Correlation of ischemic area and coronary flow with ameroid size in a porcine model

Abstract

Background: Ameroid constriction has long been used to induce chronic hibernating myocardium in animal models.

Materials and methods: Thirty-six pigs underwent surgical implantation of an ameroid constrictor around their left circumflex (LCx) coronary artery. The device had an internal diameter of 2.25 (n=9), 2.50 (n=16), or 2.75 (n=11) mm. Thrombolysis in Myocardial Infarction (TIMI) grade coronary flow was assessed angiographically during device placement and on postoperative d 30. The ischemic and total left ventricular (LV) areas were measured with endocardial voltage mapping (NOGA) on d 30.

Results: For ameroid constrictor diameters of 2.25, 2.50, and 2.75 mm, the ratio of the ischemic area versus the total LV area averaged 24% ± 10%, 21% ± 6%, and 23% ± 9%, respectively (P=NS). Coronary angiography revealed complete LCx occlusion in all animals. TIMI grade-1 flow was the statistical mode for all groups and was independent of constrictor diameter. Normalization of the device diameter with the vessel diameter did not affect the statistical results.

Conclusions: For the range of ameroid constrictor sizes evaluated in this study, coronary flow and the ischemic LV area were independent of device size. The ischemic area and coronary flow created by ameroid constrictor placement were highly homogeneous and accurate for an experimental model of hibernating myocardium.