Decreased fibrin network permeability and impaired fibrinolysis in the acute and convalescent phase of ischemic stroke

IntroductionWe investigated fibrin network permeability and fibrinolysis in the acute and convalescent phase of ischemic stroke.Methods20 patients with a mean age of 74 years were studied in the acute (day 1) and convalescent phase (day 60) of ischemic stroke. 23 healthy individuals (controls) were also investigated. Fibrin formation in the samples was triggered by addition of tissue factor (1 pmol/L) and washed frozen-thawed platelets obtained from a healthy donor. The permeability constant (Ks), which reflects fibrin network permeability, was then calculated from liquid flow measurements. A global assay newly developed in our group was also employed to determine the balance between fibrin formation (“Coagulation profile”; Cp) and fibrin degradation (“Fibrinolysis profile”; Fp) in the same samples. We also measured PAI-1 antigen and fibrinogen concentrations in plasma.ResultsAs compared to controls, the stroke patients had lower Ks (lower fibrin network permeability) both on day 1 and on day 60 (p < 0.01 and p < 0.05, respectively). Fibrinolysis, assessed by Fp, was reduced on both day 1 and day 60 (p < 0.001, compared to controls), and PAI-1 concentrations were increased (p < 0.01 for both, compared to controls). Fibrin formation capacity in plasma (i.e. Cp) was increased in the acute phase (p < 0.05) but not in the convalescence, as compared to controls.ConclusionThe combination of a proneness to form a tighter fibrin network and impaired fibrinolysis is a feature of ischemic stroke that is present in both the acute and convalescent phase of the disease.