The soluble ST2 level predicts 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 included in the prospective follow-up, the final analysis included 131 patients whose follow-up duration reached 18 months after the end of the blanking period (3 months after RFA). The median age of patients was 59.0 (50.0; 64.0) years, and 80 (61%) were men. Paroxysmal AF was present in 103 (79%) and persistent AF in 28 (21%) patients. All patients underwent transthoracic and transesophageal echocardiography, and electroanatomic mapping was used to assess the area of low-voltage zones (LVZ). sST2 and GDF-15 levels were determined by ELISA using GDF-15/MIC-1 analytical kits (BioVender, Czech Republic) and Presage ST2 (Critical Diagnostics, USA) before RFA. After RFA, patients 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 s, recorded on an ECG or during daily ECG monitoring, after a blanking period. RESULTS: At the 18-month follow-up, 47 patients (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 patients with AFr, the proportion of those 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, 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 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.