A novel experimental thrombotic myocardial infarction and primary angioplasty model in atherosclerotic swine

Abstract

We sought to develop a reproducible, percutaneous basic science and translational animal model for the generation of thrombotic occlusion acute myocardial infarction in adult atherosclerotic pigs. A vascular coil COOK TORNADO® 38 inches (3–3.5 × 20–50 mm) was placed in the right coronary artery or the left anterior descending artery in 26 downsized spontaneously hypercholesterolemic pigs and left untreated until a thrombotic intracoronary occlusion was present. After the angiographic confirmation of total occlusion, we proceeded to crossing the newly formed thrombotic occlusion with a guidewire, followed by pre-dilatation with a semi compliant balloon, thrombus visualization with Optical Coherence Tomography (OCT) imaging and, finally, deployment of a stent and repeated OCT. After revascularization, we calculated the index of microcirculatory resistance (IMR) to estimate microvascular obstruction. AMI was confirmed by ECG, biochemical, histological, macroscopic examination and TTC imaging. After feasibility phase (6 animals), acute thrombotic occlusion was achieved in 20 pigs. In total, 18 were successful revascularized and survived until the previously selected time for sacrifice. Time to occlusion after coil placement was 69 ± 29 min, thrombus formation was confirmed by OCT, thrombin-antithrombin complexes (TAT) measurements and pathology examination. Myocardial necrosis by troponin I elevation, myocardial staining and pathology examination. Distal thrombotic embolization and microvascular obstruction were supported by increased IMR and pathology examination. Thrombotic occlusion AMI in miniaturized adult spontaneously atherosclerotic pigs is feasible by percutaneous intracoronary placement of a coil. The reperfusion by angioplasty mirrors human pathological conditions with myocardial infarction, necrosis and distal embolization. Our model closely simulates human presentation of AMI and can be used to evaluate antithrombotic agents and primary angioplasty techniques.