Regionale Hirndurchblutung und zerebrovaskuläre Reservekapazität in der Indikationsstellung zur gefäßrekonstruktiven Operation

Effect of Extra-Intracranial Bypass and Carotid Thrombendarterectomy. The causal treatment of cerebral ischemia requires an exact analysis of the basic deficit of cerebral blood flow. Cerebral ischemia can be the result of hemodynamic insufficiency or frequently a consequence of thromboembolic event. The distinction of both forms of ischemia is possible only by dynamic measuring of regional cerebral blood flow and evaluation of the cerebral vascular reserve capacity. This allows to select of a small group of patients who suffer from carotid occlusion or a combined occlusion with stenosis of the contralateral side, where a characteristic disturbance of the cerebrovascular reserve capacity can be proved. By performing an extra-intracranial bypass, the cerebral collateral blood supply can be improved in order to reduce the risk of stroke. In this study 26 patients received an extra-intracranial bypass. 7 weeks after surgery a normalization of the limited cerebrovascular reserve capacity was observed. With regard to carotid stenosis, thrombendarterectomy was conducted in 63 patients. Although the cerebrovascular reserve capacity had not been impaired in this group preoperatively, a further increase was observed following thrombendarterectomy. It is indisputable that the indication for thrombendarterectomy is aiming towards elimination of the source of emboli. However, our results indicate that thrombendarterectomy has an additionally positive hemodynamic effect.