In a late-breaking trials session at VIVA, Richard Saxon, San Diego Cardiac and Vascular Institute, North County Radiology Medical Group in Oceanside, USA, principal investigator of the VIPER study, discussed the one-year results from the trial.
The study evaluated the performance of the new Viabahn with heparin bioactive surface in treating long-segment superficial femoral artery lesions (>5cm in length). The single-arm, prospective study enrolled 119 patients at 12 sites.
Saxon said that the heparin surface may theoretically improve patency by decreasing all modes of stent graft failure, especially occlusion/edge stenosis in small vessels and devices. “In our experience, over two out of three of edge stenoses are at the proximal as opposed to the distal edge of the device. The contoured edge should improve wall apposition and decrease in-folding of the graft material proximally.”
The primary endpoints in VIPER were primary patency at one year and 30-day procedure-related major adverse events.
There was one event (0.8%) leading to a surgical bypass after target lesion occlusion, but the device was markedly oversized in this case. At 12 months, duplex follow-up for 103 patients showed primary patency of 74%, assisted patency of 87% and secondary patency of 92%. The average lesion length was 19cm.
Saxon told delegates that the VIPER results support the conclusion that the Viabahn device with contoured edge and heparin bioactive surface exhibits improved patency in superficial femoral artery lesions relative to the previous device. He added that patency is independent of lesion length, with >20cm lesions showing similar patency to lesions 5–20cm. Importantly, when the instructions for use are followed, primary patency is remarkably high (>85%). He also noted that the 5mm device patency is equivalent to other sizes. “The results with the 5mm device are substantially improved with the heparin coating compared to previous results.”
“There are multiple options for superficial femoral artery intervention. If we treat the correct subset of patients with this newer stent graft, patency will be excellent, and re-interventions will be low. This is an excellent technique for long lesions, but we need adequate landing zones. We do need to measure, using quantitative angiography or intravascular ultrasould. Your ‘eyeball’ is just not good enough.”
He told Vascular News: “I believe the 12-month results of VIPER as well as the results of many of the other trials presented recently give the interventionalist a lot more information on how to achieve better, more durable results in the superficial femoral artery. It is now incumbent on us as physicians to take the time to develop an understanding of how to best treat different subsets of patients differently. It is no longer a ‘dealer’s choice’ situation in which there is no data, so you can argue for whatever technique you feel like using on a given day. Now we have to take the time to analyse the patient’s anatomy carefully and treat the patient based on the data available.”
In order to improve the clinical results with endovascular approach in the superficial femoral artery, physicians must follow the instruction for use, Saxon said.
“If one uses quantitative means to size a vessel such as intravascular ultrasound or quantitative angiography and is careful to not oversize the endoprosthesis too much (<20% according to the instruction for use, I think ideally <10%) then, according to VIPER, one gets results that are over 20% better than if you do not follow these guidelines. The 5mm diameter results were far better than before, so people should no longer try to put 6mm devices in vessels <5mm in diameter, as their results will be worse. The industry can spend a lot of money to improve their devices enough to get 20% better patency at a year, all we interventionalists need to do is to be more rigorous about our technique. I think that is the key challenge now. We need to educate everyone on these results and more rigorously tailor our approach to the superficial femoral artery based on the anatomy we are treating.”