Invited commentary

Abstract

The strengths of this multicenter prospective trial comparing bare nitinol stents to polytetrafluoroethylene stent grafts for TransAtlantic Inter-Society Consensus 1 C and D superficial femoral artery lesions include an uncommon effort to standardize methodology and an uncommon glimpse at 3-year outcomes. The investigators are to be commended for attempting to drive a guidepost into the riverbed and refusing to go with the flow, simply assuming that any decent study will be outdated by intercurrent innovations such as drug-eluting stents and heparin-bonded stent grafts. The study tests the reasonable hypothesis that covered stents would eliminate in-stent restenosis, a chief cause of nitinol stent failure. Though the patency comparisons at 3 years suffer from some attrition of patients with cautionary wobble in the Kaplan-Meier curves, there was no apparent patency advantage to stent grafts. The reader remains intrigued by the lack of details regarding the ultrasound and angiographic lesions responsible for device failure, which given the surveillance protocol and high rate of reintervention, must have been available to allow distinction between intimal hyperplasia at the stent margins or within the stents and progression of disease in untreated adjacent arterial segments. Among patients followed for 36 months, the stent fracture rate was 50% for nitinol stents and only 2% for stent grafts. Acknowledging that the impact of stent fracture is controversial, if one assumes a negative impact of fracture on nitinol stent patency and a positive impact of less in-stent restenosis on stent graft patency, we might have expected an unequivocal patency advantage for stent grafts rather than the somewhat disappointing equivalency between the two groups. If indeed nitinol stents and stent grafts do have similar efficacy, device cost would assume more importance in the current penny-pinching era. Comparison of trial results with surgical bypass is invalidated by randomization of patients only after lesions had been crossed by a guidewire. Nonetheless, optimal results at 3 years were attained only after one or more reinterventions in 40% of patients, a much higher rate than might be expected in a series of superficial femoral artery bypasses. Again, costs need consideration. The study employed somewhat confusing patency definitions unfamiliar to most surgeons accustomed to tracking bypass grafts. Development of standards for reporting has been one of the signal contributions to vascular surgery over the years, and we must extend this effort to the endovascular arena, including our colleagues in related subspecialties. Only by adopting uniform research methodology can we build fruitfully on earnest efforts such as those of the VIBRANT trial team. Three-year results of the VIBRANT trial of VIABAHN endoprosthesis versus bare nitinol stent implantation for complex superficial femoral artery occlusive diseaseJournal of Vascular SurgeryVol. 58Issue 2PreviewThe predominant mode of bare nitinol stent failure is diffuse in-stent restenosis, and failure rates correlate to the length and complexity of the treated lesion. Addition of an expanded polytetrafluoroethylene lining to a nitinol stent frame, as found in the VIABAHN endoprosthesis, mitigates the ingrowth of intimal hyperplasia. We compared the long-term outcomes of complex superficial femoral artery disease intervention using the VIABAHN endoprosthesis to those obtained with bare nitinol stent implantation. Full-Text PDF Open Archive