Association between atrial fibrillation and gastrointestinal bleeding: pathophysiology, risk stratification, and...

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly increasing the risk of thromboembolic events, necessitating anticoagulation therapy. However, anticoagulation, particularly with novel oral anticoagulants, elevates the risk of gastrointestinal bleeding (GIB), creating a clinical dilemma in managing AF patients. This narrative review explores the pathophysiology linking AF and GIB, emphasizing the hypercoagulable state in AF and the mucosal damage caused by anticoagulants. Epidemiological data reveal that GIB incidence in AF patients ranges from 1.32% to 5.4% annually, with risk factors including older age, prior GIB, and concomitant antiplatelet use. Risk stratification tools such as CHA₂DS₂-VASc and HAS-BLED aid in balancing thromboembolic and bleeding risks, though their predictive performance remains modest. Comparative studies highlight that rivaroxaban carries a higher GIB risk, while apixaban offers a safer profile. Management strategies include proton pump inhibitors for prophylaxis, endoscopic interventions for acute bleeding, and individualized decisions on resuming anticoagulation post-GIB, typically within 7-30 days. Emerging research on the gut microbiome's role in AF pathogenesis suggests potential novel therapeutic avenues. A multidisciplinary approach involving cardiologists, gastroenterologists, and hematologists is essential to optimize outcomes. Future directions include developing safer anticoagulants, refining risk prediction models, and exploring microbiome-targeted therapies.