Nitinol stent performs better than balloon angioplasty alone in treating lesions of the popliteal artery


Results from the ETAP trial, presented by Thomas Zeller, professor of Clinic Cardiology and Angiology and chief of the Department of Angiology at Universitäts-Herzzentrum Freiburg Bad Krozingen, Germany, at the TCT congress, have found that a nitinol stent performed better than balloon angioplasty alone in treating blockages in the popliteal artery.

Due to its location behind the mobile knee joint, it is controversial whether to implant a stent in the popliteal artery for all cases or only for cases in which balloon angioplasty alone results in a suboptimal result. In this study, investigators conducted a prospective, randomised, multicentre trial comparing primary nitinol stent placement to angioplasty alone in patients who had a single, de-novo obstructive lesion in the popliteal artery.

“Results from this trial indicate that treatment of popliteal artery obstructive lesions with a nitinol self-expanding stent is safe. Additionally, one-year primary patency and target lesion revascularisation rates (including acute angioplasty failures) were substantially better with the nitinol stent than with balloon angioplasty,” said Zeller, who is the lead investigator of the study.

A total of 246 patients from nine centres in Europe were included in this trial. Patients were randomly assigned to either a self-expanding nitinol stent (N=119) or a standard balloon angioplasty procedure (N=127). The primary study endpoint was one-year duplex ultrasound-derived primary patency, defined as freedom from target lesion restenosis without further intervention. Secondary endpoints included target lesion revascularisation, secondary patency, changes in Rutherford categories from baseline, and limb salvage rates. X-rays were taken at one year and examined for stent fractures.

The mean lesion length for the percutaneous transluminal angioplasty (PTA) group was 43.2mm compared to 41.3mm for the stent group. Six patients (2.4%) died during the follow up period. The one-year primary patency rate was significantly higher in the nitinol-stent group (67.4%) than in the balloon angioplasty group (44.9%, P<0.05). Post procedure target lesion revascularisation rates were 15.4% for the stent group and 21.4% for the optimal angioplasty group (P=0.29). No significant differences between the treatment groups could be observed concerning secondary patency, limb salvage rates, and the clinical course by Rutherford categories. Two stent fractures were reported at one year.

Patients in the stent group also reported more improved walking distances at one year than the angioplasty group.

The trial was supported by an unrestricted study grant by CR Bard.