Faster fibrin clot degradation characterizes patients with central pulmonary embolism at a low risk of recurrent peripheral embolism.

It is unclear whether thrombus location in pulmonary arteries is associated with particular clot characteristics. We assessed 156 patients following either central or peripheral pulmonary embolism (PE). Plasma clot lysis time, the rate of D-dimer release from plasma clots (D-Drate) with the maximum D-dimer concentration achieved (D-Dmax), as well as fibrin formation on turbidimetry, plasma clot permeation, thrombin generation, and fibrinolytic parameters were measured 3-6 months after PE. Patients following central PE (n = 108, 69.3%) were more likely smokers (38.9% vs 18.8%; p = 0.01), less likely carriers of factor XIII Val34Leu allele (40.7% vs 62.5%, p = 0.01), exhibited 16.7% higher D-Drate and 12.7% higher tissue plasminogen activator antigen (tPA:Ag) compared with peripheral PE (p = 0.02 and p < 0.0001, respectively). Saddle PE patients (n = 31, 19.9%) had 11.1% higher D-Drate and 7.3% higher D-Dmax compared with central PE (both p < 0.05). Twenty-three recurrent PE episodes, including 15 central episodes, during a median follow-up of 52.5 months were recorded. Plasma D-dimer and tPA:Ag were independent predictors for central recurrent PE, whereas D-Drate and peak thrombin predicted peripheral recurrent PE. Plasma clots degradation is faster in patients following central PE compared with peripheral PE and fibrinolysis markers might help to predict a type of recurrent PE.