Effects of aortic valve stenosis on coronary artery flow using an in-vitro flow model

Abstract

Patients with aortic valve stenosis (AS) may experience angina pectoris even if they have angiographically normal coronary arteries. Angina is associated with a marked increase in the risk of sudden death in AS patients. Moreover, as only a few in vitro models describing the interaction between LV and aortic pressures, and the coronary circulation have been reported, we have developed an in vitro model that is able to mimic the coronary circulation under physiological and pathological conditions. After validating the model under physiological conditions, we have examined and quantified the effects of AS on a model of the normal left coronary artery. Moreover, this coronary in vitro model allowed us to validate the mathematical model of the interaction between AS and the coronary flow circulation (V³C) previously developed in the laboratory. In the coronary in vitro model without AS, the amplitude and the shape of coronary flow were similar to in vivo measurements obtained under physiological conditions, as described by Judd et al. The presence of an AS induced an increase of the maximum and the mean coronary flow rate (113% and 109% respectively, for a very severe AS). Furthermore, when AS was very severe, a retrograde flow occurred during systole. Comparison between the in vitro model and the V³C mathematical model without and with AS has shown a very good agreement, even if a minor difference could be observed. So our coronary in vitro model allowed us to quantify the effects of AS on a normal coronary left artery and to validate the V³C mathematical model.