title: Pulmonary effects of chronic elevation in microvascular pressure differ between hypertension and myocardial infarct induced heart failure.
abstract: BACKGROUND
  Chronic heart failure (CHF) following coronary artery ligation and myocardial infarction in the rat leads to a homeostatic reduction in surface tension with associated alveolar type II cell hyperplasia and increased surfactant content, which functionally compensates for pulmonary collagen deposition and increased tissue stiffness. To differentiate the effects on lung remodelling of the sudden rise in pulmonary microvascular pressure (Pmv) with myocardial infarction from its consequent chronic elevation, we examined a hypertensive model of CHF.
  
  
  METHODS
  Cardiopulmonary outcomes due to chronic pulmonary capillary hypertension were assessed at six and 15 weeks following abdominal aortic banding (AAB) in the rat.
  
  
  RESULTS
  At six weeks post-surgery, despite significantly elevated left ventricular end-diastolic pressure, myocardial hypertrophy and increased left ventricular internal circumference in AAB rats compared with sham operated controls (p≤0.003), lung weights and tissue composition remained unchanged, and lung compliance was normal. At 15 weeks post-surgery increased lung oedema was evident in AAB rats (p=0.002) without decreased lung compliance or evidence of tissue remodelling.
  
  
  CONCLUSIONS
  Despite chronically elevated Pmv, comparable to that resulting from past myocardial infarction (LVEDP>19mmHg), there is no evidence of pulmonary remodelling in the AAB model of CHF.
authors.affiliation: Intensive and Critical Care Unit, Adelaide, Australia 5001; Department of Critical Care Medicine, Adelaide, Australia 5001. Electronic address: dani.dixon@flinders.edu.au.
authors.forename: Dani-Louise
authors.initials: DL
authors.lastname: Dixon
authors.affiliation: Department of Critical Care Medicine, Adelaide, Australia 5001.
authors.forename: Kim M
authors.initials: KM
authors.lastname: Griggs
authors.affiliation: Cardiac Services, Flinders Medical Centre, Bedford Park, Australia 5042; Department of Medicine Flinders University, Adelaide, Australia 5001.
authors.forename: Carmine G
authors.initials: CG
authors.lastname: De Pasquale
authors.affiliation: Intensive and Critical Care Unit, Adelaide, Australia 5001; Department of Critical Care Medicine, Adelaide, Australia 5001.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Bersten
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002196:Capillaries / Q000503:physiopathology*; D002908:Chronic Disease; D004195:Disease Models, Animal; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology*; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
keywords: Abdominal aortic banding; Lung mechanics; Pulmonary oedema; Pulmonary remodelling; Rat