title: Experimental acute type B aortic dissection: different sites of primary entry tears cause different ways of propagation.
abstract: BACKGROUND
  Many dissections seem to also have a retrograde component. The aim of the study was to evaluate different sites of primary entry tears and the propagation of the dissecting membrane, antegrade and retrograde, in an experimental model of acute type B aortic dissection.
  
  
  METHODS
  The entire thoracic aortic aorta including the supraaortic branches was harvested from 26 adult pigs. An intimal tear of 15 mm was created by contralateral incisions sites 20 mm downstream the origin of the left subclavian artery. In 13 cases the dissection was created at the concavity and in 13 cases at the convexity. The aortic annulus was then sewn into a silicon ring of a driving chamber. The distal aorta was connected to a tubing with adjustable resistance elements. The circulation was driven by the pneumatically driven Vienna heart to mimic aortic flow and pressure.
  
  
  RESULTS
  Mean circulation time was 64 ± 45 minutes. A mean pressure of 152 ± 43 mm Hg and a mean flow of 4.5 ± 1.0 L/minute were reached. The median antegrade propagation length of the dissecting membrane was 65 mm. The median retrograde propagation length in primary entry tears at the convexity was 20 mm and was stopped by the left subclavian artery. In aortas with the primary entry tear at the concavity, median retrograde propagation length was 21 mm extending up to the ascending aorta in 16%.
  
  
  CONCLUSIONS
  In this experimental model of acute type B aortic dissection, we confirmed that many type B dissections do also have a retrograde component. At the convexity, this component is stopped by the left subclavian artery as an anatomic barrier. At the concavity, the propagation of the dissecting membrane may extend up to the ascending aorta and may therefore cause retrograde type A dissection. These findings may substantiate clinical need for treatment of type B dissections with a primary entry tear at the concavity.
authors.affiliation: Center for Medical Physics and Biomedical Engineering, Medical University Vienna-Ludwig Boltzmann Cluster for Cardiovascular Research, and Department of Cardiac Surgery, Medical University of Vienna, Vienna, Austria.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Dziodzio
authors.forename: Andrzej
authors.initials: A
authors.lastname: Juraszek
authors.forename: David
authors.initials: D
authors.lastname: Reineke
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Jenni
authors.forename: Etienne
authors.initials: E
authors.lastname: Zermatten
authors.forename: Daniel
authors.initials: D
authors.lastname: Zimpfer
authors.forename: Martin
authors.initials: M
authors.lastname: Stoiber
authors.forename: Verena
authors.initials: V
authors.lastname: Scheikl
authors.forename: Heinrich
authors.initials: H
authors.lastname: Schima
authors.forename: Michael
authors.initials: M
authors.lastname: Grimm
authors.forename: Martin
authors.initials: M
authors.lastname: Czerny
mesh_terms: D000784:Aortic Dissection / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology*; D017545:Aortic Aneurysm, Thoracic / Q000473:pathology / Q000503:physiopathology*; D001794:Blood Pressure; D004195:Disease Models, Animal; D018450:Disease Progression; D012039:Regional Blood Flow; D013552:Swine