Matteo Selmi1,2, Wei-Che Chiu3, Venkat Keshav Chivukula4, Giulio Melisurgo5, Jennifer Ann Beckman6, Claudius Mahr6, Alberto Aliseda4, Emiliano Votta1, Alberto Redaelli1, Marvin J Slepian3,7, Danny Bluestein3, Federico Pappalardo5,8,9, Filippo Consolo1,8,9. 1. 1 Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy. 2. 2 Department of Surgery, Division of Cardiac Surgery, Università di Verona, Verona, Italy. 3. 3 Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA. 4. 4 Department of Mechanical Engineering, University of Washington, Seattle, WA, USA. 5. 5 Anesthesia and Cardiothoracic Intensive Care, San Raffaele Scientific Institute, Milano, Italy. 6. 6 Division of Cardiology, University of Washington, Seattle, WA, USA. 7. 7 Departments of Medicine and Biomedical Engineering, The University of Arizona, Tucson, AZ, USA. 8. 8 Advanced Heart Failure and Mechanical Circulatory Support Program, San Raffaele Scientific Institute, Milano, Italy. 9. 9 Università Vita-Salute San Raffaele, Milano, Italy.
Abstract
INTRODUCTION: : Despite significant technical advancements in the design and manufacture of Left Ventricular Assist Devices, post-implant thrombotic and thromboembolic complications continue to affect long-term outcomes. Previous efforts, aimed at optimizing pump design as a means of reducing supraphysiologic shear stresses generated within the pump and associated prothrombotic shear-mediated platelet injury, have only partially altered the device hemocompatibility. METHODS: : We examined hemodynamic mechanisms that synergize with hypershear within the pump to contribute to the thrombogenic potential of the overall Left Ventricular Assist Device system. RESULTS: : Numerical simulations of blood flow in differing regions of the Left Ventricular Assist Device system, that is the diseased native left ventricle, the pump inflow cannula, the impeller, the outflow graft and the anastomosed downstream aorta, reveal that prothrombotic hemodynamic conditions might occur at these specific sites. Furthermore, we show that beyond hypershear, additional hemodynamic abnormalities exist within the pump, which may elicit platelet activation, such as recirculation zones and stagnant platelet trajectories. We also provide evidences that particular Left Ventricular Assist Device implantation configurations and specific post-implant patient management strategies, such as those allowing aortic valve opening, are more hemodynamically favorable and reduce the thrombotic risk. CONCLUSION: : We extend the perspective of pump thrombosis secondary to the supraphysiologic shear stress environment of the pump to one of Left Ventricular Assist Device system thrombosis, raising the importance of comprehensive characterization of the different prothrombotic risk factors of the total system as the target to achieve enhanced hemocompatibility and improved clinical outcomes.
INTRODUCTION: : Despite significant technical advancements in the design and manufacture of Left Ventricular Assist Devices, post-implant thrombotic and thromboembolic complications continue to affect long-term outcomes. Previous efforts, aimed at optimizing pump design as a means of reducing supraphysiologic shear stresses generated within the pump and associated prothrombotic shear-mediated platelet injury, have only partially altered the device hemocompatibility. METHODS: : We examined hemodynamic mechanisms that synergize with hypershear within the pump to contribute to the thrombogenic potential of the overall Left Ventricular Assist Device system. RESULTS: : Numerical simulations of blood flow in differing regions of the Left Ventricular Assist Device system, that is the diseased native left ventricle, the pump inflow cannula, the impeller, the outflow graft and the anastomosed downstream aorta, reveal that prothrombotic hemodynamic conditions might occur at these specific sites. Furthermore, we show that beyond hypershear, additional hemodynamic abnormalities exist within the pump, which may elicit platelet activation, such as recirculation zones and stagnant platelet trajectories. We also provide evidences that particular Left Ventricular Assist Device implantation configurations and specific post-implant patient management strategies, such as those allowing aortic valve opening, are more hemodynamically favorable and reduce the thrombotic risk. CONCLUSION: : We extend the perspective of pump thrombosis secondary to the supraphysiologic shear stress environment of the pump to one of Left Ventricular Assist Device system thrombosis, raising the importance of comprehensive characterization of the different prothrombotic risk factors of the total system as the target to achieve enhanced hemocompatibility and improved clinical outcomes.
Authors: Peng Fang; Jianjun Du; Andrea Boraschi; Silvia Bozzi; Alberto Redaelli; Marianne Schmid Daners; Vartan Kurtcuoglu; Filippo Consolo; Diane de Zélicourt Journal: Front Cardiovasc Med Date: 2022-03-11