Dr David Rosenthal, Surgery Program Director at Atlanta Medical Center, talked to Vascular News about Remote SFA Endarterectomy and how this offers an alternative to above-knee femoral-popliteal bypass. Dr David Rosenthal defined Remote SFA Endarterectomy as a minimally invasive procedure offering complete debulking of the SFA with a combination of surgery and endovascular technologies performed through a small standard femoral artery cutdown.In performing the procedure, Dr Rosenthal stated, “A femoral artery cutdown and arteriogram is performed, which delineates the point of proximal popliteal artery reconstitution. That is your Remote Endarterectomy endpoint. The patient is heparinized, an arteriotomy is made in the proximal superficial femoral artery and the standard subadventitial endarterectomy cleavage plane is entered using a dissector spatula. Once the intimal core is defined, it is transected at the proximal SFA and the core is threaded onto a conventional dissection ring stripper, which comes in various diameters. Alternatively, a Martin Dissector (Vascular Architects, San Jose, CA) can be used for the core dissection. The ‘remote’ endarterectomy is performed as the ring stripper or Martin Dissector is passed down the SFA under fluoroscopic surveillance continuing the dissection of the subadventitial plane to the endpoint (popliteal reconstitution). This is where the remote component of the procedure is derived. Once the dissection has been completed, the dissection ringer stripper or Martin Dissector is removed and a second device, a MollRing Cutter (Vascular Architects, San Jose, CA) is passed to the endpoint, over the atheromatous core, where the plaque is transected, and the entire atheromatous core, is removed from the proximal SFA, through the incision. The core is typically 25 to 30 centimeters long and weighs 8 to 10 grams. The last step, the endovascular component, involves passing a guidewire across the endpoint and a balloon-stent angioplasty is performed to tack the distal plaque and provide a smooth transition zone to the popliteal artery.”
Although this procedure has been attempted in the past, in recent years changes associated with the procedure have improved the outcomes. Dr Rosenthal highlighted several of these changes, “We knew we had to improve the management of the distal endpoint. When we initially started doing this procedure we placed stainless steel, and later, nitinol stents across the outflow tract. However, we observed an approximate 25% incidence of restenosis. I think the development of the aSpire stent, made by Vascular Architects, has been a tremendous adjunct to the procedure, as it is a PTFE covered stent, which eliminates the metal to artery contact which may incite neointimal hyperplasia. Additionally, the stent’s unique helical design allows for collateral preservation, which is a real bonus of the procedure. The stent has very good radial strength, yet is flexible enough to withstand the extrinsic compression and torsion forces across the knee joint.” He then pointed out the importance of hemorheologic components, such as Plavix and coumadin, to inhibit intimal hyperplasia and promote flow.
According to Rosenthal, Remote Endarterectomy is primarily for “tough cases – long segment occlusions, those longer than 15cms” of the SFA. In other words, the typical bypass surgery patient. “The beauty of this procedure is that it is minimally invasive,” explained Rosenthal, “You avoid a second incision, and it can be performed in the absence of the saphenous vein. The procedure also allows the surgeon to save the saphenous vein for subsequent peripheral or cardiac procedures. If indicated, a common femoral and/or profunda endarterectomy may be performed all at the same time. Obviously, it is a nice alternative to above-knee femoral-popliteal (AKFP) bypass. The big question, however, is will the patencies remain the same as AKFP – will they be as durable?”
Describing a multi-center study in which he was involved, Rosenthal told Vascular News, “We had at 33 months follow-up a primary patency rate of 69% and a primary assisted-patency rate of 88%. To achieve this primary-assisted patency, it was necessary to perform either balloon and/or stent angioplasty to keep the SFA patent.”
According to Rosenthal, complete debulking of the vessel with Remote Endarterectomy reduces the incidence of recoil and remodeling. “I think anytime you recanalize an SFA with a guidewire, laser or an atherectomy catheter, in combination with some form of PTA or PTA and stenting, you get recoil and remodeling of the artery. By complete debulking the vessel you are removing the potential for that to occur.
“With Remote Endarterectomy, you open up the exuberant collateral network. These are mostly TASC D lesions, occlusions, and when you look at your intraoperative arteriogram you see nothing from the proximal SFA to the adductor canal. After the remote endarterectomy a repeat arteriogram demonstrates the now opened collateral network and the geniculate vessels around the knee. We, therefore, open the collateral network and also preserve the collaterals when we place the stent, because Vascular Architects’ aSpire stent can be reconfigured if you do not like its position, which is a real benefit.”
The procedure continues to evolve, Rosenthal continued, with the development of new remote endarterectomy instruments. “The hope is that with the instruments and the use of the aSpire stent, we will improve the durability and get improved outcomes. In addition, we are able to expand the applications for use in the SFA, including diffuse segmental disease, mid-SFA occlusions, and recanalizing native vessels in patients which have previously failed AKFP bypass,” said Rosenthal.
“The Achilles heel of this procedure, as in all SFA interventions, is intimal hyperplasia, which probably causes a restenosis rate of somewhere approaching 15%. In the future with the use of improved antiplatelet medication, drug treatments, endothelial cell seeding, and possibly brachytherapy, these adjuncts in concert with remote endarterectomy should give us better and more durable patency rates.”
Rosenthal explained that vascular surgeons look closely at patency and durability. “Our responsibility to our patients is to give them a durable procedure with the same results as those of an above-knee femoral-popliteal bypass.” Therefore, ongoing data that continues to confirm this is needed from clinical trials.
