Soluble receptor for advanced glycation end products as an indicator of pulmonary vascular injury after cardiac surgery

Background: Cardiac surgery is frequently complicated by an acute vascular lung injury and this may be mediated, at least in part, by the (soluble) receptor for advanced glycation end products (sRAGE). Methods: In two university hospital intensive care units, circulating sRAGE was measured together with the (68)Gallium-transferrin pulmonary leak index (PLI), a measure of pulmonary vascular permeabiliy, in 60 consecutive cardiac surgery patients stratified by the amount of blood transfusion, within 3 hours of admission to the intensive care. Results: Cardiac surgery resulted in elevated plasma sRAGE levels compared to baseline (315 +/- 181 vs 110 +/- 55 pg/ml, P = 0.001). In 37 patients the PLI was elevated 50% above normal. The PLI correlated with sRAGE (r(2) = 0.11, P = 0.018). Plasma sRAGE discriminated well between those with an elevated PLI and those with a normal PLI (area under the operator curve 0.75; P = 0.035; 95% CI 0.55 0.95), with 91% sensitivity but low specificity of 36% at a cutoff value of 200 pg/mL. Blood transfusion did not influence sRAGE levels. Conclusions: sRAGE is elevated in plasma after cardiac surgery and indicates increased pulmonary vascular permeability. The level of sRAGE is not affected by transfusion.