Big data concerning polytetrafluoroethylene above- and below-knee bypass grafts provide more questions than answers

Abstract

A recent retrospective review of femoral-popliteal bypass in the Vascular Quality Initiative database compared saphenous vein grafts with expanded polytetrafluoroethylene (PTFE) grafts from 2003 to 2018.1Humbarger O. Siracuse J.J. Rybin D. Stone D.H. Goodney P.P. Schermerhorn M.L. et al.Broad variation in prosthetic conduit use for femoral-popliteal bypass is not justified on the basis of contemporary outcomes favoring autologous great saphenous vein.J Vasc Surg. 2019; 70: 1514-1523Abstract Full Text Full Text PDF Scopus (4) Google Scholar Important findings were that at 1 year, saphenous vein bypass had superior patency and amputation-free survival for both above-knee and below-knee popliteal bypass compared with PTFE. However, mentioned only at the end of the limitations section is the fact that variations of PTFE, such as heparin bonding or manufacturer, were not studied. Recent data suggest that heparin-bonded PTFE outperforms standard PTFE at both the above-knee and below-knee popliteal level.2Samson R.H. Morales R. Showalter D.P. Lepore M.R. Nair D.G. Heparin-bonded expanded polytetrafluoroethylene femoropopliteal bypass grafts outperform expanded polytetrafluoroethylene grafts without heparin in a long-term comparison.J Vasc Surg. 2016; 64: 638-647Abstract Full Text Full Text PDF PubMed Scopus (26) Google Scholar, 3Lindhol J.S. Gottschalksen B. Johannesen J. Dueholm D. Ravn H. Christensen E.D. et al.The Scandinavian Propaten 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: 668-673Abstract Full Text Full Text PDF Scopus (90) Google Scholar, 4Piffaretti G. Dorigo W. Ottavi P. Pulli R. Castelli P. Pratesi C. PROPATEN Italian Registry GroupResults of infrainguinal revascularization with bypass surgery using a heparin-bonded graft for disabling intermittent claudication due to femoropopliteal occlusive disease.J Vasc Surg. 2019; 70: 166-174.e1Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar However, the absolute difference in occlusion-free survival for PTFE grafts compared with saphenous vein was only 5%.1Humbarger O. Siracuse J.J. Rybin D. Stone D.H. Goodney P.P. Schermerhorn M.L. et al.Broad variation in prosthetic conduit use for femoral-popliteal bypass is not justified on the basis of contemporary outcomes favoring autologous great saphenous vein.J Vasc Surg. 2019; 70: 1514-1523Abstract Full Text Full Text PDF Scopus (4) Google Scholar It is therefore conceivable that if only heparin-bonded grafts were studied, the difference in patency may have been negligible. Furthermore, according to the study, only 33% of PTFE grafts were treated with postoperative P2Y12 antagonists. Like heparin-bonding, these medications have also been shown to improve patency rates of PTFE grafts. Therefore, it is also possible that better patency could have been achieved with more widespread use of these drugs. Although PTFE bypass patients were more likely to receive anticoagulation at discharge (14% great saphenous vein vs 19% PTFE), anticoagulation per se has not been shown to improve patency of PTFE bypasses. Rather, there is evidence to suggest that anticoagulation may improve patency of vein grafts, thus also muddling the conclusions. In writing this letter, I am not supporting preferential use of heparin-bonded PTFE over saphenous vein but simply to highlight some problems with the authors' conclusions. Broad variation in prosthetic conduit use for femoral-popliteal bypass is not justified on the basis of contemporary outcomes favoring autologous great saphenous veinJournal of Vascular SurgeryVol. 70Issue 5PreviewSingle-segment great saphenous vein (GSV) has been the preferred conduit for femoral-popliteal (FP) bypass, particularly for a popliteal artery target below the knee. Yet, controversy persists surrounding whether prosthetic conduit can yield comparable outcomes to GSV for FP bypass to either the above-knee (AK) or below-knee (BK) popliteal artery. We sought to analyze national variation in conduit use and to compare contemporary outcomes in FP bypass. Full-Text PDF ReplyJournal of Vascular SurgeryVol. 71Issue 5PreviewWe would like to thank Dr Samson for his letter to the editors of the Journal of Vascular Surgery highlighting our recent work that showed broad variation in prosthetic conduit use for femoral-popliteal bypass.1 His letter illustrates why differing interpretations of varying quality data have led to such variation in practice patterns nationwide. Full-Text PDF