Autologous CD34+ Cell Therapy for Angina

Study Questions:

Does intramyocardial (IM) injection of autologous CD34+ cells improve outcomes in patients with refractory angina?


This was a meta-analysis of randomized, double-blind trials involving treatment with IM autologous CD34+ cells (n = 304) compared to placebo injection (n = 89). Endpoints included total exercise time (TET), angina frequency (AF), and major adverse cardiac events (MACE).


Autologous CD34+ cell therapy improved TET by 46.6 s at 3 months (p = 0.007), 49.5 s at 6 months (p = 0.016), and 44.7 s at 12 months (p = 0.065). AF was also reduced at 3 months (0.78; p = 0.032), 6 months (0.66; p = 0.012), and 12 months (0.58; p = 0.011) compared to placebo. CD34+ cell therapy also decreased mortality (12.1% vs. 2.5%; p = 0.0025) with a trend to MACE reduction at 24 months (38.9 vs. 30.0%; p = 0.14).


The authors concluded that autologous CD34+ cell treatment resulted in clinically meaningful and durable improvements in TET and AF, as well as a reduction in 24-month mortality in this patient-level meta-analysis.


Refractory angina not amenable to coronary revascularization remains a vexing clinical problem and is associated with increased mortality. Cell therapy using endothelial progenitor cells (CD34+) is attractive given the potential for promotion of angiogenesis, which could increase myocardial blood flow and relieve angina. However, trials performed thus far have been underpowered (or terminated early for financial reasons), and the efficacy of this approach remains unsettled. The current meta-analysis is helpful, although still underpowered to make definitive conclusions, and supports further clinical investigation in this area. Additional progress in identifying relevant downstream proangiogenic mediators could also lead to more feasible and effective therapeutic approaches to refractory angina.

Clinical Topics: Acute Coronary Syndromes

Keywords: Acute Coronary Syndrome, Angina Pectoris, Cell- and Tissue-Based Therapy, Endothelial Cells, Exercise Tolerance, Injections, Ischemia, Outcome Assessment (Health Care), Stem Cell Research, Vascular Diseases

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