Interim Report of the Unruptured Cerebral Aneurysm Study in Japan III

Abstract

Unruptured cerebral aneurysm study in Japan (UCAS Japan) is conducted to clarify natural course and treatment risks of unruptured cerebral aneurysms (UCA), and build national data bank. This is a prospective cohort study and enrolled patients are cases with newly diagnosed UCA after Jan. 1, 2001. Data of all patients with UCA, either treated or observed, are stored into the head-quarter computer through internet registration. All cases are scheduled to have periodic follow-up at 3 months, 12 months and 36 months after diagnosis. As of April 2003, 4,940 patients (6,080 aneurysms) with newly diagnosed UCA were registered from 395 institutions. So far, there is a difference in registry status between geographic locations in Japan. Male-female ratio was 1: 2 and median age of patients was 64 years old. Size of aneurysm ranged 3∼45 mm (median 5 mm). The most frequent reason for imaging, which leaded diagnosis of UCA, was ill-defined symptoms such as headache or dizziness. Multiple aneurysms were found in 17% of cases and 96% of aneurysms were saccular ones. At the first registration, craniotomy was indicated in 34% and endovascular treatment in 5% of cases. Three months follow-up were reported in 4,077 cases and 12 months report in 2,285 cases. Treatment was performed in 1,743 cases with 2,007 aneurysms. So far, data of 4,090 person-year has been constructed. We are planning to call for further patient's enrollment and conform reliable data source to direct future management of UCA.