Efficacy and Safety of Different Courses of Tongxinluo Capsule as Adjuvant Therapy for Coronary Heart Disease after Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Tongxinluo capsule (TXLC) is a widely used traditional Chinese medicine for coronary heart disease (CHD). However, the efficacy and safety of different courses of TXLC for CHD after percutaneous coronary intervention (PCI) have not been systematically evaluated yet. The Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure, Wanfang Database, and Chinese Scientific Journal Database were searched from the inception to 26 August 2021. A meta-analysis was performed using a fixed- or random-effects model. The risk of adverse cardiovascular events, mortality, or adverse effects was evaluated by risk ratio (RR) with 95% confidence interval (CI). Thirty-four studies involving 3652 patients were finally included. After the 6-month treatment, compared with conventional treatment alone, TXLC combined with conventional treatment achieved better efficacy in lowering the risk of angiographic restenosis (RR = 0.37, 95% CI = 0.28–0.48, p < 0.001), myocardial infarction (RR = 0.38, 95% CI = 0.25–0.60, p < 0.001), heart failure (RR = 0.32, 95% CI = 0.18–0.56, p < 0.001), angina (RR = 0.26, 95% CI = 0.17–0.38, p < 0.001), revascularization (RR = 0.20, 95% CI = 0.09–0.46, p < 0.001), all-cause mortality (RR = 0.24, 95% CI = 0.10–0.58, p = 0.001), and mortality due to any cardiovascular event (RR = 0.27, 95% CI = 0.09–0.80, p = 0.018). After the 12-month treatment, TXLC reduced the recurrence risk of angina (RR = 0.40, 95% CI = 0.20–0.80, p = 0.009). However, there was no difference in any outcomes after the 3-month treatment. Besides, no difference was found in the incidence of adverse effects after the 3-month and 6-month treatments (3 months: RR = 0.73, 95% CI = 0.35–1.56, p = 0.418; 6 months: RR = 1.71, 95% CI = 0.74–3.93, p = 0.209). The certainty of evidence ranged from very low to moderate due to the risk of bias, inconsistency, and imprecision. TXLC showed beneficial effects on reducing the adverse cardiovascular events without compromising safety for CHD patients after PCI on the 6-month course. However, due to the unavoidable risk of bias, more high-quality and long-term studies are still needed to further evaluate the efficacy and safety of TXLC in many countries, not only in China.