proportional to their starting size and have increased rates of expansion in those with prior aortic aneurysm expansion (ref 1). Rupture probably signals a tendency to expand rapidly. There is evidence that iliac ectasia and aneurysms left over after tube graft repair (aorto-aortic) of AAA is benign and can be safely observed (ref 2), but these were all small at the start.

I had been trained at the dusk of the open surgical era and the dictum was aortobi-iliac bypasses to avoid future problems with the iliac arteries. With EVAR, and soon bifurcated iliac branched stent-grafts (currently on trial), staged repair of metachronous iliac aneurysms after tube graft repair of AAA has not only an appeal, but some logic as open bypass to iliac bifurcations, particularly in large men, is challenging and potentially morbid. This is a case of a patient who had a large iliac aneurysm that was not repaired initially due to the exigencies of ruptured AAA and had refused planned staged repair. His aneurysm grew from over 5cm to 13cm in 2 years time without rupturing. Such good fortune is very rare.

Vascular surgeons like to collect large aneurysm stories like fishermen talk about big fish. This is the largest unruptured common iliac artery aneurysm I have seen. While it is baffling to many who are in healthcare, it is important to understand noncompliance is common. Denial is a powerful urge, and a uniquely human one.

2014-03-25

References

J Vasc Surg. 2009 Apr;49(4):881-5
Surgery. 2008 Nov;144(5):822-6.

Never Stop Following Stent Grafts -Type IV endoleak causing slow growth in 12 year old stent graft

Posted on November 26, 2015November 26, 2015 by docpark

Centerline

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.

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.

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.

2015-11-26 13_25_23

This was done percutaneously and in short followup, there has been stabilization and even some reduction in the aneurysm circumference.

CT Scans

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.

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.

A Matter of Degrees: The Terrible Aortic Neck Solved With Geometry

Posted on September 27, 2015September 28, 2015 by docpark

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.

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.

neck

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.

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