Visualization of periventricular collaterals in moyamoya disease with flow-sensitive black-blood magnetic resonance angiography: preliminary experience

RNF213 p.Arg4810Lys Wild Type is Associated with De Novo Hemorrhage in Asymptomatic Hemispheres with Moyamoya Disease

Clinical implications of RNF213 genetic variants, other than p.Arg4810Lys, in moyamoya disease (MMD), remain unclear. This study aimed to investigate the association of RNF213 variants with clinical phenotypes in MMD. This retrospective cohort study collected data regarding the clinical characteristics of 139 patients with MMD and evaluated the angioarchitectures of 253 hemispheres using digital subtraction angiography at diagnosis. All RNF213 exons were sequenced, and the associations of clinical characteristics and angiographical findings with p.Arg4810Lys, p.Ala4399Thr, and other rare variants (RVs) were examined. Among 139 patients, 100 (71.9%) had p.Arg4810Lys heterozygote (GA) and 39 (28.1%) had the wild type (GG). Fourteen RVs were identified and detetcted in 15/139 (10.8%) patients, and p.Ala4399Thr was detected in 17/139 (12.2%) patients. Hemispheres with GG and p.Ala4399Thr presented with significantly less ischemic events and more hemorrhagic events at diagnosis (p = 0.001 and p = 0.028, respectively). In asymptomatic hemispheres, those with GG were more susceptible to de novo hemorrhage than those with GA (adjusted hazard ratio [aHR] 5.36) with an increased risk when accompanied by p.Ala4399Thr or RVs (aHR 15.22 and 16.60, respectively). Within the choroidal anastomosis-positive hemispheres, GG exhibited a higher incidence of de novo hemorrhage than GA (p = 0.004). The GG of p. Arg4810Lys was a risk factor for de novo hemorrhage in asymptomatic MMD hemispheres. This risk increased with certain other variants and is observed in choroidal anastomosis-positive hemispheres. A comprehensive evaluation of RNF213 variants and angioarchitectures is essential for predicting the phenotype of asymptomatic hemispheres in MMD.

Acute Magnetic Resonance Imaging Findings in Young Children With Moyamoya Disease

BACKGROUND

To describe the diffusion-weighted imaging (DWI) findings in young children with moyamoya disease (MMD) during the acute period of the condition.

METHODS

Clinical data were collected from 12 children with MMD aged less than six years, in whom abnormalities were observed on DWI scans obtained within one week after the appearance of symptoms related to MMD. The DWI abnormalities were classified into gyral, atypical territorial, honeycomb, classical territorial, multiple-dot, border zone, and deep lacunar patterns. The severity of arterial stenosis was graded by angiographic stages that have been previously described.

RESULTS

In all but one child, the DWI abnormalities were restricted to the cerebral cortex. The lesions were gyral in nature in seven children and atypical territorial in five; all differed from those of typical arterial strokes. Internal carotid artery stenosis was observed in all 12 children, although the stenosis was mild in 11. The severity of arterial stenosis did not match the regions of ischemic lesions in some children. There was no statistically significant difference in the severity of arterial stenosis according to the presence or absence of ischemic lesions or the pattern of the lesions.

CONCLUSIONS

Lesions located mainly in the cerebral cortex, i.e., not in arterial territories, are characteristic of young children with MMD.

High resolution vessel-wall imaging for peripheral aneurysms in adult moyamoya disease: a report of three cases

Peripheral aneurysms in patients with moyamoya disease have been reported to be hazardous owing to their rupture-prone nature. High-resolution vessel wall imaging has recently emerged as a useful modality for evaluating intracranial aneurysmal status. We present the vessel-wall imaging of peripheral aneurysms in three patients with moyamoya disease. Strong circumferential wall enhancement was observed in ruptured peripheral aneurysms. Peripheral aneurysms were located at the connection point between the single main stem and the multiple medullary tributaries of the choroidal anastomosis. Using high-resolution vessel-wall imaging, we identified the characteristics of peripheral aneurysms in patients with moyamoya disease.

