Percutaneous coronary intervention (PCI) is commonly performed for coronary revascularization in patients with stable angina or acute coronary syndrome (ACS) [
1]. Nevertheless, there are several medications with proven benefit to patients with cardiovascular disease, such as dual-antiplatelet therapy, statins, β-blockers, and angiotensin-converting enzyme inhibitors [
2]. Unfortunately, the risk of cardiovascular events remains high in patients after PCI [
3]. Many patients do not receive the conventional treatment due to the side effects, contraindications, and drug-drug interactions [
4]. Selecting the optimal clinical strategies to prevent the occurrence of cardiovascular events is challenging.
Traditional Chinese medicine (TCM) has been used to treat coronary heart disease (CHD) for thousands of years [
5]. From the perspective of TCM, patients with CHD can be divided into different syndromes (i.e., different
zhengs). In the diagnosis of CHD, the “Qi and Yin inadequacy syndrome” is the important subtype. In 2005, Xinyue capsules were approved by the China Food and Drug Administration for treatment of CHD. The main component of Xinyue capsules—
Panax quinquefolius saponin (PQS)—is extracted from the stem and leaves of
Panax quinquefolium, which in TCM theory could reinforce Qi and nourish Yin. Previous studies have shown that PQS has various pharmacological actions, including anti-myocardial cell damage [
6], protection of heart function, reduction of myocardial oxygen consumption [
7,
8], improvement of myocardial perfusion [
9] and ventricular remodeling after acute myocardial infarction (MI) [
10], antiapoptosis of ischemic myocardial cells [
11,
12], regulation of glucose and lipid metabolism [
13], and improvement of insulin resistance [
14,
15]. A multicenter randomized clinical study [
16] showed that the combination of Xinyue capsules with Chuanxiong capsules and conventional Western interventions could reduce the occurrence of cardiovascular events in patients with ACS after PCI without increasing the risk of major bleeding. The results of pharmaceutical chemistry and pharmacokinetics conducted jointly by Xiyuan Hospital and Medical University of Vienna showed that the fingerprint of Xinyue capsules from different batches or the same batch at different time points was consistent, and the measurements of heavy metal and pesticide residues were within European Union standards.
Based on the multifactorial effect on CHD of Xiyue capsule, our hypothesis is that Xiyue capsules plus conventional treatment can improve cardiovascular outcomes in patients with CHD after interventional treatment compared with conventional treatment alone. If successful, it will provide a novel, promising alternative strategy for further reducing cardiovascular events.