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Drug-Eluting Stents vs. Bare-Metal Stents: The Ontario Experience

Two-year results from a population-based, propensity-matched cohort study suggest that DES are more effective than BMS.

Amid the controversy surrounding the benefits and long-term risks of drug-eluting stents (DES), many groups are reporting their experience with these devices. In this well-designed study, investigators examined data from a prospective clinical registry of all invasive cardiac procedures performed in Ontario during a 16-month period, with essentially complete follow-up. Propensity analysis was used to identify 3751 pairs of DES and bare-metal stent (BMS) recipients matched for 21 factors predictive of target-vessel revascularization (TVR), MI, or death. All patients received clopidogrel for at least 1 year.

Overall, 38% of implanted stents were DES; 83% of which were paclitaxel-eluting. DES recipients were less likely to present with acute MI and had smaller mean vessel diameters and longer mean lesion length than BMS recipients. In the propensity-matched cohort, TVR was less frequent during 2-year follow-up in DES recipients (7.4%) than in BMS recipients (10.7%, P<0.001). The greatest reductions in TVR were found in patients with diabetes, vessel diameter <3 mm, or long (>20 mm) lesions; in patients with all three of these risk factors, the TVR rate was 7.2% with DES, compared with 17.6% with BMS. There was no significant between-group difference in MI rates at 2 years of follow-up, but by 3 years, mortality was slightly higher in the BMS recipients (7.8%) than in the DES recipients (5.5%, P<0.001).

Comment: In this analysis of a large, population-based database, drug-eluting stents were more effective than bare-metal stents at reducing target-vessel revascularization rates — particularly in cases involving long lesions or small vessels — and were not associated with an increase in risk for MI or death. This study population is covered by a system that provides drug benefits to all citizens; thus, the results may not be entirely generalizable to systems in which patient adherence to treatment can be affected by cost. Nonetheless, these findings add weight to randomized trial data documenting the benefits of DES and provide some reassurance of the devices’ safety when used in patients at high risk for restenosis.

— Howard C. Herrmann, MD

Published in Journal Watch Cardiology October 3, 2007

Citation(s):

Tu JV et al. Effectiveness and safety of drug-eluting stents in Ontario. N Engl J Med 2007 Oct 4; 357:1393.

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