Investigators testing various coatings discussed their research at a press conference on Sunday. Researchers from France and Brazil presented positive data from their clinical studies using sirolimus-eluting stents. But a trial from Germany showed negative results with heparin-coated stents.

The heparin-coated stent trial was described by Michael Haude, MD, Med Klinik II, University of Essen, Essen, Germany. In the trial, 600 patients with recurrent small-vessel disease were randomized to receive PTCA, an uncoated JOSTENT Flex stent, or the same stent with a heparin coating.

Median lumen diameters at six months were almost identical, at 1.34 mm for PTCA, 1.47 mm for the uncoated stent, and 1.45 mm for the coated stent. There were no deaths in the PTCA group but two each in the stent trial arms. And there was one thrombotic event each in the stent arms versus none in the PTCA arm.

“We conclude that the heparin-coated stent does not provide any angiographic or clinically-related benefit in small native coronary arteries,” Dr. Haude said.

More promising data come from two studies using stents coated with the naturally-occurring antibiotic sirolimus.

Jean Fajadet, MD, Clinique Pasteur, Toulouse, France, reported on the 210-day followup of the RAVEL study, which found no late loss and no restenosis in the 120 patients randomized to receive a sirolimus-eluting Bx Velocity balloon-expandable stent. This compares very favorably with an average late loss of 0.8 mm and restenosis rate of 26 percent among the 118 controls who received the uncoated stent.

Dr. Fajadet said especially impressive was that patients with diabetes who were treated with the coated stent also had no late loss or restenosis compared with a late loss of 0.82 mm and restenosis rate of 42 percent for the controls.

And survival at one year was 94 percent with the sirolimus stent versus 71 percent for the controls.

“Use of the sirolimus stent is safe and there were no deaths related to its use,” Dr. Fajadet said.

Results from another sirolimus-coated stent trial were similarly encouraging. Jose Eduardo Sousa, MD, Institute Dante Pazzanese of Cardiology, Sao Paulo, Brazil, said the two-year followup of implantation with the sirolimus-eluting stent showed no mortality and no restenosis in the stent.

“At two years followup, the sirolimus-eluting stent continues to be a major breakthrough in the fight against restenosis,” Dr. Sousa said.

He presented data on 45 patients followed by serial angiography and ultrasound examination on multiple occasions during the two-year followup.

The percent of arterial blockage before treatment was 61 percent, Dr. Sousa said. Immediately post procedure it was 4.2 percent, and 1.4 percent at two-year followup.

“These angiographic results were confirmed by intravascular ultrasound that demonstrated minimal scar-tissue growth in the stent,” Dr. Sousa said. “The clinical benefits observed after placement of the sirolimus stent appear durable at late followup.”