Coronary circulation roughly follows Open tree fractal structure at the beginning of life and progresses to communicating mesh as the age advances. It is differentiated from rest of microcirculation in the following manners. Supply is for mechanical function unlike metabolic function.(cf liver, kidney,Spllen) It has the highest oxygen extraction almost extraction is complete. Its flow is during diastole unlike most of the organs where flow is predominantly systolic.
Flow has 2 compartments which have a diff physiologic characteristics. Roughly circulation can be divided into Epicardial ( meaning on the surface of the heart) and intramuscular. Intramuscular can be further subdivided into subendocardial ( means just beneath the inner layer) and rest. Most of the current tests can evaluate the epicardial compartment but there is no direct anatomical and only indirect ( FFR) for…
