Masao Sugita

Size of cerebral aneurysms and related factors in patients with subarachnoid hemorrhage

BACKGROUND As the indication for surgical treatment of incidentally discovered small aneurysms remains controversial. METHODS We retrospectively investigated the characteristics of small ruptured aneurysms and examined the relationship between the size and location of ruptured intracranial aneurysms and the sex, age, lifestyle, and medical history of 280 patients with ruptured aneurysm treated at our institute. RESULTS The mean diameter of ruptured aneurysms in this series was 7.6 mm. In diameter, 135 (48.2%) ranged between 5 and 10 mm; 73 (26.1%) were smaller than 5 mm. The size of the ruptured aneurysms was significantly smaller (mean 6.5 mm) in patients with non- or poorly controlled hypertension than in normotensive patients (mean 8.3 mm) (p < 0.05). Ruptured aneurysms in the anterior communicating artery (AcomA) and anterior cerebral artery (ACA) were significantly smaller (p < 0.01) than those in the internal carotid artery or middle cerebral artery. Among 58 patients with multiple aneurysms, only 7 (12%) suffered rupture of aneurysms smaller than 5 mm (p < 0.01). Patients younger than 40 years and patients with a family history of subarachnoid hemorrhage appeared to predispose to the rupture of small-sized aneurysms, although those did not affect the statistical significance. CONCLUSIONS This study shows that even aneurysms smaller than 10 mm may rupture. However, treatment decisions for unruptured aneurysm should not be based solely on the size of the unruptured aneurysms. Our data implies that even small aneurysms in the AcomA and ACA had an increased tendency for rupture, and that hypertensive patients were at higher risk for the rupture of small aneurysms.

Diffusion tensor tractography predicts motor functional outcome in patients with spontaneous intracerebral hemorrhage.

OBJECTIVEWe prospectively investigated the predictive value of diffusion tensor tractography for motor functional outcome in a case series of patients with intracerebral hemorrhage. METHODSDiffusion tensor tractography was performed in 17 patients with intracerebral hemorrhage (putamen, nine patients; thalamus, seven patients; combined, one patient) within 5 days after onset. Mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the corticospinal tracts at the level of the hematoma were measured bilaterally, and the ratios of values (hematoma side/contralateral side) were determined as FA and ADC ratios, respectively. Patients were evaluated for motor function on admission and at 3 months after onset using the manual muscle test score and then divided into good (manual muscle test, 4–5) and poor (manual muscle test, 0–3) motor function groups. RESULTSFA ratio measured shortly after the onset of intracerebral hemorrhage correlated well with motor functional outcome at 3 months (P < 0.05) but not with motor function on admission. FA ratios in the group with good motor functional outcome were significantly higher than those in the group with poor motor functional outcome (P < 0.01). The ADC ratio did not correlate with motor function either on admission or at 3 months. All patients with an FA ratio greater than 0.8 had a good motor functional outcome. In three patients, however, motor functional outcomes were favorable even though FA ratios were not high; in these patients, ADC ratios tended to be elevated. CONCLUSIONMotor functional outcome in patients with intracerebral hemorrhage can be predicted by measuring FA values using diffusion tensor tractography.

Surgical management of aneurysms of the bifurcation of the internal carotid artery

Internal carotid artery (ICA) bifurcation aneurysms are rare and easily bleed in younger patients, but are difficult to treat surgically, due to perforators surrounding and adherent to the aneurysm. A series of 25 patients treated by clipping under the operating microscope are analyzed and compared with previous cases. Twenty-five patients, 11 men and 14 women (mean age 51 years), were treated by the same neurosurgeon. Seventeen patients presented with subarachnoid hemorrhage (Hunt & Kosnik Grade I in three, II in five, III in two, IV in seven), five with unruptured ICA bifurcation aneurysms, and three with unruptured ICA bifurcation aneurysms but another ruptured aneurysm. There were 23 small, one large, and one giant ICA bifurcation aneurysms. The projection was superior in 12, anterior in seven, and posterior in six cases. Pterional approach was employed for all cases. Outcomes were evaluated at discharge with the Glasgow Outcome Scale. Favorable outcomes (good recovery (GR) and moderate disability (MD)) were obtained in ten of 17 patients with ruptured ICA bifurcation aneurysm. Favorable outcomes were significantly greater in Grades I and II (three in I, four in II) than in Grades III and IV (one in III, two in IV; P=0.0498). Seven of eight patients with unruptured ICA bifurcation aneurysm had favorable outcomes. Temporary clipping and projection of the aneurysm did not affect the outcome. Causative factors of unfavorable outcomes were primary brain damage in cases of small and large aneurysms and perforator damage in the case of giant aneurysm. Poor clinical grade and vasospasm are the causative factors of poor outcome in patients with ruptured ICA bifurcation aneurysm. Preservation of perforators is crucial in cases of giant aneurysm. Clipping of unruptured ICA bifurcation aneurysms is recommended since they tend to bleed at a lower age than other aneurysms.

Improvement of cerebral blood flow and clinical symptoms associated with embolization of a large arteriovenous malformation: case report.

We report a patient with an unruptured, large arteriovenous malformation that was treated by staged, superselective embolization with liquid agents and by an investigation of the hemodynamic changes accompanying embolization. A 29-year-old man presented with headache and left upper quadrantanopsia. A neuroradiological study revealed a large right temporo-occipital arteriovenous malformation, and angiography disclosed poor filling of the adjacent vessels. In the venous phase, marked cortical reflux, suggesting venous hypertension, was also observed. Single photon emission computed tomography scanning with N-isopropyl-p-iodine-123- iodoamphetamine disclosed a low-perfusion area in the ipsilateral occipital and temporal lobes. After embolization, cerebral blood flow and the clinical symptoms attributed to ischemia improved. A follow-up study 1 year later demonstrated that the patients improvement was stable. Single photon emission computed tomography confirmed that embolization achieves an improved cerebral blood flow.

