NEW YORK (Reuters Health) – Intracoronary artery infusion of autologous stem cells after primary PCI or thrombolysis for acute myocardial infarction improves left ventricular ejection fraction and left ventricular volumes, according to the results of a systematic review and meta-analysis of 33 trials published in the Cochrane Library.
However, the ultimate clinical benefit is still uncertain. “The results of all trials together suggest a small reduction in the incidence of mortality and morbidity, in favour of BMSC (bone marrow-derived stem cell) treatment, but this finding is not statistically significant,” the authors report.
Dr. Enca Martin-Rendon, at John Radcliffe Hospital in Oxford, UK, and colleagues identified 20 more randomized trials to add to the 13 that were included in the last Cochrane review of the subject published in 2008. The current analysis includes data on a total of 1765 acute MI patients who were randomized to receive autologous BMSC treatment or not after undergoing standard primary revascularization.
Left ventricular ejection fraction was the main outcome measured in all trials. It improved significantly by a mean of 1.78 percentage points during the first year in patients given stem/progenitor cell treatment compared to controls, and the difference increased to 3.07% subsequently, the researchers found.
Also, they report, “With certain measurements and at certain times, stem cell treatment was observed to reduce left ventricular end systolic and end diastolic volumes (LVESV & LVEDV) and infarct size significantly in long-term follow up.”
While the relative mortality risk associated with stem cell treatment was 0.70, this failed to reach statistical significance, the report indicates. Similarly, differences in morbidity risk –measured by re-infarction, hospital readmission, restenosis and target vessel revascularization – were not significant.
As Dr. Martin-Rendon and colleagues point out, “Because mortality rates after successful revascularization of the culprit arteries are very low, larger number of participants would be required to assess the full clinical effect of this treatment.”
This is in fact being undertaken, according to a journal statement citing Dr. Anthony Mathur, a co-author of this Cochrane review and principal investigator for the BAMI trial. He noted, ”The BAMI trial will be the largest stem cell therapy trial in patients who have suffered heart attacks and will test whether this treatment prolongs the life of these patients.”
SOURCE:
Stem cell treatment for acute myocardial infarction
Cochrane Database Syst Rev 2012, Issue 2. Art. No.: CD006536.
