Medicare data supports benefit of DES over BMS

25 June 2008

Medwire News: The widespread adoption of drug-eluting stents (DES) has led to a decline in repeat revascularizations with no increase in mortality or myocardial infarction (MI), an observational study of US Medicare patients reveals.

David Malenka (Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA) and team compared outcomes of patients undergoing non-emergency coronary stenting before and after the introduction of DES.

Uncertainty remains over the trade-off between safety and effectiveness of DES, since trials have suggested they are associated with increased risks for both early and late stent thrombosis - in turn associated with a high risk for MI and death.

Most previous studies have focused on comparing outcomes between patients receiving DES and those receiving bare-metal stents (BMS), the researchers explain.

However, they point out: "Another important aspect on the safety and effectiveness of DES could be obtained by assessing how the rapid adoption of DES use affected the health of the entire stented population."

The researchers observed outcomes of 38,917 Medicare beneficiaries undergoing percutaneous coronary intervention (PCI) with stenting from October 2002 to March 2003, when only bare-metal stents (BMS) were available. They then compared these with outcomes of 28,086 patients undergoing the procedure from September to December 2003, after the introduction of DES, by which time already 61.5% of patients had received the newer form of stent, while 38.5% had received BMS.

Relative to patients treated in the earlier BMS era, patients treated in the DES era had significantly lower 2-year risks for repeat PCI (17.1% vs 20.0%, p<0.001) and coronary artery bypass graft (CABG) surgery (2.7% vs 4.2%, p<0.01).

These differences remained significant after adjustment for risk factors, the team notes in the Journal of the American Medical Association.

There was no significant difference in crude mortality rates between DES and BMS eras, at 8.4% in both groups at 2 years.

The crude risk for ST-elevation MI (STEMI) was significantly lower in the DES versus BMS era cohort, although the absolute difference was small at 2 years (2.0% vs 2.4%, p=0.02). And the adjusted relative risk for the combined endpoint of death or STEMI at 2 years was not significantly lower for the DES versus BMS era, at a hazard ratio of 0.96.

The researchers comment: "Although other data may suggest some incremental risk of stent thrombosis with the use of DES, we can detect no adverse consequence to the health of the population."

They conclude: "We speculate that whatever the increased risk of stent thrombosis associated with DES use is, it is more than offset by a decrease in the risk of developing restenosis and the attendant risk of a procedure to treat that restenosis."

JAMA 2008; 299: 2868-2876