Table 1.

Clinical grade on admission (World Federation of Neurological Surgeons [WFNS] and rates of secondary ischemia from day 0 to day 21 in the subgroups of patients who had early operation (within 4 days after onset of subarachnoid hemorrhage), patients who had late operation (after 10 days), and patients who were not operated

WFNSEarly operationLate operationNo operation
N (% of all patients with early operation)Patients with ischemia between days 0–21Patient days at risk between days 0–21Event rate per 100 patient daysN (% of all patients with late operation)Patients with ischemia between days 0–21Patient days at risk between days 0–21Event rate per 100 patient daysN (% of all patients without operation)Patients with ischemia between days 0–21Patient days at risk between days 0–21Event rate per 100 patient days
All131 (100)4121481.974 (100)241327.51.8124 (100)258492.9
I74 (56)2112961.616 (22)33141.012 (10)2179.51.1
II31 (24)124592.623 (31)83962.017 (14)4189.52.1
III13 (10)41922.18 (11)11710.610 (8)455.57.2
IV6 (5)2992.014 (19)62422.514 (11)41163.4
V7 (5)21022.013 (17)61963.171 (57)11308.53.6