被殻出血における脳血管のautoregulationとCO2反応性に関する臨床的研究

A STUDY OF CEREBROVASCULAR AUTOREGULA-TION AND CO2 REACTIVITY IN PUTAMINAL HEMORRHAGE

　抄録　¹³³Xe吸入法によるsingle photon emission CTを用い，被殻出血33例に対し脳血管のautoregula—tionとCO₂反応性を検討し以下の結果を得た。1）脳虚血の程度とautoregulationおよびCO₂反応性の障害程度は正の相関を示し，とくに血腫周囲の脳虚血が正常の約30〜40％以上のときにautoregulationやCO₂反応性が障害される。ただし，虚血の程度が正常の30〜40％以上でも発症後1〜2週では"false auto—regulation"を認めた。2） autoregulationとCO₂反応性の障害は，血腫量50ml未満では認められず，50〜74mlでは発症後1〜2カ月で病側が健側に比し強度であり，75ml以上では両側性障害を示す。3） auto—regulation, CO₂反応性とも病側大脳基底核血腫隣接部における障害が最も高度である。4）被殻出血の発作後1年時の日常生活活動レベル（ADL）はautoregulationおよびCO₂反応性障害と関連性を有し，ADL1,2の症例ではこれらの脳血管反応性は良好であるのに対し，ADL 4,5の重度障害残存群では高率に障害を認める。とくに半球全体における脳血管反応性の障害例は局所障害例にくらべ予後不良である。以上より，被殻出血におけるautoregulation試験やCO₂負荷試験による脳血管反応性の検索は，本疾患の病巣周辺脳の病態や治療成績を判定する上で重要であると考えられる。

Regional cerebral blood flow (rCBF) during hypertension and hypercapnia was studied in 33 patients with putaminal hemorrhage, using a single photon emission CT by means of Xenon 133 inhalation method. The results obtained were as follows :

1) A significant relationship was obtained between the impairment of autoregulation, CO₂ reactivity and the degree of cerebral ischemia, i. e, in most cases, these vascular responses were impaired in cases of ischemia showing the rCBF decrease over 30 to 40% of normal values. How-ever, there were particular cases with cerebral ischemia of over 30 to 40% in which autoregula-tion seemed to be preserved in the acute stage, which was considered to be the similar phenome-non as so called "false autoregulation".

2) The cerebrovascular responses such as auto-regulation and CO₂ reactivity were preserved in cases of less than 50 ml of hematoma volume. Incases with 50 to 74 ml of hematoma volume how-ever, autoregulation and CO₂ reactivity were mostly impaired, especially in the affected hemi-sphere rather than the non-affected, in the period of 1 to 2 months from the onset. Furthermore, the impairment was also involved in both hemispheres if the hematoma was over 75 ml in volume.

3) The cerebrovascular responses were markedly impaired in the region of basal ganglia of the affected hemisphere which corresponded well to the hematoma site.

4) There was a close correlation between the cerebrovascular responses and the activity of daily life (ADL), i. e, the prognosis might be poor in cases with global impairment, but which seemed to be rather good in cases with local impairment.

It might be concluded, from the results mention-ed above, that the study of autoregulation and CO₂ reactivity is probably significant in estimating the pathogenesis and the treatment of cerebral ischemia following hypertensive putaminal hemor-rhage.