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

BACKGROUND: The first-degree relatives of patients who have subarachnoid hemorrhage from ruptured intracranial aneurysms are themselves at risk for subarachnoid hemorrhage. We studied the benefits and risks of screening for aneurysms in the first-degree relatives of patients with sporadic subarachnoid hemorrhage.
METHODS: We screened 626 first-degree relatives (parents, siblings, or children) of 160 patients with sporadic subarachnoid hemorrhage, from a prospective series of 193 consecutive index patients. Magnetic resonance angiography was the screening tool, and conventional angiography was used as the reference test in subjects thought to have aneurysms. Six months after elective operation, outcome was assessed by means of the modified Rankin scale of neurologic function. This observational study design was combined with a decision-analysis model to estimate the effectiveness of screening. The efficiency of screening was defined by the number of relatives who needed to be screened in order to prevent one subarachnoid hemorrhage.
RESULTS: Aneurysms were found in 25 of 626 first-degree relatives (4.0 percent; 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 aneurysms that were 5 to 11 mm in diameter, 11 had aneurysms that were less than 5 mm, and 2 had both small and medium-sized 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 relatives who would need to be screened in order to prevent 1 subarachnoid hemorrhage on a lifetime basis was 149, and 298 would have to be screened in order to prevent 1 fatal subarachnoid hemorrhage.
CONCLUSIONS: Implementation of a screening program for the first-degree relatives of patients with sporadic subarachnoid hemorrhage does not seem warranted at this time, since the resulting slight increase in life expectancy does not offset the risk of postoperative sequelae.