title: Studies in a modified auxiliary abdominal rat heart transplantation model: preservation with colloid-free University of Wisconsin solution.
abstract: BACKGROUND
  Current clinical heart preservation is still limited to 6 hours. A suitable heart transplantation model to rapidly screen the effectiveness of new solutions is essential. This study examines a new screening test-a modification of the conventional abdominal rat heart transplantation model that overcomes its serious limitation of lack of quantitative evaluation of function.
  
  
  METHODS
  Rat hearts, with an externalized intraventricular balloon-tipped catheter, were transplanted immediately (controls) or flushed and stored in colloid-free University of Wisconsin solution in ice for 6, 9, or 12 hours before transplantation. One and 7 days later this catheter was connected to a pressure transducer and a calibrated syringe. Heart rate, maximum developed pressure, and maximum rate of left ventricular pressure rise were determined. Grafts were prepared for histologic study on day 7.
  
  
  RESULTS
  All preserved hearts commenced beating within 2 minutes (controls beat within 20 seconds). On day 1 the heart rate and chamber stiffness (deltaP/deltat) were similar in all groups. The 9- and 12-hour-preserved hearts had significantly (p < 0.05) diminished developed pressure and contractility. On day 7 contractility and developed pressure improved in 9- and 12-hour-preserved grafts. There was extensive muscular atrophy and necrosis, with extensive cellular infiltrate in the 9- and 12-hour-preserved grafts; other grafts showed no damage.
  
  
  CONCLUSIONS
  This quantitative model provides an ischemia-related gradation of function and greater discrimination than conventional methods. It has refuted previous studies suggesting effective preservation for 20 hours and demonstrated that functional testing is essential in evaluating preservation regimens.
authors.affiliation: Monash University, Department of Surgery, Monash Medical Centre, Clayton, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Baxter
authors.forename: B O
authors.initials: BO
authors.lastname: Howden
authors.forename: X
authors.initials: X
authors.lastname: Jin
authors.forename: P
authors.initials: P
authors.lastname: Jablonski
mesh_terms: D000241:Adenosine; D000493:Allopurinol; D000818:Animals; D004699:Endocardium / Q000473:pathology; D005978:Glutathione; D016027:Heart Transplantation / Q000473:pathology / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D007328:Insulin; D008297:Male; D008955:Models, Cardiovascular; D009206:Myocardium / Q000473:pathology; D009926:Organ Preservation; D019188:Organ Preservation Solutions; D011887:Raffinose; D051381:Rats; D011919:Rats, Inbred Strains; D016042:Transplantation, Heterotopic / Q000473:pathology / Q000502:physiology*
chemical_list: D007328:Insulin; D019188:Organ Preservation Solutions; C055206:University of Wisconsin-lactobionate solution; D000493:Allopurinol; D005978:Glutathione; D000241:Adenosine; D011887:Raffinose