Effect of Shexiang Tongxin dropping pill on stable coronary artery disease patients with normal fractional flow reserve and coronary microvascular disease: A study protocol

INTRODUCTION: Coronary microvascular disease (CMVD) can affect the structure, function, and metabolism of the heart, and has an important impact on the occurrence, development and prognosis of coronary artery disease (CAD). Shexiang Tongxin dropping pill (STDP) can dilate blood vessels, alleviate inflammation, reduce endothelial damage, and improve coronary microvascular function in mice with myocardial infarction. This study aims to assess the impact of STDP on stable coronary artery disease (SCAD) patients with normal FFR and CMVD. METHODS AND ANALYSIS: This is a single-center, prospective randomized trial that will enroll 64 SCAD patients, CAD with normal FFR and CMVD. Patients will be randomly divided into study group and control group in a 1:1 fashion. On the basis of conventional drug treatment, the former will receive STDP while the latter will not. The follow-up period of the subjects is 12 months, and clinical follow-up will be conducted before discharge, 30 days, 3 months, 6 months, and 12 months after procedure to complete the detection of relevant indicators. The primary endpoint is the change of index of microcirculatory resistance (ΔIMR) at 12-month follow-up. DISCUSSION: The present study will be the first randomized control study to evaluate the efficacy and safety of STDP on SCAD patients, CAD with normal FFR and CMVD, which will provide a broader idea and more experimental basis for improving the treatment of CMVD. TRIAL REGISTRATION: This is a protocol for the randomized clinical trial which has been registered in the Chinese clinical Trial Registry with an identifier: ChiCTR2000032429.