Absence of plasma protease-antiprotease imbalance in the formation of saccular cerebral aneurysms.

Objective: We examined the hypothesis that a plasma protease-antiprotease imbalance contributes to the formation of saccular cerebral aneurysms and the suggestion that the assay of these enzymes might be a screening tool for people at higher risk for aneurysm formation.

Methods: From June 1997 through May 1998, the plasma leukocyte elastase, which is an important proteolytic enzyme, and alpha-antitrypsin and alpha2-macroglobulin, which are important antiproteolytic enzyme plasma proteins, were examined in 18 patients with ruptured aneurysms, 9 patients with unruptured aneurysms, and 22 controls.

Results: The elastase:alpha1-antitrypsin ratio and the elastase:alpha2-macroglobulin ratios were significantly higher in patients with ruptured aneurysms within 24 hours after subarachnoid hemorrhage (SAH) than in the controls.