Peripheral Reactive Hyperemia Index and Coronary Microvascular Function in Women With no Obstructive CAD:The iPOWER Study

Objectives This study investigated whether digital reactive hyperemia index (RHI) measured by digital pulse amplitude tonometry is a sensitive indicator of coronary microvascular dysfunction (CMD). Background CMD is an early marker of cardiovascular disease. However, CMD is a complex diagnosis and consists of multiple abnormalities of the coronary circulation. Impaired RHI is a noninvasive measure of peripheral vascular dysfunction that can identify individuals with acetylcholine induced coronary vascular dysfunction. It is largely unknown whether there is also an association between RHI and the endothelial-independent aspect of CMD assessed as a coronary flow velocity reserve (CFVR). Methods We included 339 women with chest pain suggestive of angina pectoris and a diagnostic invasive coronary angiogram without significant coronary artery stenosis (