Effect of Xinyue capsules on patients with coronary heart disease after percutaneous coronary intervention: study protocol for a randomized controlled trial

BACKGROUND: The risk of cardiovascular events remains high in patients with coronary heart disease (CHD) after successful percutaneous coronary intervention (PCI). Panax quinquefolius saponin, a major component of Xinyue capsule, has been used to treat patients with CHD. The aim of this study is to evaluate the efficacy and safety of Xinyue capsules in patients with CHD after PCI. METHODS/DESIGN: This study is a multicenter, placebo-controlled, double-blind, randomized controlled clinical trial. A total of 1100 participants are randomly allocated to two groups: the intervention group and a placebo group. The intervention group receives Xinyue capsules plus conventional treatment, and the placebo group receives placebo capsules plus conventional treatment. The patients receive either Xinyue or placebo capsules three times daily (1.8 g/day) for up to 24 weeks. The primary outcome measure is the time from randomization to the first occurrence of major adverse cardiovascular events. The secondary outcome measure is the time from randomization to the first occurrence of stroke, pulmonary embolism, and peripheral vascular events, as well as death due to any cause. All outcome measures will be assessed at 12, 24, 36, and 48 weeks after randomization. Adverse events will be monitored during the trial. DISCUSSION: The aim of this study is to evaluate the effects of Xinyue capsules on patients with CHD after interventional treatment. The results of this trial will provide critical evidence regarding Chinese herbal medicine treatment for CHD. TRIAL REGISTRATION: Chinese Clinical Trials Registry identifier ChiCTR-IPR-14005475. Registered on 10 November 2014. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13063-016-1531-x) contains supplementary material, which is available to authorized users.