BASKET-PROVE: DES as Safe as Bare-Metal Stents in Larger Coronary Arteries, With Less TVR

Reed Miller

November 17, 2010

November 17, 2010 (Chicago, Illinois) — The concerns about the safety of drug-eluting stents in larger-diameter vessels that were raised by the Basel Stent Cost-effectiveness Trial--Late Thrombotic Events (BASKET-LATE) trial are not confirmed by the randomized, prospective BASKET-PROVE trial [1].

A three-year retrospective analysis of the patients treated with 3.0-mm or larger diameter stents in the BASKET-LATE trial found a higher rate of late cardiac events in patients treated with first-generation drug-eluting stents (DES) than with bare-metal stents, but no difference in target vessel revascularization (TVR).

Dr Christoph Kaiser

BASKET-PROVE was designed to see whether that safety difference was real or just another misleading artifact of retrospective analysis. The results show that "in contemporaneous stenting of large coronary arteries, late safety problems with drug-eluting stents could not be confirmed, and there was even a trend in the opposite direction," Dr Christoph Kaiser (University Hospital Basel, Switzerland) explained at the American Heart Association (AHA) 2010 Scientific Sessions, where he presented the BASKET-PROVE results. The results were simultaneously published online by the New England Journal of Medicine.

The trial randomized 2314 patients needing a coronary stent 3.0 mm in diameter or larger to either a first-generation sirolimus-eluting stent (Cypher Select, Cordis), a bare-metal cobalt-chromium stent (Vision, Abbott), or a second-generation everolimus-eluting stent (Xience V, Abbott Vascular). All patients were prescribed aspirin and clopidogrel for at least one year postimplant.

The primary end point was a composite of death from cardiac causes or nonfatal MI at two years. The main secondary end points were late events (seven to 24 months) and TVR. The rates of the primary end point were statistically similar for all three groups: 2.6% for the sirolimus-eluting-stent group, 3.2% for the everolimus-eluting-stent group, and 4.8% for the bare-metal-stent group. There were no significant differences in the rates of late events or the rates of death, MI, or stent thrombosis.

However, the non-MI-related TVR rates were 3.7% for the sirolimus-eluting-stent group, 3.1% for the everolimus-eluting-stent group, and 8.9% for the bare-metal-stent group. The difference in TVR between the DES patients and bare-metal-stent patients was statistically significant (p=0.007), but the difference between the two DES groups was not.

BASKET-PROVE Trumps BASKET-LATE

Dr Marco Valgimigli

Commenting on the BASKET-PROVE results during the conference, Dr Marco Valgimigli (University of Ferrara, Italy) explained that larger vessels may be a proxy for less advanced coronary disease and are more common in younger and nondiabetic patients. Previous studies have suggested that advanced age and diabetes protect against very late thrombosis, which may explain why the original BASKET-LATE study found more late thrombosis in the larger vessels, he said. He also noted that the BASKET-LATE study has been the only study to show a safety problem with DES specifically in large vessels.

He speculated that the higher late-event rate with DES seen in BASKET-LATE may not have appeared in BASKET-PROVE because of random chance, because the implantation technique of the interventionalists was better in the later study, or because BASKET-PROVE's protocol called for one year of dual antiplatelet therapy, whereas BASKET-LATE assigned patients to only six months of antiplatelet therapy.

This study is indeed highly reassuring in that the safety issue that was noted in BASKET-LATE has not been confirmed here.

He pointed out that the BASKET-PROVE trial was powered to prove or disprove the hypothesis that the cardiac death/MI rates would be 6% in the bare-metal stent group and 10.5% in the DES groups. Because the actual rates were much lower than that, especially in the DES patients, the study is "technically underpowered." Therefore, the results cannot rule out the possibility that there is a difference in the safety of DES and bare-metal stents in large vessels that is too small for this trial to detect.

Valgimigli said, however, "Based on the results, this study is indeed highly reassuring in that the safety issue that was noted in BASKET-LATE has not been confirmed here."

Commenting on the study, interventionalist Dr David Holmes (Mayo Clinic, Rochester, MN) said that BASKET-PROVE "answers the question" of whether DES are less safe than bare-metal stents in larger vessels. And, because target vessel revascularization with DES was about half that of bare-metal stents in the trial, it is evidence "against those who say that in larger vessels, you don't need drug-eluting stents because TVR is so rare anyway."

Kaiser reports consulting arrangements with Eli Lilly and Astra Zenec and is on the speakers' bureau for Biotronik, Abbott Vascular, Eli Lilly, and Daiichi-Sankyo. BASKET-PROVE coauthor Dr Matthias Pfisterer (University of Basel, Switzerland) reports consulting arrangements with Hoffmann La Roche, Pfizer, and Eli Lilly and is on the speakers' bureau for Sanofi-Aventis and Medtronic.

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