Risk of left atrial appendage thrombus in patients with atrial fibrillation and chronic kidney disease

Background: Atrial fibrillation (AF) and chronic kidney disease (CKD) are associated with an increased risk of ischemic stroke. The aim of this study was to compare the clinical characteristics, the incidence of left atrial appendage (LAA) thrombus and its predictors, and spontaneous echo contrast (SEC) in a population of patients with AF depending on estimated glomerular filtration rate (eGFR) values. Methods: This study included 1962 patients who underwent transesophageal echocardiographic ex- amination prior to cardioversion or ablation in the years 2014-2018 in three cardiac centers. Results: More than a quarter of AF patients had decreased eGFR (< 60 mL/min/1.73 m(2)) and were characterized as a high-risk population, with more comorbidities, higher thromboembolic and bleed- ing risk compared to those with normal renal function. Oral anticoagulation (OAC) was prescribed in 97% and 93% of patients with decreased and normal eGFR, respectively, with a higher prevalence of prescribed non-vitamin K antagonist oral anticoagulants (NOACs). The incidence of LAA thrombus (24%, 9% and 4%) and SEC (25%, 25% and 19%) increases simultaneously with a decrease in eGFR (< 30, 30-59 and >= 60 mL/min/1.73 m(2), respectively). Among patients prescribed reduced doses of NOAC, those with decreased eGFR were more often observed with LAA thrombus (10% vs. 2.5%). Non-paroxysmal AF, heart failure and previous bleeding were predictors of LAA thrombus, irrespective of eGFR value. CKD was the predictor of LAA thrombus in all patients including those with non-pa- roxysmal AF, males, without diabetes, without hypertension and with CHA2DS2-VASc < 2. Conclusions: Despite OAC, patients with concomitant AF and CKD remain at high risk for LAA thrombus formation.