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.
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.


METHODS
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.


CONCLUSIONS
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.
Scheule
A M
AM
Department of Surgery, Tübingen University Hospital, Germany.
Bohl
A
A
Heinemann
M K
MK
Ziemer
G
G
Henze
E
E
D000818:Animals; D001802:Blood Substitutes / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D005466:Fluorocarbons / Q000494:pharmacology*; D007036:Hypothermia, Induced; D009682:Magnetic Resonance Spectroscopy; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism*; D013552:Swine
D001802:Blood Substitutes; D005466:Fluorocarbons; D010710:Phosphates; D010725:Phosphocreatine; C008807:perfluorotributylamine