Christof Karmonik1, Sasan Partovi2, Matthias Loebe3, Bastian Schmack4, Alexander Weymann4, Alan B Lumsden3, Matthias Karck4, Arjang Ruhparwar4. 1. Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Tex. Electronic address: CKarmonik@tmhs.org. 2. Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Tex; Department of Radiology University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio. 3. Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Tex. 4. Department of Cardiac Surgery, University Hospital of Heidelberg, Heidelberg, Germany.
Abstract
OBJECTIVE: Increased use of continuous-flow left ventricular assist devices for long-term mechanical support necessitates a better understanding of hemodynamic changes in the native heart and the ascending aorta. By using patient-specific computational models, correlations of potentially adverse hemodynamic conditions with the orientation of the left ventricular assist device outflow graft and their relationship with aortic insufficiency and ischemic events were investigated. METHODS: Computed hemodynamic parameters, including wall shear stress, pressure in the ascending aorta, and dissipation of turbulent energy, were correlated with the orientation of the left ventricular assist device graft outflow in 5 patients (4 with the HeartMate II device [Thoratec Corp, Pleasanton, Calif] and 1 with the HeartWare Ventricular Assist Device [HeartWare Inc, Framingham, Mass]; 3 patients experienced moderate aortic insufficiency, and 2 patients experienced ischemic events). Hemodynamic conditions for aortic insufficiency and ischemic events were differentiated by linear discriminant analysis. RESULTS: Positive correlations between left ventricular assist device outflow graft orientation and wall shear stress, pressure, and turbulent energy dissipation in the ascending aorta were found (R(2) > 0.68). Linear discriminant analysis indicated a relationship of the velocity magnitude of retrograde flow toward the aortic root with aortic insufficiency and of the turbulent energy and wall shear stress with ischemic events. CONCLUSIONS: Computational fluid dynamic simulations using clinical image data indicate altered hemodynamic conditions after left ventricular assist device implantation. Consequently, the left ventricular assist device outflow graft should be placed so the jet of blood is aimed toward the lumen of the aortic arch to avoid turbulences that will increase wall shear stress and retrograde pressure of the aortic root. Further investigations are warranted to confirm these findings in a larger patient cohort.
OBJECTIVE: Increased use of continuous-flow left ventricular assist devices for long-term mechanical support necessitates a better understanding of hemodynamic changes in the native heart and the ascending aorta. By using patient-specific computational models, correlations of potentially adverse hemodynamic conditions with the orientation of the left ventricular assist device outflow graft and their relationship with aortic insufficiency and ischemic events were investigated. METHODS: Computed hemodynamic parameters, including wall shear stress, pressure in the ascending aorta, and dissipation of turbulent energy, were correlated with the orientation of the left ventricular assist device graft outflow in 5 patients (4 with the HeartMate II device [Thoratec Corp, Pleasanton, Calif] and 1 with the HeartWare Ventricular Assist Device [HeartWare Inc, Framingham, Mass]; 3 patients experienced moderate aortic insufficiency, and 2 patients experienced ischemic events). Hemodynamic conditions for aortic insufficiency and ischemic events were differentiated by linear discriminant analysis. RESULTS: Positive correlations between left ventricular assist device outflow graft orientation and wall shear stress, pressure, and turbulent energy dissipation in the ascending aorta were found (R(2) > 0.68). Linear discriminant analysis indicated a relationship of the velocity magnitude of retrograde flow toward the aortic root with aortic insufficiency and of the turbulent energy and wall shear stress with ischemic events. CONCLUSIONS: Computational fluid dynamic simulations using clinical image data indicate altered hemodynamic conditions after left ventricular assist device implantation. Consequently, the left ventricular assist device outflow graft should be placed so the jet of blood is aimed toward the lumen of the aortic arch to avoid turbulences that will increase wall shear stress and retrograde pressure of the aortic root. Further investigations are warranted to confirm these findings in a larger patient cohort.
Authors: Anthony R Prisco; Alberto Aliseda; Jennifer A Beckman; Nahush A Mokadam; Claudius Mahr; Guilherme J M Garcia Journal: ASAIO J Date: 2017 Jul/Aug Impact factor: 2.872
Authors: W Coenen; C Gutiérrez-Montes; S Sincomb; E Criado-Hidalgo; K Wei; K King; V Haughton; C Martínez-Bazán; A L Sánchez; J C Lasheras Journal: AJNR Am J Neuroradiol Date: 2019-06-13 Impact factor: 3.825
Authors: Alberto Aliseda; Venkat Keshav Chivukula; Patrick Mcgah; Anthony R Prisco; Jennifer A Beckman; Guilherme J M Garcia; Nahush A Mokadam; Claudius Mahr Journal: ASAIO J Date: 2017 Jan/Feb Impact factor: 2.872