Association between the reflection magnitude and blood-pressure in a multi-ethnic cohort: The helius study

OBJECTIVE: The reflection magnitude (RM), the ratio of the amplitudes of the backward and forward central arterial pressure waves, has been shown to be predictive for future cardiovascular events, but the association between blood pressure (BP) and RM remains unknown. We aimed to assess the association between RM, BP and hypertension in a large multi-ethnic population-based cohort study. DESIGN AND METHOD: We assessed RM in 10 195 individuals of Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish and Moroccan origin aged between 18-70 years (54.2% female) participating in the HEalthy Life in an Urban Setting (HELIUS) study. To determine RM, central arterial pressure and flow were reconstructed from non-invasive finger BP measurements using a generalized transfer function and Windkessel model, whereafter wave separation was performed (Fig 1, panel A & B). Hypertension was defined based on office-BP and use of BP lowering medication. Associations between RM and systolic- and diastolic BP, hypertension, and hypertension mediated end-organ damage were assessed using regression models with correction for age, height, ethnicity and an interaction term for sex. RESULTS: Mean RM was 62.5% (SD 8.0) in men and 63.8% (SD 8.1) in women. For every 10 mmHg increase in systolic BP, RM increased linearly by 1.35 (95% CI 1.23-1.46) from 120 mmHg onwards, while for every 10 mmHg increase in diastolic BP above 80 mmHg RM increased by 1.99 (95% CI 1.61 - 2.38) (Fig 1, panel C & D). RM was 2.40 (95% CI 2.04-2.76) higher in hypertensive men and 3.82 (95% CI 3.46-4.19) higher in hypertensive women compared to normotensive men and women. RM was 1.64 (95% CI 1.09-2.20) and 0.94 (95% CI 0.37-1.52) higher in hypertensive men and women with ECG-based left ventricular hypertrophy or increased albuminuria compared to hypertensive men and women without hypertensive organ damage. Following correction for height ethnic and sex differences in RM were attenuated, however the relation with BP did not change. CONCLUSIONS: Hypertension is associated with a higher RM in men and women of different ethnic origins, and may, in part, explain disparities in hypertension associated cardiovascular risk.