Cooperative study of intracranial aneurysms and subarachnoid hemorrhage: a long-term prognostic study. II. Ruptured intracranial aneurysms managed conservatively
H. Nishioka, J. C. Torner, C. J. Graf, N. F. Kassell, A. L. Sahs and L. C. Goettler
The late natural history of ruptured intracranial aneurysms was studied in
568 cases reported to the Cooperative Study of Intracranial Aneurysms and
Subarachnoid Hemorrhage from 1958 to 1965. The patients had been selected
for conservative management of their aneurysms at the time of diagnosis. A
follow-up search in 1981 and 1982 revealed 378 known deaths; 40% had
occurred within six months of hemorrhage. During the next two decades, the
patients' survival probabilities were significantly worse than those of a
matched US population. Multiple aneurysms did not differ prognostically
from single aneurysms, but posterior circle aneurysms carried a better
prognosis after ten-year survival. The rate of probable recurrent bleeding
after six months was 2.2% per year for the first 9 1/2 years and 0.86% per
year for the second decade. Reported rebleeding episodes were fatal in 78%.
