Does black ethnicity influence the development of stent thrombosis in the drug-eluting stent era?

BACKGROUND: It has been suggested that black race predicts stent thrombosis (ST) after drug-eluting stent implantation. Whether socioeconomic status or comorbid conditions confound the contribution of black race to the development of ST is unclear. METHODS AND
RESULTS: We compared 1594 black patients who underwent drug-eluting stent implantation with 5642 nonblack patients. Overall, 108 definite STs were reported. Multivariable Cox regression analysis was performed with adjustment for comorbidities, including median household income as a marker of socioeconomic status, to assess the impact that black race may have on the development of ST. On univariable analysis, black patients were younger (63.43±12.42 versus 65.15±12.59 years; P<0.001) and more likely to have a history of hypertension (89.8% versus 81.7%; P<0.001), diabetes mellitus (45.5% versus 30.8%; P<0.001), chronic renal insufficiency (19.2% versus 10.7%; P<0.001), and congestive heart failure (18.7% versus 13.1%; P<0.001). Clopidogrel compliance at the time of the ST event was higher in the black than in the nonblack population (87.5% versus 77.8%; P=0.068). After multivariable analysis, including adjustment for median income and clopidogrel compliance, black race emerged as a strong predictor of definite late ST.
CONCLUSIONS: Black race is an independent predictor of definite drug-eluting stent ST. Because clopidogrel compliance was higher in black patients and socioeconomic status was not associated with ST, further investigation into the potential mechanisms of this influence of race on ST must be pursued.