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Tomoo Tokime, Shinichiro Okamoto, Sen Yamagata and Tsuneki Konishi

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Study of the posterior circulation in moyamoya disease

Part 2: Visual disturbances and surgical treatment

Susumu Miyamoto, Haruhiko Kikuchi, Jun Karasawa, Izumi Nagata, Ikuo Ihara and Sen Yamagata

✓ The involvement of the posterior circulation in moyamoya disease was studied in 178 patients. Forty-three had several types of disturbance such as visual field defect, decreased visual acuity, episodes of blindness, and scintillating scotomata. Most of these symptoms were attributed to occlusive lesions in the posterior circulation. Visual disturbances were seen more often in patients with a juvenile onset than in cases of adult onset.

Superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis and encephalomyosynangiosis (EMS) improved the cerebral perfusion both in the anterior and posterior circulation by redistribution of blood. In most cases, the visual symptoms subsided or were stabilized after STA-MCA anastomosis and EMS. These surgical procedures did not, however, lead to direct revascularization in cases of ischemia in the visual cortex. In five patients with impending blindness, transplantation of the omentum to the occipital lobe led to improved vision.

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Hitoshi Fukuda, Kosuke Hayashi, Takafumi Moriya, Satoru Nakashita, Benjamin W. Y. Lo and Sen Yamagata

OBJECT

Intrasylvian hematoma (ISH) is a subtype of intracranial hematoma caused by aneurysmal rupture and often presents with a poor initial neurological grade; it is not well studied. The aim of this study was to elucidate outcomes of aneurysmal subarachnoid hemorrhage (SAH) with ISH.

METHODS

Data for 97 patients with poor-grade SAH (World Federation of Neurosurgical Societies Grade IV or V) were retrospectively analyzed from a single-center, prospective, observational cohort database. Ultra-early surgical clipping, removal of hematoma, external decompression for brain swelling, and prevention of vasospasm by cisternal irrigation with milrinone were combined as an aggressive treatment. Characteristics and clinical courses of SAH with ISH were identified. The authors also evaluated any correlations between poor admission-grade SAH and ISH with good functional outcome.

RESULTS

Patients with poor admission-grade SAH and with ISH were more likely to have initial cerebral edema (p < 0.001, Mann-Whitney U-test), which significantly resolved overtime (p < 0.001, Mann-Whitney U-test). These patients had a better chance of functional survival (modified Rankin Scale scores of 1–3; OR 5.75; 95% CI 1.36–24.3; p = 0.017) at 6 months after hospital discharge, after adjustment for potential confounders such as younger age and better initial neurological grade by multivariable analysis.

CONCLUSIONS

ISH predicted good functional recovery from poor-grade aneurysmal SAH.

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Hitoshi Fukuda, Benjamin Lo, Yu Yamamoto, Akira Handa, Yoshiharu Yamamoto, Yoshitaka Kurosaki and Sen Yamagata

OBJECTIVE

Plasma D-dimer levels elevate during acute stages of aneurysmal subarachnoid hemorrhage (SAH) and are associated with poor functional outcomes. However, the mechanism in which D-dimer elevation on admission affects functional outcomes remains unknown. The aim of this study is to clarify whether D-dimer levels on admission are correlated with systemic complications after aneurysmal SAH, and to investigate their additive predictive value on conventional risk factors for poor functional outcomes.

METHODS

A total of 187 patients with aneurysmal SAH were retrospectively analyzed from a single-center, observational cohort database. Correlations of plasma D-dimer levels on admission with patient characteristics, initial presentation, neurological complications, and systemic complications were identified. The authors also evaluated the additive value of D-dimer elevation on admission for poor functional outcomes by comparing predictive models with and without D-dimer.

RESULTS

D-dimer elevation on admission was associated with increasing age, female sex, and severity of SAH. Patients with higher D-dimer levels had increased likelihood of nosocomial infections (OR 1.22 [95% CI 1.07–1.39], p = 0.004), serum sodium disorders (OR 1.11 [95% CI 1.01–1.23], p = 0.033), and cardiopulmonary complications (OR 1.20 [95% CI 1.04–1.37], p = 0.01) on multivariable analysis. D-dimer elevation was an independent risk factor of poor functional outcome (modified Rankin Scale Score 3–6, OR 1.50 [95% CI 1.15–1.95], p = 0.003). A novel prediction model with D-dimer had significantly better discrimination ability for poor outcomes than conventional models without D-dimer.

CONCLUSIONS

Elevated D-dimer levels on admission were independently correlated with systemic complication, and had an additive value for outcome prediction on conventional risk factors after aneurysmal SAH.