Characteristics and Clinical Implication of White Matter Lesions in Patients With Adult Moyamoya Disease

BACKGROUND AND OBJECTIVES

White matter hyperintensities (WMHs) are reportedly increased in moyamoya disease (MMD); however, their clinical importance is not well-established owing to their pathophysiologic heterogeneity by distribution. This study aimed to evaluate the burden and pattern of WMHs and its clinical implications in the MMD trajectory.

METHODS

Adult patients with MMD without significant structural lesions were 1:1 propensity score-matched with healthy controls for sex and vascular risk factors. The total, periventricular, and subcortical WMH volumes were segmented and quantified fully automatically. WMH volumes were detrended by age and compared between the 2 groups. MMD severity based on Suzuki stage and future ischemic events were assessed for their association with WMH volumes.

RESULTS

A total of 161 pairs of patients with MMD and controls were analyzed. MMD significantly correlated with increased total WMH volume (B [standard error], 0.126 [0.030]; p < 0.001), periventricular WMH volume (0.114 [0.027]; p < 0.001), and periventricular-to-subcortical ratio (0.090 [0.034]; p = 0.009). In the MMD subgroup (n = 187), advanced MMD had an independent association with the total WMH volume (0.120 [0.035]; p < 0.001), periventricular WMH volume (0.110 [0.031]; p < 0.001), and periventricular-to-subcortical ratio (0.139 [0.038]; p < 0.001). Periventricular WMH volume (adjusted hazard ratio [95% confidence interval], 5.12 [1.26-20.79]) and periventricular-to-subcortical ratio (3.80 [1.51-9.56]) were associated with future ischemic events in patients with medically followed up MMD. However, no demonstrable association was found between subcortical WMH volume and MMD, MMD severity, or future ischemic events.

DISCUSSION

Periventricular WMHs, but not subcortical WMHs, may represent the main pathophysiology of MMD. Periventricular WMHs may be used as a marker for ischemic vulnerability in patients with MMD.

Larger Posterior Revascularization Associated with Reduction of Choroidal Anastomosis in Moyamoya Disease: A Quantitative Angiographic Analysis

BACKGROUND AND PURPOSE

Choroidal anastomosis, a hemorrhage-prone periventricular collateral manifestation in Moyamoya disease, outflows to the cortex posterior to the central sulcus. The objective of the present study was to test whether the angiographic extent of revascularization posterior to the central sulcus contributes to the postoperative reduction of choroidal anastomosis.

MATERIALS AND METHODS

This retrospective cohort study included choroidal anastomosis-positive hemispheres before direct bypass surgery. The postoperative reduction of choroidal anastomosis was determined by a consensus of 2 raters according to the previous research. An imaging software automatically traced the angiographic revascularization area, which was subsequently divided into anterior and posterior parts by an anatomic line corresponding to the central sulcus. Each area was quantitatively measured as a percentage relative to the whole supratentorial area.

RESULTS

Postoperative reduction of choroidal anastomosis was achieved in 68 (85.0%) of the 80 included hemispheres. The revascularization area posterior to the central sulcus was significantly larger in the hemispheres with reduction than in those with no reduction (mean, 15.2% [SD, 7.1%] versus 4.2% [SD, 3.4%], P < .001), whereas no significant difference was observed in the revascularization area anterior to the central sulcus. Multivariate analysis revealed that the revascularization area posterior to the central sulcus was the only significant factor associated with reduction (OR, 1.57; 95% CI, 1.21-2.03, for every 1% increase).

CONCLUSIONS

The results suggest that a larger revascularization posterior to the central sulcus is associated with postoperative reduction of choroidal anastomosis regardless of the extent of anterior revascularization. It might facilitate optimal selection of the revascularization site for preventing hemorrhage.

