Risks and benefits of screening for intracranial aneurysms in first-degreerelatives of patients with sporadic subarachnoid hemorrhage

Background The first-degree relatives of patients who have subarachnoid hem orrhage from ruptured intracranial aneurysms are themselves at risk for sub arachnoid hemorrhage. We studied the benefits and risks of screening for an eurysms in the first-degree relatives of patients with sporadic subarachnoi d hemorrhage. Methods We screened 626 first-degree relatives (parents, siblings, or child ren) of 160 patients with sporadic subarachnoid hemorrhage, from a prospect ive series of 193 consecutive index patients. Magnetic resonance angiograph y was the screening tool, and conventional angiography was used as the refe rence test in subjects thought to have aneurysms. Six months after elective operation, outcome was assessed by means of the modified Rankin scale of n eurologic function. This observational study design was combined with a dec ision-analysis model to estimate the effectiveness of screening. The effici ency of screening was defined by the number of relatives who needed to be s creened in order to prevent one subarachnoid hemorrhage. Results Aneurysms were found in 25 of 626 first-degree relatives (4.0 perce nt; 95 percent confidence interval, 2.6 to 5.8 percent). Eighteen underwent surgery, which resulted in a decrease in function in 11 (disabling in 1). Five had medium-sized aneurysms that were 5 to 11 mm in diameter, 11 had sm all aneurysms that were less than 5 mm, and 2 had both small and medium-siz ed aneurysms. On average, surgery increased estimated life expectancy by 2. 5 years for these 18 subjects (or by 0.9 month per person screened), at the expense of 19 years of decreased function per person. The number of relati ves who would need to be screened in order to prevent 1 subarachnoid hemorr hage on a lifetime basis was 149, and 298 would have to be screened in orde r to prevent 1 fatal subarachnoid hemorrhage. Conclusions Implementation of a screening program for the first-degree rela tives of patients with sporadic subarachnoid hemorrhage does not seem warra nted at this time, since the resulting slight increase in life expectancy d oes not offset the risk of postoperative sequelae. (N Engl J Med 1999;341:1 344-50.) (C) 1999, Massachusetts Medical Society.