Animal Model For Comprehensive Assessment Of Hemodynamic Effects Of Differently Oriented Paravalvular Leakage Jets
Lukas Glaus1, Markus Kofler2, Miriam Weisskopf3, Eva S. Peper4, Christian T. Stoeck4, Maximilian Y. Emmert2, Volkmar Falk2, Nikola Cesarovic1.
1Department of Health Sciences and Technology, Swiss Federal Institute of Technology, Zurich, Switzerland, 2Department of Cardiothoracic and Vascular Surgery, German Heart Center Berlin, Berlin, Germany, 3Center for Surgical Research, University Hospital Zurich, University of Zurich, Zurich, Switzerland, 4Institute for Biomedical Engineering, University and ETH Zürich, Zurich, Switzerland.
BACKGROUND:Transcatheter aortic valve replacement (TAVR) has emerged as a standard of care for patients with high and intermediate surgical risk. Paravalvular leaks (PVLs) although less frequent with the latest generation of prostheses and improved implantation techniques remains an unresolved issue after TAVR. While most PVLs remain clinically silent, even mild PVLs may have an impact on long-term outcomes. In order to classify the components of mild PVLs better, a large animal model of mild aortic regurgitation was developed. This model allows for a comprehensive approach to quantify the effects of jet origin and direction on left ventricular hemodynamics and work under different hemodynamic states. METHODS: A porcine model of PVL obtained by transcatheter piercing and dilating of the non-coronary (NCC) or right coronary cusp (RCC) of the aortic valve close to the annulus was used. An increase in heart rate and afterload were achieved with various doses of dobutamine and phenylephrine infusions, respectively. PVL severity was assessed by echocardiography and contrast fluoroscopy-based densitometry. Detailed data on left ventricular hemodynamics and work was gathered with a pressure-volume loop (PV-loop) conductance catheter. Blood flow patterns and energy dissipation were assessed using phase contrast magnetic resonance imaging (MRI).
RESULTS: Targeted isolated NCC and RCC lesions were set in 5/8 animals with successful PV-loop and 4D Flow MRI measurements. Drug induced stimulation with subsequent return to baseline before and after the intervention was performed. Video densitometric analysis of the regurgitation jet was feasible in the porcine model. Preliminary PV-loop, echocardiography and MRI data analysis indicated an increase of PVL flow as well as increased left ventricular work indices when increasing afterload with phenylephrine.
CONCLUSIONS:The proposed model provides a comprehensive study of the hemodynamic effects of PVL induced jets based on their location and direction. Linking the hemodynamic effect and the jet characteristics may allow for a more precise analysis of PVL severity, prognosis and need for further intervention. LEGEND: A) Paravalvular leak (PVL) in the right coronary cusp (RCC) of the aortic valve B) Contrast fluoroscopy-based densitometry of a PVL jet (arrow) through the RCC C) Defect (triangle) in the non-coronary cusp (NCC) of the aortic valve induced by transcatheter piercing and dilating D) Pressure-volume loops of baseline (light green/dark green) as well as dobutamine (light blue/dark blue) and phenylephrine (yellow/orange) stimulation before/after applying the lesion in the RCC
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