In vitro modeling of fluid dynamics in the left and right coronary arteries during rest and exercise conditions

Abstract

Accurate understanding and simulation of coronary artery perfusion are crucial for assessing the heart function under varying cardiac workloads. This is particularly important given that sudden cardiac death (SCD) events have been observed during intense physical activity, not only in individuals with congenital coronary anomalies but also in healthy individuals. In response, we developed a novel in vitro laboratory setup to study the fluid dynamics of the left (LCA) and right (RCA) coronary arteries, using an anatomically accurate model of a healthy human aortic root and ascending aorta under different workloads. A key achievement is the simultaneous measurement of pressure in the left ventricle (LV), aorta (Ao), LCA, and RCA, along with flow rates in both coronary arteries. This is the first study to provide high-resolution, simultaneous in vitro data on pressure and flow values in coronary arteries under both rest and exercise conditions. During rest, the aortic pressure waveform decreases linearly, while during exercise, it displays a secondary diastolic peak. This distinctive aortic pressure feature during exercise is reflected in the coronary fluid dynamics, highlighting differences in the mechanisms of rest and exercise conditions. The RCA pressure closely mirrors the aortic pressure under all conditions, but the LCA pressure shows a secondary diastolic peak during exercise, phase-shifted by \(\sim 0.2T\) from the cardiac cycle. This peak arises from a backward propagating pressure wave from its distal part, generated by myocardium contraction loads. Our findings highlight the amplified interaction of incident and reflected waves during exercise, making LCA perfusion highly sensitive to wave dynamics.