External iliac remote endarterectomy restores the artery to normal, opening the way for EVAR, TAVR, TEVAR, and transplant: alternate applications of EndoRE

preop-cta

One of the nice things  about practicing at the Clinic is being able to offer unique solutions. A severely diseased or occluded external iliac artery (EIA) can be a vexing problem, particularly if bilateral, in this endovascular era. Many cardiovascular devices require femoral access that has to traverse compromised iliac arteries -those with large (>16F) delivery systems require a sufficiently wide path to get the devices to the heart and aorta. Also, living related donor kidney transplantation is predicated on minimizing risk to maximize results and having significant iliac plaque negates one as a recipient for this high stakes elective procedure. In situations where the EIA is too small to accommodate devices because of atherosclerotic plaque, the typical solution is placement of a conduit to the common iliac artery or the aorta. The practice of “endopaving” with a covered stent graft and ballooning is also described, but its long term outcomes are not reported and the internal iliac artery is usually sacrificed in this maneuver.

This patient presents with lifestyle limiting claudication and an absent right femoral pulse. ABI is moderately reduced on the right to 0.57, and he had no rest pain. CTA at our clinic revealed an occluded EIA bracketed by severely calcified and nearly occlusive plaque of the common iliac artery (CIA) and common femoral artery (CFA).

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Centerline Projection

The patient was amenable to operation. Traditionally, this would have been treated with some form of bypass -aortofemoral or femorofemoral with a common femoral endarterectomy. While endovascular therapy of the occluded segment is available, one should not expect the patencies to be any better than that of occlusive lesions (CTO’s) in other arteries. Hybrid open/endovascular therapy is an option as well with CFA endarterecotmy and crossing CIA to EIA stents, but I have a better solution.

The common femoral endarterectomy rarely ends at the inguinal ligament, and is uniquely suitable for remote endarterectomy, a procedure from the early to mid twentieth century.

endoRE graphic
Steps in Remote Endarterectomy

 

The addition of modern fluoroscopic imaging and combining with endovascular techniques makes this a safe and durable operation.

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The patient was operated on in a hybrid endovascular OR suite. A right groin incision was made to expose the common femoral artery for endarterectomy and left common femoral access was achieved for angiographic access, but also to place a wire across the occlusion into the common femoral artery.

All actions on the external iliac artery plaque are done with an up-and-over wire, allowing for swift action in the instance that arterial perforation or rupture occur. This event is exceedingly rare when the operation is well planned. With this kind of access, an occlusive balloon or repairing stent graft can be rapidly delivered.

The common femoral endarterectomy is done from its distal most point and the Vollmer ring is used to mobilize the plaque. A Moll Ring Cutter (LeMaitre Vascular) is then used to cut the plaque.

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The plaque is extracted and re-establishes patency of the EIA.

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Plaque Specimen

The plaque end point is typically treated with a stent -in this  case, the common iliac plaque was also treated.

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What is nice about this approach is that this artery has been restored to nearly its original condition. I have taken biopsies of the artery several months after the procedure in the process of using the artery as inflow for a cross femoral bypass, and the artery clamped and sewed like a normal artery and the pathology returned normal artery.

This has several advantages over conduit creation which can be a morbid and high risk procedure in patients who require minimally invasive approach. A graft is avoided. The artery is over 8mm in diameter where with stenting up to 8mm with an occlusive plaque, the danger of rupture is present, and often ballooning is restricted to 6mm-7mm. This is insufficient for many TEVAR grafts and TAVR valves.

For patients being worked up for living related donor transplants who are turned down because of the presence of aortoiliac plaque, those with the right anatomy can undergo this procedure and potentially become candidates after a period of healing.

 

A Troublesome Accessory Renal Artery Complicating a Complicated Patient

Preop Figure

The patient is an 65 year old man with a growing right common iliac artery aneurysm of 3.7cm, a small AAA, and severe COPD (not oxygen dependent, FEV 1.5L) . He had a prior left nephrectomy for cancer as well as a bladder resection and prostatectomy with an ileal conduit (Indiana pouch or neobladder), with complex abdominal wall closure complicated by infection of Marlex in the past, and prior operations for small bowel obstruction. He is morbidly obese. His kidney function was stable with a Cr 1.5dL/mL, calculated GFR or 44mL/min. His nuclear cardiac stress test (pharmacologic) was normal.

A magnified view of the accessory renal artery is shows below with the arrow

mag preop CT

He needed to have his right CIAA treated but the issues were what to do with his accessory renal artery. Vascular surgery is all about making the right decisions with fall back plans. As with most complicated patients, the options are numerous.

