Myocardial distribution of asanguineous solutions retroperfused under low pressure through the coronary sinus.

Asanguineous retroperfusion of the coronary sinus can penetrate a significant microvascular bed in proximity to myocardial cells. Myocardial regions permeated by this technique are located in the apex, septum, endocardium, and free wall of the left ventricle. Retrograde drainage patterns heavily favor the Thebesian-sinusoid system over the capillary-arterial route by more than a 3:1 ratio. Microscopic india ink preparations, regional flow studies, and retrograde roentgenograms indicate that asanguineous cardioplegic agents and core cooling can penetrate important regions of the heart at a microvascular level and may be an alternative route when routine antegrade perfusion via the coronary arteries is unavailable or disadvantageous. Because the flows established are primarily venous (Thebesian), the use of this route for chronic revascularization may be limited as the metabolic implications have not been fully investigated.