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Drug-eluting stents decrease mortality, reduce repeat revascularization rates in acute MI compared with bare-metal stents, retrospective study suggests

Monday, October 13 2008 | Comments

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What's This? Patients with acute myocardial infarction (MI) treated with drug-eluting stents have better 2-year survival and require fewer repeat revascularization procedures when compared with a matched cohort of patients treated with bare-metal stents, according to the results of a multicenter, retrospective review.

For the study, which was funded by the Massachusetts Department of Public Health, researchers reviewed percutaneous coronary intervention (PCI) data contained in the Massachusetts Data Analysis Center database. They identified 7,217 state residents aged >=18 years who presented between April 1, 2003, and September 30, 2004, with acute MI and were treated with PCI and stent placement. MI with ST-segment elevation (STEMI) was present in 3,379 patients and MI without ST-segment elevation (NSTEMI) occurred in 3,838 patients.

Of the total, 4,016 received drug-eluting stents and 3,201 were given bare-metal stents. Of those treated with drug-eluting stents, 71% received sirolimus-eluting stents only, 27% received paclitaxel-eluting stents only, and 2% received both.

Before the subjects were matched based on propensity scores, researchers found that patients with diabetes mellitus, hyperlipidemia, hypertension, or NSTEMI were more likely to be given drug-eluting stents than bare-metal stents, as were patients with multi-vessel disease and multiple lesions. In contrast, patients presenting with cardiogenic shock were more likely to be given bare-metal stents, as were those being treated emergently and those with high-risk lesions.

Two-year data indicated that the unadjusted rates of death, MI, and repeat revascularization were lower in patients with drug-eluting stents. In addition, regardless of the stent type, patients with STEMI had lower rates of death and MI as compared with patients with NSTEMI, but there was no difference in repeat revascularization rates between these 2 groups.

After propensity-score matching, patients with drug-eluting stents had significantly lower rates of death at 2 years as compared with those with bare-metal stents in the matched cohort of patients with any MI (10.7% vs 12.8%; P=.02). The difference remained significant in patients with STEMI (8.5% vs 11.6%; P=.008), as well as in those patients with NSTEMI (12.8% vs 15.6%; P=.04).

After matching, no significant differences were seen in the 2 stent groups in the rate of reinfarction after 2 years (8.8% drug-eluting vs 10.2% bare-metal; P=.09), with the exception of patients with NSTEMI (10.3% vs 13.3%; P=.02).

Patients with any MI and drug-eluting stents had significantly lower rates of repeat target-vessel revascularization at 2 years (9.6% vs 14.5%; P<.001). Similar reductions were seen in both MI subtypes.

Risk-adjusted mortality for all MIs 2 days after stent placement was 0.7% for the cohort with drug-eluting stents versus 1.2% for the cohort with bare-metal stents (risk difference, -0.5%; 95% CI, -1.0% to 0.0%; P=.06). Respective risk differences were statistically significant in the segment of patients with STEMI (risk difference, -0.9%; P=.04), but not in the segment with NSTEMI (risk difference, -0.3%; P=.32).

When the data were adjusted to consider the length of time after introduction of drug-eluting stents, the results showed that event rates in the group receiving drug-eluting stents were either similar to or lower than those in the group receiving bare-metal stents. The risk differences for death after STEMI were consistent with the primary findings when the data were analyzed to exclude patients treated at hospitals with no on-site cardiac surgery facilities or who presented more than 24 hours after the onset of MI symptoms.

The researchers called for large, randomized trials with long-term follow-up to confirm their findings. (Mauri L, et al. NEJM 2008; 359:1330-1342.)

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