The coronary artery--from geometry to RNA turnover

This review compares the geometry of conduit coronary arteries in man and animals, namely the wall/diameter ratio (1:7.4 and 1:15 respectively). The left and right ventricle volume determines the geometry (segment length and diameter) of both branches of the left coronary artery: ramus interventricularis anterior and ramus circumflexus; the range of deformation of the latter was substantially smaller. The heterogeneity of deformation was also found along the ramus interventricularis anterior, the deformation decreasing towards the apex. The above relations have consequences (i) on the haemodynamics (passive changes in conduit segment resistance), (ii) the deformation of coronary arteries triggers metabolic processes in the coronary wall. Four hours' lasting cardiac volume or pressure overload brought about an increase in the RNA content not only in the myocardium, but also in the coronary artery. The process is reversible. Moreover, the range of the RNA increase is in full concert with the heterogeneous deformability of the respective segment of the coronary tree.