Implantation of oxygen enhanced, three-dimensional microporous L-PLA polymers: a reproducible porcine model of chronic total coronary occlusion.

Abstract

We have hypothesized that oxygen enhanced three-dimensional microporous poly-L-lactic acid (L-PLA) bioabsorbable polymer constructs could be implanted to produce a subacute occlusion in a porcine coronary artery, forming a thrombofibrotic occlusion containing microvascular channels. Chronic total occlusion (CTO) is increasingly prevalent in patients who present for percutaneous interventions. No reproducible animal coronary model simulating human CTOs has previously been developed. Swine coronary arteries were cannulated and a microporous L-PLA polymer pledget was advanced into a preselected segment of coronary. The coronary arteries were angiographically re-imaged at day 3, day 10, and day 28, to document the presence or absence of an occlusion. Histopathology was also performed at each time point to evaluate the lesion characteristics. A novel three-dimensional L-PLA microporous polymer construct, when implanted into porcine coronary arteries, reproducibly results in the development of a CTO at day 3. The histopathology in this porcine coronary model of CTO at day 28 closely mimics human coronary CTO, including the presence of microvascular channels and dense collagen and elastic tissue in the occlusion.