  1. Direct transabdominal open repair
  2. Open retroperitoneal repair –Left sided approach.
  3. Open retroperitoneal repair –Right sided approach
  4. Open debranching right accessory renal artery and EVAR
  5. Parallel graft to right accessory renal artery and EVAR
  6. Coil embolization right accessory renal artery, anticipate worst case postop GFR 20ml/min
  7. Medical management

I informally polled my partners and found an absence of consensus except for rejecting #1, 2, and 7. The first two options were not optimal because of his prior operation and because of the location of his disease. The third option had its proponents, but I felt that the kidney and pouch were in jeopardy from dissection in that area. The open debranching had its appeal for others, but for the same reasons that I rejected #3, I rejected #4 –potential harm to the kidney. #5 may be an option, but in my experience, I have seen too many patients referred for failure of parallel grafts to feel secure about offering it.  #6 would be reasonable if the patient could avoid dialysis. With a calculated CGF of 44ml/min, losing half the remaining kidney would barely leave him off dialysis. By appearances though, the smart money was on losing less than 50% but more than 20%. A 30% loss would result in a GFR of 30mL/min or a Cr of 2.1 which made dialysis not likely. In my experience, the kidney does have some collateralization as evidenced by backbleeding of accessory renals with an infrarenal clamp so it may be that he might lose only 10-15%. I discussed all of these options and medical management with the patient who agreed to proceed with option 5 under my recommendation. My plan was to assess the flow from the accessory renal and proceed if it was small, with plan B being a parallel graft, plan C debranching.

nephrogram

In the OR, the right accessory renal artery was selectively catheterized and a nephrogram revealed that it supplied less than 20% of the kidney. The above diagram shows the extent of the total kidney and the area perfused by the accessory renal artery. I proceeded with coil embolization of it and the right hypogastric artery and EVAR of the AAA/R.CIAA.

post CT

In followup, the patient had a Cr of 1.7mg/dL, representing about 15% loss of kidney function. As the case was done percutaneously, he only had 1cm incision in both groins, and was pleased with his result. No endoleak was seen (CT above).

The telling lesson about this case is that at the time of initial consultation, my first instinct was to prepare the patient for open repair via a right retroperitoneal approach with debranching of the right accessory renal artery as a fallback position. Open surgery is my fallback as it was the foundation of my training. But experience has also taught me that patients with multiple comorbidities often struggle to recover from big operations even if one particular problem is not prohibitively severe. Finally, having smart partners to bounce ideas off of is a not only a luxury but a critical asset.

External iliac remote endarterectomy in lieu of a conduit for TEVAR

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The patient had diffuse atherosclerosis with small luminal area even in areas without calcified plaque. It predicted inaccessibility for the 22 French sheath required to deliver the 32mm C-TAG device to be placed for a symptomatic type B thoracic aortic dissection associated with a small but expanding proximal aneurysm.

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My options included direct aortic puncture, an aortofemoral conduit, or an endoconduit. The aorta was heavily calcified and the bifurcation was narrowed by circumferential plaque down to 6-7mm at its narrowest and the left iliac had a severe narrowing due to this plaque. The common femoral artery was severely diseased with a lumen diameter of 4mm due to heavily calcified plaque.

I have come to favor direct aortic puncture over conduits, but the heavily calcified aorta and the absence of safe areas to clamp made me think about other options. My experience with endoconduits has been limited to revising problems of endoconduits from elsewhere, but others report it as a feasible option.

The problem with a long artery narrowed with irregular plaque and even intimal thickening is that it will readily expand to accommodate a large sheath but removing it involves the frictional resistance of the whole artery and typically the “iliac on a stick” avulsion involves the whole length of external iliac artery, likely because the common iliac is anchored by the aortoiliac plaque, the smaller diameter of the EIA, and the longer more tortuous path offering greater resistance in the EIA compared to the aorto-common iliac segment.

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Remote endarterectomy, a technique involving endarterectomizing an artery through a single arteriotomy, offers the possibility of increasing the lumen of even a mildly diseased artery and reducing the frictional coefficient, assuming the remnant smooth adventitia is less resistant than rough irregular intimal plaque.

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The plan was to expose the right common femoral artery and endarterectomize it and gain wire access from the R. CFA. A wire would be placed on the left iliofemoral system to protect it for later kissing iliac stents. A right EIA remote endarterectomy would be performed, and then the right aorto-common iliac segment would be balloon dilated to 8mm.

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The operation went as planned. The external iliac plaque was removed in a single piece from the EIA origin.

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Arteriography showed the right EIA to be free of intimal disease, and dilators and ultimately the 22F sheath went in easily.

