Combined Use of Transmyocardial Laser Revascularization and Endothelial Progenitor Cells Enhances Neovascularization and Regional Contractility in a Canine Model of Ischemic Hearts

The purpose of this study was to determine the combined effect of transmyocardial laser re- vascularization （TMLR） and the implantation of endothelial progenitor cells （EPCs） on cardiac function of ischemic hearts in canines. The left anterior descending artery （LAD） was occluded to establish the canine model of acute myocardial infarct （AMI）. Four weeks later, the animals were randomly divided into four groups： TMLR group, in which transmyocardial laser-induced channels were established at the ischemic region; EPCs＋TMLR group, in which EPCs were locally transplanted into laser-induced chan- nels at the ischemic region; EPCs group, in which the EPCs were injected into the ischemic region; con- trol group, in which the AMI animals received neither TMLR nor EPCs. The peripheral blood （50 mL） was sampled in all groups. Mononuclear cells from the peripheral blood were separated and cultured to obtain spindle-shaped attaching （AT） cells in vitro. AT cells were labeled with 1, 1 ＇-dioctadecyl-1 to 3,3, 3＇,3＇-tetramethyl-indocarbocyanine perchlorate （DiI） before injecting into the laser-induced channels or ischemic region. Four weeks after the first operation, TMLR was performed in the TMLR group and EPCs＋TMLR group, and at the same time, the EPCs originating from the AT cells were mixed with cal- cium alginate （CA）. Then the EPCs-CA composites were implanted into myocardial channels induced by laser in the EPCs＋TMLR group, and into the myocardial infarct area in the EPCs group. All dogs underwent echocardiography at second month after LAD occlusion. Finally the samples of myocardium around the LAD were subjected to histochemical and immunohistologic examinations. The results showed there was no significant difference in the diameter of left atrium and ventricle before treatment among all groups （P〉0.05）. Eight weeks after modeling, the regional contractility in the LAD territory in the EPCs＋TMLR group was increased as compared with control group and TMLR group, but there was no significant difference between control group and TMLR group. Neoangiogenesis was observed in the EPCs＋TMLR group, and the fibrosis was seen in the TMLR group. There was no significant dif- ference in neoangiogenesis around the channels induced by laser among EPCs＋TMLR, EPCs and TMLR groups. It was concluded that TMLR combined with EPCs could improve the regional and global cardiac function in AMI, and augment neovascularizaiton in channels of ischemic myocardium induced by laser.

Single-center report of 5-year follow-up on 94 patients underwent transmyocardial laser revascularization

Background Transmyocardial laser revascularization （TMLR） has been used in the treatment of patients with end-stage coronary artery disease （CAD） since 1990. The aim of this study was to evaluate the long-term effectiveness of TMLR in patients with diffuse CAD.Methods Ninety-four consecutive patients underwent TMLR in one center from July 1997 to December 2000. The follow-up data of these patients were obtained through face-to-face, mail questionnaires, or telephone interviews in July 2004 and December 2004. Four cases failed to respond. Mean follow-up time was （5.5±1.0） years. Results Mean Canadian Cardiovascular Society （CCS） angina scores of TMLR patients were 3.1±0.8 at baseline, 1.7±0.9 at 1 year （P〈0.05）, 1.7±0.9 at 3 years （P〈0.05）, and 1.9±0.9 at 5 years （P〈0.05）. At an average of 5 years, 69% of the patients had 〉 1 angina class reduction, mean NYHA class level （1.9±0.9） ameliorated compared to the baseline （2.5±0.7, P〈0.001）, the rate of re-hospitalization was 2.7 times/person. Kaplan-Meier survival rate was 87% at 1 year, 69% at 3 years and 64% at 5 years. The causes of death were attributed more to heart failure （58.9%） and myocardial infraction （14.7%） after TMLR. The patients with no angina relief, or who died after TMLR, had a higher percentage of preoperative unstable anginas or prior myocardial infraction compared to the survivors. The assorted shapes of myocardial laser channels were detected in some patients by the color Doppler velocity technique. Conclusions TMLR provided a long-term improvement in the quality of life, including CCS angina class or NYHA heart functional class for about 70% of Chinese patients with severely disabling angina pectoris. The various myocardial laser channels would always be visible after TMLR. 5-years after TMLR as a sole therapy, the survival rate of the patients was 64%.