A closed-chest porcine model of coronary dissection and thrombosis

Coronary dissection and thrombosis are important as pathophysiological mechanisms in acute coronary syndromes and as consequences of various interventional procedures. The present study was designed to develop and characterize a simple percutaneous method to produce coronary dissection and thrombosis in the pig.

The porous balloon (Wolinski type) was slightly oversized (balloon-to-artery ratio, 1.21 +/- 0.08) and placed in the left anterior descending artery in 12 domestic pigs using standard percutaneous techniques. The balloon was inflated using a pressure-activated syringe at 5 atm to deliver 1 ml of either saline or a small amount of bovine thrombin (500 units) in saline. The balloon was withdrawn, serial angiograms recorded, and ECG and aortic pressure were monitored throughout. At coronary occlusion or at 30 min, the hearts were removed and fixed for histological analysis.

Seven pigs received thrombin and five received saline. On microscopic examination the internal elastic lamina was disrupted in all arteries in both groups. Subintimal and medial dissection was noted in 80% of arterial cross sections in the saline group, and 86% in the thrombin group. Partial occlusion of the coronary artery with thrombus was seen in 20% of samples in the saline group and in 43% of the thrombin group. Thrombus with complete occlusion of the coronary artery was observed in 86% of thrombin-treated vessels but in none of the arteries that received saline. Complete occlusion was observed at 28 +/- 9 min by angiography.

Percutaneous delivery of a small amount of thrombin through a slightly oversized porous balloon catheter produces coronary dissection and thrombosis in a more reproducible and timely fashion than previously described methods. This model may be useful for testing interventional and pharmacologic treatment strategies.