In vitro study on the pressure drop-flow relationship of a compliant coronary stenosis

The effect of a partially flexible stenosis on the pressure-drop-flow relationship was studied in an in vitro model of the coronary circulation. Partially compliant stenoses of different severities and degrees of flexible wall circumference were inserted into thin-walled latex tubing, and pressure and flow data were collected during simulated cardiac cycles. For each stenosis severity, the pressure drop increased with increasing fraction of flexible wall, while the flow rate decreased as compared to the corresponding rigid model. Furthermore, the pressure-drop-flow relationship of highly flexible severe stenoses presents an open-loop rather than a single curvilinear relation, reflecting a passive decrease in stenotic area during the diastolic high-flow period