BURN INJURY ALTERS CORONARY ENDOTHELIAL FUNCTION

This study examined the effects of burn injury on coronary endothelial function and coronary vascular reactivity. Adult rabbits were given a scald burn over 30% of the total body surface area (or sham burn for controls) and resuscitated with Ringer's lactate solution (4 ml/kg/% b urn), Subgroups of burned (n = 6) and sham-burned (n = 6) animals were sacrificed at 2, 6, and 24 hr after injury; hearts were harvested and perfused. Changes in coronary perfusion pressure (CPP, mm Hg) and cor onary vascular resistance (CVR, mm Hg/min) were determined at a consta nt preload and constant coronary flow rate. Changes in coronary endoth elial function were determined by the ability of the endothelium to re lease cGMP as an indicator of nitric oxide production. Compared to val ues measured in sham burns, CPP and CVR progressively fell during the early postburn period but increased toward values measured in the sham burn group by 24 hr. Cyclic GMP, fmole/ml of coronary perfusate, was significantly lower in burned hearts (27 +/- 1) compared to values mea sured in effluents from sham burn hearts (310 +/- 40, P < 0.05). Alter ations in coronary effluent cGMP levels after burn injury suggest that thermal injury disrupts coronary endothelial function, likely contrib uting to postburn changes in cardiac performance. (C) 1996 Academic Pr ess, Inc.