title: Aortic Root Biomechanics After Sleeve and David Sparing Techniques: A Finite Element Analysis.
abstract: BACKGROUND
  Aortic root aneurysm can be treated with valve-sparing procedures. The David and Yacoub techniques have shown excellent long-term results but are technically demanding. Recently, a new and simpler procedure, the Sleeve technique, was proposed with encouraging results. We aimed to quantify the biomechanics of the initially aneurysmal aortic root (AR) after the Sleeve procedure to assess whether it induces abnormal stresses, potentially undermining its durability.
  
  
  METHODS
  Two finite element (FE) models of the physiologic and aneurysmal AR were built, accounting for the anatomical asymmetry and the nonlinear and anisotropic mechanical properties of human AR tissues. On the aneurysmal model, the Sleeve and David techniques were simulated based on the corresponding published technical features. Aortic root biomechanics throughout 2 consecutive cardiac cycles were computed in each simulated configuration.
  
  
  RESULTS
  Both sparing techniques restored physiologic-like kinematics of aortic valve (AV) leaflets but induced different leaflets stresses. The time course averaged over the leaflets' bellies was 35% higher in the David model than in the Sleeve model. Commissural stresses, which were equal to 153 and 318 kPa in the physiologic and aneurysmal models, respectively, became 369 and 208 kPa in the David and Sleeve models, respectively.
  
  
  CONCLUSIONS
  No intrinsic structural problems were detected in the Sleeve model that might jeopardize the durability of the procedure. If corroborated by long-term clinical outcomes, the results obtained suggest that using this new technique could successfully simplify the surgical repair of AR aneurysms and reduce intraoperative complications.
authors.affiliation: Cardiovascular Department, Operative Unit of Cardiac Surgery, Ospedale "A. Manzoni" di Lecco, Lecco, Italy; Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy. Electronic address: giordano.tasca67@gmail.com.
authors.forename: Giordano
authors.initials: G
authors.lastname: Tasca
authors.affiliation: Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy; Division of Cardiovascular Surgery, Università degli Studi di Verona, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Selmi
authors.affiliation: Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Votta
authors.affiliation: Cardiovascular Department, Operative Unit of Cardiac Surgery, Ospedale "A. Manzoni" di Lecco, Lecco, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Redaelli
authors.affiliation: Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sturla
authors.affiliation: Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milano, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Redaelli
authors.affiliation: Cardiovascular Department, Operative Unit of Cardiac Surgery, Ospedale "A. Manzoni" di Lecco, Lecco, Italy.
authors.forename: Amando
authors.initials: A
authors.lastname: Gamba
mesh_terms: D001013:Aorta, Thoracic / Q000503:physiopathology* / Q000601:surgery*; D017545:Aortic Aneurysm, Thoracic / Q000503:physiopathology* / Q000601:surgery*; D001696:Biomechanical Phenomena / Q000502:physiology*; D003198:Computer Simulation; D020342:Finite Element Analysis; D006801:Humans; D008955:Models, Cardiovascular; D017711:Nonlinear Dynamics; D012850:Sinus of Valsalva / Q000503:physiopathology / Q000601:surgery