Fibrosis-4 index is independently associated with poor coronary collateral development and lesion complexity in chronic total occlusion: A single-center cohort study

Background: The fibrosis-4 (FIB-4) index, a non-invasive liver fibrosis index, has not been studied in chronic total occlusion (CTO). Aims: Our aim was to examine whether FIB-4 is associated with poor collateral development, lesion complexity, and procedural outcomes. Methods: Consecutive patients with angiographically confirmed CTO (December 2023–April 2026) were analyzed; those with chronic liver disease or acute hepatic injury were excluded. FIB-4 was categorized as low (<1.3), intermediate (1.3–2.67), or high (>2.67). Collateral was graded by three blinded readers (Rentrop and Werner classifications). The primary outcome was poor collateral (Rentrop 0–1); logistic regression was adjusted for age, diabetes, estimated glomerular filtration rate, ejection fraction, multivessel disease, and J-CTO score. Results: Of 193 patients, poor collateral prevalence rose across FIB-4 strata (31.9%, 42.1%, 80.8%; P <0.001). Per-unit FIB-4 was independently associated with poor collateral (adjusted odds ratio, 1.71; 95% confidence interval, 1.19–2.47; P = 0.004) and with high lesion complexity (J-CTO score ≥2: adjusted odds ratio, 2.43; P = 0.001); the estimate was attenuated but remained significant after adjustment for body mass index, smoking, C-reactive protein, statin use, and platelet count, and was consistent in multiple imputation. Adding FIB-4 to a clinical model improved discrimination (area under the curve 0.65 to 0.72, optimism-corrected 0.60 to 0.67; DeLong P = 0.02). Procedural success declined across strata. Among 181 patients with completed follow-up, FIB-4 was not associated with one-year major adverse cardiovascular events (adjusted hazard ratio, 1.13; P = 0.22). Conclusions: Higher FIB-4 shows a graded association with poor collateral development, greater lesion complexity, and lower procedural success in CTO, but not with 1-year outcomes.