Phosphodiesterase 5 inhibitor, zaprinast, selectively increases cerebral blood flow in the ischemic penumbra in the rat brain

Abstract Background: Guanosine 3′, 5′-cyclic monophosphate (cGMP) acts as a relaxant second messenger in the cerebral vessels. cGMP-specific phosphodiesterase type 5 (PDE5) inhibitor increases intracellular cGMP levels. This study investigated the effect of the PDE5 inhibitor on the ischemic brain. Methods: Regional cerebral blood flow (rCBF), cGMP concentration, and infarction volume were measured in the rat middle cerebral artery occlusion model. Ten minutes after ischemia, the animals received an intravenous (i.v.) infusion of vehicle (phosphate-buffered saline), PDE5 inhibitor, zaprinast (10 mg/kg), or nitric oxide donor, S-nitroso-N-acetyl-penicillamine (SNAP, 100 μg/kg). rCBF was measured continuously by laser-Doppler flowmetry in the ischemic penumbra of the ischemic and contralateral sides under continuous blood pressure monitoring. cGMP concentrations were determined using the enzyme immunoassay and infarct volumes were estimated by 2,3,5-triphenyltetrazolium chloride staining. Results: The administration of zaprinast significantly increased rCBF in the ischemic brain compared with the pre-drug control value despite the decreased mean blood pressure, whereas it did not affect rCBF in the contralateral side. The cGMP concentration was significantly higher in the ischemic cortex compared with the contralateral side. SNAP infusion increased the cGMP concentration in the bilateral cortices to a similar extent. The volume of cerebral infarction was significantly decreased by zaprinast administration. Conclusions: The PDE5 inhibitor zaprinast may selectively increase CBF in the ischemic brain via increased cGMP levels, thus providing a new strategy against acute cerebral infarction.

Surgical outcomes in elderly patients with aneurysmal subarachnoid hemorrhage

The optimum management for elderly patients with aneurysmal subarachnoid hemorrhage (SAH) remains controversial. The surgical indications for aneurysmal SAH in elderly patients were investigated. Materials and methods: This study retrospectively reviewed 148 elderly patients over 70 years old among 1019 patients surgically treated for SAH. The patients were divided into three groups: group A, 93 patients aged 70–74 years; group B, 33 patients aged 75–79 years; and group C, 22 patients aged over 80 years. The outcomes were evaluated using the Glasgow Outcome Scale, with good recovery and moderate disability considered as favorable. The surgical outcome was analyzed compared with the preoperative Hunt and Kosnik grade, location of the aneurysm and causes of complication. Results: A favorable outcome for patients in preoperative Hunt and Kosnik grades I and II was achieved in 84.8% of group A, 63.8% of group B and 57.1% of group C, and for patients in grades III–V, 40.4% of group A, 15.4% of group B and 12.5% of group C. The rate of favorable outcome decreased with age and worse preoperative clinical grade. In patients remaining conscious before operation, the differences in recovery rates were not statistically significant by advancing age. For those patients with disturbance of consciousness, however, the recovery rate was significantly worse in groups B and C as compared with group A. The causes of poor outcome were primary brain damage, vasospasm and muscle weakness due to extended bed rest. In addition, more than half of the patients in a severely disabled or vegetative state at the time of discharge resulted in death within 5 years. Conclusion: Surgery should be considered for elderly patients with aneurysmal SAH leading a normal life before onset and without severe systemic disease, even in those over 80 years, but not in patients with disturbance of consciousness due to primary brain damage.

Surgical Treatment of Multiple Aneurysms

The authors reviewed surgical results of 618 surgically treated patients with intracranial aneurysms. Multiple aneurysms were observed in 106 (20%) patients. In cases of multiple aneurysms, their policy has been to treat all aneurysms, ruptured and unruptured, in a one-stage operation whenever possible. All aneurysms of 92 patients were treated in one-stage operations. Eighty three (90%) patients improved or remained stationary, 6 (7%) deteriorated, 3 (3%) died postoperatively. The cause of deterioration or death were due to cerebral vasospasm, primary brain damage or surgical procedure for ruptured aneurysms. No significant difference was found in comparing the rupture site of the aneurysm or the timing of the operation in each preoperative clinical grade. Furthermore, all patients were classified into three groups according to the location of the aneurysms. Sixty-two patients had unilateral aneurysms including aneurysms in the midline, i.e. anterior communicating artery aneurysms, distal basilar artery aneurysms and/or bilateral pericallosal artery aneurysms (unilateral group), and 30 patients had bilateral aneurysms (bilateral group). Morbidity and mortality in unilateral group was 6% and 3%, while in bilateral group, 7%, 3% respectively. No significant difference was observed in the bilateral group compared with the unilateral group, and surgical results of each group appeared to be satisfactory. Neither death nor deterioration was found attributable to operative procedure when unruptured aneurysms were added to the surgery for ruptured aneurysms in a one-stage operation. These surgical results for 92 cases were similar to the results in the rest of the 526 cases. Based on these results, the one-stage operation is recommended, whenever possible, for patients with multiple aneurysms, even if bilateral craniotomy is needed.