title: Aortic valve adaptation to aortic root dilatation: insights into the mechanism of functional aortic regurgitation from 3-dimensional cardiac computed tomography.
abstract: BACKGROUND
  The 3-dimensional relationship between aortic root and cusp is essential to understand the mechanism of aortic regurgitation (AR) because of aortic root dilatation (ARD). We sought to test the hypothesis that the stretched cusps in ARD enlarge to compensate for ARD.
  
  
  RESULTS
  Computed tomography imaged 92 patients (57 with ARD, 29 with moderate to severe AR, 28 without significant AR) and 35 normal controls. Specialized 3-dimensional software measured individual cusp surface areas relative to maximal mid-sinus cross-sectional area and minimal 3-dimensional annular area, coaptation area fraction, and asymmetry of sinus volumes and intercommissural distances. Total open cusp surface area increased (P<0.001) from 7.6±1.4 cm(2)/m(2) in normals to 12.9±2.2 cm(2)/m(2) in AR-negative and 15.2±3.3 cm(2)/m(2) in AR-positive patients. However, the ratio of closed cusp surface area to maximal mid-sinus area, reflecting cusp adaptation, decreased from normals to AR-negative to AR-positive patients (1.38±0.20, 1.15±0.15, 0.88±0.15; P<0.001), creating the lowest coaptation area fraction. Cusp distensibility (closed diastolic versus open area) decreased from 20% in controls and AR-negative patients to 5% in AR-positive patients (P<0.001). Multivariate determinants of AR and coaptation area fraction reflected both sinus size and cusp-to-annular adaptation. ARD was also progressively asymmetrical with root size, and individual cusp surface areas failed to match this asymmetry.
  
  
  CONCLUSIONS
  Aortic cusp enlargement occurs in ARD, but cusp adaptation and distensibility become limited in prominent, asymmetrical ARD, leading to AR. Optimal AR repair tailored to individual patient anatomy can benefit from appreciating valve adaptation and 3-dimensional relationships; understanding cusp adaptation mechanisms may ultimately provide therapeutic opportunities to improve such compensation.
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Dae-Hee
authors: DH
authors: Kim
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Mark D
authors: MD
authors: Handschumacher
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Robert A
authors: RA
authors: Levine
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Byung Joo
authors: BJ
authors: Sun
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Jeong Yoon
authors: JY
authors: Jang
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Dong Hyun
authors: DH
authors: Yang
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Joon-Won
authors: JW
authors: Kang
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Jong-Min
authors: JM
authors: Song
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Duk-Hyun
authors: DH
authors: Kang
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.).
authors: Tae-Hwan
authors: TH
authors: Lim
authors: From the Cardiac Imaging Center, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, South Korea (D.-H. Kim, B.J.S., J.Y.J., D.H.Y., J.-W.K., J.-M.S., D.-H. Kang, T.-H.L., J.-K.S.); and Cardiac Ultrasound Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, MA (M.D.H., R.A.L.). jksong@amc.seoul.kr.
authors: Jae-Kwan
authors: JK
authors: Song
mesh_terms: D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001018:Aortic Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: aortic aneurysm; aortic regurgitation; aortic valve insufficiency; computed tomography; three dimensional imaging