Reduced fibrin clot permeability on admission and elevated E-selectin at 3 months as novel risk factors of residual pulmonary vascular obstruction in patients with acute pulmonary embolism.

BACKGROUND: Residual pulmonary vascular obstruction (RPVO) is common following pulmonary embolism (PE) but its association with fibrin clot properties is poorly understood. We investigated whether prothrombotic state and hypofibrinolysis markers can identify patients with RPVO.

METHODS: In 79 normotensive noncancer patients (aged 56 ± 13.3 years) with acute PE, we determined fibrin clot permeability (Ks ), clot lysis time (CLT), endogenous thrombin potential (ETP), fibrinolysis proteins, oxidative stress markers, and E-selectin on admission before initiation of anticoagulant therapy, after 5-7 days, and 3 months of anticoagulation. RPVO was diagnosed using computed tomography angiography 3-6 months since PE.

RESULTS: Patients with RPVO (n = 23, 29.1%) had at baseline higher simplified Pulmonary Embolism Severity Index (sPESI) (P = 0.004), higher N-terminal brain natriuretic propeptide (P = 0.006) and higher D-dimer (P = 0.044). Patients with versus without RPVO had lower Ks (P < 0.001) and longer CLT (P < 0.05), both at baseline and 5-7 days since admission, but not at 3 months. Patients with RPVO showed 40.6% higher E-selectin (P < 0.001) solely at 3 months. By multivariable logistic regression, baseline Ks (odds ratio [OR] 0.010, 95% confidence interval [CI] 0.001-0.837, P = 0.042, per 10- 9 cm2 ), baseline D-dimer (OR 1.105, 95% CI 1.000-1.221, P = 0.049, per 100 ng/ml), and E-selectin levels after 3 months (OR 3.874, 95% CI 1.239-12.116, P = 0.020, per 1 ng/ml) were associated with RPVO.

CONCLUSIONS: RPVO patients despite anticoagulation characterize with the formation of denser fibrin clots on admission and higher E-selectin at 3 months. Those parameters could be the potential novel RPVO risk factors that warrant further evaluation in an independent cohort.