Abstract 15252: Segmental Myocardial Perfusion Improves after Repeated Intramyocardial Cell Injection

Introduction: We previously demonstrated that intramyocardial bone marrow mononuclear cell (MNC) injection improves segmental myocardial perfusion. This study was designed to evaluate in patients with recurrent refractory angina the effect of repeated injection on segmental myocardial perfusion. Methods: Twenty-one patients with recurrent refractory angina pectoris, who received 100x10^6 autologous MNC intramyocardially using the NOGA-system for a second time, were enrolled. Single-photon emission computed tomography was performed at baseline and 3 months after both injection procedures. The myocardium was divided into 17 segments and in both stress and rest images, segmental tracer activity was categorized on a 4-point scale. (1=>75%; 2=50%-74%; 3=25%-49%; 4=<25%) Segments demonstrating increased perfusion of at least 1 point in stress or rest perfusion were categorized as improved. Results: The second injection procedure was 4.6 ± 2.5 years after the first. In total, 139 segments were injected for the first time during either of the procedures, of which 80(58%) segments improved. Repeated injection in the same segment was performed in 45 segments. Of these segments, 18(40%) improved, less than after a first injection (P=0.030). Repeatedly injected segments can be subdivided in 29 previously responding segments (improved after the first injection) and 16 previously non-responding segments (not improved after the first injection). Of the responding segments, 13(45%) segments improved after repeated injection and of the non-responding segments, 5(31%) segments improved. This difference was not significant (P=.476). Conclusions: Segmental myocardial perfusion can improve after repeated intramyocardial MNC injection independently of the effect of the first injection, but the first injection is more effective.