The soluble ST2 level predicts the risk of atrial fibrillation recurrences in long-term period after radiofrequency ablation

Abstract Background and Objectives: The hypothesis of the study was the assumption that the serum levels of soluble ST2 (sST2) and growth differentiation factor (GDF-15) can be predictors of atrial fibrillation (AF) recurrence in long-term period after primary radiofrequency catheter ablation (RFA). Methods: Of the 165 patients (pts) included in the prospective follow-up, the final analysis included 131 pts whose follow-up duration reached 18 months after the end of the blanking period (3 months after the date of RFA). The median age of pts was 59.0 (50.0; 64.0) years, and 80 pts (61%) were men. 103 (79%) pts had paroxysmal and 28 (21%) persistent AF. All pts underwent transthoracic and transesophageal echocardiography, electroanatomic mapping to assess the area of low-voltage zones (LVZ) and determination of sST2 and GDF-15 levels by ELISA using analytical kits GDF-15/MIC-1 (BioVender, Czech Republic) and Presage ST2 (Critical Diagnostics, USA). After RFA pts had regular follow-up visits at 3-6-9-12-18 months with 12-lead ECG or Holter ECG monitoring and with clinical evaluation. The primary endpoint was the occurrence of the first symptomatic AF recurrence (AFr) lasting >30 seconds, recorded on an ECG or during daily ECG monitoring, after a blanking period. Results: During follow-up of 18 months, 47 pts (35.9%) had AFr. The groups with and without AFr didn`t differ in the LVZ area. The medians of NT-proBNP, GDF-15 and sST2 also didn`t differ significantly between the groups, but in pts with AFr, the proportion of pts with sST2 ≥36 ng/ml (the border of the lower and middle terziles) was higher (p=0.03). According to the one-factor Cox regression analysis, late AFr were associated with four factors: AF history ≥1 year, early AFr (during the blanking period), left atrial appendage flow velocity (LAAFV) <54 cm/sec and sST2 ≥36 ng/ml. In the multivariate Cox analysis two independent predictors of late AFr were obtained: sST2 ≥36 ng/ml (HR=3.8; 95% CI 1.5-9.8, p=0.006) and LAAFV <54 сm/sec (HR=1.96; 95% CI 1.01-3.82, p=0.048). Conclusions: Serum sST2 level with a cut-off value of 36 ng/ml or more can be used as a predictor of AF recurrence in the long-term period after primary RFA.