Prognosis of patients in end-stage heart failure with atrial fibrillation treated with ablation - Insights from Castle HTX

BACKGROUND: The CASTLE-HTx trial demonstrated the benefit of atrial fibrillation (AF) ablation compared to medical therapy in decreasing mortality, need for left ventricular assist device (LVAD) implantation or heart transplantation (HTx) in patients with end-stage heart failure (HF). OBJECTIVES: The aim of this analysis was to identify risk factors related to adverse outcomes in patients with end-stage HF and to assess the impact of ablation. METHODS: The CASTLE-HTx protocol randomized 194 patients with end-stage HF and AF to ablation versus medical therapy. We identified left ventricular ejection fraction (LVEF) <30%, NYHA-class =3 and AF burden >50% as predictors for the primary end point. The CASTLE-HTx risk-score assigned weights to these risk factors. Patients with a risk-score =3 were identified as high-risk. RESULTS: Eighty-nine patients (45.9%) were categorized to the low- and 105 (54.1%) to the high-risk group. After a median follow-up of 18 months, a primary end point event occurred in 6 and 31 patients of the low- and high-risk group (HR, 4.98; 95% CI, 2.08-11.9). The incidence rate (IR) difference between ablation and medical therapy was much larger in high-risk patients (8/49 (IR 11.4) vs. 23/56 (IR 36.1)) when compared to low-risk patients (2/48 (IR 2.6) vs. 4/41 (IR 6.3)). The IR difference for ablation was significantly higher in high-risk patients (24.69) compared to low-risk patients (3.70). CONCLUSIONS: The absolute benefit of ablation is more pronounced in high-risk patients, but low-risk patients may also benefit. The CASTLE-HTx risk-score identifies patients with end-stage HF that will particularly benefit from ablation.