Objective: Noninvasive flow-mediated vasodilation (FMD) is a widely used method to assess endothelial function, but its technical difficulty and problems remain obstacles for use in clinical practice. Reactive hyperemia-peripheral arterial tonometry (RH-PAT) was developed as a simpler and more reproducible method. We compared FMD and RH-PAT in patients with stable angina. Furthermore, the differences in these two techniques according to coronary artery disease (CAD) severity and complexity were also assessed.
Materials and methods: We consecutively enrolled 80 patients who underwent elective coronary angiography. Endothelial function was assessed before angiography using brachial artery FMD and RH-PAT. The complexity and extent of the coronary lesions were assessed angiographically. The extent of CAD was defined as the number of diseased coronary arteries (>70%) and complexity of CAD was assessed by the SYNTAX score algorithm.
Results: In the overall study group (61±9 years, 57% men), the mean FMD was 8.5±5.1% and the mean reactive hyperemia index (RHI) measured by RH-PAT was 1.7±0.4. A significant correlation was observed between FMD and RHI irrespective of sex, diabetes, or presence of CAD. FMD and RHI were significantly lower in patients with multivessel and complex CAD. A receiver-operating characteristic curve analysis showed that both techniques were comparable in terms of predicting the presence of CAD and complexity.
Conclusion: Assessment of RH-PAT could be a less operator-dependent and noninvasive method of evaluating vascular endothelial function in patients with stable angina.