Ann Thorac Surg 2001;72:112-113
© 2001 The Society of Thoracic Surgeons
Invited commentary
William L. Holman, MDa
a Department of Cardiothoracic Surgery, University of Alabama at Birmingham, 1530 3rd Ave S—ZRB 719, Birmingham, AL 35294-0007, USA
e-mail: wholman{at}its.uab.edu
This article by Kevelaitis and associates shows that application of heat stress to a cold arrested donor heart immediately prior to storage improves systolic and diastolic function as measured after 2 hours of reperfusion. The authors evaluated the mechanism for this finding by measuring expression of heat shock protein (HSP) 72 and pharmacologically blocking the pathway for preconditioning at three different points. Pharmacologic blockade of preconditioning nullified the benefit of prestorage heating, however, the role of HSP 72 was not confirmed. Thus, the authors present a mixed message, but certainly enough evidence to warrant further exploration of this potentially useful adjunct to myocardial protection in cardiac transplantation.
As interesting aspect of this study is the question it raises regarding metabolism in the arrested hypothermic heart. These data suggest that even the cold arrested heart is capable of appropriately responding to a stress (ie, topical application of the 42.5°C probe), although the nature of this response may be substantively different than the response of the normothermic perfused heart. Manipulation of the excised heart at the back table to stimulate endogenous protective pathways is an exciting new line of investigation with important potential benefits. As the authors point out, much work remains to be done before this technique is applied clinically. The mechanism for this benefit and the role of HSPs should be elucidated. More importantly, the benefits must be confirmed in hearts from brain-dead animals. Finally, the usefulness of this technique in extending the limits of cold storage should be determined. With current techniques including Celsior or University of Wisconsin solutions, 4 to 6 hours of storage are usually well tolerated. If prestorage heat stress allows longer durations of storage, or if this novel technique helps marginal donor hearts (eg, older donors or donor hearts with impaired function prior to procurement), it will be very useful to clinical transplantation.
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