Christian Binter1, Alexander Gotschy1, Simon H Sündermann1, Michelle Frank1, Felix C Tanner1, Thomas F Lüscher1, Robert Manka1, Sebastian Kozerke2. 1. From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (S.K.). 2. From the Institute for Biomedical Engineering, University and ETH Zurich, Switzerland (C.B., A.G., S.K.); Department of Cardiology, University Heart Center (A.G., M.F., F.C.T., T.F.L., R.M.), Division of Internal Medicine (A.G.), and Institute of Diagnostic and Interventional Radiology (R.M.), University Hospital Zurich, Switzerland; Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Germany (S.H.S.); and Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom (S.K.). kozerke@biomed.ee.ethz.ch.
Abstract
BACKGROUND: Turbulent kinetic energy (TKE), assessed by 4-dimensional (4D) flow magnetic resonance imaging, is a measure of energy loss in disturbed flow as it occurs, for instance, in aortic stenosis (AS). This work investigates the additional information provided by quantifying TKE for the assessment of AS severity in comparison to clinical echocardiographic measures. METHODS AND RESULTS: Fifty-one patients with AS (67±15 years, 20 female) and 10 healthy age-matched controls (69±5 years, 5 female) were prospectively enrolled to undergo multipoint 4D flow magnetic resonance imaging. Patients were split into 2 groups (severe and mild/moderate AS) according to their echocardiographic mean pressure gradient. TKE values were integrated over the aortic arch to obtain peak TKE. Integrating over systole yielded total TKEsys and by normalizing for stroke volume, normalized TKEsys was obtained. Mean pressure gradient and TKE correlated only weakly (R2=0.26 for peak TKE and R2=0.32 for normalized TKEsys) in the entire study population including control subjects, while no significant correlation was observed in the AS patient group. In the patient population with dilated ascending aorta, both peak TKE and total TKEsys were significantly elevated (P<0.01), whereas mean pressure gradient was significantly lower (P<0.05). Patients with bicuspid aortic valves also showed significantly increased TKE metrics (P<0.01), although no significant difference was found for mean pressure gradient. CONCLUSIONS: Elevated TKE levels imply higher energy losses associated with bicuspid aortic valves and dilated ascending aortic geometries that are not assessable by current echocardiographic measures. These findings indicate that TKE may provide complementary information to echocardiography, helping to distinguish within the heterogeneous population of patients with moderate to severe AS.
BACKGROUND: Turbulent kinetic energy (TKE), assessed by 4-dimensional (4D) flow magnetic resonance imaging, is a measure of energy loss in disturbed flow as it occurs, for instance, in aortic stenosis (AS). This work investigates the additional information provided by quantifying TKE for the assessment of AS severity in comparison to clinical echocardiographic measures. METHODS AND RESULTS: Fifty-one patients with AS (67±15 years, 20 female) and 10 healthy age-matched controls (69±5 years, 5 female) were prospectively enrolled to undergo multipoint 4D flow magnetic resonance imaging. Patients were split into 2 groups (severe and mild/moderate AS) according to their echocardiographic mean pressure gradient. TKE values were integrated over the aortic arch to obtain peak TKE. Integrating over systole yielded total TKEsys and by normalizing for stroke volume, normalized TKEsys was obtained. Mean pressure gradient and TKE correlated only weakly (R2=0.26 for peak TKE and R2=0.32 for normalized TKEsys) in the entire study population including control subjects, while no significant correlation was observed in the AS patient group. In the patient population with dilated ascending aorta, both peak TKE and total TKEsys were significantly elevated (P<0.01), whereas mean pressure gradient was significantly lower (P<0.05). Patients with bicuspid aortic valves also showed significantly increased TKE metrics (P<0.01), although no significant difference was found for mean pressure gradient. CONCLUSIONS: Elevated TKE levels imply higher energy losses associated with bicuspid aortic valves and dilated ascending aortic geometries that are not assessable by current echocardiographic measures. These findings indicate that TKE may provide complementary information to echocardiography, helping to distinguish within the heterogeneous population of patients with moderate to severe AS.
Authors: Michal Schäfer; Alex J Barker; James Jaggers; Gareth J Morgan; Matthew L Stone; Uyen Truong; Lorna P Browne; Ladonna Malone; D Dunbar Ivy; Max B Mitchell Journal: Eur J Cardiothorac Surg Date: 2020-03-01 Impact factor: 4.191
Authors: Emilie Bollache; Kristopher D Knott; Kelly Jarvis; Redha Boubertakh; Ryan Scott Dolan; Claudia Camaioni; Louise Collins; Paul Scully; Sydney Rabin; Thomas Treibel; James C Carr; Pim van Ooij; Jeremy D Collins; Julia Geiger; James C Moon; Alex J Barker; Steffen E Petersen; Michael Markl Journal: Radiol Cardiothorac Imaging Date: 2019-06-27
Authors: Luca Rosalia; Caglar Ozturk; Jaume Coll-Font; Yiling Fan; Yasufumi Nagata; Manisha Singh; Debkalpa Goswami; Adam Mauskapf; Shi Chen; Robert A Eder; Efrat M Goffer; Jo H Kim; Salva Yurista; Benjamin P Bonner; Anna N Foster; Robert A Levine; Elazer R Edelman; Marcello Panagia; Jose L Guerrero; Ellen T Roche; Christopher T Nguyen Journal: Nat Biomed Eng Date: 2022-09-26 Impact factor: 29.234
Authors: Ashitha Pathrose; Liliana Ma; Haben Berhane; Michael B Scott; Kelvin Chow; Christoph Forman; Ning Jin; Ali Serhal; Ryan Avery; James Carr; Michael Markl Journal: Magn Reson Med Date: 2020-10-26 Impact factor: 4.668
Authors: Michal Schäfer; Alex J Barker; Vitaly Kheyfets; Kurt R Stenmark; James Crapo; Michael E Yeager; Uyen Truong; J Kern Buckner; Brett E Fenster; Kendall S Hunter Journal: J Am Heart Assoc Date: 2017-12-20 Impact factor: 5.501