Prevalence and impact of comorbid atrial fibrillation in patients with pulmonary hypertension

Abstract

BACKGROUND: Pulmonary hypertension (pulm-HTN) is associated with progressive increases in pulmonary vascular resistance, with resultant impairment of right ventricular and right atrial function. Atrial fibrillation (AF) is associated with adverse atrial remodelling and fibrosis, a process recognised to involve the right atrium as well. We sought to evaluate the prevalence and clinical impact of comorbid AF in patients with pulm-HTN. METHODS: Patients referred to the pulm-HTN clinic at our quaternary institution between January 2017 and December 2020 were evaluated. Detailed evaluation of patient demographics, pulm-HTN aetiology and comorbidities was performed, and the clinical course of these patients was followed for up to five years for the primary outcome of all-cause death and major adverse cardiovascular events (MACE). Classification of pulm-HTN was performed by two pulm-HTN specialists blinded to clinical outcomes. RESULTS: 221 patients (mean age 64.2+/-16.8 years, 61% female) with a range of pulm-HTN subtypes (49% Type-1 pulm-HTN, 21% Type-2 pulm-HTN, 18% Type-3 pulm-HTN, 10% Type-4 pulm-HTN, 3% Type-5 pulm-HTN) were included. AF was present in 18% of the cohort, with a significantly higher prevalence amongst patients with post-capillary pulm-HTN relative versus pre-capillary pulm-HTN (39% vs 13%, p<0.01). Amongst patients with pre-capillary pulm-HTN, AF was most prevalent amongst Type-1 patients. On log-rank tests, the presence of comorbid AF was associated with a greater likelihood of death and MACE (p=0.046). CONCLUSIONS: AF is highly prevalent amongst patients with pulm-HTN, with higher rates amongst those with post-capillary pulm-HTN, and is associated with worse clinical outcomes in this population.