Cardiovascular response to orthostatic stress: multiscale modeling with focus on the coronary circulation

Cardiovascular modeling has shown impressive potentialities in understanding and predicting cardio vascular system (CVS) functioning, disorders and response under several conditions. By adopting a recent closed-loop multiscale model of the entire CVS, we computationally investigated the coronary hemodynamics response to passive orthostatic stress elicited by upright head-up tilt (HUT). Beside known CVS consequences following passive upright tilting – such as heart rate and blood pressure augmentation, stroke volume and cardiac output drop – we found that coronary blood flow (CBF) was enhanced by up to 18% at 70◦ HUT, in response to a coronary perfusion pressure (CPP) rise of 26%.