Abstract 19533: The Relationship Between Aortic-brachial Stiffness Mismatch and Mean Blood Pressure

Abstract

Background: Carotid-femoral pulse wave velocity (cf-PWV) is considered to be the gold standard for assessment of aortic stiffness. The impact of aortic stiffness on peripheral end-organ damage is explained by the loss or reversal of physiological impedance mismatch between aorta and medium-sized muscular conduit arteries. The main limitation of cf-PWV is its positive relationship with mean blood pressure. Recently, we have shown that assessment of aortic-brachial stiffness mismatch (PWV ratio) outperforms cf-PWV for the prediction of mortality in dialysis population. As both carotid-radial PWV (cr-PWV) and cf-PWV depend on blood pressure, we hypothesized that PWV ratio is not influenced by mean blood pressure. Method: In 310 dialysis patients (median age of 67 years [25 th -75 th percentiles: 56 - 76], 185(60%) men, 134 (43%) diabetes and 162 (52%) cardiovascular disease), cf-PWV and cr-PWV were measured using direct distance (Complior) and maximal upstroke algorithm. Mean blood pressure was obtained using arterial tonometry calibrated with brachial systolic and diastolic blood pressures in a controlled environment. In a linear regression analysis, we examined the relationship between MBP and cf-PWV, cr-PWV and PWV ratio. Results: The mean cf-PWV, cr-PWV, PWV ratio and MBP were respectively 13.52±4.06 m/s, 8.76±1.68 m/s, 1.59±0.52 and 92±16 mmHg. The linear relationships between MBP, cf-PWV and cr-PWV are shown in figures 1A-B. However, there were no relationship between MBP and PWV ratio (Figure 1C). There were no interaction between age, gender and the absence of a relationship between MBP and PWV ratio. Conclusion: As PWV ratio is mechanistically a logical parameter for explaining target organ damage and it has no significant relationship with MBP, it seems to be an ideal index for macro-circulatory disease. These findings need to be validated in independent cohorts.