破裂脳動脈瘤早期手術後の血管攣縮と6カ月転帰—9年間における発生頻度と転帰の推移

Vasospasm and its Outcome after Early Surgery for Ruptured Cerebral Aneurysms—Changing pattern of its incidence and outcome during this 9-year period

I．はじめに

　クモ膜下出血後の脳血管攣縮は破裂脳動脈瘤の治療において予後を左右する重大な病態であり，1980年代前半に日本も参加して行われた国際共同研究では，脳血管攣縮は破裂動脈瘤に対する早期手術における転帰不良の原因の約1／3を占めることが報告されている^10,11）．この血管攣縮の予防あるいは一旦発生した攣縮に対する治療として様々な試みがなされてきたが，未だに決定的な方法は確立されていない^4）．しかしながら最近の当院での臨床経験では，重篤な血管攣縮発生が減少し，攣縮が発生しても死亡する例が減って全体として治療成績が向上しているとの印象がある．そこで本研究では，われわれの施設における急性期手術例の血管攣縮を症状とCT所見の面から解析し，攣縮の頻度と転帰が1980年代の前半と後半とでどのように変化してきたかを比較検討した．

The occurrence and outcome of vasospasm (VS) were analyzed in 240 patients who had aneurysm surgery within 7 days of a hemorrhage during 9-year period (1981-89). Occurrence of VS was evaluated by the appearance of ischemic symptoms, (A) with or (B) without CT evidence of infarcts. The surgical Outcome was assessed by the Glasgow Outcome Scale 6 months postoperatively. The results in the first and the latter halves of the period were compared.

The overall incidence of VS (A+B) was 34.8% (A: 23.5%, B: 11.3%) and 33.6% (A: 15.2%, B: 18.4%) in the first and the latter halves, respectively. Thus, VS leading to infarction showed a tendency to decrease in the latter half of the period, though the overall inci-dence of VS itself was almost identical in both the first and second halves of the period. The results were alsoanalyzed according to preoperative grading based on the Glasgow Coma Scale (GCS). The tendency toward decreased severity of VS in the latter term was most remarkable in patients with GCS total scores between 14 and 13. The decreased incidence of severe VS proved to be reflected in decreased mortality and in in-creased rate of good outcome in the latter half of the period. In order to confirm whether the results obtained in our clinic are universal, we applied the same analysis for control groups in four cooperative double-blind cli-nical trials performed during this period in Japan. The study again showed that the rate of infarction has de-creased significantly over the decade, resulting in the improved surgical outcome.

The present studies show that the incidence and severity of VS have decreased, and that the occurrence of infarction has significantly diminished over the de-cade. In consequence, the rate of poor outcome due to VS after early surgery is now only 10%.