The 24-month data from the Viabahn BX Flex balloon-expandable stent (Gore) investigational device exemption (IDE) trial are “promising” with sustained clinical and patency benefits and a favourable safety profile consistent with the previously published nine-month outcomes.
These results were presented at the Leipzig Interventional Course (LINC; 30 January–2 February, Leipzig, Germany) by Christopher Metzger (Wellmont CVA Heart & Vascular Institute, Kingsport, USA).
Metzger noted that it is known that balloon-expandable covered stents are superior to non-covered balloon-expandable stents for TASC C and D lesions and allow operators to confidently treat lesions such as aneurysmal/ectatic disease and perforations. That being said, the earlier generation balloon-expandable stents had limitations in that they had relatively small size matrix in terms of both length and diameter, tended to foreshorten and were more rigid.
In response, the Viabahn BX stent has the potential advantages of a much larger size matrix, is conformable and flexible and can be inflated larger with less foreshortening.
The Viabahn BX Flex IDE trial was designed to evaluate the safety and efficacy of the Viabahn BX for the treatment of arterial occlusive disease in patients with de novo or restenotic lesions in the common and/or external iliac arteries. The prospective, multicentre, single-arm study enrolled 134 patients at 27 sites. The primary endpoint was composite of major adverse events at nine months and patients will be followed through three years.
Metzger explained that while this trial primarily enrolled patients with severe claudication, it should also be noted that the patients enrolled were particular complex, one third with TASC C and D classification.
“The results at nine months showed a very high technical and procedural success rate. One hundred per cent of the devices were successfully delivered and there was £30% residual stenosis, and there was a 97% procedural success rate with four procedural-related serious adverse events that were successfully resolved. There were no major events,” he reported.
At 12-month follow-up the patients did well clinically with a sustained improvement in the Rutherford Becker score and a sustained improvement in the ankle brachial index. Primary patency of 97% was also sustained.
The 24-month data are under review for publication and Metzger therefore could not give the full picture, but he did present the results from his own centre—which was the highest enrolling site in the USA with 20 patients—and indicated the overall strong trends of the 24-month data.
“A quarter of our patients were TASC C and D. At two-years there was a 100% freedom from target lesion revascularisation. The ankle brachial index at two years was 0.99, and all but one patient had sustained improvement in the Rutherford scale and one other was maintained. All patients had improvements in walking scores,” he reported.
Overall, he added, patients had sustained clinical benefit at two years and well over 90% maintained their improvement of at least 1 in the Rutherford Becker scale. Patients also had a sustained ankle brachial index response well above 0.9. Further, he reported an extremely low device-related major adverse event rate, and no amputations.
“The 24-month results are overall consistent with the results seen at nine months,” he indicated.