Abstract 365: Extracorporeal Cardiac Shock Wave Therapy Ameliorates Left Ventricular Remodeling after Myocardial Ischemia-Reperfusion Injury in Pigs
We have previously demonstrated that low-energy extracorporeal cardiac shock wave (SW) therapy effectively induces angiogenesis and improves cardiac function in a porcine model of chronic myocardial ischemia and in patients with end-stage coronary artery disease. We also have recently demonstrated that SW therapy improves left ventricular (LV) remodeling after acute myocardial infarction (AMI) caused by a permanent coronary artery ligation in pigs in vivo. However, in the clinical setting, most of the patients with AMI receive reperfusion therapy. In this study, we thus examined whether our SW therapy ameliorates LV remodeling after myocardial ischemia-reperfusion (I/R) injury in pigs. Sixteen pigs were subjected to ischemia (90 min occlusion of the left anterior descending coronary artery) and reperfusion using a balloon catheter. Three hours after the reperfusion, they were randomly assigned to the 2 groups with or without the SW therapy to the ischemic border zone (0.09 mJ/mm2, 200 pulses/spot, 9 spots/animal, n=8 each) on day 1, 3 and 5. Control group received the same procedures but without the SW therapy on the same schedule. After I/R, the maximum serum concentrations of cardiac troponin T were comparable between the 2 groups, indicating the comparable extent of myocardial I/R injury. Furthermore, on day 1 after I/R and before the SW treatment, LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV end-diastolic pressure (LVEDP) and wall thickening fraction (WTF) of ischemic border zone were all comparable between the 2 groups. Four weeks after I/R, LVEDV was markedly increased and LVEDP was elevated in the control group, and both indices of LV remodeling were significantly ameliorated in the SW group (LVEDV, 100±7 vs. 130±9 ml; LVEDP, 4±1 vs. 11±2 mmHg, both P<0.05). Consequently, LVEF was significantly improved in the SW group as compared with the control group (36±3 vs. 28±2 %, P<0.05). In the SW group, as compared with the control group, WTF (24±4 vs. 15±2 %, P<0.05) and capillary density in the ischemic border zone (1614±50 vs. 1227±48/mm2, P<0.01) also were increased. These results indicate that our SW therapy also is effective to ameliorate LV remodeling after myocardial I/R injury in vivo.