title: Biventricular structural and functional responses to aortic constriction in a rabbit model of chronic right ventricular pressure overload.
abstract: OBJECTIVE
  Chronic right ventricular (RV) pressure overload results in pathologic RV hypertrophy and diminished RV function. Although aortic constriction has been shown to improve systolic function in acute RV failure, its effect on RV responses to chronic pressure overload is unknown.
  
  
  METHODS
  Adjustable vascular banding devices were placed on the main pulmonary artery and descending aorta. In 5 animals (sham group), neither band was inflated. In 9 animals (PAB group), only the pulmonary arterial band was inflated, with adjustments on a weekly basis to generate systemic or suprasystemic RV pressure at 28 days. In 9 animals, both pulmonary arterial and aortic devices were inflated (PAB + AO group), the pulmonary arterial band as for the PAB group and the aortic band adjusted to increase proximal systolic blood pressure by approximately 20 mm Hg. Effects on the functional performance were assessed 5 weeks after surgery by conductance catheters, followed by histologic and molecular assessment.
  
  
  RESULTS
  Contractile performance was significantly improved in the PAB + AO group versus the PAB group for both ventricles. Relative to sham-operated animals, both banding groups showed significant differences in myocardial histologic and molecular responses. Relative to the PAB group, the PAB + AO group showed significantly decreased RV cardiomyocyte diameter, decreased RV collagen content, and reduced RV expression of endothelin receptor type B, matrix metalloproteinase 9, and transforming growth factor β genes.
  
  
  CONCLUSIONS
  Aortic constriction in an experimental model of chronic RV pressure overload not only resulted in improved biventricular systolic function but also improved myocardial remodeling. These data suggest that chronically increased left ventricular afterload leads to a more physiologically hypertrophic response in the pressure-overloaded RV.
authors: Division of Cardiology, Hospital for Sick Children, University of Toronto, Ontario, Canada.
authors: Christian
authors: C
authors: Apitz
authors: Osami
authors: O
authors: Honjo
authors: Tilman
authors: T
authors: Humpl
authors: Jing
authors: J
authors: Li
authors: Renato S
authors: RS
authors: Assad
authors: Mi Y
authors: MY
authors: Cho
authors: James
authors: J
authors: Hong
authors: Mark K
authors: MK
authors: Friedberg
authors: Andrew N
authors: AN
authors: Redington
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects* / Q000503:physiopathology; D062186:Arterial Pressure; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D003250:Constriction; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D065627:Familial Primary Pulmonary Hypertension; D006333:Heart Failure / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D017380:Hypertrophy, Right Ventricular / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D011651:Pulmonary Artery / Q000503:physiopathology / Q000601:surgery; D011817:Rabbits; D017466:Receptors, Endothelin / Q000235:genetics / Q000378:metabolism; D020127:Recovery of Function; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right; D017725:Ventricular Pressure; D020257:Ventricular Remodeling
chemical_list: D019332:Endothelin-1; D017466:Receptors, Endothelin; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor; D003094:Collagen; D017364:Collagenases