Association Between Hepatitis C Virus Infection and SYNTAX Score in Patients with ST-Segment Elevation Myocardial Infarction: A Propensity Score-Matched Analysis

Background: Chronic hepatitis C virus (HCV) infection is increasingly recognized as a systemic inflammatory condition associated with accelerated atherosclerosis and adverse cardiovascular outcomes. However, its relationship with coronary anatomical complexity in patients presenting with ST-segment elevation myocardial infarction (STEMI) remains insufficiently defined. Aims: This study aimed to evaluate the association between chronic HCV infection and coronary artery disease complexity assessed by the SYNTAX score in STEMI patients undergoing primary percutaneous coronary intervention (pPCI) and to investigate its relationship with in-hospital mortality. Methods: In this retrospective single-center cohort study, 1647 STEMI patients treated with pPCI between January 2021 and December 2025 were analyzed; 106 (6.4%) were HCV-positive. Propensity score matching based on baseline demographic and cardiovascular risk factors yielded 105 matched pairs. The primary endpoint was the SYNTAX score, while the secondary endpoint was in-hospital all-cause mortality. Results: HCV-positive patients demonstrated significantly higher SYNTAX scores than HCV-negative patients before (19.5 ± 8.5 vs. 15.8 ± 9.6; p < 0.001) and after propensity score matching (19.4 ± 8.5 vs. 15.6 ± 9.2; p = 0.002). Coronary artery bypass grafting referral was more frequent among HCV-positive patients both before (11.3% vs. 5.3%; p = 0.010) and after matching (11.4% vs. 2.9%; p = 0.016). Notably, HCV-positive patients exhibited higher coronary anatomical complexity despite lower total and LDL cholesterol levels. In multivariable analyses, HCV positivity remained independently associated with higher SYNTAX scores in both unmatched and matched cohorts. In-hospital mortality rates were comparable between groups, and HCV positivity was not independently associated with mortality. Conclusions: Chronic HCV infection was independently associated with increased coronary anatomical complexity in STEMI patients undergoing pPCI, suggesting a relationship with a more diffuse and structurally complex atherosclerotic phenotype rather than short-term in-hospital outcomes. These findings support the concept of HCV infection as a non-traditional cardiovascular risk factor associated with adverse coronary vascular remodeling.