Aim: In-stent restenosis (ISR) remains the major limitation of percutaneous coronary intervention (PCI), and the mechanism of ISR is neointimal growth. Higher serum total bilirubin (TBIL) inhibits the inflammatory response and the proliferation of vascular smooth muscle cells; however, the relationship between TBIL and ISR is still unclear. This study aimed to determine whether the serum bilirubin level is associated with ISR after coronary stenting in patients with coronary artery disease.
Methods: This study investigated 1076 consecutive patients who underwent coronary stenting and follow-up angiography (average period: 236 days) using the Fukuoka University Hospital Registry. We used multivariate logistic regression analysis to identify independent predictors of ISR.
Results: The baseline TBIL level was significantly lower in patients with ISR at follow-up compared to those without ISR [0.53 ± 0.26 mg/dL vs. 0.62 ± 0.69 mg/dL, p= 0.036]. When we divided the patients into 4 groups according to their baseline TBIL level ["low", "low-normal", "high-normal group" and "high" (0.18 ± 0.04, 0.50 ± 0.13, 0.93 ± 0.12 and 2.11 ± 2.68 mg/dL)], the ISR rate at follow-up was significantly correlated with the TBIL level [31.0, 32.3, 22.1, and 15.6%, respectively; p= 0.008 for trend]. A significant negative correlation between the TBIL level and ISR was revealed by multivariate analyses [odds ratio, 0.6; 95% confidence interval, 0.39-0.89, p= 0.015]. This risk reduction was comparable to those of other known ISR risk factors and covariates.
Conclusion: To the best of our knowledge, this is the first report to demonstrate that a higher TBIL level may be a useful independent predictor of ISR risk after PCI.