Pulse wave velocity in blacks and whites, and relations to left ventricular hypertrophy

Abstract

People of Black African descent worldwide have greater risks of hypertensive target organ damage than would be anticipated for a given level of resting or ambulatory blood pressure. We therefore compared ethnic differences in arterial stiffness and associations with left ventricular hypertrophy. A cross-sectional, population based study of 103 Europeans and 99 African Caribbeans aged 40–64 in the UK. Pulse wave velocity (PWV) and left ventricular hypertrophy on echocardiography were measured. PWV in the mainly elastic carotid-femoral segment was elevated by 1.3 m/s in African Caribbean men (p=0.02), and 1.7 m/s in African Caribbean women (p<0.0001) compared to Europeans. Elevated resting and ambulatory pressure could account for this difference in men, but not women. Interventricular septal thickness was elevated by 0.3 mm in African Caribbeans (p=0.009). This was associated with both elevated blood pressure and PWV, with the former accounting for much of the difference. Stiffness in the generally muscular carotid-radial segment did not differ by ethnicity overall, but while elevated blood pressure was positively associated with PWV in Europeans, there was little association in African Caribbeans (p=0.02 for interaction). Stiffness of the central elastic arteries is increased in African Caribbeans compared to Europeans, is related to left ventricular hypertrophy, and is only partly accounted for by elevated blood pressure. Stiffness of the upper limb muscular arteries does not differ overall, but remains favourable in the presence of hypertension in African Caribbeans, while being increased in Europeans. We suggest that this is due to ethnic differences in vascular remodelling patterns, similar to those observed in the left ventricle.