Impact of preoperative left ventricular function and time from infarction on the long-term benefits after intramyocardial CD133+ bone marrow stem cell transplant

Objective: Our objective was to elucidate long-term clinical and functional effects of intramyocardial stem cell transplant and to identify patients who will show sustained benefit. Methods: Long-term outcomes of 35 patients after intramyocardial CD133(+) bone marrow stem cell transplant during coronary artery bypass grafting were compared with those of a control group of 20 patients after coronary artery bypass grafting alone. Clinical effects were assessed with the New York Heart Association classification system and the Minnesota Living With Heart Failure questionnaire. Electrocardiography, 24-hour Holter monitoring, echocardiography, myocardial perfusion scanning, magnetic resonance imaging, and computed tomography were performed. Logistic regression analyses were used to identify prognostic factors for improvement in long-term left ventricular ejection fraction after stem cell treatment. Results: The stem cell group revealed similar New York Heart Association and life quality scores to the control group. Myocardial perfusion score at the area of risk was significantly increased in the stem cell group after 36-month follow-up (P = .024 vs control). Multivariate logistic regression analysis revealed a 44-fold higher probability of at least 5% improvement in left ventricular ejection fraction for patients with preoperative left ventricular ejection fraction not greater than 40% than for patients with preoperative ejection fraction greater than 40% (P = .018). Furthermore, patients operated on between 7 and 12 weeks after myocardial infarction had a 56-fold higher chance of at least 5% improvement in left ventricular ejection fraction than patients treated later than 12 weeks after infarction (P = .023). Conclusions: Intramyocardial stem cell therapy was safe but lacked significant lasting benefits beyond 6 months in our study cohort with a limited number of patients. Preoperative left ventricular ejection fraction and time since myocardial infarction may be critical parameters for selection of patients who can benefit most from intramyocardial stem cell treatment during coronary artery bypass grafting. (J Thorac Cardiovasc Surg 2011;142:1530-9)