Elevated NT-proBNP is associated with unfavorably altered plasma fibrin clot properties in atrial fibrillation.

BACKGROUND: Dense fibrin clot formation and hypofibrinolysis have been reported in atrial fibrillation (AF). It is unclear which factors affect fibrin clot properties in AF.

METHODS AND RESULTS: We investigated plasma fibrin clot permeability (Ks ), clot lysis time (CLT), endogenous thrombin potential (ETP) as well as other coagulation and fibrinolysis parameters along with N-terminal pro-B-type natriuretic peptide (NT-proBNP) in 160 AF patients (median age, 70.5years). Previous stroke (n=15; 9.4%) was associated with decreased Ks (P=0.04) and longer CLT (P=0.005), together with higher antiplasmin (P=0.03) and lower tissue-type plasminogen activator (P=0.01). Lower Ks (P=0.04) and tendency towards longer CLT (P=0.10) were observed in patients with a left atrium diameter>40mm. Patients with a CHA2 DS2 -VASc score of 3 or more (82.5%) were characterized by higher thrombin-activatable fibrinolysis inhibitor antigen (P=0.009). Ks was inversely correlated with log NT-proBNP (r=-0.34, P<0.0001), plasminogen activator inhibitor-1 (PAI-1) antigen (r=-0.24, P=0.002) and C-reactive protein (r=-0.18, P=0.02), while CLT was positively correlated with log NT-proBNP (R=0.61, P<0.0001) and ETP (r=0.37, P<0.0001), which were interrelated (r=0.59, P<0.0001). After adjustment for potential confounders, PAI-1 (odds ratio [OR]: 1.14; 95% confidence interval [CI]: 1.02-1.26) was the only independent predictor of low Ks (the lowest quartile,≤6×10-9 cm2 ), while NT-proBNP (OR: 1.21; 95% CI: 1.12-1.31) and PAI-1 (OR: 1.30; 95% CI: 1.12-1.51) both predicted prolonged CLT (the top quartile,≥109min).

CONCLUSION: In AF patients prothrombotic fibrin clot properties assessed ex vivo are determined by PAI-1 and NT-proBNP and this phenotype is associated with prior ischemic stroke.