Microvascular function vs. blood pressure in different clinical and non-clinical settings

Abstract Background Microvascular dysfunction is considered as the gateway not only to cardiovascular disease (CVD) but also kidney failure, lung disease, dementia, etc. However, studies comparing Microvascular dysfunction vs. blood pressure (BP) in various clinical and non-clinical settings are scarce. Digital Thermal Monitoring (DTM) of microvascular function is a new automated method based on monitoring fingertip temperature fall and rebound during and after a 5-minute arm-cuff occlusion. DTM reports Vascular Reactivity Index (VRI) which is significantly reduced in patients with coronary heart disease and high CVD factors. Methods A total of 3,184 cases were included in this study comprising (1) known CVD patients from cardiology clinics, (2) patients from internal medicine and wellness clinics, (3) apparently healthy college students in the US, and (4) apparently healthy factory worker volunteers in China. The tests were conducted using FDA-approved DTM device (VENDYS, Endothelix Inc) which measures both BP and VRI. Density plots comparisons using Jensen-Shannon (JS) Divergence and Receiver-Operator Curve (ROC) analyses were performed. Results VRI showed the highest discriminative power in distinguishing between different populations compared to blood pressure. JS Divergence score for VRI (0.335) was higher than those for systolic (0.296) and diastolic (0.199) blood pressure. The ROC area under the curve (AUC) for detecting CVD patients vs. healthy volunteers for VRI, BP, and VRI+BP were 0.89, 0.72, 0.9 respectively (p<0.05). Conclusion VRI outperformed BP in risk stratification based on clinical and non-clinical settings. Further studies are warranted to evaluate the clinical utility of VRI in addition to BP as a vital sign of vascular health.