Intravascular imaging of atherosclerotic human coronaries in a porcine model: a feasibility study

Abstract

To perform intravascular imaging of atherosclerotic human coronary conduits in an animal model under conditions of flow and cardiac motion that approximate those encountered in vivo. Given the lack of animal models of vulnerable plaque, a model which would allow imaging of human disease and simulate coronary motion and blood flow could advance the development of emerging technologies to detect vulnerable plaques. Human coronary segments from adult cadaver hearts were prepared as xenografts. In anesthetized Yorkshire pigs (45-50 kg) the chest was opened and the exposed aorta and right atrium were cannulated and attached in an end-to-end fashion to the human coronary xenograft, forming an aorto-atrial conduit. The xenograft was fixed to the anterior wall of the heart to simulate motion. Angiography and intravascular ultrasound (IVUS) of each graft were performed. Twelve human coronary grafts (10 from right coronary segments) were prepared and implanted successfully in seven animals. All animals tolerated the procedure. The average graft length was 39 +/- 2.3 mm. Blood flow rates distal to the graft were >100 ml/min in nine grafts. IVUS was performed in all 12 grafts and documented expansion of arterial (6.9%) and luminal (9.3%) dimensions during the cardiac cycle (P < 0.001 for both). There was a wide range of coronary atherosclerotic pathology within the grafts, including intimal thickening, fibrocalcific plaque, and deep lipid pools. This human-to-porcine coronary xenograft model allows intravascular imaging of human coronary pathology under conditions of blood flow and motion, and may be used to develop technologies aimed at identifying high-risk plaques.