Hoda Hatoum1,2, Shelly Singh-Gryzbon1,3, Fateme Esmailie1, Philipp Ruile4, Franz-Josef Neumann4, Philipp Blanke5, Vinod H Thourani6, Ajit P Yoganathan1, Lakshmi Prasad Dasi7. 1. Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313, USA. 2. Department of Biomedical Engineering, Michigan Technological University, Houghton, MI, USA. 3. Department of Chemical & Process Engineering, The University of the West Indies, St Augustine, Trinidad and Tobago. 4. Department of Cardiology and Angiology II, University Heart Center Freiburg-Bad Krozingen, Bad Krozingen, Germany. 5. University of British Columbia and St. Paul's Hospital in Vancouver, Vancouver, Canada. 6. Department of Cardiovascular Surgery, Marcus Heart Valve Center, Piedmont Heart Institute, Atlanta, GA, USA. 7. Department of Biomedical Engineering, Georgia Institute of Technology, 387 Technology Circle, Atlanta, GA, 30313, USA. lakshmi.dasi@gatech.edu.
Abstract
PURPOSE: Leaflet thrombosis is a significant adverse event after transcatheter aortic valve (TAV) replacement (TAVR). The purpose of our study was to present a semi-empirical, mathematical model that links patient-specific anatomic, valve, and flow parameters to predict likelihood of leaflet thrombosis. METHODS: The two main energy sources of neo-sinus (NS) washout after TAVR include the jet flow downstream of the TAV and NS geometric change in volume due to the leaflets opening and closing. Both are highly dependent on patient anatomic and hemodynamic factors. As rotation of blood flow is prevalent in both the sinus of Valsalva and then the NS, we adopted the vorticity flux or circulation (Г) as a metric quantifying overall washout. Leaflet thrombus volumes were segmented based on hypo-attenuating leaflet thickening (HALT) in post-TAVR patient's gated computed tomography. Г was assessed using dimensional scaling as well as computational fluid dynamics (CFD) respectively and correlated to the thrombosis volumes using sensitivity and specificity analysis. RESULTS: Г in the NS, that accounted for patient flow and anatomic conditions derived from scaling arguments significantly better predicted the occurrence of leaflet thrombus than CFD derived measures such as stasis volumes or wall shear stress. Given results from the six patient datasets considered herein, a threshold Г value of 28.0 yielded a sensitivity and specificity of 100% where patients with Gamma < 28 developed valve thrombosis. A 10% error in measurements of all variables can bring the sensitivity specificity down to 87%. CONCLUSION: A predictive model relating likelihood of valve thrombosis using Г in the NS was developed with promising sensitivity and specificity. With further studies and improvements, this predictive technology may lead to alerting physicians on the risk for thrombus formation following TAVR.
PURPOSE: Leaflet thrombosis is a significant adverse event after transcatheter aortic valve (TAV) replacement (TAVR). The purpose of our study was to present a semi-empirical, mathematical model that links patient-specific anatomic, valve, and flow parameters to predict likelihood of leaflet thrombosis. METHODS: The two main energy sources of neo-sinus (NS) washout after TAVR include the jet flow downstream of the TAV and NS geometric change in volume due to the leaflets opening and closing. Both are highly dependent on patient anatomic and hemodynamic factors. As rotation of blood flow is prevalent in both the sinus of Valsalva and then the NS, we adopted the vorticity flux or circulation (Г) as a metric quantifying overall washout. Leaflet thrombus volumes were segmented based on hypo-attenuating leaflet thickening (HALT) in post-TAVR patient's gated computed tomography. Г was assessed using dimensional scaling as well as computational fluid dynamics (CFD) respectively and correlated to the thrombosis volumes using sensitivity and specificity analysis. RESULTS: Г in the NS, that accounted for patient flow and anatomic conditions derived from scaling arguments significantly better predicted the occurrence of leaflet thrombus than CFD derived measures such as stasis volumes or wall shear stress. Given results from the six patient datasets considered herein, a threshold Г value of 28.0 yielded a sensitivity and specificity of 100% where patients with Gamma < 28 developed valve thrombosis. A 10% error in measurements of all variables can bring the sensitivity specificity down to 87%. CONCLUSION: A predictive model relating likelihood of valve thrombosis using Г in the NS was developed with promising sensitivity and specificity. With further studies and improvements, this predictive technology may lead to alerting physicians on the risk for thrombus formation following TAVR.
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Authors: Hoda Hatoum; Jennifer Dollery; Scott M Lilly; Juan A Crestanello; Lakshmi Prasad Dasi Journal: Ann Biomed Eng Date: 2018-08-27 Impact factor: 3.934
Authors: Maria Del Trigo; Antonio J Muñoz-Garcia; Harindra C Wijeysundera; Luis Nombela-Franco; Asim N Cheema; Enrique Gutierrez; Vicenç Serra; Joelle Kefer; Ignacio J Amat-Santos; Luis M Benitez; Jumana Mewa; Pilar Jiménez-Quevedo; Sami Alnasser; Bruno Garcia Del Blanco; Antonio Dager; Omar Abdul-Jawad Altisent; Rishi Puri; Francisco Campelo-Parada; Abdellaziz Dahou; Jean-Michel Paradis; Eric Dumont; Philippe Pibarot; Josep Rodés-Cabau Journal: J Am Coll Cardiol Date: 2016-02-16 Impact factor: 24.094