The role of vascular resistance on coronary perfusion: differences between healthy and anomalous coronary origin under rest and exercise conditions

Abstract

Sudden cardiac death (SCD) is a leading cause of mortality in young athletes and is frequently linked to congenital anomalies of the coronary arteries, particularly the anomalous origin of the left coronary artery from the right sinus of Valsalva (AOLRS). Despite extensive research, the underlying mechanism remains unclear—especially in cases without structural cardiac abnormalities. In our previous studies, we identified abnormal coronary wave dynamics (“wave pathology”) as a potential factor impairing perfusion in such anomalies. Building on these findings, the present study investigates the hemodynamic consequences of changes in distal coronary resistance in normal and anomalous coronary anatomies. Two in-vitro anatomical models—a normal configuration and an AOLRS model with an intramural aortic segment—were tested under rest and exercise conditions in a physiological simulator. By independently varying distal coronary resistances as an experimental representation of distal vasodilation, we observed that decreasing resistance increased flow in the manipulated coronary branch and was accompanied by a modest reduction in mean aortic pressure. In a separate set of tests, decreasing mean aortic pressure while maintaining the coronary resistance settings reduced both LCA and RCA flow, with a stronger pressure-flow dependence during exercise. These results identify a coupling between distal resistance, aortic pressure, and coronary perfusion whose effect becomes more important during exercise. In the anomalous model, this mechanism acts in a coronary circulation in which altered wave propagation and reflection were previously observed, and may add to the hemodynamic vulnerability associated with AOLRS. Its contribution to exercise-induced ischemia and SCD remains to be established.