Murata Yoshihiro, Katayama Yoichi, Sakatani Kaoru, Fukaya Chikashi, Kano Tsuneo
Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
J Neurosurg. 2003 Aug;99(2):304-10. doi: 10.3171/jns.2003.99.2.0304.
It has been reported that extracranial-intracranial (EC-IC) arterial bypass surgery can be useful in preventing stroke in patients with hemodynamic compromise. Little is yet known, however, regarding the extent to which the bypass contributes to maintaining adequate cerebral blood oxygenation (CBO) and its temporal changes following surgery. The authors evaluated bypass function repeatedly by using near-infrared spectroscopy (NIRS) after surgery.
The authors investigated 30 patients who had undergone EC-IC bypass surgery. Single-photon emission computerized tomography revealed a decrease in regional cerebral blood flow (rCBF) and a lowered rCBF response to acetazolamide. Changes in CBO were evaluated in the sensorimotor cortex during compression of the anastomosed superficial temporal artery (STA). When decreases in oxyhemoglobin (HbO2) and total hemoglobin (Hb) concentrations were observed, the bypass was considered to have maintained CBO in the sensorimotor cortex given that decreases in HbO2 and total Hb indicate cerebral ischemic changes. The bypass maintained CBO immediately after surgery in 36.7% of patients (Group I, 11 patients) and at some time after surgery, mostly within 1 year, in 43.3% of patients (Group II, 13 patients); however, it did not maintain it throughout the follow-up period in 20% of patients (Group III, six patients). Note that the preoperative rCBF in patients in Groups I and II was lower than that in patients in Group III (p < 0.004). In fact, the preoperative rCBF predicted whether a bypass would maintain CBO at a cutoff value of 24.5 to 25 ml/100 g/min. Among Groups I and II, 18 patients demonstrated an increase in deoxyhemoglobin during STA compression. The preoperative rCBF in these cases was lower than that in the six remaining patients (p < 0.006). Note that the preoperative rCBF predicted the postoperative deoxyhemoglobin response at a cutoff value of 22.2 to 24 ml/100 g/min.
The EC-IC bypass surgery can maintain CBO immediately after surgery or gradually within 1 year when the preoperative rCBF is below 24.5 to 25 ml/100 g/min. Furthermore, bypass flow plays a critical role in maintaining an adequate CBO when preoperative rCBF is below 22.2 to 24 ml/100 g/min.
据报道，颅外-颅内（EC-IC）动脉搭桥手术有助于预防血流动力学受损患者发生中风。然而，关于搭桥手术在维持足够的脑血氧合（CBO）方面的作用程度及其术后的时间变化，目前仍知之甚少。作者在术后使用近红外光谱（NIRS）反复评估搭桥功能。
作者调查了30例行EC-IC搭桥手术的患者。单光子发射计算机断层扫描显示局部脑血流量（rCBF）减少，对乙酰唑胺的rCBF反应降低。在吻合的颞浅动脉（STA）受压期间，评估感觉运动皮层的CBO变化。当观察到氧合血红蛋白（HbO2）和总血红蛋白（Hb）浓度降低时，鉴于HbO2和总Hb降低表明脑缺血变化，认为搭桥手术维持了感觉运动皮层的CBO。36.7%的患者（I组，11例）术后立即搭桥维持了CBO，43.3%的患者（II组，13例）在术后一段时间（大多在1年内）搭桥维持了CBO；然而，20%的患者（III组，6例）在整个随访期内搭桥未能维持CBO。注意，I组和II组患者的术前rCBF低于III组患者（p < 0.004）。事实上，术前rCBF在截断值为24.5至25 ml/100 g/min时可预测搭桥是否能维持CBO。在I组和II组中，18例患者在STA受压期间脱氧血红蛋白增加。这些病例的术前rCBF低于其余6例患者（p < 0.006）。注意，术前rCBF在截断值为22.2至24 ml/100 g/min时可预测术后脱氧血红蛋白反应。
当术前rCBF低于24.5至25 ml/100 g/min时，EC-IC搭桥手术可在术后立即或在1年内逐渐维持CBO。此外，当术前rCBF低于22.
