Stem cells treatment in chronic ischemic heart disease: a narrative review

Chronic ischemic heart disease remains a major cause of morbidity and mortality worldwide. Several trials have been performed to evaluate benefit of stem cells transplantation to restore cardiac function in short- and long-term period after myocardial infarction. This narrative review analyzes 24 clinical trials between 2005 and 2023 comprising 1824 patients with chronic heart disease without heart failure. Percent increase in left ventricular ejection fraction (LVEF) and decrease in New York Heart Association (NYHA) class at 6/12 months after stem cells transplantation are reported. Thirteen trials showed a statistically significant percent LVEF increase between 4% to 19% at 6/12 months after stem cells transplantation (p values from 0.05 to 0.0001). No significant differences in LVEF were observed between patients who underwent intracoronary or intramyocardial transplantation. NYHA class decrease from severe to mild/moderate was demonstrated in 10 trials reporting a significant LVEF increase. Patients transplanted with bone marrow and peripheral blood CD133+ stem cells showed a doubling of percentage LVEF increase in comparison to patients transplanted with CD133- cells. This narrative review reports the conflicting results on this topic. Multicenter randomized clinical trials should be performed to define the efficacy of stem cells transplantation in chronic ischemic heart disease.