Improved preservation of endothelial function at 4UC

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)