AN ANIMAL-MODEL OF CORONARY-THROMBOSIS AND THROMBOLYSIS - COMPARISONSOF VASCULAR DAMAGE AND THROMBUS FORMATION IN THE CORONARY AND FEMORALARTERIES AFTER BALLOON ANGIOPLASTY

The purpose of this study was to compare vascular damage and thrombus formation in the coronary and femoral arteries after balloon angioplas ty, and to develop a physiological animal model of intracoronary occlu sive thrombus using the balloon angioplasty technique. Angioplasty of the left anterior descending coronary arteries of 14 dogs was performe d with an oversized balloon catheter at a high inflation pressure (150 PSI). This was followed angiographically (PTCA protocol). Dogs that s howed arterial occlusion were divided into 2 groups. The dogs in 1 gro up were killed with an overdose of sodium pentobarbital, and those in the other group were infused with a tissue-type plasminogen activator (t-PA; 300,000 unit/kg). Angioplasty of the femoral and profunda femor is arteries (n=5) was performed in 5 other dogs (PTA protocol). All of the animals were eventually sacrificed and tissue preparations were m ade from all 3 types of arteries. In the PTCA protocol, acute arterial occlusion was seen angiographically within 2 h in 10 of the 14 dogs. A histological study of the acutely occluded arteries (n=5) showed thr ombotic occlusion and severe arterial damage with medial tearing. T-PA was infused to 5 of the dogs with acute occlusion, and all showed rep erfusion. A histological study of these animals showed severe arterial damage, but no macroscopic thrombus. In 4 dogs without acute occlusio n, none of the 10 arteries examined were acutely occluded. In the PTA protocol, none of the 10 arteries were acutely occluded. A histologica l study showed fewer thrombi and less severe arterial damage. The medi a and adventitia of normal coronary arteries had less elastic fiber th an the normal femoral and profunda femoris arteries. Differences in ar terial structure can account for the differences in arterial damage an d thrombus formation. Thus, oversize balloon angioplasty of canine cor onary arteries frequently resulted in acute thrombotic occlusion. This method may be useful as an animal model of thrombosis.