Carbon dioxide reactivity and patterns of cerebral infarction in patients with carotid artery occlusion.

A total of 106 patients with 112 internal carotid artery occlusions were investigated by cranial computed tomography and transcranial Doppler ultrasonography (CO2 test), giving a measure of the cerebrovascular reserve capacity. The morphological patterns of the ischaemic lesions were classified into three categories: lacunar, thromboembolic and haemodynamic infarctions. Of 29 patients with an exhausted CO2 reactivity, 19 showed a haemodynamic type of infarction, whereas of 45 cases with a normal CO2 reactivity only 2, and of 38 patients with a diminished CO2 reactivity only 3 had haemodynamically caused infarctions (P less than 0.001). The correlation between an exhausted CO2 reactivity and the presence of haemodynamic infarctions could be of value for therapy in patients with carotid artery occlusions.