Clinical Determinants of the Macrovascular Reactivity Response as Assessed by Flow Mediated Slowing in People at Risk for Cardiovascular Disease

Objective: Non-invasive methods assessing endothelial function may enhance cardiovascular risk evaluation in primary care. Previous research showed that flow-mediated slowing (FMS) of the brachial-radial pulse wave velocity (PWV) reflects cardiovascular risk, but larger studies on the FMS response in at-risk populations are required to further unravel its clinical and added value for cardiovascular risk stratification. We investigated clinical correlates on the FMS response in people at risk for cardiovascular disease. Design and method: We collected baseline FMS data from a subsample of 157 participants enrolled in the PRIORITY-trial. Participants had at least one of following risk factors: systolic blood pressure (BP) / diastolic BP between 130/80 – 159/99mmHg and/or antihypertensive treatment, prediabetes with fasting plasma glucose of 5.6-6.9mmol/L or HbA1c 5.7%-6.4%, diabetes mellitus, obesity (BMI > 30kg/m2), or evidence of subclinical diastolic dysfunction. We continuously recorded brachial-radial PWV using a Vicorder in supine position at rest and after 5-minutes of supra-systolic occlusion of the upper arm. Stepwise linear regression analyses assessed clinical correlates of the FMS response. We illustrated the effect of important correlates on the FMS response by plotting the estimated marginal means for each FMS post-occlusion interval by the mean and one standard deviation. Results: The study sample was on average 60.2±11.2 years and included 74 women(47.1%). Until 180 seconds post-occlusion, lower FMS response was significantly associated with higher DBP and higher triglycerides levels (P<0.05 for 0-180s intervals). Higher age only correlated with less decline in brachial-radial PWV in the 60 to 90 seconds post-occlusion interval (P=0.050). Participants with elevated triglycerides or elevated DBP or both exhibited significantly less decline in brachial-radial PWV as compared to those with average or below average levels (Figure1). Conclusions: In individuals at increased risk for cardiovascular disease, worse macrovascular reactivity was associated with hypertriglyceridemia and high DBP. Our findings suggest that the use of FMS may have clinical value for cardiovascular risk evaluation and highlight the importance of optimal control of triglycerides and DBP for adequate cardiovascular risk management. More studies are needed for assessing the additive value of such testing for cardiovascular disease prediction and management.