Cerebral Aneurysms with Internal Carotid Artery Agenesis: A Unique Case Similar to Moyamoya Disease and Literature Review

Internal carotid artery (ICA) agenesis/aplasia is occasionally accompanied with cerebral aneurysms caused by hemodynamic stress. If the aneurysms are located around the circle of Willis, they are managed with clipping or coil embolization. Herein, we report a case of ICA agenesis with perforating artery aneurysms treated successfully with revascularization. Moreover, a literature review of ICA agenesis with cerebral aneurysms was performed to compare with the current case. We conducted a literature review using data from PubMed. A secondary search was also performed by reviewing the references of each article previously searched. In our case, the aneurysms shrank and disappeared after direct and indirect bypass surgeries, and indirect bypass developed as in moyamoya disease (MMD). The epidemiological and clinical features of aneurysms accompanied with ICA agenesis were identified via a literature review. Aneurysms with ICA agenesis categorized as type F based on the Lie classification system, or referred to as rete mirabile, are occasionally located in an untreatable site; hence, they cannot be treated with clipping or coil embolization. Moreover, results showed that previous studies did not use revascularization for the treatment of aneurysm. In conclusion, if an aneurysm with ICA agenesis is difficult to approach directly or via an endovascular procedure, revascularization can be a treatment option.

Validation of choroidal anastomosis on high-resolution magnetic resonance imaging as an imaging biomarker in hemorrhagic moyamoya disease

OBJECTIVES

This study aimed to investigate the association between dilation and proliferation and anastomosis of perforating arteries, and intracranial hemorrhage in moyamoya disease (MMD) patients, using high-resolution magnetic resonance imaging (HRMRI).

METHODS

Adult patients with MMD at advanced stages were prospectively enrolled and underwent HRMRI exams. Dilation and proliferation of the lenticulostriate artery (LSA), medullary artery, and anterior or posterior choroidal arteries (AChA or PChA) were assessed. Abnormal anastomoses were identified between (1) the LSA and the medullary or insular arteries; (2) the thalamo-geniculate, thalamo-tuberal, or thalamo-perforating arteries and the medullary or insular arteries; and (3) the AChA or PChA and the medullary or insular arteries. The association between these variables and hemorrhagic events was calculated using univariate and multivariate analyses.

RESULTS

Fifty patients (14 men; mean age, 35.4 ± 9.7 years) were finally analyzed, including 17 hemorrhagic patients and 33 non-hemorrhagic patients. The inter-rater agreement for the qualitative evaluation of perforating arteries was good. Dilation and proliferation of the AChA or PChA (88.2% versus 54.5%, p = 0.027), and choroidal anastomosis (64.7% versus 18.2%, p = 0.002) were more frequently observed in patients with hemorrhage. Multivariate logistic regression showed that choroidal anastomosis remained significantly associated with hemorrhage (odds ratio = 5.95, 95% confidence interval = 1.21-29.25, p = 0.028).

CONCLUSIONS

Choroidal anastomosis is independently associated with hemorrhagic events in adult patients with MMD at advanced stages. HRMRI can provide detailed information on both the anatomies and abnormal collaterals in MMD, which facilitates risk estimates of bleeding in MMD.

KEY POINTS

• High-resolution magnetic resonance imaging allows for the evaluation of perforating arteries in patients with moyamoya disease. • Choroidal anastomosis is associated with hemorrhagic events in patients with moyamoya disease. • High-resolution magnetic resonance imaging might facilitate further grading and classification of moyamoya vessels.

Cortical Distribution of Fragile Periventricular Anastomotic Collateral Vessels in Moyamoya Disease: An Exploratory Cross-Sectional Study of Japanese Patients with Moyamoya Disease

BACKGROUND AND PURPOSE

Collateral vessels in Moyamoya disease represent potential sources of bleeding. To test whether these cortical distributions vary among subtypes, we investigated cortical terminations using both standardized MR imaging and MRA.

MATERIALS AND METHODS

Patients with Moyamoya disease who underwent MR imaging with MRA in our institution were enrolled in this study. MRA was spatially normalized to the Montreal Neurological Institute space; then, collateral vessels were measured on MRA and classified into 3 types of anastomosis according to the parent artery: lenticulostriate, thalamic, and choroidal. We also obtained the coordinates of collateral vessel outflow to the cortex. Differences in cortical terminations were compared among the 3 types of anastomosis.

