Fibrinolytic activity in retinal vein occlusion

Impaired fibrinolytic function is a common finding in patients with thrombotic disease. The present study was initiated to evaluate the fibrinolytic response to a venous occlusion test (VOT) in patients with retinal vein occlusion.

Euglobulin clot lysis time (ECLT), tissue plasminogen activator (t-PA) activity, and plasminogen activator inhibitor (PAI) activity were measured before and after VOT in a group of 26 consecutive patients presenting with retinal vein occlusion and in 15 healthy age- and sex-matched controls.

Before VOT (baseline), a higher proportion of patients (54%) had an ECLT of more than 5 h compared with controls (6.7%) (p = 0.0027) indicating decreased overall fibrinolytic activity. Patients had non-significantly lower t-PA and higher PAI activities compared with controls. After VOT, a higher proportion of patients (34.6%) had an ECLT of more than 5 h compared with controls (6.7%) (p = 0.05). Patients had significantly lower t-PA activity (p = 0.0232) and significantly higher PAI activity (p = 0.0292). Subgroup analysis revealed that patients with an ECLT of more than 5 h had significantly higher levels of PAI activity at baseline (p = 0.0326) and after VOT (p = 0.0184) compared with patients with an ECLT of less than 5 h. However, t-PA activity was significantly higher (p = 0.0153) at baseline, and non-significantly higher after VOT in patients with an ECLT of more than 5 h when compared with patients with an ECLT of less than 5 h.

These findings suggest that impaired fibrinolysis due to increased PAI activity may play a role in the pathogenesis of retinal vein occlusion.