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<p>Left ventricular assist devices (LVADs) are mechanical circulatory support used in case of heart failure; however, their implantation can lead to hemodynamic complications, including aortic regurgitation (AR) and vascular damage. In this study, we analyze the impact of LVAD outflow graft inclination angles on aortic flow patterns, wall shear stress (WSS) distribution, and turbulent kinetic energy (TKE) using computational fluid dynamics (CFD) simulations. Simulations were performed in a patient-specific aortic geometry for four idealized graft angles (45°, 60°, 75°, and 90°) across three cardiac phases: systole, diastole with a closed aortic valve (AV-closed), and diastole with aortic regurgitation (AR). A full patient-specific model incorporating a real graft inclination of 89° was also analyzed for comparison. Our simulation results demonstrated that smaller inclination angles (e.g., 45°) induce elevated WSS at the brachiocephalic artery (BCA) branch and pronounced recirculation zones in the aortic lumen. In contrast, steeper angles (e.g., 90°) cause high WSS and recirculating flow near the aortic root and valve, which may exacerbate the risk of AR. The patient-specific 89° graft closely resembles the 90° idealized model, but exhibits broader WSS distribution at epiaortic branch inlets, higher outer wall WSS, and more complex vortices resulting from sharply bent and narrowed cannula. The left common carotid artery (LCCA) consistently exhibited the highest WSS among epiaortic vessels, which might be attributed to its smaller diameter and higher blood flow velocity. Hemolysis was assessed using shear strain rate and scalar shear stress (SSS), showing strong sensitivity to graft inclination, with the 75° configuration producing the largest high-shear volume fractions, while steeper angles sustained elevated shear under regurgitant conditions. These findings highlight the importance of optimizing LVAD outflow graft positioning to mitigate adverse hemodynamic effects on both aortic valve (AV) and carotid arteries.</p> Graphical abstract

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Hemodynamic impact of LVAD outflow graft inclination angles on aortic regurgitation

  • 期刊论文

  • 发表日期：

    2026年6月16日

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  • Jaehyeon Song,
  • Shehnaz Akhtar,
  • Sang-Wook Lee,
  • Hong Min Kim,
  • Jong-Chan Youn,
  • Kwan Yong Lee

摘要

Left ventricular assist devices (LVADs) are mechanical circulatory support used in case of heart failure; however, their implantation can lead to hemodynamic complications, including aortic regurgitation (AR) and vascular damage. In this study, we analyze the impact of LVAD outflow graft inclination angles on aortic flow patterns, wall shear stress (WSS) distribution, and turbulent kinetic energy (TKE) using computational fluid dynamics (CFD) simulations. Simulations were performed in a patient-specific aortic geometry for four idealized graft angles (45°, 60°, 75°, and 90°) across three cardiac phases: systole, diastole with a closed aortic valve (AV-closed), and diastole with aortic regurgitation (AR). A full patient-specific model incorporating a real graft inclination of 89° was also analyzed for comparison. Our simulation results demonstrated that smaller inclination angles (e.g., 45°) induce elevated WSS at the brachiocephalic artery (BCA) branch and pronounced recirculation zones in the aortic lumen. In contrast, steeper angles (e.g., 90°) cause high WSS and recirculating flow near the aortic root and valve, which may exacerbate the risk of AR. The patient-specific 89° graft closely resembles the 90° idealized model, but exhibits broader WSS distribution at epiaortic branch inlets, higher outer wall WSS, and more complex vortices resulting from sharply bent and narrowed cannula. The left common carotid artery (LCCA) consistently exhibited the highest WSS among epiaortic vessels, which might be attributed to its smaller diameter and higher blood flow velocity. Hemolysis was assessed using shear strain rate and scalar shear stress (SSS), showing strong sensitivity to graft inclination, with the 75° configuration producing the largest high-shear volume fractions, while steeper angles sustained elevated shear under regurgitant conditions. These findings highlight the importance of optimizing LVAD outflow graft positioning to mitigate adverse hemodynamic effects on both aortic valve (AV) and carotid arteries.

Graphical abstract