Tuesday, July 31, 2007

The EVASTENT Matched-Cohort Registry

Risk Factors for Stent Thrombosis After Implantation of Sirolimus-Eluting Stents in Diabetic and Nondiabetic Patients

The EVASTENT Matched-Cohort Registry

Objectives: We sought to assess the frequency and causes of stent thrombosis in diabetic and nondiabetic patients after implantation of sirolimus-eluting stents.

Background: Safety concerns about late stent thrombosis have been raised, particularly when drug-eluting stents are used in less highly selected patients than in randomized trials.

Methods: The EVASTENT study is a matched multicenter cohort registry of 1,731 patients undergoing revascularization exclusively with sirolimus stents; for each diabetic patient included (stratified as single- or multiple-vessel disease), a nondiabetic patient was subsequently included. Patients were treated with aspirin + clopidogrel for at least 3 months and were followed for 465 (range 0 to 1,062) days (1-year follow-up in 98.5%). The primary end point was a composite of stent thrombosis (according to Academic Research Consortium definitions), cardiovascular death, and nonfatal myocardial infarction (major adverse cardiac events [MACE]).

Results: During follow-up, MACE occurred in 78 patients (4.5%), cardiac death in 35 (2.1%), and stent thrombosis in 45 (2.6%): 30 definite, 23 subacute, and 22 late, including 9 at >6 months. In univariate analysis, the 1-year stent thrombosis rate was 1.8 times higher in diabetic than in nondiabetic patients (3.2% vs. 1.7%; log rank p = 0.03), with diabetic patients with multiple-vessel disease experiencing the highest rate and nondiabetic single-vessel disease patients the lowest (4.3% vs. 0.8%; p < 0.001). In multivariate analysis, in addition to the interruption of antithrombotic treatment, independent stent thrombosis predictors were previous stroke, renal failure, lower ejection fraction, calcified lesion, length stented, and insulin-requiring diabetes.

Conclusions: The risk of sirolimus stent thrombosis is higher for multiple-vessel disease diabetic patients.

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