Teiichi Takasago

The effect of EC-IC bypass surgery on resting cerebral blood flow and cerebrovascular reserve capacity studied with stable Xe-CT and acetazolamide test

SummaryCerebral blood flow (CBF) and cerebrovascular reserve capacity (CRC) were measured by stable xenon computerized tomography (Xe-CT) and acetazolamide test in 15 patients with cerebrovascular disease before and after extracranial-intracranial (EC-IC) bypass surgery for minor stroke, reversible ischemic neurological deficit or transient ischemic attack. All had angiographically shown occlusive lesions of the major arterial trunk. In the present series, global analysis showed that the bypass did not increase the resting rCBF, but did increase the rCRC. We divided the patients into four groups according to the preoperative resting rCBF and rCRC. All 3 patients with normal resting rCBF and reduced rCRC showed postoperative improvement of rCRC. Of 6 patients with reduced CBF and reduced CRC, three had postoperative increase in resting CBF and four had increased CRC. One of two patients with reduced CBF and normal CRC showed only an increase in CRC. We propose that reduced CRC or reduced CBF with reduced CRC are criteria for selection of candidates for bypass surgery. We conclude that Xe-CT with the Diamox test is a useful and simple method for evaluating cerebral hemodynamics. Preoperative grouping with a combination of preoperative resting cCBF and preoperative rCRC is useful for predicting the effect of EC-IC bypass surgery.

Cerebral Aneurysms in the Elderly in Yamaguchi, Japan Analysis of the Yamaguchi Data Bank of Cerebral Aneurysm From 1985 to 1995

BACKGROUND AND PURPOSE The number of elderly people is markedly increasing in Japan. We have investigated the epidemiology and management outcome of cerebral aneurysms in elderly patients aged > or = 70 years. METHODS A total of 3100 patients were enrolled in the Yamaguchi Data Bank of Cerebral Aneurysm between 1985 and 1995. Of these, 598 with ruptured cerebral aneurysms and 120 with unruptured cerebral aneurysms were elderly (ie, aged > or = 70 years). RESULTS The number of elderly patients with cerebral aneurysms has markedly increased since 1991, and in 1995 approximately 30% of all patients with cerebral aneurysms were elderly. In cases of ruptured cerebral aneurysms, the proportion of patients with severe neurological grade did not change and that with an unfavourable outcome did not decrease throughout the 11 years. The proportion of patients with severe neurological grade in the elderly group was higher than in the younger group (< 70 years), and the management outcome of elderly patients for each neurological grade on admission was worse than that of younger patients (P < .01). However, the incidence rate of symptomatic cerebral vasospasm and rebleeding was the same for the two age groups. Eventually, 60.4% of all elderly patients with ruptured cerebral aneurysms had an unfavorable outcome. In cases of unruptured cerebral aneurysms, 63.3% of the selected elderly patients were surgically treated, and the surgical morbidity and mortality rates were 26.3% and 4.0%, respectively. These rates were nonsignificantly higher than those for younger patients. CONCLUSIONS The number of elderly patients with cerebral aneurysms has markedly increased in Yamaguchi. Because of the unsatisfactory management outcome of ruptured cerebral aneurysms and surgical outcome of unruptured cerebral aneurysms in elderly patients during the 11-year period, we propose the treatment of unruptured cerebral aneurysms at a younger age and the use of a screening system to detect these subjects.

Revascularization with split duro-encephalo-synangiosis in the pediatric Moyamoya disease—surgical result and clinical outcome

Dural arteries are potential donor arteries for cortical revascularization. In this report, a technique of indirect anastomosis using a split dura is presented. At surgery, the dura near the branches of the middle meningeal artery was split into outer and inner layers, and the split surface of the outer layer was attached to the cortical surface (split duro-encephalo-synangiosis; split DES). This procedure, combined with standard encephalo-duro-arterio-synangiosis, was applied to 25 hemispheres in 18 patients with pediatric Moyamoya disease (mean age, 6 years). Postoperative superselective angiograms demonstrated effective cortical revascularization through the dural arteries in addition to the supply from the scalp arteries. All the patients were symptom free by 1.5 years after surgery. Postoperative reversible ischemic neurological deficit and infarction were seen in three (12%) and one (4%), respectively. The follow-up period ranged from 1 to 12 years (mean, 6.5 years). Thirteen of 16 (81%) patients led normal lives and three were mildly handicapped due to mental retardation that existed preoperatively. The split DES is a useful technique to extend the area of revascularization of ischemic hemispheres in Moyamoya disease.

