title: Intravenous phenylephrine preconditioning of cardiac grafts from non-heart-beating donors.
abstract: BACKGROUND
  Hypoxia and warm ischemia produce severe injury to cardiac grafts harvested from non-heartbeating donors. To potentially improve recovery of such grafts, we studied the effects of intravenous phenylephrine preconditioning.
  
  
  METHODS
  Thirty-seven blood-perfused rabbit hearts were studied. Three groups of non-heart-beating donors underwent intravenous treatment with phenylephrine at 12.5 (n = 8), 25 (n = 7), or 50 microg/kg (n = 7) before initiation of apnea. Non-heart-beating controls (n = 8) received saline vehicle. Hypoxic cardiac arrest occurred after 6 to 12 minutes of apnea, followed by 20 minutes of warm in vivo ischemia. A 45-minute period of ex vivo reperfusion ensued. Nonischemic controls (n = 7) were perfused without antecedent hypoxia or ischemia.
  
  
  RESULTS
  Phenylephrine 25 microg/kg significantly delayed the onset of hypoxic cardiac arrest compared with saline controls (9.6 +/- 0.5 versus 7.7 +/- 0.4 minutes; p = 0.00001), yet improved recovery of left ventricular developed pressure compared with saline controls (57.1 +/- 5.3 versus 41.0 +/- 3.4 mm Hg; p = 0.04). Phenylephrine 25 microg/kg also yielded a trend toward less myocardial edema than saline vehicle (p = 0.09).
  
  
  CONCLUSIONS
  Functional recovery of nonbeating cardiac grafts is improved by preconditioning. We provide evidence that the myocardium can be preconditioned with phenylephrine against hypoxic cardiac arrest.
authors.affiliation: Department of Surgery, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Cope
authors.forename: M C
authors.initials: MC
authors.lastname: Mauney
authors.forename: D
authors.initials: D
authors.lastname: Banks
authors.forename: O A
authors.initials: OA
authors.lastname: Binns
authors.forename: C L
authors.initials: CL
authors.lastname: Moore
authors.forename: J J
authors.initials: JJ
authors.lastname: Rentz
authors.forename: K S
authors.initials: KS
authors.lastname: Shockey
authors.forename: R C
authors.initials: RC
authors.lastname: King
authors.forename: I L
authors.initials: IL
authors.lastname: Kron
authors.forename: C G
authors.initials: CG
authors.lastname: Tribble
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001834:Body Water / Q000378:metabolism; D006323:Heart Arrest / Q000601:surgery*; D016027:Heart Transplantation / Q000379:methods*; D007262:Infusions, Intravenous; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D017202:Myocardial Ischemia / Q000601:surgery; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D010656:Phenylephrine / Q000008:administration & dosage*; D011817:Rabbits; D016277:Ventricular Function, Left
chemical_list: D010656:Phenylephrine