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Yoshitaka Kurosaki, Kazumichi Yoshida, Ryu Fukumitsu, Nobutake Sadamasa, Akira Handa, Masaki Chin and Sen Yamagata

OBJECT

Plaque characteristics and morphology are important indicators of plaque vulnerability. MRI-detected intraplaque hemorrhage has a great effect on plaque vulnerability. Expansive remodeling, which has been considered compensatory enlargement of the arterial wall in the progression of atherosclerosis, is one of the criteria of vulnerable plaque in the coronary circulation. The purpose of this study was risk stratification of carotid artery plaque through the evaluation of quantitative expansive remodeling and MRI plaque signal intensity.

METHODS

Both preoperative carotid artery T1-weighted axial and long-axis MR images of 70 patients who underwent carotid endarterectomy (CEA) or carotid artery stenting (CAS) were studied. The expansive remodeling ratio (ERR) was calculated from the ratio of the linear diameter of the artery at the thickest segment of the plaque to the diameter of the artery on the long-axis image. Relative plaque signal intensity (rSI) was also calculated from the axial image, and the patients were grouped as follows: Group A = rSI ≥ 1.40 and ERR ≥ 1.66; Group B = rSI< 1.40 and ERR ≥ 1.66; Group C = rSI 1.40 and ERR < 1.66; and Group D = rSI < 1.40 and ERR < 1.66. Ischemic events within 6 months were retrospectively evaluated in each group.

RESULTS

Of the 70 patients, 17 (74%) in Group A, 6 (43%) in Group B, 7 (44%) in Group C, and 6 (35%) in Group D had ischemic events. Ischemic events were significantly more common in Group A than in Group D (p = 0.01).

CONCLUSIONS

In the present series of patients with carotid artery stenosis scheduled for CEA or CAS, patients with plaque with a high degree of expansion of the vessel and T1 high signal intensity were at higher risk of ischemic events. The combined assessment of plaque characterization with MRI and morphological evaluation using ERR might be useful in risk stratification for carotid lesions, which should be validated by a prospective, randomized study of asymptomatic patients.

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Hitoshi Fukuda, Akira Handa, Masaomi Koyanagi, Benjamin Lo and Sen Yamagata

OBJECTIVE

Although endovascular therapy is favored for acutely ruptured intracranial aneurysms, hematological factors associated with acute subarachnoid hemorrhage (SAH) may predispose to procedure-related ischemic complications. The aim of this study was to evaluate whether an elevated level of plasma D-dimer, a parameter of hypercoagulation in patients with acute SAH, is correlated with increased incidence of thromboembolic events during endovascular coiling of ruptured aneurysms.

METHODS

The authors analyzed data from 103 cases of acutely ruptured aneurysms (in 103 patients) treated with endovascular coil embolization at a single institution. Factors associated with elevated D-dimer level on admission were identified. The authors also evaluated whether D-dimer elevation was independently correlated with increased incidence of perioperative thromboembolic events.

RESULTS

An elevated D-dimer concentration (≥ 1.0 μg/ml) on admission was observed in 70 (68.0%) of 103 patients. Increasing age (p < 0.001, Student t-test) and poor initial neurological grade representing World Federation of Neurosurgical Societies (WFNS) grade IV or V (p = 0.0018, chi-square test) were significantly associated with D-dimer elevation. Symptomatic thromboembolic events occurred in 11 cases (10.7%). Elevated D-dimer levels on admission (OR 1.34, 95% CI 1.10–1.62, p = 0.0029) independently carried a higher risk of thromboembolic events after adjustment for potential angiographic confounders, including wide neck of the aneurysm and large aneurysm size.

CONCLUSIONS

Elevated D-dimer levels on admission of patients with acute SAH were significantly associated with increased incidence of thromboembolic events during endovascular coiling of ruptured aneurysms.

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Shin-ichi Miyatake, Haruhiko Kikuchi, Tomoaki Koide, Sen Yamagata, Izumi Nagata, Shun-suke Minami and Reinin Asato

✓ A case of Cobb's syndrome, which is characterized by spinal and vertebral angiomas and a skin nevus at the same metameric level, is reported. The spinal angiomas were treated with liquid embolization using ethylene vinyl alcohol.

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Kazumichi Yoshida, Hideki Endo, Nobutake Sadamasa, Osamu Narumi, Masaki Chin, Katsumi Inoue, Kazuaki Mitsudo and Sen Yamagata

Object

The goal of this study was to evaluate the usefulness of long-axis black-blood MR (BB–MR) imaging for assessing plaque morphology and distribution in patients with atherosclerotic carotid artery (CA) stenosis.

