James C. Torner

The International Cooperative Study on the Timing of Aneurysm Surgery evaluated the results of surgical and medical management in 3521 patients between December, 1980, and July, 1983. At admission, 75% of patients were in good neurological condition and surgery was performed in 83%. At the 6-month evaluation, 26% of the patients had died and 58% exhibited a complete recovery. Vasospasm and rebleeding were the leading causes of morbidity and mortality in addition to the initial bleed. Predictors for mortality included the patient's decreased level of consciousness and increased age, thickness of the subarachnoid hemorrhage clot on computerized tomography, elevated blood pressure, preexisting medical illnesses, and basilar aneurysms. The results presented here document the status of management in the 1980's.

PURPOSE: The aim of this updated statement is to provide comprehensive and evidence-based recommendations for management of patients with unruptured intracranial aneurysms. METHODS: Writing group members used systematic literature reviews from January 1977 up to June 2014. They also reviewed contemporary published evidence-based guidelines, personal files, and published expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulated recommendations using standard American Heart Association criteria. The guideline underwent extensive peer review, including review by the Stroke Council Leadership and Stroke Scientific Statement Oversight Committees, before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee. RESULTS: Evidence-based guidelines are presented for the care of patients presenting with unruptured intracranial aneurysms. The guidelines address presentation, natural history, epidemiology, risk factors, screening, diagnosis, imaging and outcomes from surgical and endovascular treatment.

A prospective, observational clinical trial was conducted by the International Cooperative Study on the Timing of Aneurysm Surgery to determine the best time in relation to the hemorrhage for surgical treatment of ruptured intracranial aneurysms. Sixty-eight centers contributed 3521 patients in a 2 1/2-year period beginning in December, 1980. Analysis by a prespecified "planned" surgery interval demonstrated that there was no difference in early (0 to 3 days after the bleed) or late surgery (11 to 14 days). Outcome was worse if surgery was performed in the 7 to 10-day post-bleed interval. Surgical results were better for patients operated on after 10 days. Patients alert on admission fared best; however, alert patients had a mortality rate of 10% to 12% when undergoing surgery prior to Day 11 compared with 3% to 5% when surgery was performed after Day 10. Patients drowsy on admission had a 21% to 25% mortality rate when operated on up to Day 11 and 7% to 10% with surgery thereafter. Overall, early surgery was neither more hazardous nor beneficial than delayed surgery. The postoperative risk following early surgery is equivalent to the risk of rebleeding and vasospasm in patients waiting for delayed surgery.

The case records of 191 patients with a cerebral arteriovenous malformation (AVM) were reviewed to determine bleeding characteristics of these lesions. Possible influences of age, sex, the location and size of the AVM, type of initial hemorrhage, and condition of the patients were analyzed. Of these 191 patients, 102 had a single hemorrhage, 32 had a recurrent hemorrhage, and 57 never bled. The follow-up period for patients with an unruptured AVM was a mean of 4.8 years and a maximum of 31 years; for those with a ruptured AVM, the mean was 2 years, and the maximum 37 years. Size of the AVM was significantly related to the risk of first hemorrhage. The average yearly risk for first hemorrhage was between 2% and 3%. Bleeding occurred most frequently in the 11- to 35-year-old age group. The risk of rebleeding increased with advancing age. Among 93 patients followed after their AVM had ruptured, the risk of rebleeding was 6% in 1 year. After the first year, the average rebleeding rate was about 2% per year up to 20 years.