Real-time assessment of flow reversal in an eccentric arterial stenotic model.

Plaque rupture is the leading cause of acute coronary syndromes and stroke. Plaque formation, otherwise known as stenosis, preferentially occurs in the regions of arterial bifurcation or curvatures. To date, real-time assessment of stenosis-induced flow reversal remains a clinical challenge. By interfacing microelectromechanical system (MEMS) thermal sensors with the high frequency pulsed wave (PW) Doppler ultrasound, we proposed to assess flow reversal in the presence of an eccentric stenosis. We developed a 3-D stenotic model (inner diameter of 6mm, an eccentric stenosis with a height of 2.75 mm, and width of 21 mm) simulating a superficial arterial vessel. We demonstrated that heat transfer from the sensing element (2 x 80 μm²) to the flow field peaked as a function of flow rates at the throat of the stenosis along the center/midline of arterial model, and dropped downstream from the stenosis, where flow reversal was detected by the high frequency ultrasound device at 45 MHz. Computational fluid dynamics (CFD) codes are in agreement with the ultrasound-acquired flow profiles upstream, downstream, and at the throat of the stenosis. Hence, we characterized regions of eccentric stenosis in terms of changes in heat transfer along the midline of vessel and identified points of flow reversal with high spatial and temporal resolution.