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Drug Eluting Stents for Primary PCI in STEMI

Is it time to endorse explicitly an already-widespread practice in the U.S.?

Most early drug-eluting stent (DES) trials did not include patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment–elevation MI (STEMI). The exclusions were, in part, because these patients tend to have lower restenosis rates than other patient groups and because of perceptions that the coated stents pose a slightly greater thrombosis risk than uncoated stents. Now, we have data from two DES trials that focus specifically on primary PCI in STEMI patients.

In a trial funded by the manufacturer of the FDA-approved sirolimus-eluting stent, 712 STEMI patients (16% diabetic) with symptom onset less than 12 hours before catheterization were randomized to receive that stent or an uncoated stent. Both groups had a mean reference-vessel diameter of about 2.8 mm. Incidence of the primary composite endpoint — target-vessel revascularization (TVR), reinfarction, or death at 1 year — was significantly lower with the coated stent than with the uncoated stent (7.3% vs. 14.3%), due almost entirely to fewer TVRs (5.6% vs. 13.4%). The two groups had similar rates of death (2.3% and 2.2%), reinfarction (1.1% and 1.4%), and any stent thrombosis (3.4% and 3.6%). According to a 170-patient angiographic substudy at month 8, the sirolimus-eluting stent had clear advantages over the uncoated stent in mean in-stent late luminal loss (0.14 mm vs. 0.83 mm) and the incidence of in-stent restenosis (3.5% vs. 20.3%).

In a trial funded by the manufacturer of the FDA-approved paclitaxel-eluting stent, 619 STEMI patients (11% diabetic) with symptom onset less than 6 hours before catheterization were randomized to receive that stent or an uncoated stent. Both groups had a mean reference-vessel diameter of about 3.2 mm. Incidence of the primary endpoint — target-lesion revascularization, reinfarction requiring hospitalization, or death from cardiac causes at 1 year — was lower with the coated stent (8.8% vs. 12.8%), but not significantly so. Target-lesion revascularization rates were 5.3% and 7.8%, respectively. The stent-thrombosis rate was 1% in both groups.

Comment: Together, these trials document positive results with drug-eluting stents in primary PCI. Various factors unrelated to the stents themselves could explain the differences in outcomes between the studies: (1) a smaller percentage of diabetes patients and larger reference-vessel diameters in the paclitaxel-stent trial; (2) later administration of clopidogrel and a less conservative definition of stent thrombosis in the sirolimus-stent trial, possibly contributing to a higher rate of such thromboses; (3) use of only one type of uncoated stent in the paclitaxel-stent trial (vs. use of any commercially available uncoated stent in the sirolimus-stent trial), possibly limiting repeat revascularization in the paclitaxel trial’s uncoated-stent arm; (4) routine noninvasive testing for all subjects in the sirolimus-stent trial and angiography conducted in a subgroup at 8 months, possibly leading to more repeat revascularizations (although still a lower rate than in the paclitaxel trial).

These particulars notwithstanding, the data show that drug-eluting stents benefit STEMI patients by reducing restenosis and the need for subsequent interventions, apparently without increasing the risks for stent thrombosis or death, relative to those from uncoated stents. Although the editorialist cautions against routine DES use for primary PCI, the new data provide justification for this already widespread practice in the U.S.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology September 13, 2006

Citation(s):

Spaulding C et al. Sirolimus-eluting versus uncoated stents in acute myocardial infarction. N Engl J Med 2006 Sep 14; 355:1093-104.

• Original article (Subscription may be required)
• Medline abstract (Free)

Laarman GJ et al. Paclitaxel-eluting versus uncoated stents in primary percutaneous coronary intervention. N Engl J Med 2006 Sep 14; 355:1105-13.

• Original article (Subscription may be required)
• Medline abstract (Free)

Van de Werf F. Drug-eluting stents in acute myocardial infarction. N Engl J Med 2006 Sep 14; 355:1169-70.

• Original article (Subscription may be required)
• Medline abstract (Free)