Improved preservation of endothelial function at 4 degrees C

Hypothermia combined with chemical cardioplegia is routinely used clinically for perioperative myocardial protection and for donor heart preservation. Profound hypothermia can have an adverse influence on post-preservation endothelial and myocardial functions. In this study, we investigated the effect of temperature on endothelial and myocardial functions following global cardiac ischaemia in the isolated rat heart. A 5-hydroxytryptamine (5-HT)-induced increase in coronary flow was used as a selective probe to assess endothelial function, while myocardial function was measured by a working rat heart model. After recording control observations for endothelial and myocardial functions, hearts were kept ischaemic for 30 or 60 min without cardioplegia (groups 1 and 2, respectively) and for 60, 90 or 120 min following a single infusion of St. Thomas' Hospital solution (groups 3, 4 and 5, respectively). In each group, hearts were kept ischaemic at 20 degrees C or at 4 degrees C (n = 12 in each group). Endothelial and myocardial functions were reevaluated and compared with control values.(ABSTRACT TRUNCATED AT 250 WORDS)