乌鸦传媒

The sirolimus-eluting coronary stent (Cypher) reduced the need for target-vessel revascularization (TVR) by 50% compared with its bare-metal counterpart, according to five-year follow-up data from four large, randomized clinical trials.

Pooled data from the studies showed no difference in morbidity or mortality between patients treated with the two types of stents, investigators reported online in the Journal of the American College of Cardiology.

Moreover, the rate of stent thrombosis was virtually identical in the two patient populations, Roxana Mehran, MD, of the Cardiovascular Research Foundation in New York, and co-authors wrote.

"The highly significant differences in rates of target-lesion revascularization [TLR] and TVR between patients randomized to sirolimus-eluting stents versus bare-metal stents persisted from one to five years," the authors reported. "Thus, it is unlikely that the use of sirolimus-eluting stents is associated with a late catch-up phenomenon."

Dramatic reductions in rates of restenosis and TLR in clinical trials led to led to rapid growth in the use of sirolimus-eluting stents following FDA approval.

However, a theoretical risk of thrombogenicity and delayed arterial healing with drug-eluting stents raised concern that the devices might be associated with an increased risk of late stent thrombosis, the authors noted.

Four-year outcomes from a pooled analysis of four large trials showed no increased risks associated with sirolimus-eluting versus bare-metal stents (N Engl J Med 2007; 356: 989-97). The current analysis represented continued follow-up to five years, as required by the FDA.

The four trials involved a combined total of 1,748 patients at 115 centers worldwide. Five-year follow-up was 87% complete, and all patients included in the five-year analysis had been followed for at least 1,800 days.

At five years, the two patient groups did not differ significantly in all-cause mortality, cardiac death, and incidence of myocardial infarction (MI). The composite endpoint of death or MI was similar between the two groups at five years and from years one to five.

The frequency of TLR and TVR was significantly lower among patients who received sirolimus-eluting stents.

• TLR, 9.6% versus 24.7% (HR 0.34, P<0.0001)
• TVR 15.2% versus 30.1% (HR 0.44, P<0.0001)

The two groups did not differ significantly with respect to the total incidence of stent thrombosis (4.6% for sirolimus-eluting stents, 4.4% for bare-metal stents), very late definite stent thrombosis (1.1% versus 0.5%, P=0.16), or very late definite/probable stent thrombosis (1.4% versus 0.7%, P=0.22).

Late definite/probable stent thrombosis occurred less often with the sirolimus-eluting stent during the first year of follow-up (0.2% versus 0.9%, P=0.05).

From year one to year five, the annual rate of definite/probable stent thrombosis was 0.4% with the sirolimus-eluting stent and 0.2% with the bare-metal stent, which was not a statistically significant difference, the authors wrote.

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