Higher IL-6 levels but not IL6 −174G > C or −572G > C genotype are associated with post-operative complication following coronary artery bypass graft (CABG) surgery

• Published in: Atherosclerosis Vol. 204; no. 1; pp. 196 - 201
• Main Authors: Sanders, Julie, Hawe, Emma, Brull, David J, Hubbart, Christina, Lowe, Gordon D.O, Rumley, Ann, Humphries, Steve E, Montgomery, Hugh E
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ireland Ltd 01.05.2009; Elsevier
• Subjects: Aged; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Biomarkers - blood; Blood and lymphatic vessels; CABG; Cardiology. Vascular system; Cardiovascular; Coronary Artery Bypass - adverse effects; Elective Surgical Procedures; Female; Genetic Predisposition to Disease; Humans; IL-6-572G > C; IL6 -174G > C; Inflammation; Inflammation - genetics; Inflammation - immunology; Interleukin-6 - blood; Interleukin-6 - genetics; Logistic Models; Male; Medical sciences; Middle Aged; Phenotype; Polymorphism, Genetic; Post-operative outcome; Predictive Value of Tests; Prospective Studies; Risk Assessment; Risk Factors; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Time Factors; Treatment Outcome; Up-Regulation; Whites - genetics; Inflammation; IL6 -174G > C; IL-6-572G > C; CABG; Post-operative outcome; Prognosis; Cytokine; Genotype; Cardiovascular disease; Coronary heart disease; Vascular disease; Interleukin 6; IL6 - 174G > C; Surgery; Atherosclerosis; Complication
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2008.08.032

Abstract Large increases in inflammatory markers, particularly IL-6, occur after cardiac surgery. However, despite interventions to reduce the inflammatory response, great variability still remains which could in part be attributable to genetic predisposition. Since increased IL-6 levels following surgery are also associated with poorer outcome we sought to determine whether baseline and post-operative levels of Interleukin-6 (IL-6) and functional common variants of the Interleukin-6 ( IL6 ) gene are associated with post-operative outcome following coronary artery bypass grafting (CABG). Caucasian patients undergoing first-time elective CABG were studied. IL-6 levels were measured pre-, 6 h and 24 h following surgery and genotypes for IL6 gene variants −174G > C and −572G > C were obtained. Clinical data was collected daily until patient discharge. Patient outcome was categorised as with (ICUC, n = 177) and without (NICUC, n = 189) a post-operative complication during the ICU period and with (POC, n = 215) and without (NC, n = 151) a post-operative complication during hospitalisation. IL-6 levels pre- and at 24 h were greater in POC and ICUC than NC and NICUC, respectively. Pre- IL-6 levels independently predicted (for 1 standard deviation increase in log IL-6) POC (OR 1.4, 95% CI 1.1–1.7, p = 0.008) and ICUC (OR 1.3, 95% CI 1.0–1.6, p = 0.02) outcomes. Overall, the IL6 -572G > C had an effect over time on IL-6 levels ( p = 0.04) and on IL-6 levels in NC (P = 0.008) and NICUC ( p = 0.006). However, no associations were found with the IL6 −572G > C or −174G > C variants on IL-6 levels at individual time-points or by outcome group. Thus, in conclusion, elevated pre-operative IL-6 levels, but not IL6 gene variants predict poor patient outcome following CABG.