TCT: DES may have a role below the knee
Image source: Spectranetics

WASHINGTON, D.C.--The implantation of a polymer-free sirolimus-eluting stent (SES) (Yukon-BTX, Translumina) for infrapopliteal peripheral vascular disease results in significant improvements in primary and secondary patency, compared with bare-metal stents (BMS), based on the results of DES-BTK [below the knee] trial, a late breaking clinical trial Sept. 24 at the annual Transcatheter Cardiovascular Therapeutics (TCT) conference.

Because drug eluting stents (DES) have been proven to reduce the restenosis rate in the coronary arteries, Thomas Zeller, MD, from Herz-Zentrum Bad Krozingen in Bad Krozingen, Germany, and colleagues conducted a prospective, randomized, multicenter, double-blind trial from April 2006 to April 2008, comparing balloon-expandable Yukon-BTX SES with a placebo-coated Yukon-BTX BMS in patients with either intermittent claudication or critical limb ischemia (CLI), who had a de novo lesion up to 5 cm length in an infrapopliteal artery.

The primary endpoint was one-year primary patency rate, defined as freedom from in-stent-restenosis (50 percent or greater) detected with angiography or if appropriate with duplex ultrasound. The secondary endpoint was six-month primary patency rate; secondary patency rates; target lesion revascularization rates; changes in Rutherford-Becker classification; ankle-brachial index; and major adverse events.

The investigators enrolled 161 patients, 82 of which received the SES. In the SES arm, 14 patients died and six were lost during follow-up. In the BMS arm, 11 patients died and five were lost during follow-up. Therefore, at year of follow-up, there were 62 patients in the SES group and 63 patients in the BMS group.

Zeller reported that they used a maximum of two stents with a maximum length of 25 mm.

At one-year, the primary patency rate was 55.6 percent in the BMS group, compared with 80.6 percent in the SES group. The secondary patency rate was 71.4 percent in the BMS group, versus 91.9 percent in the in SES group.

The ankle-brachial index also showed statistically significant improved outcomes for DES at one year—0.69 versus 0.75 percent at one year. Also, the hazard ratio for restenosis for BMS compared with SES was 3.2.

Zeller noted that the study was not powered for showing any clinical differences.

The researchers assessed event-free survival free from target lesion revascularisation, major and minor amputation, MI and death by a Kaplan-Meier analysis with the use of the Mantel-Cox log-rank test. With the analysis, they saw a “slight trend“ toward better outcomes with the SES, Zeller said.

“We enrolled patients with Rutherford-Becker class two to five and about 50 percent of the patients were suffering from either claudification or CLI, which may be why the outcomes did not show superiority for the SES,” Zeller said. “In conclusion, we could prove that the SES showed superior technical outcome after one year, with a significantly better patency rate compared with the BMS.