RESULTS

We investigated 219 patients with Moyamoya disease, and a total of 190 collateral vessels (lenticulostriate anastomosis, n = 72; thalamic anastomosis, n = 21; choroidal anastomosis, n = 97) in 46 patients met the inclusion criteria. We classified the distribution patterns of collateral anastomosis as follows: lenticulostriate collaterals outflowing anteriorly (P < .001; 95% CI, 67.0-87.0) and medially (P < .001; 95% CI, 11.0-24.0) more frequently than choroidal collaterals; lenticulostriate collaterals outflowing anteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 34.0-68.0); and choroidal collaterals outflowing posteriorly more frequently than thalamic collaterals (P < .001; 95% CI, 14.0-34.0). Lenticulostriate anastomoses outflowed to the superior or inferior frontal sulcus and interhemispheric fissure. Thalamic anastomoses outflowed to the insular cortex and cortex around the central sulcus. Choroidal anastomoses outflowed to the cortex posterior to the central sulcus and the insular cortex.

CONCLUSIONS

Cortical distribution patterns appear to differ markedly among the 3 types of collaterals.

Hemorrhagic events associated with unfused or twig-like configuration of the Middle cerebral artery: A rare vascular anomaly with clinical relevance

INTRODUCTION

Twig-like middle cerebral artery configuration (Tw-MCA) is a rare and commonly misdiagnosed vascular anomaly characterized by a plexiform arterial network that replaces the normal M1 segment. The prevalence and clinical relevance of this anomaly is not fully established.

MATERIAL AND METHODS

We sought to explore the prevalence of Tw-MCA in patients clinically referred to digital angiography in a single academic comprehensive endovascular center and evaluated the radiological and clinical findings among patients with hemorrhagic events.

RESULTS

From 2011 to 2020, a total of 10,234 patients underwent a cerebral angiography at our institution. During this period, 9 (0.088%) Tw-MCAs were identified. Out of these, 5 patients (62.5%) were admitted due to an intracranial hemorrhage. Two patients had a ruptured intracranial aneurysm on the anterior communicating artery, one with multiple brain aneurysms; two patients presented an intraparenchymal hematoma (IPH) due to the presence of a periventricular anastomosis and one patient an intraventricular hemorrhage with unclear origin.

CONCLUSION

Tw-MCA is a very rare vascular anomaly associated with hemorrhagic events. Adequate identification of this anomaly is essential in order to avoid misdiagnosis as steno-occlusive disorders.

Intracranial arterial stenosis associated with Hashimoto's disease: angiographic features and clinical outcomes

BACKGROUND

Hashimoto's disease has reportedly been associated with stroke; however, cerebrovascular morphology and clinical course remain poorly documented. The present study aimed to determine the angiographic features and clinical outcomes of intracranial arterial stenosis (IAS) associated with Hashimoto's disease in a retrospective cohort.

METHODS

Overall, 107 adult patients with IAS were screened for anti-thyroid antibodies; of these, 26 patients tested positive. The 42 affected hemispheres were classified into subgroups according to the steno-occlusion site and the development of abnormal collateral (moyamoya) vessels. These subgroups were dichotomized into moyamoya vessels positive (MM type) and negative (non-MM type). The initial presentation, IAS progression, and vascular events during the follow-up period were compared.

RESULTS

The following sites of stenosis were identified: the bifurcation of the internal carotid artery in 11 (26.2%), M1 or A1 in 29 (69.0%), and more distal (M2-M4/A2-A4) in 2 (4.8%) hemispheres. Further, 17 hemispheres were categorized into the MM type and 25 were classified into the non-MM type. During the follow-up period (mean 2.5 years), IAS progression was identified in 8 (32%) hemispheres of the non-MM type and 0 (0%) hemispheres of the MM type (p = 0.041). Ischemic attacks occurred in 5 (20.0%) hemispheres of the non-MM type (4.6%/year) and 0 hemispheres of the MM type (p = 0.08). Further, 4 (23.5%) hemispheres of the MM type experienced intracerebral hemorrhage, whereas none of the non-MM type hemorrhaged (p = 0.012).

