RESUMO
Objective:To evaluate the effect of remote ischemic conditioning (RIC) on left ventricular (LV) myocardial perfusion, myocardial viability, LV remodeling, regional and global LV function serially following acute myocardial infarction (AMI) in Chinese mini-pigs.Methods:AMI was established in 12 Chinese mini-pigs (8 males, 4 females; age: 6-8 months) and they were randomly divided into RIC group ( n=6) and non-RIC group ( n=6). RIC was performed in pigs by blood pressure inflation on the lower limbs for 5 min period and 4 cycles immediately after surgery. A series of myocardial perfusion imaging and gated 18F-fluorodeoxyglucose (FDG) myocardial metabolism PET/CT imaging were performed longitudinally at the 1st, 14th, 28th and 56th days after AMI, and parameters including total perfusion defect (TPD), hibernating myocardium (HM), Scar, left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), summed motion score (SMS), summed thickening score (STS) and changes of these parameters were obtained. Independent-samples t test and Mann-Whitney U test were used to analyze data. Results:Nine Chinese mini-pigs survived after surgery and were performed imaging. Compared to non-RIC group ( n=4), HM at the 28th ((6.0±2.4)% vs (17.0±4.6)%; t=-4.158), TPD 14th-1st ((-11.8±5.4)% vs 9.0%(4.5%, 15.0%); z=2.449), TPD 28th-1st ((-15.3±3.9)% vs (12.0±3.0)%; t=-10.071), TPD 56th-1st ((-18.0±6.5)% vs 9.0%(4.5%, 12.0%); z=2.449), HM 28th-1st ((-10.5±6.9)% vs (8.3±2.1)%; t=-4.507), HM 56th-1st (-15.0%(-17.5%, -8.5%) vs 2.0%(0%, 7.0%); z=2.449) and LVEDV 14th-1st (-0.5(-2.5, 0) ml vs (13.0±4.4) ml; z=2.470) were reduced in RIC group ( n=5; all P<0.05). Conclusion:RIC can improve myocardial perfusion, delay LV remodeling in the acute stage and salvage hibernating myocardium in the subacute stage and chronic stage.