Effect of direct intramyocardial autologous stem cell grafting in the sub-acute phase after myocardial infarction.

Background: To assess the efficacy and safety of intramyocardial autologous bone marrow mononuclear stem cells (BMMNC) grafting combined with coronary artery bypass grafting (CABG) on ventricular remodeling and global and regional wall motion after acute transmural myocardial infarction (AMI).

Methods: Randomized controlled trial including 20 patients with non-revascularized transmural AMI, left ventricular ejection fraction (LVEF) lower than 50% and surgical indication for CABG. The stem cell group was treated with BMMNC grafting by direct intramyocardial injection between the 10th and 15th days after AMI (subacute phase) combined with CABG under cardiopulmonary bypass; the control group was only treated with CABG. Magnetic resonance imaging with gadolinium and stress echocardiography were performed presurgery and 9 months postsurgery.

Results: Seventeen patients completed the follow-up. The baseline characteristics of both groups were homogeneous. No significant differences were found in the increase in LVEF (control: 6.99±4.60, cells: 7.47±6.61, P=0.876) or in the decrease in global (control: 0.28±0.39, cells: 0.22±0.28, P=0.759) or regional (control: 0.52±0.38, cells: 0.74±0.60, P=0.415) wall motion indices between the control and stem cell groups of AMI patients. No differences were found in the recovered non-viable segments (control: 1.29±1.11, cells: 2.50±1.41, P=0.091) or in the decrease in end-diastolic (control: 14.05±19.72, cells: 18.40±29.89, P=0.725) or end-systolic (control: 15.42±13.93, cells: 23.06±25.03, P=0.442) volumes. No complications from stem cell grafting were observed.

Conclusions: The results from our study reported herein suggest that intramyocardial BMMNC administration during CABG in patients with AMI causes no medium- to long-term improvement in ventricular remodeling.