Drug-eluting stents, bare-metal stents have similar rates of death, nonfatal spontaneous MI at 6 years

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Millions of patients each year undergoing PCI are implanted with drug-eluting or bare-metal stents. Comparisons between the types of stents have been limited, although a recent randomized study in Norway showed similar outcomes between the two categories.

After six years of follow-up, patients undergoing PCI had similar rates of the primary composite outcome of death from any cause and nonfatal spontaneous MI whether they received drug-eluting stents or contemporary bare-metal stents.

Lead researcher Kaare H. Bønaa, MD, PhD, of St. Olav’s University Hospital in Trondheim, Norway, and colleagues published their results online in the New England Journal of Medicine on Aug. 30.

The findings were also presented at the European Society of Cardiology (ESC) Congress in Rome.

Bønaa said in a news release that the efficacy of drug-eluting stents versus contemporary bare-metal stents was lower than expected.

“Although ESC guidelines recommend new [drug-eluting stents] over [bare metal stents] as default for coronary revascularization, this recommendation may need to be modified in light of the NorStent findings,” he said. “Both stent types may be recommended.”

In the NorStent (Norwegian Coronary Stent Trial) study, the researchers enrolled 9,013 patients undergoing PCI in Norway between Sept. 15, 2008, and Feb. 14, 2011. Patients were randomly assigned in a 1:1 ratio to receive drug-eluting stents or bare-metal stents after diagnostic angiography and before PCI.

Patients in the bare-metal stent group underwent placement of contemporary devices with thin struts. Among patients receiving drug-eluting stents, 82.9 percent received everolimus-eluting stents and 13.1 percent received zotarolimus-eluting stents.

Six years after patients underwent PCI, 16.6 percent of the drug-eluting stent group and 17.1 percent of the bare-metal stent group had the primary composite outcome of death from any cause and nonfatal spontaneous MI.

The groups had similar rates of the primary composite outcome even after adjusting for baseline imbalances in smoking status, hypertension, history of MI, target-lesion type and total stent length. The results remained consistent in all subgroups, as well.

After six years, the cumulative rate of spontaneous MI was 11.4 percent in the drug-eluting stent group and 12.5 percent in the bare-metal stent group, while the rate of any revascularization was 16.5 percent and 19.8 percent, respectively.

The absolute revascularization risk reduction of 3.3 percentage points was statistically significant in favor of the drug-eluting stent group.

“On the basis of this result, 30 patients would need to be treated with drug-eluting stents rather than bare-metal stents to prevent one repeat revascularization,” the researchers wrote. “The difference in any revascularization between groups was driven by lower rates of target-lesion revascularization in the group receiving drug-eluting stents.”

Further, at six years, the rates of definite stent thrombosis were 0.8 percent in the drug-eluting stent group and 1.2 percent in the bare-metal stent group, while the rates of major bleeding were 5.5 percent and 5.6 percent, respectively. The researchers also mentioned that the groups had similar disease-specific health status and quality of life measures.

The study had several limitations, according to the researchers, including its open-label design. In addition, the FDA has approved a few stents since patients were recruited from 2008 through 2011. However, the researchers noted that 95 percent of patients received everolimus-eluting or zotarolimus-eluting stents, which physicians still use. Further, they noted that the primary outcomes did not include periprocedural MI and that the Seattle Angina Questionnaire that they used might not be sensitive enough to evaluate the stents’ performance.