Ethnicity and Left Ventricular Diastolic Function in Hypertension: An ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) Substudy

Abstract

We investigated whether diastolic function differs between hypertensive patients of African-Caribbean or white European origin and established whether differences could be explained by confounding variables. African Caribbeans are known to have a higher prevalence of heart failure than white Europeans but it is unclear whether this is a result of known risk factors. Tissue Doppler technology now allows accurate quantification of diastolic function, which is recognized as an important factor in the development of heart failure. Participants from a single center participating in the ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial), composed of patients with hypertension but no evidence of heart failure, were studied. Left ventricular structure and function were measured in 509 patients using conventional and tissue Doppler echocardiography. Diastolic function was assessed using the tissue Doppler early diastolic velocity E' (averaged from 3 left ventricular segments) and the ratio of this and the transmitral early filling velocity E (E/E'). In African-Caribbean patients, mean E' was significantly lower (7.7 cm/s vs. 8.6 cm/s, p = 0.003) and mean E/E' was significantly higher (8.85 vs. 7.93, p = 0.003). After adjustment for confounding variables-age, gender, systolic blood pressure, pulse pressure, cholesterol, smoking, ejection fraction, left ventricular mass index, and diabetes mellitus-the effect of African-Caribbean ethnicity on diastolic function remained highly significant (E': 7.52 vs. 8.51; p < 0.001; E/E': 8.89 vs. 7.93; p = 0.003; African Caribbeans vs. white Europeans for both comparisons). Diastolic function is significantly worse in hypertensive patients of African-Caribbean origin than in white Europeans. This difference in diastolic performance is not due to known confounding variables.