Branching patterns in coronary artery and ischemic areas induced by coronary arterial occlusion in the CLAWN miniature pig.

This study of 28 CLAWN miniature pigs (male 17, female 11, mean weight 29 kg) was undertaken to investigate the coronary arterial branching patterns and the ischemic area induced by surgical occlusion of the left anterior descending artery (LAD) and change in the ischemic area over time. These results were compared with those in dogs, which have frequently been used in myocardial ischemic research. Regarding the coronary arterial branching pattern, there were fewer ventricular branches from the right and left coronary arteries than in dogs. The septal branches arose from only the LAD and the posterior descending artery (PD). The largest septal artery branched from the LAD. There were two types of septal artery branching patterns. In approximately 80% of the CLAWN miniature pigs, the PD arose from the right coronary artery (Right dominance). The peculiarity of the coronary arterial branching pattern in the CLAWN miniature pigs was more similar to human beings than to dogs. The ischemic area induced by occlusion at three-fifths distal section of the LAD was 12.1% to 22.6% (mean 17.1%) of the left ventricle. The ischemic area in all animals that died of global left ventricular malfunction and hemodynamic instability after LAD occlusion was more than 25% of the left ventricle.