High Frequency of Microvascular Dysfunction in US Outpatient Clinics: A Sign of High Residual Risk? Data from 7,105 Patients.

Morteza Naghavi,Ruoyu Zhuang,Hirofumi Tanaka,Stanley Kleis,Albert A Yen,Ahmed Gul,Ralph Metcalfe,Yasamin Naghavi,Alberto Caggiati

doi:10.1155/2022/4224975

Abstract

Previous studies have linked peripheral microvascular dysfunction measured by arterial tonometry to high residual risk in on-statin patients. Digital thermal monitoring (DTM) of microvascular function is a new and simplified technique based on fingertip temperature measurements that has been correlated with the burden of atherosclerosis and its risk factors. Here, we report analyses of DTM data from two large US registries: Registry-I (6,084 cases) and Registry-II (1,021 cases) across 49 US outpatient clinics. DTM tests were performed using a VENDYS device during a 5-minute arm-cuff reactive hyperemia. Fingertip temperature falls during cuff inflation and rebounds after deflation. Adjusted maximum temperature rebound was reported as vascular reactivity index (VRI). VRI distributions were similar in both registries, with mean ± SD of 1.58 ± 0.53 in Registry-I and 1.52 ± 0.43 in Registry-II. In the combined dataset, only 18% had optimal VRI (≥2.0) and 82% were either poor (<1.0) or intermediate (1.0-2.0). Women had slightly higher VRI than men (1.62 ± 0.56 vs. 1.54 ± 0.47, p < 0.001). VRI was inversely but mildly correlated with age (r = −0.19, p < 0.001). Suboptimal VRI was found in 72% of patients <50 years, 82% of 50-70 years, and 86% of ≥70 years. Blood pressure was not correlated with VRI. In this largest registry of peripheral microvascular function measurements, suboptimal scores were highly frequent among on-treatment patients, possibly suggesting a significant residual risk. Prospective studies are warranted to validate microvascular dysfunction as an indicator of residual risk.

Highlights

Of the three layers of an artery, the intima or endothelial layer has gathered the most attention as it is a critical regulator of the overall hemodynamic function [1,2,3]
When the cuff was released after the 5-minute occlusion, blood flow to the forearm and hand was restored, and this resulted in a “temperature rebound” in the fingertip that was directly related to the hyperemic blood flow response resulting from microvascular reactivity [14]
The Vascular reactivity index (VRI) distributions in both registries are shown in Figure 3. 79% of patients in Registry-I and 87% in Registry-II were categorized as having suboptimal VRI (Figure 4)

Summary

Introduction

Of the three layers of an artery, the intima or endothelial layer has gathered the most attention as it is a critical regulator of the overall hemodynamic function [1,2,3]. It is involved in controlling vascular homeostasis and repair and regulating blood pressure and blood flow acting via vascular tone. Reactive hyperemia that produces shear stress is the most practical and commonly used way of assessing endothelial function This function can be measured both at macrovascular (conduit artery) and microvascular levels

Methods

Results

Conclusion