Objective: To investigate whether ECC may produce regional liberation of inflammatory mediators capable of inducing vascular effects and organ damage.
Experimental design: Comparative study [corrected].
Setting: Cardiac surgery department in a University hospital.
Patients: Fifteen patients undergoing coronary artery bypass grafting (CABG, group A) and ten patients operated for infrarenal abdominal aortic aneurysm (controls, group B) have been studied.
Measures: Levels of Interleukin 1beta (IL1), Tumor Necrosis Factor alpha (TNF), Interleukin 6 (IL6), and Endothelin 1 (ET1) were measured in pulmonary capillary, arterial, and venous blood and in bronchoalveolar lavages (BAL) before, during and after extracorporeal circulation (ECC) or surgical intervention.
Results: TNF-alpha (never >35 pg/ml) and IL1beta (range 20-300 pg/ml) values did not change over time for both groups. IL6 concentrations in all samples of group A increased between five and twenty fold, during and after ECC (from 3-5 pg/ml up to 240 pg/ml, p<0.001). This trend was similar in controls after surgical stress. Endothelin 1 was always undetectable in the BAL fluid, with a modest, but significant increase in pulmonary capillary blood of group A, after ECC, (from 11+/-4 pg/ml to 18+/-5 pg/ml, p<0.001). This increment correlated well with the PVR increase, but was transient and after 24 hours, ET1 values returned to baseline levels. Mean values of ET1 increased also in controls, but not significantly.
Conclusions: ECC may induce ET1 liberation in pulmonary circulation with transient pulmonary vasoconstriction, but wihout intra-alveolar release, or lung damage. Augmented concentrations of IL6 probably express a response to surgical procedure rather than an effect exclusively related to ECC.