Methods

Sixty-eight carotid arteries in 67 patients who were scheduled to undergo CA endarterectomy or CA stent placement due to atherosclerotic stenosis were included in this study. The patients had undergone CA BB–MR imaging and digital subtraction (DS) angiography within 3 weeks of revascularization. The DS angiography studies were performed using the transfemoral artery approach with selective common CA catheterization. The BB–MR images were acquired using a 1.5-T whole-body MR imaging unit, and T1-weighted images parallel to the long axis of the artery at 1-mm intervals were obtained. Plaque distribution was evaluated by measuring the distance between the CA bifurcation and the point that appeared to be the distal extent of the plaque on BB–MR imaging (D–MR imaging) and DS angiography images (D–DS angiography).

Results

Plaque distribution was clearly shown in 88.2% of the cases using long-axis BB–MR images, except for 8 arteries with poor image quality. In 4 arteries, D–DS angiography could not be obtained because the distal plaque end could not be confirmed. In 56 vessels, both the D–DS angiography and D–MR imaging could be measured; the mean D–MR imaging (19.75 ± 6.85 mm [standard deviation]) was significantly longer than the average D–DS angiography (16.32 ± 7.07 mm).

Conclusions

Long-axis BB–MR imaging can provide a noninvasive and accurate way to show CA plaque distribution; it is of great use not only for stroke risk assessment in patients with CA atherosclerosis but also for preoperative evaluation in patients requiring CA endarterectomy or CA stent placement.

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Masaomi Koyanagi, Hitoshi Fukuda, Benjamin Lo, Minami Uezato, Yoshitaka Kurosaki, Nobutake Sadamasa, Akira Handa, Masaki Chin and Sen Yamagata

OBJECTIVE

Delayed cerebral ischemia (DCI) is an important complication after aneurysmal subarachnoid hemorrhage (aSAH). Although intrathecal milrinone injection via lumbar catheter to prevent DCI has been previously reported to be safe and feasible, its effectiveness remains unknown. The goal of this study was to evaluate whether intrathecal milrinone injection treatment after aSAH significantly reduced the incidence of DCI.

METHODS

The prospectively maintained aSAH database was used to identify patients treated between January 2010 and December 2015. The cohort included 274 patients, with group assignment based on treatment with intrathecal milrinone injection or not. A propensity score model was generated for each patient group, incorporating relevant patient variables.

RESULTS

After propensity score matching, 99 patients treated with intrathecal milrinone injection and 99 without treatment were matched on the basis of similarities in their demographic and clinical characteristics. There were significantly fewer DCI events (4% vs 14%, p = 0.024) in patients treated with intrathecal milrinone injection compared with those treated without it. However, there were no significant differences between the 2 groups with respect to their 90-day functional outcomes (46% vs 36%, p = 0.31). The likelihood of chronic secondary hydrocephalus, meningitis, and congestive heart failure as complications of intrathecal milrinone injection therapy was also similar between the groups.

CONCLUSIONS

In propensity score–matched groups, the intrathecal administration of milrinone via lumbar catheter showed significant reduction of DCI following aSAH, without an associated increase in complications.

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Kazumichi Yoshida, Ryu Fukumitsu, Yoshitaka Kurosaki, Takeshi Funaki, Takayuki Kikuchi, Jun C. Takahashi, Yasushi Takagi, Sen Yamagata and Susumu Miyamoto

OBJECT

The purpose of the present study was to investigate the association between carotid artery (CA) expansive remodeling (ER) and symptoms of cerebral ischemia.

METHODS

One hundred twenty-two consecutive CAs scheduled for CA endarterectomy (CEA) or CA stent placement (CAS) were retrospectively studied. After excluding 22 CAs (2 were contraindicated for MRI, 8 had near-occlusion, 6 had poor image quality, and 6 had restenosis after CEA or CAS), there were 100 CAs (100 patients) included in the final analysis. The study included 50 symptomatic patients (mean age 73.6 ± 8.9 years, 6 women, mean stenosis 68.5% ± 21.3%) and 50 asymptomatic patients (mean age 72.0 ± 5.9 years, 5 women, mean stenosis 79.4% ± 8.85%). Expansive remodeling was defined as enlargement of the internal carotid artery (ICA) with outward plaque growth. The ER ratio was calculated by dividing the maximum distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA by the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis using long-axis, high-resolution MRI.

RESULTS

The ER ratio of the atherosclerotic CA was significantly greater than that of normal physiological expansion (carotid bulb; p < 0.01). The ER ratio of symptomatic CA stenosis (median 1.94, interquartile range [IQR] 1.58–2.23) was significantly greater than that of asymptomatic CA stenosis (median 1.52, IQR 1.34–1.81; p = 0.0001). When the cutoff value of the ER ratio was set to 1.88, the sensitivity and specificity to detect symptoms were 0.6 and 0.78, respectively. The ER ratio of symptomatic patients was consistently high regardless of the degree of stenosis.

CONCLUSIONS

There was a significant correlation between ER ratio and ischemic symptoms. The ER ratio might be a potential indicator of vulnerable plaque, which requires further validation by prospective observational study of asymptomatic patients.