Introduction: Chronic ischemic heart disease remains a major cause of morbidity and mortality. Several clinical trials have been performed to evaluate benefit of stem cells transplantation to restore cardiac function. Aim: The review reports potential benefit of stem cells therapy in chronic ischemic heart disease. Methods: Trials were selected applying as search terms “bone marrow cells”, “stem cells”, “mesenchymal cells”, and “chronic ischemic heart disease” in www.pubmed.gov and Cochrane library from 2005 to 2023. Studies were included if they were randomized blinded trials, randomized unblinded trials, non-randomized trials. Left ventricular ejection fraction (LVEF) increase and New York Heart Association (NYHA) class decrease were the outcome parameters at 6 and 12 months follow up. Results: We analyzed 20 trials including 1812 patients (939 treated, 789 males, mean age 62 years). Bone marrow (BMC), peripheral blood (PBC), cardiac (CDC) or mesenchymal (MES) stem cells were utilized in 8, 5, 7 trials, respectively. Total number of transplanted cells ranged from 5 x 10 6 to 1,300 x 10 6 (median 70 x 10 6 ) depending on cell type, cell population purification, and transplantation route. Transplant procedure was intracoronary in 9 trials and intramyocardial in 11 trials. At baseline mean LVEF was 33.5 % (range 27.1 - 46.0 %). Eleven trials reported a statistically significant percent LVEF increase between 4% to 19% (mean 9.6%) at 12 months after stem cells transplantation ( p values ranging from 0.05 to 0.001). BMC and PBC stem cells were utilized in all these studies. A significant correlation was found between number of transplanted cells and percent LVEF increase (Pearson correlation coefficient 0.74, p = 0.01). Conclusions: Results seem to favor a moderate positive effect of stem cells transplantation in chronic ischemic heart disease at 12 months follow up. The positive effect was correlated with the number of transplanted cells. However, caution should be exercised in the evaluation of clinical trials due to the different stem cells utilized, transplant protocols and endpoints.
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