P5425Prognostic value of NYHA functional class in heart failure patients undergoing primary prevention implantable cardioverter defibrillator therapy
Authors: Briongos Figuero S , Estevez A , Perez M L , Martinez-Ferrer J B , Garcia E , Vinolas X , Arenal A , Alzueta J B , Basterra N , Lozano I , Munoz-Aguilera R 
Published: October 2019

Abstract

Background
NYHA functional class (FC) is used for selection of heart failure (HF) patients who are candidates to primary prevention (PP) implantable cardioverter defibrillator (ICD) therapy. However, FC is subjectively estimated and concerns about its real prognostic value are still present in this setting.

Purpose
To compare whether mortality and arrhythmic risk are different, in a cohort of HF patients undergoing PP ICD-only implant, according to their FC.

Methods
All HF patients with left ventricle ejection fraction (LVEF) ≤35%, undergoing first prophylactic ICD-only implant were collected from the UMBRELLA nationwide registry (2006–2015). The sample was divided into three groups: no symptoms (NYHA I), mildly symptomatic patients (NYHA II) and severely symptomatic (NYHA III) patients. Outcomes were studied as follow: all-cause death, cardiovascular mortality and arrhythmia free survival (surrogate marker of sudden cardiac death) defined as survival free of first appropriate ICD therapy delivered in ventricular fibrillation (VF) window. Arrhythmic events were collected by remote monitoring and reviewed by a committee of experts.

Results
Six hundred and twenty one patients were identified (61.1±11.4 years, 87.3% male). Distribution of study groups was as follow: 101 patients in NYHA I; 411 in NYHA II; and 109 in NYHA III. More symptomatic patients were older and had higher prevalence of atrial fibrillation (AF) and chronic kidney disease (CKD). Higher rates of optimal medical treatment were present among study groups (beta-blockers: 92.1%; ACEI or ARB: 86.8%; aldosterone antagonists: 60.2%). After a median follow-up of 4.2 years (IQR, 2.7–5.7 years) 126 patients died (event rate: 20.3%). All-cause mortality was higher in patients with worse FC (13.9% vs. 18.3% vs. 32.9% for NYHA I, II and III respectively; p<0.001, log-rank test). Seventy-eight out of 126 deaths were related to cardiovascular causes (overall event rate: 12.6%). Cardiovascular mortality risk was also higher in more symptomatic patients (6.9% vs. 11% vs. 23.9% for NYHA I, II and III respectively; p<0.001, log-rank test). One hundred and seventeen patients received afirst appropriate ICD therapy (19.4%). Arrhythmia free survival was not different among study groups (20.8% vs. 18.7% vs. 20.8% for NYHA I, II and III, respectively; p=0.495, log-rank test). Cumulative incidence curves for the three outcomes are shown in Figure 1. After multivariate analysis, worse NYHA class independently predicted cardiovascular mortality but not all-cause death. Moreover, diabetes, AF and CKD strongly predicted both all-cause and cardiovascular mortality.
Figure 1

Conclusions
In HF patients, prophylactic ICD seems to be useful in preventing death due to life threatening arrhythmias, regardless of the baseline FC. Nevertheless, the combination of NYHA class with other comorbidities may be useful to select those ICD candidates who obtain less survival benefit.