Incomplete recovery of working heart function after twenty-four-hour preservation with a modified University of Wisconsin solution.

BACKGROUND AND METHODS: This study was designed to determine the function of isolated rabbit hearts after static preservation with modified University of Wisconsin solution for 24 hours. Commercially available University of Wisconsin solution, modified with CaCl2 1 mmol/L and 2,3-butanedione monoxime 30 mmol/L, was used as the preservative. After flushing the coronary vasculature with medium, hearts were submersion stored at 1 degree C to 4 degrees C. After preservation, isolated heart function at 37 degrees C was quantified for 30 minutes in a non-ejecting mode and for 4 hours ejecting at a physiologic workload. Fresh control hearts (n = 5) and University of Wisconsin solution-preserved hearts (n = 6) were studied.
RESULTS: Nonworking (non-ejecting) left ventricular function of the two groups did not differ, except for peak rate of left ventricular pressure development which was higher for the University of Wisconsin solution hearts than for controls. When the hearts were subjected to a physiologic workload, however, left ventricular function of the two groups differed significantly. Three of the six University of Wisconsin solution hearts failed before the 4-hour perfusion end point, whereas all five control hearts maintained stable working function for the full 4 hours. The University of Wisconsin solution hearts, while in the ejecting mode, exhibited significantly impaired function. Mean values were as follows (p < 0.05): left ventricular systolic pressure (in millimeters of mercury), control 105 +/- 1, University of Wisconsin solution 86 +/- 4; peak rate of left ventricular pressure development (in millimeters of mercury per millisecond), control 3.33 +/- 0.11, University of Wisconsin solution 2.39 +/- 0.24; cardiac output (in milliliters per minute per gram), control 400 +/- 25, University of Wisconsin solution 288 +/- 26; stroke work (in milliJoules per gram), control 20.1 +/- 1.3, University of Wisconsin solution 11.9 +/- 1.1; left ventricular end-diastolic pressure (in millimeters of mercury), control 5.4 +/- 0.3, University of Wisconsin solution 10.2 +/- 1.3; peak aortic flow rate (in milliliters per minute), control 946 +/- 9, University of Wisconsin solution 659 +/- 44; millimoles of lactate produced in 30 min/Joule stroke work, control 0.50 +/- 0.06, University of Wisconsin solution 6.99 +/- 0.37.
CONCLUSIONS: These results indicate that (1) hypothermic storage in this modified University of Wisconsin solution does not preserve hearts sufficiently to support a physiologic workload for an extended period and (2) assessment of post-preservation function with a non-ejecting heart model does not accurately predict the ability of the preserved heart to support a physiologic workload.