Ethnicity and left ventricular diastolic function in hypertension an ASCOT (Anglo-Scandinavian Cardiac Outcomes Trial) substudy.

OBJECTIVES: 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. BACKGROUND: 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. METHODS: 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'). RESULTS: 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). CONCLUSIONS: 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.

Measurement of pulse wave velocity: site matters.

BACKGROUND: Aortic pulse wave velocity (PWV) predicts mortality from cardiovascular disease, ischaemic heart disease and stroke. However, a comparison of associations between PWV measured at different sites and atherosclerosis in coronary, carotid and femoral arteries has not been made. METHODS: In 159 men (ages 45-82 years) with and without known coronary artery disease, PWV measurements were made between carotid-femoral, carotid-radial and femoral-posterior tibial sites, using an ultrasound technique. Coronary artery calcification (CAC) scores were measured by multislice computed tomography. Carotid and femoral intima-media thickness (IMT) and presence of plaque were determined by ultrasound. Known coronary artery disease was confirmed by angiography. Participants were grouped into four categories of CAC score: 0-10, 11-100, 101-400, > 400 Hounsfield Units (HU). Measurements of blood pressure, heart rate and fasting bloods were made in all individuals. RESULTS: Carotid-femoral PWV correlated positively with CAC score and increased with incremental coronary calcification category (median carotid-femoral PWV 16.8 m/s in those with CAC score > 400 HU and 13.8 m/s in those with CAC score < 10 HU; P = 0.003). Carotid-femoral PWV also correlated with carotid and femoral IMT (P < 0.001, P = 0.004, respectively) and with carotid and femoral plaque (P = 0.001, P = 0.038, respectively). Increased carotid-femoral PWV also correlated with increasing age (P < 0.001), systolic blood pressure (P < 0.001), mean arterial pressure and pulse pressure (P < 0.001). Carotid-radial and femoral-posterior tibial PWV were not significantly associated with CAC score, carotid or femoral IMT or carotid plaque. CONCLUSIONS: Carotid-femoral PWV is a better indicator of atherosclerosis than either carotid-radial or femoral-posterior tibial PWV, and should be used preferentially in studies of atherosclerosis and in stratifying risk in clinical settings.

Indian Asian men have less peripheral arterial disease than European men for equivalent levels of coronary disease.

OBJECTIVES: Indian Asians have high rates of heart disease and stroke, but risks of peripheral arterial disease appear to be low. This paradox, and reasons for it, have not been explored. We compared ethnic differences in peripheral arterial disease for a given level of coronary disease. METHODS: We studied 83 European and 84 Indian Asian men with a range of coronary disease. Extent of coronary atheroma was quantified by coronary artery calcification score on multislice CT. Femoral intima-media thickness (IMT) was measured by ultrasound. RESULTS: Femoral IMT was 1.58, 2.06, 2.12, and 2.69 mm in Europeans, and 0.61, 1.41, 1.81 and 2.29 in Indian Asians by increasing categories of coronary atheroma (p=0.003 for ethnic difference, adjusted for age and lumen diameter). Adjustment for smoking and systolic blood pressure, the only risk factors adversely distributed in Europeans, only partly accounted for this ethnic difference (p=0.05). Other risk factors, including lipids, obesity, insulin and glycaemic status, more adversely distributed in Indian Asians, could not account for ethnic differences. Prevalence of abnormal ankle brachial index and lower limb atherosclerotic plaque was also greater in Europeans. CONCLUSIONS: For a given level of coronary disease, Indian Asians have less lower limb atherosclerosis than Europeans, unexplained by established risk factors. Further study of these populations would help tease out relative contributions of risk factors to atherosclerosis in different vessel beds.