Grading of Subarachnoid Hemorrhage: Modification of the World Federation of Neurosurgical Societies Scale on the Basis of Data for a Large Series of Patients

3567 patients with aneurysmal subarachnoid hemorrhage (SAH) treated between 1991 and 1997, derived from four randomized clinical trials of tirilazad

A newly derived grading scale incorporating age, WFNS grade, history of hypertension, systolic blood pressure at admission, ruptured aneurysm location and size, blood clot thickness on computed tomographic scans, and angiographic vasospasm at admission

World Federation of Neurosurgical Societies (WFNS) grading scale

Outcomes assessed 3 months after SAH with the Glasgow Outcome Scale