The Impact of Heart Rate and Cardiac Output on Retrograde Flow in the Human Thoracic Aorta

Abstract

Changes in aortic flow characteristics have previously been linked with cardiovascular disease (CVD). The purpose of the study is to determine the effects of heart rate (HR), cardiac output (CO), and the temporal flow profile on retrograde flow and wall shear stress (WSS) in the thoracic aorta. Pulsatile flow in a human thoracic aorta model was simulated for eleven combinations of HR (60–150 beats per minutes, BPM), CO and temporal flow profiles. Retrograde flow and WSS effects were characterized with common biomechanical metrics along with new markers. The results underpin the importance of temporal variation of the cardiac flow rate and the impact of the deceleration phase of systole and diastole on retrograde flow. During retrograde flow, the near-wall region may be stagnant (with low WSS) at low HR. At high HR, the WSS increases and becomes oscillatory in space and time. This finding may explain the clinical observation that increasing HR is associated with risk for CVD.