Heart vessel crosstalk: association between left ventricular diastolic function and macrovascular reactivity, captured by brachial-radial flow-mediated slowing

Abstract Background Endothelial dysfunction is recognized as an early sign of cardiovascular (CV) disease and has been closely linked to left ventricular (LV) diastolic function through shared mechanisms such as nitric oxide imbalance. While flow-mediated dilation (FMD) is the gold standard for assessing endothelial function, its technical complexity limits its use in daily clinical practice. Flow-mediated slowing (FMS), a non-invasive and user-friendly technique that measures transient changes in brachial-radial pulse wave velocity (PWV) during reactive hyperaemia, may offer a reproducible and practical alternative. Purpose This study investigates the association between brachial-radial FMS and LV diastolic function, to evaluate the value of FMS as a clinically applicable marker of macrovascular reactivity and, in extent, endothelial health for CV risk stratification. Methods A cross-sectional analysis was performed of 420 adults with and without CV risk factors from the FLEMENGHO and the baseline PRIORITY cohort. Brachial-radial FMS was assessed using the Vicorder® device as the relative change in brachial-radial PWV following five minutes of brachial cuff occlusion. FMS was quantified as the relative PWV change at each 30-second interval (until four minutes post-occlusion) and categorized as (ab)normal peak FMS based on age-specific reference cutoffs and as (ab)normal FMS trajectory. LV diastolic function was evaluated using transthoracic echocardiography. Associations between FMS and parameters of diastolic function were examined using correlation analysis and multivariable regression modelling. Results Among 420 adults (mean age 61.7 ± 10.5 years; 44.5% women), 319 had at least one CV risk factor, while 101 were apparently healthy. Less decline in brachial-radial PWV within the first 180 seconds post-occlusion, indicating worse FMS response, was significantly correlated with lower E peak velocity, E/A ratio and E′ peak velocity, markers of worse LV diastolic function (p 0.01 for all) (Figure 1). No significant correlations were found with E/E′ ratio or A peak velocity. The inverse associations with E peak velocity, E/A ratio and E’ peak velocity remained significant after multivariable adjustment (p 0.05 for all) (Table 1). Categorically, an abnormally low FMS peak was associated with significantly lower E peak velocity (p 0.01). Conclusion(s) Worse macrovascular reactivity as assessed by brachial-radial FMS was associated with worse LV diastolic function, particularly LV relaxation. These findings are in line with the documented physiological coupling between endothelial health and myocardial relaxation. Overall, these results support the potential use of FMS as a practical, non-invasive tool for early detection of ventricular-vascular mismatches.For image description, please refer to the figure legend and surrounding text. For image description, please refer to the figure legend and surrounding text.