Tongxinluo Capsule () for Cardiac Syndrome X: A Systematic Review and Meta-Analysis

To evaluate the efficacy and safety of Tongxinluo Capsule (, TXL) for patients with cardiac syndrome X (CSX).

Randomized controlled trials (RCTs) regarding TXL in the treatment of CSX were searched in Chinese Biomedicine Literature Database, China National Knowledge Infrastructure, Chinese Scientific Journal Database, Wanfang Database, PubMed, EMBASE, Cochrane Central Register of Controlled Trial, websites of the Chinese and International Clinical Trial Registry platform up to June 30, 2015. The intervention was either TXL alone or TXL combined with conventional treatment, while the control intervention was conventional treatment with or without placebo. Data extraction, methodological quality assessment and data analyses were performed according to the Cochrane criteria. The primary outcome was a composite event of death, acute myocardial infarction (AMI), angina requiring hospitalization, revascularization, and heart failure. The secondary outcome measures were angina symptom improvement, electrocardiograph (ECG) improvement, and serum endothelin-1 (ET-1) level. The adverse events were also recorded. RevMan 5.3 software was applied for data analyses.

Twelve RCTs (696 patients) were included. Compared with conventional treatment, the addition of TXL to conventional treatment showed some benefits on relieving angina symptoms [risk ratio (RR): 1.46, 95% confidence interval (CI) (1.25, 1.71), P<0.01], and improving ECG [RR: 1.45, 95% CI (1.21, 1.74), P<0.01]. The pooled result did not support a benefit of TXL on reducing the incidence of primary outcome [RR: 0.20, 95% CI (0.02, 1.61), P=0.13]. In addition, TXL decreased serum ET-1 concentration of CSX patients [standardized mean number:-1.63, 95% CI (-2.29,-0.96), P<0.01]. No serious adverse events were reported.

TXL documents potential benefits on attenuating angina symptoms, improving ECG and decreasing serum ET-1 level for CSX patients. However, more rigorous RCTs with high quality are needed to confirm its efficacy and safety.