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The TEVAR also went uneventully -the left subclavian which had a prior common carotid to subclavian bypass, was covered and the aneurysm and flap were excluded from the left CCA to the celiac axis.

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The most difficult part of the operation was removing the sheath, as is usually the case with a tight iliac, but the friction point was largely at the common iliac and not the external iliac. No artery could be seen extruding with the sheath at the groin while steady tension was applied to the sheath under fluoro. The aortic bifurcation was repaired with kissing iliac stent. The patient recovered well and her chest pain resolved.

I have done this for EVAR, including reopening occluded external iliac arteries, and even for a 26F access for TAVR, avoiding the need for placement of a conduit in selected patients.

Addendum: in followup, I had the chance to check up on the repair -the EIA remained large and patent.

before after

The Parallel Bar -higher than you’d think

eye tiger big

At last week’s Veith Symposium, there was a straw poll for parallel grafts versus fenestrated stent grafts in emergent setting, and the results were a populist parallelist majority. This is clearly the result of years of inability to access this technology and reflects market forces making the decision over careful science. There are clear examples of this in the past -the adoption of laparoscopic cholecystectomy and appendectomy, done without randomized control trials shows that RCT’s be damned, people and surgeons will get what they want.

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The several presentations on parallel grafts caught my eye. First was the Eye of the Tiger technique which sounds like a kung-fu move. Presented by Dr. David Minion of the University of Kentucky, the gist of it is that the gutters created by parallel grafts can be obviated by reshaping the branch grafts from circles to lenticular shapes (illustration). The sequence of moves is to deploy a balloon expandable stent graft outside of the main graft and deploy it, then deflate the balloon. The aortic graft is then ballooned, crushing the branch graft. With the balloon inflated, the branch graft is then inflated, now taking a lenticular configuration. This, I will put in my tool box.

Bullfrog catheter tracking (top) and inflated for infusion (botton) with needle out.
Bullfrog catheter tracking (top) and inflated for infusion (botton) with needle out.

The other presentation was on the bullfrog catheter, by Dr. Christopher Owen of UCSF. It inflates to press the catheter portion of it in the middle of the length of the balloon against the stent graft wall. A penetrating needle then comes out through the graft material, allowing for infusion of a sealing embolic material. This has not been tried in humans but application in an animal model is ongoing.

The first time I saw Nellix, this is what I thought...
The first time I saw Nellix, this is what I thought…

I have a feeling parallel grafts will be with us for a while. Using these in conjunction with the Nellix graft, juxtarenal aortic aneurysms were treated, which brings me to think that with the inevitable progression of paravisceral segment aneurysm disease, we will be seeing secondary endobags (not a pejorative) for treatment of paravisceral aortic aneurysms with parallel grafts, and we will see something like this on CT scans one day (illustration). Mr. Ian Loftus of St. George’s Vascular Institute reported on 19 patients (11 single, 5 double, 3 triple branch) over 12 months who were unsuitable for OR/EVAR solutions, treated with 100% technical success, one type I endoleak. Dr. Michel Reijnen presented the Arnhem experience with this technique. Their series included 7 patients with juxta (5) or para (2) renal AAA’s (4 single, 2 double). He reported 100% chimney graft patency and no reinterventions in short followup. He presented a case of rupture, but warned that further investigation would be needed before using the endobag for rAAA.

I think that the whole issue points to several truths. Paravisceral and thoracoabdominal aortic aneurysms have always been viewed with trepidation and this generally caused referral of these cases to high volume centers and surgeons during the open era. Experience with EVAR has infused a sense of confidence and with mastery of infrarenal EVAR and basic endovascular interventions, most practitioners feel ready to offer an endovascular solution to the visceral segment AAA’s, but feel locked out either through lack of training or inability to access the devices, particularly not having ready solutions on the shelf. These parallel graft systems offer relative ease of delivery and use readily available components. Even I have resorted to parallel grafts in an emergency with acceptable short term result (patient lived) but with uncertainty with durability.

I think that there will never be a completely satisfactory off the shelf, “every-surgeon” solution because these patients are no less complex when approached with endovascular technique -they just present a different set of equally difficult challenges. As in open repair of these complex aortic aneurysms, endovascular repair of these should aggregate to high volume practices and centers with deep experience.

Percutaneous EVAR and TEVAR -how to get there if you aren’t doing it right now.

24F Access pEVAR
22 French Percutaneous Access circa 2008

Percutaneous access for EVAR and TEVAR does several things. First, the procedure becomes shorter by an hour or two, and (don’t discount not having nursing count instruments because the case was percutaneous). Second, the patients experience far less discomfort and it is easier to discharge them the next day when they have a bandaid versus an incision. And this leads to the third thing: not having an incision means it is far less likely that a groin infection will occur, especially in the obese.

