The Journal of Thoracic and Cardiovascular Surgery, Vol 91, 545-550, Copyright © 1986 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Effect of initial reperfusion temperature on myocardial preservation
MT Metzdorff, GL Grunkemeier and A Starr
The effect of initial postischemic reperfusion temperature on myocardial
preservation was studied in the isolated working rat heart model. After
baseline measurement of aortic flow rate, coronary flow rate, and heart
rate, 40 hearts were subjected to 60 minutes of ischemic arrest at 15
degrees C induced with a single dose of cold potassium cardioplegic
solution. Hearts were then revived with a 10 minute period of nonworking
reperfusion at 28 degrees, 31 degrees, 34 degrees, or 37 degrees C (10
hearts each), followed by 5 minutes of nonworking reperfusion at
normothermia, followed by 30 minutes of working perfusion. Repeat
measurements of function were obtained and postischemic release of creatine
kinase into coronary effluent was determined. Recovery of aortic flow was
significantly reduced at lower initial reperfusion temperatures (75% at 28
degrees C versus 88% at 37 degrees C) and the effect was approximately
linear throughout the range studied (p less than 0.05). Release of creatine
kinase into coronary effluent was greater at lower initial reperfusion
temperatures (421 ImU/min/gm wet weight at 28 degrees C versus 115
ImU/min/gm wet weight at 37 degrees C), also in a linear manner (p less
than 0.05). In this model, initial postischemic hypothermic reperfusion is
deleterious to cellular integrity and functional recovery of the preserved
myocardium. Studies in higher animals and humans are warranted to further
evaluate the effect of initial reperfusion temperature on myocardial
preservation.