CONCLUSIONS

Hashimoto's disease-associated IAS exhibits various angiographic morphologies, resulting in different clinical presentations. Screening for anti-thyroid antibodies and careful management based on vascular morphology appears important in adults with IAS.

Difference in periventricular anastomosis in child and adult moyamoya disease: a vascular morphology study

BACKGROUNDS

Periventricular anastomosis (PA), which is a novel term for extended collateral vessels in moyamoya disease (MMD), is reportedly associated with a high risk of intracranial hemorrhage in adult patients. The present study aimed to clarify the similarities and the differences in the development of PA between three MMD groups, classified by age at the time of diagnosis and clinical phenotype.

METHODS

This study included 232 hemispheres of 132 patients with MMD who underwent surgical revascularization. The subjects were classified into child ischemic (CI) group, adult ischemic (AI) group, and adult hemorrhagic (AH) group. We evaluated the lenticulostriate (LSA), thalamic (THA), choroidal (ChA), anterior choroidal (AChA), and posterior choroidal (PChA) anastomosis as well as the posterior cerebral artery (PCA) involvement. The PA scores and the sums of each grade of LSA, THA, and ChA anastomosis were also calculated in all of the cases.

RESULTS

In a multiple comparison test, the PA scores (P < 0.01), LSA (P < 0.01), and ChA anastomosis (P = 0.013) were more prominent in the CI than in the AI group. The PA scores (P < 0.01) and LSA (P = 0.011), ChA (P < 0.01), AChA (P < 0.01), and PChA anastomosis (P = 0.016) were more prominent in the AH group than in the AI group. The CI and AH groups showed similar characteristics except for PCA involvement. After multivariate adjustments using the AI group as a reference group, the PA scores and the positive rates of LSA and ChA anastomosis remained significantly higher in the CI and AH groups.

CONCLUSION

The patterns of PA development in the CI and AH groups were similar in that they were more prominent than in the AI group. These findings may contribute to a better understanding of the progression of ischemic and hemorrhagic MMD.

The Targeted Bypass Strategy for Preventing Hemorrhage in Moyamoya Disease: Technical Note

Although direct bypass is effective at preventing intracranial hemorrhage in moyamoya disease, the optimal strategy for achieving this purpose has rarely been addressed. The tailored targeting bypass strategy is a novel technical modification of direct bypass focused on hemorrhage prevention. The strategy is based on the promising theory of periventricular anastomosis, which explains the mechanism of hemorrhage in moyamoya disease. The strategy is defined as the use of multi-imaging modalities to predetermine in a tailored manner a target vessel at the point at which the medullary artery directly extends from the periventricular anastomosis of interest. Direct bypass with a wide craniotomy was performed on 13 hemispheres in eight patients according to this strategy. Marked shrinkage of the periventricular anastomosis of interest was observed in all but one hemisphere after surgery, and no new hemorrhages have occurred as of this writing. The present case series illustrates the technical aspects and preliminary results of the tailored targeting bypass strategy, an approach that might expand the potential of direct bypass in preventing hemorrhage.

Patterns of Acute Intracranial Hemorrhage in Adult Patients with Bilateral and Unilateral Moyamoya Disease

BACKGROUND

Moyamoya disease (MMD) is a rare cerebrovascular disease. The difference of hemorrhagic patterns in adult patients with bilateral and unilateral MMD is still unclear.

OBJECTIVE

For a better understanding of their characteristics, we compared the patterns of acute intracranial hemorrhage in adult patients with bilateral and unilateral MMD.

METHODS

Adult MMD patients with acute intracranial hemorrhage were retrospectively included. Clinical and radiological characteristics of adult patients with bilateral and unilateral MMD were collected and analyzed. Chi-square test, t-test, or rank sum test were used for statistical analyses.

