The relation between aneurysm size and outcome in patients with subarachnoid hemorrhage

The balance of risks of treatment for unruptured aneurysms might change if the prognosis after rupture depends on the size of the aneurysm. In a prosp ective series of patients with subarachnoid hemorrhage in whom aneurysmal s ize was measured by CT angiography performed on admission, poor outcome occ urred more often in patients with large (greater than or equal to 10 mm) an eurysms (63%) than in patients with small (<10 mm) aneurysms (41%; RR = 1.5 ; 95% CI 1.0 to 2.2). The relative risk remained essentially the same after adjustment for age, gender, location of the aneurysm, and amount of cister nal blood.