Transient occlusion of the left anterior descending coronary artery in pigs.

The purpose of this study was to define a model of transient coronary occlusion (CO) in the open-chest pig. The left anterior descending (LAD) coronary artery was occluded at its mid-length in 45 white pigs and reperfusion was performed after 30, 45, 60 or 90 min. One group of 9 animals with permanent CO served as control. During the occlusion period only slight hemodynamic changes were observed, but a period of ventricular arrhythmias was consistently observed between 15 and 30 min after CO, with an incidence of ventricular fibrillation (VF) in 8 cases (18%). All but 1 of the animals with VF could be defibrillated in less than 1 min or 3 electrical countershocks. Complex arrhythmias with marked hypotension were consistently observed after reperfusion. Histological examination showed a patent coronary artery lumen and minor changes in the LAD coronary artery at the site of occlusion in the reperfused animals and completely occluded arteries in the control group. Two pigs (4.4%) died during the night following CO. Transient CO can be performed safely in pigs with a very low complication rate and a high 24-hour survival rate.