1977 Volume 17pt2 Issue 6 Pages 539-549
Serial fluorescein cortical angiography (FCA) was performed on 13 patients with ischemic cerebrovascular diseases at the time of by-pass operation (STA-MCA anastomosis), in order to know the microcirculatory changes before and after anastomosis. In 6 out of those patients, the pressure of the middle cerebral artery(MCAP)was simultaneously measured at the site of anastomosis. In all the patients, the diagnosis of cerebral ischemia was obtained by both clinical and angiographic findings. Out of these pateints, 6 had moderate neurological deficits such as hemiparesis or dysphasia, and 7 had severe neurological deficits such as hemiplegia, aphasia or disturbance of consciousness. Twelve patients had either middle cerebral or internal carotid occlusion, and one had intracranial carotid stenosis. Preoperative brain scintigram and CT scan were also carried out in 10 and 3 patients respectively.
In six patients who were operated within fifteen days of onset, prolongation of regional circulation time (RCT) was found without any morphological change of the vessels. After anastomosis, focal hyperemia(shortening of RCT with vasodilation) was observed in a reperfused area. MCAP of the patients in this group was markedly elevated after venous injection of hypertensive agents. Those findings seem to suggest the existence of vasomotor dysfunction in the ischemic areas. In four patients, who were operated after nine to twenty days of onset, RI accumulation on brain scintigrams or marked contrast enhancement on CT scans were observed. Furthermore, patchy extravasations of fluorescein dye were also observed in all cases on FCA, after abrupt elevation of perfusion pressure (after drug induced hypertension, reconstructive surgery, or spontaneous recanalization). In one of these cases, spotted hemorrhages were also observed around venules, which suggests the possibility of hemorrhagic infarction after by-pass operation. In four patients who were operated after one month of onset, organic changes such as narrowing or occlusion of small vessels were observed and focal hyperemia after anastomosis could not be seen.
From above results, the time course of occlusive cerebrovascular diseases may be divided into three stages in terms of cerebral microcirculation; Ist Stage of vasomotor dysfunction (within 15 days of onset), IInd Stage of breakdown of blood brain barrier (after one to three weeks of onset), and IIIrd Stage of organic change of vasculature( after one month of onset).
In one series, only three patients, who had mild neurological deficits and were operated in stage I, has been improved. This suggests that the operation in stage I may be of benefit to the patient with mild neurological deficits. On the contrary, operation in stage II may accelerate the brain edema, or may cause the hemorrhagic infarction. Neurological improvement may not be expected by operation in stage III.
