The Stockholm 20-year follow-up of aneurysmal subarachnoid hemorrhage outcome.

OBJECTIVE: To assess the clinical and radiological long-term outcome after aneurysmal subarachnoid hemorrhage (SAH) in a defined referral area regarding recurrent SAH and de novo aneurysm formation.
METHODS: One hundred and two 1-year survivors after aneurysmal SAH, who were treated at the Neurosurgical Clinic, South Hospital, Stockholm, Sweden, between 1983 and 1985, were followed for 20 years. Forty-nine surviving patients were reevaluated. Hospital records and death certificates were scrutinized for all 53 nonsurviving patients. Clinical history penetration, Mini Mental Status, Rankin Disability Score, and Barthel Index were used to evaluate the outcome. Computed tomographic angiography was used to investigate the cerebral arteries.
RESULTS: One hundred and two patients were traced. Fifty-three patients were deceased. One patient had a hospital record of sustaining an aneurysmal SAH from a known but not clipped aneurysm. Three patients had nonaneurysmal intracerebral hemorrhage and two sustained traumatic SAH. There were 49 surviving patients. Six refused follow-up. None of these patients had hospital records of intracranial disease. Three of the 43 remaining patients could not be tested. None of the survivors had experienced a new SAH. Aneurysm base remnants were observed in 1% (eight patients, 790 person-years of follow-up) and de novo aneurysms were observed in 0.9% (seven patients, 790 person-years of follow-up).
CONCLUSION: From this epidemiological survey of patients with aneurysmal SAH, it was found that none of the patients experienced a recurrent subarachnoid bleed from the treated aneurysm during a 20-year follow-up period. Thus, a routine extreme long-term follow-up period is not necessary. De novo aneurysm formation and possible enlargements of aneurysm base remnants were observed in almost 2% of patients per person year and should, therefore, be subject of a routine, long-term follow-up.