Background: Recent trials have shown that intracoronary infusion of bone marrow cells (BMCs) improves functional recovery after acute myocardial infarction. However, whether this treatment is effective in heart failure as a consequence of remodeling after organized infarcts remains unclear. In this randomized trial, we assessed the hypothesis that direct intramyocardial injection of autologous mononuclear bone marrow cells during coronary artery bypass graft (CABG) could improve global and regional left ventricular ejection fraction (LVEF) at 4-month follow-up.
Methods and results: Twenty patients (age 64.8+/-8.7; 17 male, 3 female) with a postinfarction nonviable scar, as assessed by thallium (Tl) scintigraphy and cardiac magnetic resonance imaging (MRI), scheduled for elective CABG, were included. They were randomized to a control group (n =10, CABG only) or a BMC group (CABG and injection of 60.10(6)+/-31.10(6) BMC). Primary end points were global LVEF change and wall thickening changes in the infarct area from baseline to 4-month follow-up, as measured by MRI. Changes in metabolic activity were measured by Tl scintigraphy and expressed as a score with a range from 0 to 4, corresponding to percent of maximal myocardial Tl uptake (4 indicates <50%, nonviable scar; 3, 50% to 60%; 2, 60% to 70%; 1, 70% to 80%; 0>80%). Global LVEF at baseline was 39.5+/-5.5% in controls and 42.9+/-10.3% in the BMC group (P=0.38). At 4 months, LVEF had increased to 43.1+/-10.9% in the control group and to 48.9+/-9.5% in the BMC group (P=0.23). Systolic thickening had improved from -0.6+/-1.3 mm at baseline to 1.8+/-2.6 mm at 4 months in the cell-implanted scars, whereas nontreated scars remained largely akinetic (-0.5+/-2.0 mm at baseline compared with 0.4+/-1.7 mm at 4 months, P=0.007 control versus BMC-treated group at 4 months). Defect score decreased from 4 to 3.3+/-0.9 in the BMC group and to 3.7+/-0.4 in the control group (P=0.18).
Conclusions: At 4 months, there was no significant difference in global LVEF between both groups, but a recovery of regional contractile function in previously nonviable scar was observed in the BMC group.