Stem Cell Therapy Is a Promising Tool for Refractory Angina: A Meta-analysis of Randomized Controlled Trials

Background: So far, relatively few studies have addressed the use of stem cells to treat patients with refractory angina. Moreover, the results of current studies were discrepant. The objective of this meta-analysis was to evaluate the efficacy and safety of this treatment on a relatively large scale. Methods: Studies were identified through PubMed, CENTRAL, EMBASE, reviews, and reference lists of relevant papers. The weighted mean difference was calculated with random-effect models for net changes in exercise tolerance and angina frequency, and odds ratio (OR) with fixed-effect models for myocardial infarction (MI) and death. Results: Five randomized controlled trials, with a total of 381 patients, were included in the analysis. Compared with the controls, patients who received stem cell therapy had a significant improvement in exercise tolerance of 61.3 seconds (95% confidence interval [CI], 18.1-104.4; P = 0.005; I-2 = 58%); an obvious reduction in angina frequency of 7.3 episodes per week (95% CI, -13.4 to -1.2; P = 0.02; I-2 = 93%); and lower risk of MI, with an OR of 0.37 (95% CI, 0.14-0.95; P = 0.04; I-2 = 0%). No difference was detected for the risk of death (OR, 0.33; 95% CI, 0.08-1.39; P = 0.13; I-2 = 20%). Conclusions: Stem cell therapy appears to be effective and safe in the management of patients with refractory angina. The findings need confirmation in larger-scale studies with longer follow-up.