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Late stent thrombosis occurred more frequently in DES group
At more than six months, nonfatal MI, cardiac death were higher with drug-eluting stents than bare-metal.
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ATLANTA — New strategies are needed to prevent late thrombotic events in patients receiving drug-eluting stents, said Matthias E. Pfisterer, MD, University Hospital, Basel, Switzerland.
Pfisterer presented data from BASKET-Late (BASKET: Basel Stent Kosten Effektivitats) trial at the American College of Cardiology Scientific Session 2006.
Observational data have caused concern that delayed endothelialization after DES implantation may lead to late stent thrombosis and related death and MI. Currently, dual antiplatelet therapy may be recommended for one month after bare-metal stents, three months after implantation of a sirolimus-eluting stent, and six months after a paclitaxel-eluting stent.
The goal of BASKET-Late was to define the incidence of late clinical events related to stent thrombosis in a DES group vs. a bare-metal stent group after discontinuation of clopidogrel (Plavix, Sanofi-Aventis/Bristol-Myers Squibb).
A series of 746 consecutive patients were treated in BASKET-Late with percutaneous coronary interventions and stenting. About two-thirds of these patients, mean age 63 and 79% men, had multivessel disease. Patients who survived the first six months post-procedure without major adverse coronary events were included.
Patients were followed for an additional year and evaluated for cardiac death or nonfatal MI and clinically driven restenosis-related target vessel revascularization. All patients received dual antiplatelet therapy aspirin and clopidogrel for six months, irrespective of stent type. Angiography, Pfisterer said, was not conducted in the absence of symptoms of ischemia after discontinuing clopidogrel.
For the primary endpoint of cardiac death and nonfatal MI at more than six months, rates of 1.3% and 4.9% were reported in patients with bare-metal stents and patients with DES, respectively (P=.01). The rate of major adverse coronary events was 7.9% for bare-metal stents and 9.3% for DES (P=.53). Angiographically documented thrombosis, thrombosis-related clinical events, and all thrombosis-related events were not statistically higher for DES than bare-metal stents.
Multivariate analysis showed prior MI, the need for GPIIb/IIIa inhibitor use, and DES use to be independent predictors of late cardiac death or nonfatal MI. Trends for the need for restenosis-related target vessel revascularization favored DES (6.7% vs. 4.5%, P=.21) in months seven to 18, and significantly favored DES for months one through 18 (P=.02).
Pfisterer concluded that after clopido-grel discontinuation, late stent thrombosis-related events were two- to threefold more frequent after DES than after bare-metal stents and carried a fourfold higher risk of cardiac death or MI vs. nonthrombosis-related events. Also, these events occurred up to 362 days after clopidogrel discontinuation.
Prolonged dual antiplatelet therapy might be a better strategy with DES, although there is no proof for effectiveness of such a strategy and no direct relationship between stopping clopidogrel and thrombotic events.
Late thrombotic events might be prevented, he said, by bioabsorbable stents, stents promoting endothelialization or stents with other drug coatings. – by Walter Alexander
For more information:
- Pfisterer, ME. Late clinical events related to late stent thrombosis after stopping clopidogrel: prospective randomized comparison between drug-eluting versus bare-metal stenting. Presented at the American College of Cardiology Scientific Session 2006. March 11-14, 2006. Atlanta.