MRI/MRS evaluation of cariporide in a canine long‐term model of reperfused ischemic insults

Purpose To examine with magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS) the long‐term effects of cariporide in a canine cardiac ischemia/reperfusion model. Materials and Methods Twenty‐two beagles underwent a 2‐hour occlusion followed by 10 days of reperfusion. Cine MRI and 31 P MRS were performed to monitor function and metabolism of the heart in the control ( N = 10) and cariporide ( N = 12) groups. Radioactively labeled microspheres were injected to determine coronary blood flow, and contrast‐enhanced ex vivo MRI assessed infarct volumes. Results Cariporide produced a significant reduction vs. controls, in intracellular pH, during ischemia ( P < 0.05) and at days 3 and 10 postreperfusion ( P < 0.0005). Functional recovery of the myocardium was significantly improved immediately upon reperfusion (percent of baseline: 63.5% ± 3.5% for controls, 90.5% ± 7.2% for cariporide) and at day 3, but not by day 10. Normalized infarct ratios (IRs) were similar for controls and cariporide (0.58 ± 0.08, 0.58 ± 0.06, respectively). Conclusion Cariporide augments early functional recovery, while delaying normalization of intracellular pH following ischemia/reperfusion, but confers neither long‐term functional or metabolic protection nor, most importantly, myocardial salvage. J. Magn. Reson. Imaging 2003;17:136–141. © 2002 Wiley‐Liss, Inc.