Tongxinshu capsules in the treatment of stable angina pectoris due to qi deficiency and blood stasis in coronary heart disease: A multicenter, randomized, double-blind, placebo-controlled trial

OBJECTIVE: To evaluate the efficacy and safety of Tongxinshu (TXS) capsules as an adjunct treatment for stable angina pectoris (SA) with Qi deficiency and blood stasis. METHODS: From September 2020 to January 2024, a multicenter, randomized, double-blind, placebo-controlled trial was conducted in three hospitals in China. A total of 120 patients with Qi deficiency and blood stasis-type SA were randomly assigned to the TXS capsule group or the placebo group (1:1). All patients received standardized Western medication and either TXS capsules or placebo capsules, administered as two capsules three times daily for eight weeks. The primary outcome measure was the angina stability score on the Seattle Angina Questionnaire (SAQ). Secondary outcome measures included other SAQ dimensions, traditional Chinese medicine (TCM) syndrome scores, quality of life assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ), echocardiography, serum IL-6, lipid profile, and electrocardiogram changes. SAQ and TCM syndrome scores were measured at weeks 0, 4, and 8, with generalized estimating equations used for comparisons between groups at each time point. Other indices were collected at weeks 0 and 8. Adverse events (AEs) were meticulously recorded throughout the trial. RESULTS: A total of 114 patients completed the trial, with 58 in the TXS capsule group and 56 in the placebo group. Over time, both groups exhibited significant improvements in angina stability (P < 0.05), with the TXS group showing more pronounced improvements at weeks 4 and 8 compared to the placebo group (P < 0.05). Compared to baseline, both groups showed significant improvements in other SAQ dimensions, TCM syndrome scores, and MLHFQ scores (P < 0.05) after 8 weeks of treatment. Between-group comparisons revealed that the TXS group had superior improvements in physical limitation, treatment satisfaction, and TCM syndrome scores at weeks 4 and 8 (P < 0.05). Angina frequency showed significant improvement only at week 4 (P < 0.05). There was no significant difference in disease perception between the groups (P > 0.05). At week 8, the TXS group demonstrated greater improvements in MLHFQ physical domain, emotional domain, and total scores compared to the placebo group (P < 0.05). No significant differences were found between the groups in other domains (P > 0.05). Additionally, compared to baseline, the placebo group showed reductions in IL-6 and LVFS after treatment (P < 0.05). No significant differences were observed between the groups in routine blood and urine tests, electrolytes, liver and kidney functions, and electrocardiograms post-treatment (P > 0.05). Three AEs were reported in the placebo group, while no AEs occurred in the TXS group, with no statistical difference between groups (P > 0.05). CONCLUSION: The addition of TXS capsules to conventional Western medication significantly improves the severity and frequency of angina attacks, clinical symptoms, and quality of life in SA patients, with good safety (Registration number: ChiCTR2000039731).