Development of collaterals. Application of external subcritical fixed constrictors in a canine model

Abstract

A canine model for a standardized induction of collaterals is presented with a fixed external constrictor that is not designed to induce an occlusion of the coronary artery and at least over the timespan of 6 weeks does not impair perfusion under resting conditions in the myocardium-at-risk. The coronary constriction was standardized by a reduction of the postocclusive reactive hyperemia of 50%. Flow measurements were performed by flowmeter and by radioactive microspheres acutely and after an interval of 6 weeks of constriction. The results showed an increase of the collateral flow from 21.2±11.8 ml/100g/min⁻¹ to 42.8±16.2 ml/100g/min⁻¹ (p−1 as compared to 33.1±17.3 ml/100g/min⁻¹ (p−1 auf 42,8±16,2 ml/100 g/min⁻¹ (p−1 gegenüber 33,1±17,3 ml/100 g/min⁻¹ (p<0,05). Die mit dem Flowmeter gemessene reaktive Hyperämie nahm über 6 Wochen um 21% ab, bedingt durch eine Verengung der Stenosen aufgrund von Intimareaktionen im Konstriktorbereich, während die mit Mikrosphären gemessene Durchblutung aufgrund zusätzlicher Kollateralversorgung um 9% zunahm.