Stem cell therapy is a promising tool for refractory angina: a meta-analysis of randomized controlled trials

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.

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.

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%).

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.