Effect of Serum IL-6 Levels on the Progression of Non-Target Lesions in Patients after Coronary Stenting.

Background: percutaneous coronary intervention (PCI) has become the mainstay of treatment for atherosclerotic cardiovascular disease (ASCVD). Inflammatory factors have been shown to be involved in the initiation and progression of ASCVD. After PCI, the persistence of inflammation, especially the inflammation released at the target lesion, may affect the stability of non-target lesion plaques. Interleukin-6 (IL-6) is one of the most common inflammatory factors, however studies about the influence of IL-6 on the progression of non-target lesions (NTLs) of coronary artery are limited. This study investigated whether serum IL-6 levels can affect the progression of NTLs after coronary stent implantation.

Methods: We performed a retrospective cohort study including 441 patients undergoing coronary angiography (CAG) and stent implantation, who had at least one NTL, between January 2019 and December 2021. They underwent followup CAG 9 to 12 months after PCI. Quartile grouping was based on serum IL-6 levels following readmission. The relationship between serum IL-6 levels and the progression of NTLs after coronary stent implantation was analyzed by using logistic regression analysis and restricted cubic spline regression. Predictive value of IL-6 on NTL progression was evaluated using the receiver operating characteristic (ROC) curve.

Results: When compared to the first quartile (Q1) group, the probability of NTL progression was increased in Q2 (adjusted odds ratio (aOR) 3.06, 95% CI 1.29-7.29), Q3 (aOR 3.55, 95% CI 1.52-8.26), and Q4 group (aOR 7.51, 95% CI 3.30-17.05), with a trend test p $<$ 0.001. With the increase of IL-6 levels, the risk of progression of NTLs gradually increased, and there was a non-linear relationship between IL-6 and progression of NTLs (p $<$ 0.001). The ROC curve showed that the critical value of the serum IL-6 level was 12.652 pg/mL (area under the curve is 0.673, sensitivity is 54.5%, specificity is 70.9%, p $<$ 0.05).

Conclusions: A high serum IL-6 level is an independent risk factor for the progression of NTLs after coronary stent implantation, and has certain predictive value for the progression of NTLs.