Integrated control of coronary microvascular tone: in series mechanisms for a differential regulation of flow and capillary pressure

Myocardial signals modulate vasomotor tone of most distal segments of the coronary microcirculation to fit oxygen availability to the largely variable oxygen demand. This flexibility implies an adaptation of coronary resistance in vascular segments upstream from the action of metabolic signals to maintain a stable capillary pressure despite the variable flow rate. This task is accomplished by different mechanisms cooperating in series to modulate the pressure drop along the vascular tree and encompasses both endothelium and myogenic control of vascular tone. Altogether, these factors configure a true intrinsic control system whose role is control of intravascular pressure and whose alterations can contribute to atherosclerosis progression.