Monitoring fibrinolytic activity in the cerebrospinal fluid after aneurysmal subarachnoid haemorrhage: a guide to the risk of rebleeding?

Serial assay of fibrin degradation products (FDPs) was used to monitor fibrinolytic activity in blood and cerebrospinal fluid (CSF) after subarachnoid haemorrhage (SAH) in 64 patients, 43 of whom had aneurysms. CSF levels fell rapidly from high initial values over a few days, thereafter more slowly to reach normal levels after one to six weeks. Probably only the later slow decline is a measure of fibrinolysis, which is obscured in the first few days by the cross antigenicity with FDP's of fibrinogen released by the bleed. After this phase of fibrinogen clearance, early attainment of normal FDP levels appears to be associated with a lower risk of rebleeding in cases of aneurysm. This phenomenon could be useful in deciding whether marginal cases should be treated surgically or conservatively.