European Journal of Cardio-Thoracic Surgery, Vol 11, 746-750, Copyright © 1997 by European Association for Cardio-thoracic Surgery
Postischemic synthesis of high energy phosphates in isolated porcine hearts during reperfusion with 11 or 25 degrees C hypothermic perfluorocarbon emulsion FC 43. A 31P magnetic resonance spectroscopy study
AM Scheule, A Bohl, MK Heinemann, G Ziemer and E Henze
Department of Surgery, Tubingen University Hospital, Germany.
OBJECTIVE: One aim of coronary reperfusion after myocardial ischemia is to
restore the myocardial content of high energy phosphates. The superiority
of the artificial oxygen carrier perfluorocarbon emulsion FC43 over blood
solution is known, therefore, in this paper we examined the
temperature-dependence of this substance. METHOD: The changes of the high
energy phosphates phosphocreatine (PCr) and inorganic phosphate (Pi) were
documented in 29 isolated pig hearts, employing a 4.7 Tesla
magnetic-resonance-spectroscope (MRS). After 15 min warm ischemia,
reperfusion with warm blood and a cardioplegic ischemia period of 45 min,
these hearts were reperfused with either 11 or 25 degrees C hypothermic
oxygenated perfluorocarbon emulsion FC43, both under continuous
spectroscopy. MRS is able to directly measure PCr as well as Pi. Their
relation expresses the state of myocardial energy stores. RESULTS:
Reperfusion with 11 degrees C hypothermic FC43 (n = 14) caused an increase
of the relation PCr to Pi by a factor of 9, compared to an increase by a
factor of 4 with 25 degrees C emulsion (n = 15) (P < 0.05). During 80
min of reperfusion with 11 degrees C cold FC43 emulsion the average flow
rate was 90 +/- 12 and 96 +/- 11 ml/min during reperfusion with 25 degrees
C hypothermic FC43 emulsion. Both rates fell only slightly in the course of
time. CONCLUSION: We conclude that reperfusion with 11 degrees C
hypothermic oxygenated FC43 in isolated ischemic porcine hearts leads to a
clear increase of the index PCr/Pi compared with reperfusion at 25 degrees
C. The correlation between the synthesis of myocardial high energy
phosphates with postcardioplegic ventricular function is questionable. If
further studies will show an improvement of myocardial function after
perfusion with hypothermic oxygenated perfluorocarbon emulsion FC43, this
solution may find clinical application in the storage of explanted human
hearts for transplantation, during transportation to the recipient.
