Context Numerous randomized controlled studies assessing intracoronary bone marrow cell therapy (BMC) after acute myocardial infarction (AMI) have been performed.

Objective To systematically review the effect of autologous BMC therapy on left ventricular function by performing an up to date meta-analysis of randomized controlled trials (RCTs) including long-term follow-up.

Data sources Trials were indentified through a literature search from 1980 to June 2012 of the Pubmed, Embase, Cochrane database, and the Current Controlled Trials Register.

Study selection Randomized clinical trials comparing intracoronary BMC infusion to control as treatment for AMI.

Data extraction The primary endpoint was the change in left ventricular ejection fraction (LVEF) from baseline to follow-up. Secondary endpoints were changes in left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), infarct size and clinical outcomes.

Results Improvement of LVEF in patients receiving intracoronary BMC was significantly better within 6 months (23 studies, 2.23% (95% confidence interval (CI) 1.00 to 3.47); p<0.001). At 12 months of follow-up, this effect sustained with 3.91% more LVEF improvement (11 studies, (95% CI 2.56 to 5.27), p<0.001). At long-term follow-up, we found a trend for better LVEF improvement in favor of cell therapy (7 studies, 1.90% (95% CI −0.43 to 4.23); p=0.11). There was no clear effect in infarct size or LVEDV. However, we found a significant reduction in LVESV at 6 months (−4.81 ml (95% CI −7.86 to −1.76); p<0.001 and at 12 months (−9.41 ml (95% CI −13.64 to −5.17); p<0.001). Moreover, there was a statistically significant decrease in recurrent AMI (Relative Risk (RR) 0.44 (95% CI 0.24 to 0.79); p=0.007), and readmission for heart failure, unstable angina or chest pain (RR 0.59 (95% CI 0.35 to 0.98); p=0.04) in favour of cell therapy.

Conclusion Intracoronary BMC treatment leads to a moderate improvement of LVEF and reduction of LVESV at 6 months that sustained at 12 months follow-up, without a clear significant effect on LVEDV, or infarct size. Furthermore, we found that intracoronary cell therapy is significantly associated with a reduction in recurrent AMI and readmission for heart failure, unstable angina or chest pain.