title: Intermittent antegrade cardioplegia: isolated heart preservation with the Asporto heart preservation device.
abstract: BACKGROUND
  A major problem in procurement of donor hearts is the limited time a donor heart remains viable. After cardiectomy, ischemic hypoxia is the main cause of donor heart degradation. The global myocardial ischemia causes a cascade of oxygen radical formation that cumulates in an elevation in hydrogen ions (decrease in pH), irreversible cellular injury, and potential microvascular changes in perfusion.
  
  
  OBJECTIVE
  To determine the changes of prolonged storage times on donor heart microvasculature and the effects of intermittent antegrade perfusion.
  
  
  METHODS
  Using porcine hearts flushed with a Ribosol-based cardioplegic solution, we examined how storage time affects microvascular myocardial perfusion by using contrast-enhanced magnetic resonance imaging at a mean (SD) of 6.1 (0.6) hours (n = 13) or 15.6 (0.6) hours (n = 11) after cardiectomy. Finally, to determine if administration of cardioplegic solution affects pH and microvascular perfusion, isolated hearts (group 1, n = 9) given a single antegrade dose, were compared with hearts (group 2, n = 8) given intermittent antegrade cardioplegia (150 mL, every 30 min, 150 mL/min) by a heart preservation device. Khuri pH probes in left and right ventricular tissue continuously measured hydrogen ion levels, and perfusion intensity on magnetic resonance images was plotted against time.
  
  
  RESULTS
  Myocardial perfusion measured via magnetic resonance imaging at 6.1 hours was significantly greater than at 15.6 hours (67% vs 30%, P = .00008). In group 1 hearts, the mean (SD) for pH at the end of 6 hours decreased to 6.2 (0.2). In group 2, hearts that received intermittent antegrade cardioplegia, pH at the end of 6 hours was higher at 6.7 (0.3) (P = .0005). Magnetic resonance imaging showed no significant differences between the 2 groups in contrast enhancement (group 1, 62%; group 2, 40%) or in the wet/dry weight ratio.
  
  
  CONCLUSIONS
  Intermittent perfusion maintains a significantly higher myocardial pH than does a conventional single antegrade dose. This difference may translate into an improved quality of donor hearts procured for transplantation, allowing longer distance procurement, tissue matching, improved outcomes for transplant recipients, and ideally a decrease in transplant-related costs.
authors.affiliation: University of Minnesota, Minneapolis, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Rivard
authors.forename: Christina
authors.initials: C
authors.lastname: Hellmich
authors.forename: Cory M
authors.initials: CM
authors.lastname: Swingen
authors.forename: Forum D
authors.initials: FD
authors.lastname: Kamdar
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Cordova
authors.forename: Jonathan
authors.initials: J
authors.lastname: Holstad
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Baranowski
authors.forename: Richard W
authors.initials: RW
authors.lastname: Bianco
authors.forename: Ranjit
authors.initials: R
authors.lastname: John
mesh_terms: D000818:Animals; D002314:Cardioplegic Solutions; D006324:Heart Arrest, Induced / Q000295:instrumentation* / Q000379:methods*; D016027:Heart Transplantation / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009926:Organ Preservation / Q000295:instrumentation* / Q000379:methods*; D013552:Swine
chemical_list: D002314:Cardioplegic Solutions