Quality of anticoagulation and outcomes after mechanical aortic valve replacement in patients with atrial fibrillation: a nationwide cohort study

Abstract

Abstract Background Mechanical aortic valve replacement (AVR) remains predominant treatment approach for younger patients in need of aortic valve operation. However, little is known about the success of the required Vitamin K Antagonist (VKA) treatment and its relation to adverse events. Purpose We assessed the quality of VKA treatment prior to ischemic events and major bleeding episodes after mechanical AVR in AF patients. Methods The registry-based FinACAF study combining data from several Finnish health care registers covers all patients diagnosed with atrial fibrillation (AF) during 2007–2018 in Finland. In the present study, we included patients undergoing mechanical AVR before or after the AF diagnosis. Hazard ratios (HR) of first-ever ischemic stroke, any bleeding, intracranial bleeding, and myocardial infarction (MI) after AVR were estimated with Fine-Gray model adjusted for known bleeding and stroke risk factors. Results We identified 1086 patients (27.1% female, median age 62.8 (IQR 56.2–68.3) years) with mechanical AVR and AF diagnosis, either before (58.8%) or after (41.2%) the operation, and without prior bleeding episode, ischemic stroke, or MI. Cumulative incidence estimates at 10 years after AVR were 12.8% for ischemic stroke, 27.9% for significant bleeding, 5.8% for intracranial hemorrhage (ICH), and 7.2% for MI. International Normalized Ratio (INR) was <2.0 during 27.9–33.9% of ischemic events and lower mean Time in Therapeutic Range (TTR) with INR target ≥2.0 was associated with subsequent higher stroke occurrence (standardized adjusted HR 1.23 (1.03–1.49) for lower TTR, p=0.030, Figure 1). INR was >3.5 during 23.4–24.3% of major bleeding events and lower mean TTR (INR target 2.0–3.5) was associated with subsequent bleeding episode (adjusted HR 1.20 (1.03–1.41), p=0.021, Figure 2). Mortality was high (10-year estimated survival 71.1%), and lower mean TTR (INR target 2.0–3.5) was associated with higher mortality (adjusted HR 1.56 (1.39–1.72), p<0.001). Conclusions Adverse events after mechanical AVR are frequent in AF patients and mortality is high. Suboptimal mean TTR appears to identify the patients at high risk for both bleeding episodes and ischemic stroke.Figure 1.Figure 2.