Elective neck clipping for unruptured aneurysms in elderly patients

BACKGROUND With the recent advancements of neuroimaging techniques, the number of unruptured aneurysms diagnosed in elderly patients has increased. However, the surgical indications in this special subgroup have not been studied critically. The purposes of this study were to analyze the results of elective neck clipping surgery for unruptured aneurysms in the elderly and to elucidate the surgical indications. METHODS From 1985 to 1997, 96 patients, aged 70 years or older, with 103 unruptured cerebral aneurysms underwent elective neck clipping. There were 67 females and 29 males. Their ages ranged from 70 to 86, with a mean of 73.3 years. Seventy-five aneurysms were asymptomatic and 28 were symptomatic. The aneurysms were located on the internal carotid artery (46.6%), middle cerebral artery (35.9%), anterior cerebral artery (16.5%), and basilar artery (1.0%). RESULTS The surgical outcome was a good recovery in 75 patients (78.1%), mild deficits in 12 (12.5%), severe deficits in 4 (4.2%), and death in 5 (5.2%). Recovery from preoperative symptoms with improved quality of life was seen in 22 (78.6%) of the 28 symptomatic cases. Multiple regression analysis showed that increase in the size of aneurysms and location on the middle cerebral artery and internal carotid artery were significantly related to a poor outcome. The causes of the five deaths were hemorrhagic infarction, systemic infection, and myocardial infarction. CONCLUSION Surgery for elective neck clipping of unruptured aneurysms in the elderly should be considered in symptomatic patients with simple aneurysms that can be clipped without the use of temporary clips.

Cerebrovascular reserve capacity in ischemia due to occlusion of a major arterial trunk: studies by Xe-CT and the acetazolamide test.

Classifications based on clinical and radiographic criteria have proved to be inadequate predictors of the course of cerebral ischemia or its response to therapy. In this study the cerebrovascular reserve capacity (CRC) of 46 patients with symptomatic cerebrovascular ischemia was studied by stable xenon-enhanced CT (Xe-CT) combined with the acetazolamide test. Fifteen patients had internal carotid artery (ICA) occlusion, 10 had ICA stenosis, 10 had middle cerebral artery (MCA) occlusion, and 11 had MCA stenosis. In the patients with chronic cerebral ischemia due to occlusive lesions of the ICA and MCA, the CRC was reduced most in those with MCA occlusion, followed, in descending order, by those with ICA stenosis, MCA stenosis, and ICA occlusion. Our results indicate that measurement of the CRC elucidates cerebral hemodynamic factors that cannot be detected by angiography in patients with chronic cerebral ischemia and that Xe-CT combined with the acetazolamide test is useful for this purpose.

Effects of acute percutaneous transluminal recanalization on cerebral embolism

The effects of percutaneous transluminal recanalization (PTR) on critical hemodynamics of cerebral embolism were studied using stable xenon‐enhanced computed tomography in patients within 6 hours after onset. PTR was conducted in 10 cases (PTR group) and not conducted 8 cases (non‐PTR group). The development of infarction was followed by CT scan. In the cortical arterial regions, the lowest cerebral blood flow (CBF) value in regions of interests (ROIs) without development of infarction was 12.9 ml/100 g/min in the PTR group and 17.0 ml/100 g/min in the non‐PTR group. In ROIs with a cerebrovascular reserve capacity (CRC) less than 0 ml/100 g/min, even with a CBF greater than 12.9 ml/100 g/min, 3 of 4 ROIs underwent cerebral infarction. PTR conducted within 6 hours after onset of cerebral embolism would prevent the cortical regions with a CBF greater than 12.9 ml/100 g/min and with a CRC greater than 0 ml/100 g/min from undergoing cerebral infarction.