RESULTS

A total of 107 patients were included. Among 74 patients with bilateral MMD, 9 (12.2%) were at Suzuki Stage 2, 48 (64.9%) were at Stage 3, 16 (21.6%) were at Stage 4, and another (1.4%) was at Stage 5. However, in patients with unilateral MMD, 8 (24.2%) were at Stage 2, 23 (69.7%) were at Stage 3, and 2 (6.1%) were at Stage 4. Intraparenchymal hemorrhage was found in 40 (54.1%) patients with bilateral MMD and 16 (48.5%) patients with unilateral MMD (P=0.594). Intraventricular hemorrhage was shown in 65 (87.8%) patients with bilateral MMD and 19 (57.6%) patients with unilateral MMD (P<0.001). Subarachnoid hemorrhage was observed in 17 (23.0%) patients with bilateral MMD and 18 (54.5%) patients with unilateral MMD (P=0.001).

CONCLUSION

Unilateral MMD patients with acute intracranial hemorrhage are at the earlier Suzuki stage than the bilateral MMD patients. Intraventricular hemorrhage occurs more frequently in bilateral MMD, while subarachnoid hemorrhage is more frequent in unilateral MMD.

Intrinsic development of choroidal and thalamic collaterals in hemorrhagic-onset moyamoya disease: case-control study of the Japan Adult Moyamoya Trial

OBJECTIVE: This study was performed to identify the angiographic features of hemorrhagic-onset moyamoya disease (MMD) in comparison with those of patients with ischemic-onset MMD. METHODS: This case-control study compared the data set of the Japan Adult Moyamoya (JAM) Trial with the angiographic data of adult patients with ischemic-onset MMD. The authors analyzed angiograms obtained at onset, classifying the collaterals into 3 subtypes: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. They then compared the extent of these collaterals, as indicated by the collateral development grade from 0 to 2 in each subtype, between the JAM Trial group and the ischemic-onset group. They also compared the involvement of the posterior cerebral artery (PCA) and Suzuki's angiographic staging between each group. RESULTS: Among 89 ischemic-onset patients, 103 symptomatic hemispheres in 80 patients were analyzed and compared with 75 hemorrhagic hemispheres from the JAM Trial. The hemorrhagic-onset patients showed a significantly higher proportion of thalamic anastomosis (p = 0.043) and choroidal anastomosis (< 0.001), as indicated by grade 2 in each subtype, compared with ischemic-onset patients. Suzuki's angiographic staging was significantly higher in the hemorrhagic group (< 0.038). There was no difference in the extent of lenticulostriate anastomosis and PCA involvement between the groups. CONCLUSIONS: In adult MMD, the characteristic pattern of the abnormal vascular networks at the base of the brain is different between each onset type. In light of the more prominent development of thalamic and choroidal anastomosis in the JAM Trial group in the present study, development of these collaterals, especially the choroidal collateral extending beyond the lateral ventricle, may play a critical role in hemorrhagic presentation in MMD.Clinical trial registration no. C000000166 (http://www.umin.ac.jp/ctr/index.htm).

Restoration of periventricular vasculature after direct bypass for moyamoya disease: intra-individual comparison

BACKGROUND

While periventricular anastomosis, a unique abnormal vasculature in moyamoya disease, has been studied in relation to intracranial hemorrhage, no study has addressed its change after bypass surgery. The authors sought to test whether direct bypass surgery could restore normal periventricular vasculature.

METHODS

Patients who had undergone direct bypass surgery for moyamoya disease at a single institution were eligible for the study. Baseline, postoperative, and follow-up magnetic resonance angiography (MRA) scans were scheduled before surgery, after the first surgery, and 3 to 6 months after contralateral second surgery, respectively. Sliding-thin-slab maximum-intensity-projection coronal MRA images of periventricular anastomoses were scored according to the three subtypes (lenticulostriate, thalamic, and choroidal anastomosis). Baseline and postoperative MRA images were compared to obtain a matched comparison of score changes in the surgical and nonsurgical hemispheres within individuals (intra-individual comparison).

