Baseline circulating thrombospondin-1 is associated with recurrence after catheter ablation in paroxysmal atrial fibrillation: A retrospective cohort study

INTRODUCTION: Recurrence after radiofrequency catheter ablation remains common in patients with paroxysmal atrial fibrillation (AF), and clinically accessible biomarkers for pre-procedural risk stratification are limited. Thrombospondin-1 (TSP-1) is a circulating matricellular protein implicated in inflammatory and profibrotic pathways. METHODS: We conducted a single-center retrospective cohort study of 211 patients with paroxysmal AF undergoing first-time radiofrequency catheter ablation. Baseline circulating TSP-1 was measured before ablation and analysed primarily as a continuous (log-transformed) variable, with a pre-specified 75th-percentile threshold used for exploratory subgroups. The primary endpoint was AF recurrence after a 3-month blanking period. Multivariable Cox regression, restricted cubic splines, time-dependent discrimination with bootstrap optimism correction, and propensity score matching (sensitivity analysis) were performed. RESULTS: During a median follow-up of 700 days, 61 patients (28.9%) experienced AF recurrence. Higher baseline TSP-1 was independently associated with recurrence in the full cohort (adjusted HR per 1-SD of log-TSP-1, 1.54; 95% CI 1.26-1.88; p < 0.001) and persisted after propensity score matching (HR 4.73; 95% CI 2.18-10.29). Adding TSP-1 improved time-dependent discrimination at 700 days (AUC 0.62 to 0.70; optimism-corrected 0.66; Harrell's C 0.627 to 0.705), although reclassification metrics were mixed and the incremental value was exploratory. CONCLUSION: Elevated baseline circulating TSP-1 was associated with a higher risk of AF recurrence after first-time radiofrequency catheter ablation in patients with paroxysmal AF. These findings support further evaluation of TSP-1 as a candidate biomarker for pre-procedural risk stratification.