The Annals of Thoracic Surgery, Vol 43, 484-489, Copyright © 1987 by The Society of Thoracic Surgeons
Intermittent reperfusion extends myocardial preservation for transplantation
SK Beeman, TA Shuman, AM Perna, JB Atkinson, JW Hammon Jr, HW Bender Jr and WH Merrill
A protocol was developed to compare prolonged heart preservation by
hypothermic storage with prolonged hypothermic storage interrupted by a
period of reperfusion. Hearts from adult mongrel dogs were excised after
administration of 4 degrees C crystalloid cardioplegia. Group A hearts (N =
7) underwent 7.5 hours of ischemia at 4 degrees C followed by 1.5 hours of
reperfusion and rewarming (A0). Group B hearts (N = 8) underwent 3 hours of
ischemia at 4 degrees C, 1.5 hours of reperfusion and rewarming (B1), 3
additional hours of ischemia at 4 degrees C following repeat cardioplegia,
and finally 1.5 hours of reperfusion and rewarming (B2). During
reperfusion, hearts were defibrillated and left ventricular (LV) function
was assessed by measuring isovolumic peak systolic pressure and maximum
positive rate of rise of LV pressure (+dP/dtmax) with an intraventricular
balloon. LV biopsy samples for adenosine triphosphate (ATP) assay were
obtained before ischemia and after each rewarming period. One Group A heart
could not be defibrillated and studied. All Group B hearts completed the
protocol. LV function, as assessed by peak pressure and +dP/dtmax, at B1
and B2 exceeded values obtained at A0, but the differences were not
statistically significant. The mean ATP level was 63.4 +/- 7.7% of baseline
at B1 and 79.7 +/- 4.3% of baseline at B2 (p less than .03). The mean ATP
level was 57.9 +/- 5.9% of baseline at A0 (p less than .007, B2 vs. A0). It
is presumed that intermittent reperfusion allows repletion of substrate
stores, which results in improved myocardial protection.(ABSTRACT TRUNCATED
AT 250 WORDS)
