Relation of the-174 G/C polymorphism of interleukin-6 to interleukin-6 plasma levels and to length of hospitalization after surgical coronary revascularization

Interleukin (IL)-6 plasma levels are predictive of major cardiovascular eve nts. The -174 G/C promoter polymorphism of the IL-6 gene affects basal leve ls in vivo and transcription rates in vitro, but its association with IL-6 acute phase levels among patients with coronary artery disease has not been investigated. In 111 patients with multivessel coronary artery disease und ergoing elective coronary artery bypass graft surgery, we prospectively ass essed genotype at position -174 and serial blood levels of IL-6 and other i nflammatory indexes. Clinical and surgical characteristics did not differ a mong genotypic groups. IL-6 levels-measured daily up to 72 hours before sur gery, after surgery, and at discharge-showed a mean 17-fold increase, peaki ng at 24 hours (p<0.0001). IL-6 levels (but not fibrinogen, white-blood cel l count, and C-reactive protein values) differed significantly according to the -174 genotype (p=0.042 for difference between areas under the curve), the 62 GG homozygotes exhibiting higher concentrations than the 49 carriers of the C allele (widest difference at 48 hours, p=0.015 in multivariate an alysis). GG homozygosity was associated with longer stays in the intensive care unit (2.5<plus/minus>3.4 vs 1.4 +/-0.9 days, p=0.02) and in the hospit al (6.7 +/-4.0 vs 5.3 +/-1.4 days, p=0.02) than C carriership. Rates of pos toperative death, myocardial infarction, and stroke were 8% in GG homozygot es and 2% in C-carriers (p=0.16). The IL-6-174 GG genotype is associated wi th higher acute phase levels of IL-6 and with longer stays in the hospital and in the intensive care unit than C allele carriership after surgical cor onary revascularization. (C) 2001 by Excerpta Medica, Inc.