Black people have elevated risk for stent thrombosis
MedWire News: Black ethnicity is an independent risk factor for developing stent thrombosis after implantation of a drug-eluting stent (DES), US researchers report.
"Despite historically similar presentation and natural history of myocardial infarction, Black race has been reported to be an independent predictor of mortality after percutaneous coronary intervention (PCI) and coronary bypass graft surgery," note Ron Waksman (Washington Hospital Center, Washington, District of Columbia) and colleagues.
To investigate suggestions that socioeconomic status or comorbid conditions affect the contribution Black race has on clinical outcome in patients undergoing DES implantation, Waksman and team examined the incidence of stent thrombosis among patients attending a high-volume PCI center. They compared 1594 Black patients with 5642 non-Black patients.
The researchers report that the incidence of stent thrombosis was nearly three times higher among Black patients compared with non-Black patients. At 30 days, 1, 2, and 3 years the incidence was 1.71%, 2.25%, 2.78%, and 3.67%, respectively, among Black patients, compared with a corresponding 0.59%, 0.79%, 1.09%, and 1.25% among non-Black patients.
The rate of death from all causes at 3 years was also higher among Black patients, at 24.9%, compared with 13.1% among non-Black patients.
Multivariate analysis, adjusted for median income and clopidogrel compliance, revealed that clopidogrel cessation, Black race, history of diabetes mellitus, history of congestive heart failure, and previous PCI were independent predictors of early stent thrombosis (before 30 days).
However, only Black race and clopidogrel cessation independently predicted late stent thrombosis (after 30 days). Indeed, Black race was associated with a 2.6-fold increased risk for developing late stent thrombosis compared with non-Black race.
Of note, clopidogrel compliance at the time of the stent thrombosis event was higher in the Black than non-Black population (87.5% vs 77.8%).
Clopidogrel compliance was higher in Black patients and socioeconomic status was not associated with stent thrombosis, says the team. Therefore, further investigation into the potential mechanisms, such as genetic variation and responsiveness to antiplatelet therapy, behind the influence of race on stent thrombosis must be pursued, Waksman and co-author conclude in the journal Circulation.
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By Laura Dean