There are three things which you must do before undertaking pEVAR. First, you have to become comfortable with using the Perclose S device in 6F-8F access -about 5 to 10 successful closures will do. You should become facile with the deployment of the sutures and closure of the access point. Avoid small arteries or heavily calcified arteries. This leads to the second point -all of your groin access should be ultrasound guided -this has been shown to improve results in pEVAR (Ref 1). I am a firm believer that the source of groin access complications starts with the initial needle stick. The 18g needle is basically a short 11 blade rolled up into a cylinder, and during groin access without ultrasound imaging, one can shear branch arteries, skewer arteries, dissect plaque, and access too proximally or distally, or into the profunda femoris.

needle is scalpel

The third need is access to 3D reconstruction software and multislice CTA. This gives you powerful ability to predict which patients are more suitable for a percutaneous approach, and which should have a cut down, and with 3D virtual reality reconstructions, you can plan where the incisions will be. In the skinny patient, this is not a pressing issue, but in the merely obese and the frankly obese, and the super obese, choosing to go percutaneous and avoiding a groin complication, which may be the one thing that debilitates the patient far more than a stent graft deployment, becomes an easy decision with experience.

As you build your 6-8F Perclose experience, you may notice that having too tight and subcutaneous tract can result in the suture catching on SQ fat, and not closing, or that bleeding won’t surface properly and create a hematoma under Scarpa’s fascia, often after the patient gets to the recovery room. Expanding on this principle, as you leap to 12F access and preclosure, I recommend you try this -make a 10mm incision, and using a tonsil clamp, pop through Scarpa’s fascia and seat the tips of the clamp under ultrasound on top of the soft part of the CFA that you intend to access. Gently spreading creates the space that you need to deploy the sutures and ensure that any bleeding will exit the skin and not dive under the fascia. It amounts to an ultrasound guided dissection of the common femoral artery. Before you remove the tonsil, you gently maneuver a micropuncture (always) access needle between the tines of the tonsil clamp until it gets to the artery -this keeps the eventual wire going through the tunnel you just made.

12F can usually close with a single Perclose, but start practicing by placing two Perclose sutures in a 10 oclock and 2 oclock orientation. Once the sutures are in, I make sure the  two ends of the suture are pulled out and the end loop of the suture is on the artery and I clamp these sutures to the drapes medially and laterally depending on how I deploy the two sutures. This also helps avoid catching the suture and driving it into the aorta.

After performing EVAR or TEVAR, I remove the sheath, leaving a wire -typically the stiff wire originally supporting the sheath and deploy one of the sutures. This first suture should cinch down onto the artery and substantially decrease the bleeding coming from the access site. I then deploy the second suture, and if the bleeding has stopped or is a steady dribble, I remove the wire. If pulsatile bleeding persists, I recinch the sutures using the knot pushers. If this decreases flow, I remove the wire, otherwise, I place a dilator, stop the bleeding and cut down. Cutting down after SQ dissection means merely dividing skin and tissues over the dilator, and the artery is easily visible for suture placement. If I remove the wire and there is still some bleeding, and usually there is, I place Gel-Foam soaked in diluted thrombin into the tract, reverse heparin, and hold pressure for 10-20minutes. It is very rare to have to convert after this is done.

thrombin gelfoam
thrombin-gelfoam into tract

The skin is closed with an absorbable 4-0 monofilament suture, and skin glue. I usually use the micropuncture needle to give an ilioinguinal field block with Marcaine. This gives 24hrs of pain relief.

bandaids

A note about incisions. Usually, with 3D VR imaging of CTA, the CFA and its quality (size and absence of plaque), and location relative to the inguinal crease can be ascertained. I try to make the access point at the inguinal crease or distally, as this goes under the subpannus of groin fat rather than through it.

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3D-VR imaging can pinpoint optimal access

I sincerely believe sheath size is not the limiting factor to percutaneous access. Rather, it is the common femoral and iliac artery. Zakko et al at the University of Florida just published their experience on the obese with percutaneous TEVAR (ref 2), and found that while the arteries were deeper, the technical success rate of staying percutaneous (over 90%) was no different between their obese patients non-obese patients. The predictors of failure were poor access artery quality and size. I believe that you can select for patients most likely to succeed and greatly reduce failure. In this population, groin complications are potentially life threatening, and avoiding an open groin exposure is valuable.

 

References

1. J Vasc Surg 2012;55:1554-61 (ultrasound guided access)

2. J Vasc Surg 2014;60:921-928 (p-TEVAR and obesity)