RESULTS

Of 110 patients, 42 were identified for intra-individual comparisons. The periventricular anastomosis score decreased significantly in the surgical hemispheres (median, 2 versus 1; p < 0.001), whereas the score remained unchanged in the nonsurgical hemispheres (median, 2 versus 2; p = 0.57); the score change varied significantly between the surgical and nonsurgical hemispheres (p < 0.001). Of the 104 periventricular-anastomosis-positive hemispheres undergoing surgery, 47 (45.2%) were assessed as negative in the follow-up MRA. Among the subtypes, choroidal anastomosis was most likely to be assessed as negative (79.7% of positive hemispheres).

CONCLUSIONS

Periventricular vasculature can be restored after direct bypass. The likelihood of correction of choroidal anastomosis is a subject requiring further studies.

Intractable Medial Anastomotic Branches from the Lenticulostriate Artery Causing Recurrent Hemorrhages in Moyamoya Disease

BACKGROUND

Although superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is a beneficial treatment for hemorrhagic moyamoya disease, indeterminate mechanisms can cause rebleeding even after successful bypass surgery. We describe a case with a prominent collateral from the lenticulostriate artery (LSA) causing multiple recurrent hemorrhages after successful STA-MCA anastomosis.

CASE DESCRIPTION

A 49-year-old Japanese woman with moyamoya disease was referred to our institution after suffering intracranial hemorrhage on 2 occasions. Angiography revealed multiple anastomotic vessels branching from a prominent LSA to connect medullary arteries in the periventricular area corresponding to the location of the hemorrhage. She underwent STA-MCA anastomoses and the bypass widely perfused the MCA territory; however, intracranial hemorrhage recurred in the same hemisphere. Angiography revealed sustained dilatation of the medial anastomotic branches from the LSA with de novo pseudoaneurysm, whereas the lateral branches showed shrinkage. Subsequent surgical treatment included direct bypass targeting the medial hemispheric surface in which the medial branches were distributed; marked shrinkage of the branches and disappearance of the aneurysm were obtained without infarct.

CONCLUSIONS

Lenticulostriate anastomotic branches distributed medially to the anterior cerebral artery territory should be given more attention as an intractable cause of hemorrhage after successful STA-MCA anastomosis. Although challenging, direct bypass targeting the area reached by collateral vessels could be considered an alternative treatment strategy for this pathologic condition.

Longitudinal anterior-to-posterior shift of collateral channels in patients with moyamoya disease: an implication for its hemorrhagic onset

OBJECTIVE

This study aimed to assess longitudinal changes in the collateral channels originating from the lenticulostriate artery (LSA), posterior communicating artery (PCoA), and anterior and posterior choroidal arteries (AChA and PChA, respectively) during disease progression and/or aging. The impact of collateral channels on onset type was also examined.

METHODS

This study included 71 involved hemispheres in 41 patients with moyamoya disease. The disease was categorized into 6 stages according to Suzuki's angiographic staging system. The degree of development of each moyamoya vessel was categorized into 3 grades.

RESULTS

The LSA started to dilate in stage 2, showed the most prominent development in stage 3, and decreased in more advanced stages (p < 0.001). The AChA most notably developed in stage 3 and gradually shrank (p = 0.04). The PCoA started to dilate in stage 3 and showed the most prominent development in stage 4 (p = 0.03). The PChA started to dilate in stage 3 and showed the most prominent development in stages 4 to 5 (p < 0.001). Patient age was negatively related to LSA development (p = 0.01, R = 0.30) and was positively associated with the abnormal dilation and extension of the PCoA (p = 0.02, R = 0.28) and PChA (p < 0.001, R = 0.45). The PCoA, AChA, and PChA more distinctly developed in hemispheres with intracerebral or intraventricular hemorrhage than in hemispheres with ischemic stroke or transient ischemic attack (p < 0.001, p = 0.03, and p = 0.03, respectively).

CONCLUSIONS

This study suggests that the collateral channels through moyamoya vessels longitudinally shift from the anterior to posterior component during disease progression and aging, which may be closely related to the onset of hemorrhagic stroke in adult moyamoya disease.

