破裂脳動脈瘤症例の予後に影響を及ぼす術中因子の分析

Abstract

Induced hypotension has commonly been used during intracranial aneurysm surgery in order to facilitate dissection and reduce the risk of intraoperative rupture. It is not known for certain, however, whether this procedure is appropriate or not. We analyzed intraoperative prognostic factors, including induced hypotension below 60 mmHg mean arterial blood pressure (MABP) using trimetaphan camsylate, in 90 patients who underwent clipping of intracranial aneurysms. The intraoperative factors were temporary clipping, low density areas and brain swelling on postoperative CT scan, and intraoperative rupture. In addition, we investigated the Hunt & Kosnik grade, CT grade, and past history of hypertension as preoperative factors, and delayed ischemic neurological deficits (DIND) as a postoperative factor. The data were evaluated using methods of multivariate statistical analysis (quantification theory 2nd family).These factors affected the prognosis in the following order according to their relative influence strengths: preoperative factors, postoperative factor, and intraoperative factors. In all cases induced hypotension below 60 mmHg MABP had a little influence on prognosis, but in patients with a past history of hypertension or in Hunt & Kosnik grade III and IV patients, induced hypotension had an adverse effect on outcome. These patients have a high probability of developing reduced cerebral blood flow and impaired autoregulation after subarachnoid hemorrhage. Especially when extended for over 30 minutes, induced hypotension below 60 mg MABP was more harmful. It is concluded that, in order to facilitate dissection during intracranial aneurysm surgery, temporary clipping is superior to prolonged induced hypotension.