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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Cutter.png

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.

 

My First Intentional Stent Removal Case -Arterial Restoration

removed stents

In 2007, at which I had performed about 20 standard EndoRE (Remote Endarterectomy, LeMaitre Vascular) cases over about two years, this patient in his later 40’s presented to me with ischemic rest pain of his right foot. He was a current heavy smoker who initially had severe claudication and a TASC D occlusion of his right superficial femoral artery. Prior to being referred to me, he had undergone a mitral valve replacement from which he recovered uneventfully. He then had treatment of claudication starting with iliac stenting and a vein bypass. He had undergone a femoral artery to below knee popliteal artery bypass with reversed greater saphenous vein which became occluded after being complicated by MRSA wound infections. When this graft developed problems at the distal anastomosis, he underwent revision with a jump graft from the arm. This graft went down after he developed MRSA infection of the cephalic vein harvest site. He then underwent SFA stenting with 5 femoral stents (at that time, long stents were not available), but these occluded and his access site was the nidus of MRSA based sepsis. He had had multiple hospitalizations for MRSA infection from phlebotomy sites when he presented. He had reintervention for in-stent restenosis, first with balloons, then an extra stent, then cryoballoon therapy, each episode complicated by MRSA infection. He presented with severe claudication and nocturnal rest pain. On exam, he had dependent rubor, elevation pallor and absence of pulses, despite having fairly benign anatomy on CTA.

 

CTA AP

There was two vessel runoff below a reconstituted popliteal artery, with stent occlusion and visible stump of the vein bypass.

CTA medial oblique

My options included bypass with PTFE, cadaveric vein, endovascular recanalization of the occluded stents, or EndoRE. While considering the MRSA which had been extensively worked up prior to presentation by ID including TEE and multiple cultures, it was decided that he was firmly colonized with MRSA despite efforts at eradication, and PTFE was not an option. Cadaveric vein I have used in infections with acceptable short term results -never great long term except for one individual who I inherited from a surgeon in Kansas who maintained a decade of patency of a cadaveric vein to tibial artery bypass with coumadin alone. This patient was not likely to be so lucky. Endovascular recanalization with atherectomy versus laser was considered, but I had at that point become disillusioned with those modalities in such extensive disease.

EndoRE made the most sense because it was my observation in a prior patient in whom I had unintentionally removed a 4cm stent with plaque that stents are placed inside plaques and when you remove plaque, theoretically, the stents have a layer of plaque between them at the adventitia. Also, he had none of the extensive calcium that made regular EndoRE challenging. Also, it would be repaired with native tissues through a single groin incision, and covered with a sartorius flap. And that is what I did.

The common femoral artery was exposed and the SFA controlled. The plaque dissection was started and the ring fitted around plaque and stent. There was a little more friction than expected, but I did inject via a catheter cold LR with the idea that it would shrink the nitinol a bit. Also, the wire that guided the catheter did double duty as a dissector as I was subintimal with it. The rings traveled well to the end point which I achieved with little difficulty.

Vollmer Ring Dissector around plaque & stents
Vollmer Ring Dissector around plaque & stents

ex vivo stents

The end point was dissected and required a short self expanding stent. The patient recovered well and was discharged, but as in prior admissions, developed a cellulitis on the groin wound that resolved with Vancomycin, presumably with MRSA. A CTA done at that admission showed excellent patency and he had palpable pulses.

CTA post oblique with center line

Three years later, he underwent intervention by one of my partners in cardiology at that time for a restenosis in the mid SFA and had ballooning and a stent -the second set of stents in this patient, and by the time I left Iowa, he was still patent and walking.

This operation fails with randomly distributed TASC A lesions that develop in sites of remnant smooth muscle. I think today, I would treat with a drug eluting balloon. Thrombosis is the other failure mode, but unlike PTFE grafts, there is no thromboembolism of the outflow, rather, the SFA thromboses with reconstitution of the original state, and is amenable to thrombolysis. Smokers such as this patient and those with limited outflow are anticoagulated with warfarin.

The Europeans call this now arterial restoration. The vessel is returned to its baseline state with a full complement of collaterals which are revived. Also, compliance is restored and I believe this plays a significant role in maintenance of patency. Also, as the native tissues heal, they return to a normal ultrastructure -I have taken pathology specimen with aortic punches to perform bypasses to the other leg from external iliacs treated so, and they were microscopically and visibly normal.