GEOMETRY OF THE CAPILLARY NET IN HUMAN HEARTS

The geometry of the coronary capillary bed in human hearts was studied using samples obtained during cardiac surgery of children operated fo r tetralogy of Fallot and samples from fresh normal hearts used for va lve harvesting. The results revealed a similar coronary capillary dens ity and heterogeneity of capillary spacing in samples from both groups . A double-staining method was used to distinguish between capillary s egments close to the feeding arteriole (proximal capillaries) and segm ents distant from the arteriole (distal capillaries). In both groups o f hearts, capillary segment length was consistently shorter on the ven ular than the arteriolar portion of the capillary. Similarly, capillar y domain areas were also smaller and the resulting capillary supply un it was smaller along venular portions compared to arteriolar regions o f the capillary bed. This distinctive geometry would provide advantage ous geometric conditions for tissue oxygen supply.