Interleukin-6 promoter genotype and restenosis after femoropopliteal balloon angioplasty: Initial observations

PURPOSE: To investigate whether there is an association between a functional polymorphism in the interleukin (IL)-6 gene promoter (-174)G/C and restenosis after percutaneous transluminal angioplasty (PTA) of the femoropopliteal artery. MATERIALS AND METHODS: A total of 281 patients underwent PTA of the femoropopliteal artery during the study period; 23 (8%) patients had to be excluded due to missing genetic data. We studied 258 patients with intermittent claudication (n = 174) or critical limb ischemia (n = 84). The IL-6 promoter genotype was determined from venous blood samples before intervention by using a mutagenically separated polymerase chain reaction, and patients were followed up for 6 months with duplex ultrasonography for the occurrence of restenosis (greater than or equal to50%) after angioplasty. Multivariate Cox proportional hazards analysis was performed to assess the association between the IL-6 promoter genotype and restenosis, with adjustment for possible confounders such as atherosclerotic risk factors and angiographic covariates. RESULTS: The 6-month restenosis rate was 26% (23 of 90) in patients with the (-174)GG genotype, 28% (33 of 117) with the (-174)GC genotype, and 43% (22 of 51) with the (-174)CC genotype (P = .044). Homozygous carriers of the (-174)C allele ([-174]CC) exhibited a 2.42-fold increased adjusted risk for restenosis (95% CI: 1.28, 4.58; P = .007) compared with homozygous (-174)G allele carriers ([-174]GG). Heterozygous carriers ([-174]GC) had no significantly increased restenosis risk (hazard ratio, 1.37; 95% CI: 0.84, 2.22; P = .21). CONCLUSION: The IL-6 promoter polymorphism (-174)G/C seems to influence the occurrence of restenosis after PTA. Homozygous carriers of the (-174)C allele have an increased rate of intermediate-term restenosis. (C) RSNA, 2004.