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Surgical Bypass Summit — Session 4:
Sequential bypass: An option for the tibials — Jean Bismuth, MD

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Jean Bismuth, MD

The first randomized trial to compare the GORE® PROPATEN® Vascular Graft (Gore & Associates) to expanded polytetrafluoroethylene (ePTFE) found that the GORE® PROPATEN® Vascular Graft significantly decreased the relative risk of losing primary and secondary patency by 36% and 40%, respectively.1 The study joins a number of trials that have demonstrated the efficacy of prosthetic grafts.2-5 A comparison of tibial bypass with saphenous vein graft to tibial bypass with heparin-bonded PTFE performed with autologous vein patch found comparable 1-year primary patency between the two groups: 86% for saphenous vein graft and 75.4% for heparin-bonded PTFE.2 A prospective randomized trial evaluated spliced vein versus PTFE plus patch; the investigators concluded that both spliced vein bypass grafting and PTFE bypass grafting with a distal vein cuff produced acceptable limb salvage rates.3 The Vascular Study Group of New England evaluated their experience with 1,227 patients from 2003 to 20095 who received a prosthetic graft to a below-the-knee target (70%) or more distal target (30%), and concluded that patients who receive below-the-knee prosthetic bypass grafting can have similar 1-year outcomes as patients who receive greater saphenous vein conduit.5

Sequential bypass is indicated for patients with multiple failed bypasses, critical ischemia, and adequate inflow, who are fit enough to undergo a lengthy procedure. Two different techniques are frequently used for sequential bypass configurations: composite sequencing and modified configuration of the prosthetic-vein anastomosis for composite sequential bypass.6 Patients may receive sequential bypasses with PTFE and autologous vein if they do not have the required length of autologous vein. A series of six such procedures were performed at Houston Methodist Hospital over 18 months; of the six cases, four remained patent for 1 to 3 years with no intervention. The small series is consistent with results from published studies of sequential bypass. An analysis of patency rates of sequential bypass revealed 1-year patency rates of 91% with composite sequential, 73% with distal arteriovenous fistulae, and 52% with a disadvantaged vein.7 A separate trial found a small benefit from sequential bypass for patients who have a single vein.8

Although trials typically measure patency rates and limb salvage rates, surgical outcomes can also be evaluated via visualization of muscle perfusion of the leg and foot using magnetic resonance imaging (MRI) with gadolinium contrast. We used the technique to image a series of patients who received open surgery and endovascular therapy. MRI was performed both before the intervention and at 6 months after re-vascularization. MRI revealed that patients who were healthy had well-defined muscle. As patients began to show symptoms, such as a decrease in ankle-brachial index, the muscles changed and collagen fibers replaced muscle. Collagen fibers continued to become more pronounced as ischemia increased. MRI also revealed a correlation between worsening scar tissue and worsening outcomes. A closer analysis by muscle group, as well as symptomatic and asymptomatic leg, should allow for further visualization of the changes effected by revascularization.

Summary

Patients who do not have adequate saphenous vein can successfully receive a GORE® PROPATEN® Vascular Graft with a distal vein patch. An analysis of muscle perfusions suggests the perfusion effect is greater when several vessels are targeted for revascularization compared to a single vessel. We have attempted to harness this effect in a small series of sequential bypass, but this technique is best reserved as a potential last resort effort in patients fit enough to undergo a lengthy procedure.

Jean Bismuth, MD, is from the Methodist DeBakey Heart & Vascular Center in Houston, Texas. He has disclosed that he has received compensation from Gore for participating in the Summit and has received honoraria from Gore for writing this article. Dr. Bismuth may be reached at [email protected]

  1. Lindholt JS, Gottschalksen B, Johannesen N, et al. The Scandinavian Propaten(R) trial–1-year patency of PTFE vascular prostheses with heparin-bonded luminal surfaces compared to ordinary pure PTFE vascular prostheses: a randomised clinical controlled multi-centre trial. Eur J Vasc Endovasc Surg. 2011;41:668-673.
  2. Neville RF, Capone A, Amdur R, et al. A comparison of tibial artery bypass performed with heparin-bonded expanded polytetrafluoroethylene and great saphenous vein to treat critical limb ischemia. J Vasc Surg. 2012;56:1008-1014.
  3. Kreienberg PB, Darling RC 3rd, Chang BB, et al. Early results of a prospective randomized trial of spliced vein versus polytetrafluoroethylene graft with a distal vein cuff for limb-threatening ischemia. J Vasc Surg. 2002;35:299-306.
  4. Calligaro KD, Syrek JR, Dougherty MJ, et al. Use of arm and lesser saphenous vein compared with prosthetic grafts for infrapopliteal arterial bypass: are they worth the effort? J Vasc Surg. 1997;26:919-924; discussion 925-917.
  5. Suckow BD, Kraiss LW, Stone DH, et al. Comparison of graft patency, limb salvage, and antithrombotic therapy between prosthetic and autogenous below-knee bypass for critical limb ischemia. Ann Vasc Surg. 2013;27:1134-1145.
  6. Gargiulo NJ 3rd, Veith FJ, O’Connor DJ, et al. Experience with a modified composite sequential bypass technique for limb-threatening ischemia. Ann Vasc Surg. 2010;24:1000-1004.
  7. Roddy SP, Darling RC 3rd, Ozsvath KJ, et al. Composite sequential arterial reconstruction for limb salvage. J Vasc Surg. 2002;36:325-329.
  8. Mahmood A, Garnham A, Sintler M, et al. Composite sequential grafts for femorocrural bypass reconstruction: experience with a modified technique. J Vasc Surg. 2002;36:772-778.