Altered fibrin clot properties are associated with the progression of chronic kidney disease in atrial fibrillation

Introduction: Formation of denser and resistant to lysis fibrin clot networks has been shown in chronic kidney disease (CKD) and atrial fibrillation (AF). We investigated whether such prothrombotic fibrin clot properties are associated with faster progression of CKD in AF patients. Material and methods: We recruited 265 AF patients (men 49.1 %, median age of 64.0 years, median estimated glomerular filtration rate [eGFR] of 77.0 ml/min/1.73 m(2)), including 137 patients on non-vitamin K antagonist oral anticoagulants (NOACs) (51.7 %) and 109 patients (41.1 %) on vitamin K antagonists (VKAs). At baseline while off anticoagulation, we determined fibrin clot permeability (K-s), and clot lysis time (CLT), along with plasminogen activator inhibitor-1 (PAI-1), endogenous thrombin potential (ETP), and von Willebrand factor (vWF). The kidney function was assessed at baseline and after a median follow-up of 50.0 months. Results: During follow-up, a median eGFR decreased by 8.0 (5.0-11.0) ml/min/1.73 m(2), 1.8 ml/min/1.73 m(2)/year and this change correlated with age (R = 0.19, P = 0.002), K-s (R = 0.46, P < 0.0001), and CLT (R = -0.17, P = 0.005), but not ETP, fibrinogen, PAI-1 or vWF. A decrease in eGFR was lower in patients who used NOACs at baseline but not in those who started NOACs during follow-up (n = 101) as compared to the remaining patients. On multiple linear regression analysis, adjusted for age and fibrinogen, baseline K-s, eGFR, hypertension, and NOACs use independently predicted a decrease in eGFR. Conclusions: This study is the first to show that more compact fibrin clot networks may contribute to faster progression of CKD in AF, indicating novel kidney-related harmful effects of prothrombotic clot properties in humans.