Stents commonly are placed during percutaneous coronary procedures to maintain patency of vessels, but angiography rates six months after placement indicate that 15 to 40 percent of vessels are restenosed. Initial studies of stents coated with antimitotic drugs indicated that drug-eluting stents had lower rates of restenosis than conventional bare-metal stents, but the long-term safety and efficacy of drug-eluting stents are unknown. Babapulle and colleagues conducted a meta-analysis of randomized clinical trials to determine rates of restenosis and clinically relevant outcomes in placement of drug-eluting stents.
The initial search of electronic databases identified 1,137 potentially relevant papers. A refined search focusing on specific drugs and requiring six to 12 months of clinical follow-up after stenting resulted in 15 randomized controlled trials involving 5,835 patients. Two trials ended prematurely because of adverse effects. The final study analyzed outcomes of trials examining stents eluting sirolimus or paclitaxel. These studies were analyzed for the impact of stent placement on overall mortality, rates of myocardial infarction, major adverse cardiac events, and revascularization procedures.
Participants were predominantly men (67 to 94 percent) and the mean ages were between 56 and 66 years. Rates of follow-up angiography were 43 to 97 percent. Studies varied by type of antiplatelet therapy used and in inclusion and exclusion criteria. Overall, study participants had a low risk of restenosis.
The overall mortality rate and incidence of myocardial infarction were low and equal in patients treated with drug-eluting and bare-metal stent procedures (see accompanying table). However, rates of revascularization procedures and major adverse cardiac events were substantially lower in patients treated with drug-eluting stents than in those receiving bare-metal stents.
|Event||Drug-eluting stent (%)||Bare-metal stent (%)|
|Major cardiac event||7.8||16.4|
|Restenosis (on angiography)||8.9||29.3|
The authors conclude that despite the variations among studies, stents that elute antimitotic drugs appear to reduce the rates of restenosis and major adverse cardiac events compared with bare-metal stents. These advantages do not appear to translate into gains in overall mortality or reduction in myocardial infarction rates in the short term, but the effects of drug-eluting stents on restenosis and repeat revascularization have been well received by the cardiovascular subspecialists.