Abstract 14499: Impact of Pre-existing and New Incident Atrial Fibrillation on Outcomes of Patients With Acute Pulmonary Embolism: Findings From an International Registry

Background: Atrial fibrillation (AF) may occur prior to or early in the course of acute pulmonary embolism (PE). The impact of AF on outcomes of patients with PE remains uncertain. Methods: Using the data from a large prospective multicenter registry of patients with objectively-confirmed PE (04/2014 to 01/2020), we identified three patient groups: 1) those with pre-existing AF 2) patients with newly identified AF within 2 days from the index PE (incident AF) and 3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, in unadjusted and multivariable adjusted models considering those without AF as referent. Results: Among 16,497 patients with PE, 792 had pre-existing AF. Compared with those without AF, patients with pre-existing AF, had increased odds of 90-day all-cause (Odds ratio [OR]: 2.81 (95% confidence interval [CI]: 2.33-3.38) and PE-related mortality (OR: 2.38, 95% CI: 1.37-4.14). After multivariable adjustment, pre-existing AF significantly increased the odds of all-cause mortality (OR: 1.91, 95% CI: 1.57-2.32) but not PE-related mortality (OR: 1.50; 95% CI: 0.85-2.66). Pre-existing AF was associated with increased hazard for ischemic stroke at 1-year follow-up (hazard ratio [HR]: 5.48; 95% CI: 3.10-9.69). Among 16,497 patients with PE, 445 developed incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR: 2.28; 95% CI: 1.75-2.97) and PE-related (OR: 3.64; 95% CI: 2.01-6.59) mortality. Findings were similar in multivariable analyses and at 1-year follow-up (Figure). No patients with incident AF developed ischemic stroke. Conclusion: In patients with acute symptomatic PE, both pre-existing AF and incident AF predict an adverse clinical course, although the type of adverse outcomes may be different depending on the timing of AF onset.