Percutaneous transmural arterial bypass (DETOUR) for long-segment femoropopliteal artery occlusion
Recently introduced at Penn Medicine Lancaster General Health by Ruhani Nanavati, MD, the DETOUR System offers an alternative endovascular approach for the treatment of long-segment occlusion of the femoropopliteal artery.
Vascular surgeons at Penn Medicine have introduced the DETOUR System for the treatment of long-segment occlusion of the femoropopliteal artery (FPA). A minimally invasive therapy, the DETOUR System (e.g., percutaneous transmural arterial bypass, or PTAB) uses the femoral vein to bypass the arterial blockage and restore blood flow to the thigh and lower leg.
The prevalence of peripheral arterial disease (PAD) is increasing as a consequence of aging, tobacco use, and diabetes. Generally, PAD involves vascular stenosis and ischemia in the calves and feet due to atherosclerosis affecting the aorto-iliac, femoropopliteal, and infra-popliteal arteries.
Early manifestations include intermittent claudication, with later, more severe PAD, presenting as pain at rest with or without non-healing tissue loss. Patients in the latter group are at risk of developing critical limb-threatening ischemia (CLTI) and its effects, including a 25 percent one-year amputation rate.
Revascularization is central to the management of PAD. Among patients with lower extremity PAD, the FPA is the most frequent site for endovenous revascularization (EVR). Common therapeutic modalities include balloon angioplasty, stenting, atherectomy, and intravascular lithotripsy.
Length of occlusion is a critical issue in the treatment of FPA lesions, because while EVR is effective for the resolution of shorter lesions (<10cm) of the FPA, it is generally unsuccessful as therapy for longer clots. Treatment of these long-segment lesions is technically challenging, in part because these clots offer persistent and uniform blockage of the vessels.
Chronic total occlusion (CTO), or total occlusion lasting longer than three months, has been reported to occur in 40 to 50 percent of individuals presenting for treatment of the FP and tibial arteries. In long-segment CTO, EVR has been associated with restenotic lesions, arterial dissection, and generally poorer long-term patency. Other efforts at revascularization have fared little better, and in their combination of vessel preparation and intervention, present the pervasive risk of distal embolization.
An alternative route to treatment for long-segment PFA lesions
The DETOUR System, recently introduced at Penn Medicine Lancaster General Health by Ruhani Nanavati, MD, offers an alternative endovascular approach to the treatment of long-segment PFA occlusion. DETOUR enables physicians to bypass lesions in the superficial femoral artery by using stents routed through the femoral vein to restore blood flow to the leg.
DETOUR is effective for patients who have femoropopliteal lesions between 20 cm and 46 cm in length, including those who have already undergone repeat endovascular procedures, or who may not be good candidates for surgical bypass. Individuals must have a distal common femoral artery >7mm (0.7cm) in diameter and cannot have a recent history of deep vein thrombosis, thrombophilia, or disseminated malignancy, among other exclusions.
How the DETOUR System works
The DETOUR System consists of guide wires, a needle-bearing arteriovenous crossover device, a venous snare, an arterial delivery catheter, and a self-expanding nitinol wire frame stent graft. Essentially, these components are used to introduce a stent graft into the FPA until it reaches the apex of an occlusion.
At this point, the graft is diverted through an arteriovenous anastomosis into the femoral vein and descends distally to a point below the occlusion, where a second anastomosis allows it to rejoin the FPA as a conduit (or detour) for arterial blood around the clot. The width of the graft is gauged to ensure continuing blood flow through the femoral vein.
Outcomes
In clinical trials, freedom from total occlusion at one year was 92.4%. The clinical success rate at 1 year was 97.2 percent. Safety was generally excellent: the infection rate at 30 days was 0.5 percent; the freedom from major adverse events at 30 days was 93 percent; and the DVT rate at 30 days was 2.5 percent.
Case Report
Mrs. M, a 78-year-old woman, was referred to Dr. Ruhani Nanavati for consultation following multiple surgical and endovascular interventions at her left leg for CLTI. Her symptoms at this time included pain at rest.
A series of CT scans demonstrated long-segment flush occlusion of the superficial femoral artery (SFA) of Mrs. M’s left leg (Figure 1). Given her history of failed interventions and the absence of alternative procedures, Mrs. M was amenable to a novel aggressive endovascular revascularization for limb salvage, including the DETOUR System.
After reviewing the risks and benefits of the procedure, she offered her consent to proceed.
Procedure description
Mrs. M was prepared for surgery in the standard fashion and administered moderate conscious sedation for the whole of her procedure (4hrs, 42min). Under ultrasound guidance, the right common femoral artery was then accessed percutaneously, and a guide wire and flush catheter were advanced into the aorta.
The aortic bifurcation was then identified and crossed. Following further imaging of the left lower extremity, a catheter was advanced to the common femoral artery.
At this point, deep venous access of the posterior tibial vein of the distal left leg was obtained via micropuncture, and an endovascular snare in a venous sheath was advanced to the level of the lesser trochanter in the common femoral vein, which measured >10mm in diameter. A 9-16mm endovascular snare in a venous sheath was then inserted and advanced to the level of the lesser trochanter in the common femoral vein.
Following pretreatment with percutaneous transmural arterial balloon at the left SFA, the DETOUR Endocross device was advanced in the artery via guidewire distal to the profunda bifurcation and above the occlusion, where it was positioned under imaging guidance opposite the femoral vein snare.
An anastomosis was then successfully created between the left SFA and the femoral vein, and a 300 cm wire was advanced from the artery into the vein and captured by the snare system. Following several further procedures, the Endocross was pushed over the wire through the anastomosis into the vein until it reached a position below the occlusion opposite the functional femoral (now the popliteal) artery. A distal arteriovenous anastomosis was then created between the vein and artery in a manner similar to the procedure previously described.
All of the aforementioned steps occurred under imaging guidance, which was now used to visualize reconstitution of the blood flow in the popliteal artery and confirm arterial reentry.
There then followed the placement of three overlapping stent grafts in the femoral vein to create a conduit for blood between the femoral artery above the occlusion and the popliteal artery below it. The total length of these grafts was 600mm (23.63”), and the maximum width was 6.7mm (0.26”). Residual plaque at the profunda origin and distal native popliteal disease were treated, and a completion angiogram was performed, which showed brisk blood flow through the graft (Figure 2). The procedure was then concluded with removal and accounting of the sheaths, wires, and devices.
Mrs. M tolerated the procedure well, and her post-intervention course has been unremarkable, with excellent patency maintained on routine surveillance ultrasounds thus far.
Clinical consult and patient referral
To refer to Dr. Nanavati for complex PAD or DETOUR, please call the LG Health Physicians Surgical Group at 717-544-3626.
About LG Health Physicians Surgical Group
Affiliated with Penn Medicine Lancaster General Hospital, the LG Health Physicians Surgical Group is a surgical collaborative offering the full range of abdominal, endovascular, ENT, and critical care surgeries, as well as general surgery and ancillary screening, education, and support programs.