AS autologous CD34⁺ (auto-CD34⁺) cells appear to be an attractive option for treating refractory angina, a patient-level pooled analysis of randomized double-blinded trials compared intramyocardial (IM) auto-CD34⁺ cells with IM placebo injections to affect total exercise time (TET), angina frequency (AF), and major adverse cardiac events (MACE) and determined the efficacy and safety of auto-CD34⁺ cells. It was found that treatment resulted in improvements in TET and AF at 3-, 6- and 12-months, as well as a reduction in 24-month mortality. The findings revealed that TET was improved by 46.6 s, 49.5 s and 44.7 s at 3, 6 and 12 months, respectively. Moreover, the corresponding figures for relative frequency of angina were 0.78, 0.66 and 0.58, respectively. Autologous CD34 + cell therapy considerably decreased mortality (12.1% vs. 2.5%) and MACE (38.9% vs. 30%) at 24 months, results published in the European Heart Journal.