Abstract
BACKGROUND: The effect of bone marrow-derived mononuclear cells (BM-MNCs) after acute myocardial infarction (AMI) on myocardial function indices such as left ventricular ejection fraction has been widely studied. However, the effect of this intervention on major adverse cardiovascular events (MACE) was not the principal purpose of most investigations and its role is unclear. The aim of this study was to investigate the possible long-term clinical efficacy of BM-MNCs on MACE after AMI. METHODS: A comprehensive search was conducted through electronic databases for potentially eligible randomized trials investigating the impact of BM-MNC therapy following acute MI on clinical outcomes. Risk of bias of the eligible studies was assessed using the Cochrane Collaboration's tool. The effect of treatment was displayed by risk ratio (RR) and its 95% confidence interval (CI) using random-effects model. RESULTS: Initial database searching found 1540 records and 23 clinical trials with a total of 2286 participants eligible for meta-analysis. Injection of BM-MNCs was associated with lower risk of composite end points of hospitalization for congestive heart failure (CHF), re-infarction, and cardiac-related mortality (91/1191 vs. 111/812, RR = 0.643, 95% CI = 0.489 to 0.845, p = 0.002). This effect was derived from both reduction of CHF (47/1220 vs. 62/841, RR = 0.568, 95% CI = 0.382 to 0.844, p = 0.005) and re-infarction rate (23/1159 vs. 30/775, RR = 0.583, 95% CI = 0.343 to 0.991, p = 0.046), but not cardiac-related mortality (28/1290 vs. 31/871, RR = 0.722, 95% CI = 0.436 to 1.197, p = 0.207). CONCLUSION: This is the first meta-analysis focused on the cardiovascular outcomes of stem cell therapy after AMI and it revealed that transplantation of BM-MNCs may reduce composite endpoint of hospitalization for CHF, re-infarction, and cardiac related mortality driven mainly by reducing reinfarction and hospitalization for heart failure rates but not cardiovascular mortality.