Prognostic implications of negative dobutamine stress echocardiography in African Americans compared to Caucasians

BACKGROUND: African Americans (AA) have higher rates of cardiovascular morbidity and mortality than Caucasians (CA). Despite its excellent negative predictive value, the influence of race on the prognostic implications of negative dobutamine echocardiography in predicting major cardiac problems is largely unknown. METHODS: We studied 387 AA and 340 CA patients with negative dobutamine stress echocardiography (NDSE). Kaplan-Meier survival analysis was used to create freedom-from-event curves for major adverse cardiac events over a 36-month period, and a Cox proportional-hazards multivariable model to examine the influence of race on cardiac outcomes. RESULTS: AA patients were younger (69.4 ± 12.6 vs. 74.2 ± 10.7, p < .001), had higher incidence of diabetes mellitus (37% vs. 29%, p = .01), hypertension (91% vs. 85%, p = .006), left ventricular hypertrophy (70% vs. 49%, p < .001) and lower incidence of prior coronary artery disease (27% vs. 34%, p = .05) compared to CA patients. Ejection fraction ≥ 50% was comparable (81% vs. 82%, p = .8). At 3-years, AA patients had a lower freedom from nonfatal myocardial infarction (92% vs. 96%, p = .006) and any cardiac event (cardiac death, myocardial infarction) (91% vs. 95%, p = .005) compared to CA patients. CONCLUSION: This is the first study to demonstrate that AA patients have higher rates of nonfatal MI and MACE compared to CA patients with a NDSE. These patients require closer follow-up and aggressive preventive and treatment strategies should be employed to help reduce cardiovascular morbidity and mortality despite negative ischemic workup.