Aplastic or Twig-Like Middle Cerebral Artery Presenting with Intracerebral Hemorrhage During Pregnancy: Report of Two Cases

Background

An aplastic or twig-like middle cerebral artery (Ap/T-MCA) is a rare congenital anomaly that can present with both ischemic and hemorrhagic stroke. The etiology of this pathology has remained unclear. Here, we report 2 cases of intracerebral hemorrhage (ICH) owing to an Ap/T-MCA in pregnant patients.

Case Description

In both patients, cerebral angiography revealed a steno-occlusive lesion and an abnormal arterial network on the unilateral middle cerebral artery. One patient was treated conservatively for a putaminal hemorrhage, and a cesarean section was performed uneventfully 6 months after onset of the ICH. The other patient underwent a craniotomy for evacuation of the lobar hemorrhage. Subsequently, a cesarean section was performed uneventfully. Both patients gradually recovered without significant disabilities.

Conclusions

An Ap/T-MCA is a rare congenital anomaly and is a potential cause of ICH for pregnant patients. A cesarean section is a useful option for pregnant patients with this condition.

High rebleeding risk associated with choroidal collateral vessels in hemorrhagic moyamoya disease: analysis of a nonsurgical cohort in the Japan Adult Moyamoya Trial

OBJECTIVEChoroidal collateral vessels typical of moyamoya disease have received attention as a potential bleeding source. The authors' previous angiographic cross-sectional analysis suggested a possible association between choroidal collaterals and posterior hemorrhage, indicating a high risk for rebleeding. The present longitudinal analysis is intended to determine whether choroidal collaterals are a predictor of rebleeding in hemorrhagic moyamoya disease.METHODSThe Japan Adult Moyamoya Trial group designed an ancillary cohort study using 5-year follow-up data on 37 patients included in the nonsurgical arm of the original randomized controlled trial and compared the rebleeding rate of those with and those without choroidal collaterals, represented by the connection between the anterior or posterior choroidal arteries and the medullary arteries. An expert panel determined whether a choroidal collateral was present in each patient through the measurement of baseline angiography studies. The rebleeding rate comparison was adjusted for age, diagnosis of hypertension, and involvement of the posterior cerebral artery.RESULTSChoroidal collaterals were present in 21 patients (56.8%). The rebleeding rate was 13.1% per year in the collateral-positive group as compared with 1.3% in the negative group (p = 0.008, log-rank test). The adjusted hazard ratio for rebleeding in the collateral-positive group relative to the negative group remained statistically significant (HR 11.10, 95% CI 1.37-89.91). Radiographic assessment of the collateral-positive group revealed good correspondence between the distribution of collaterals and rebleeding sites.CONCLUSIONSResults of this study suggest that choroidal collaterals are a bleeding source with a high risk for hemorrhagic recurrence and a predictor of rebleeding in hemorrhagic moyamoya disease.

Association Between Champagne Bottle Neck Sign of Internal Carotid Artery and Ipsilateral Hemorrhagic Stroke in Patients with Moyamoya Disease

OBJECTIVE

To assess association between champagne bottle neck sign (CBNS) in carotid artery and intracranial hemorrhage in patients with moyamoya disease (MMD).

METHODS

This retrospective study included 76 consecutive patients with MMD without definite risk factors associated with intracranial hemorrhage who underwent preoperative angiography from January 2016 to December 2017. CBNS was defined as luminal diameter ratio of internal carotid artery/common carotid artery ≤0.5 on angiography. The right and left cerebral hemisphere in each patient was separately identified as hemorrhagic and nonhemorrhagic. Association between CBNS and intracranial hemorrhage was analyzed.

RESULTS

Of 76 patients with MMD, intracranial hemorrhage was found in 44 of 152 (28.9%) hemispheres, and 6.8% (3/44) had multiple events. Comparing carotid arteries without intracranial hemorrhage in ipsilateral hemispheres, patients with intracranial hemorrhage in the ipsilateral hemisphere had significantly smaller luminal diameter ratio of internal carotid artery/common carotid artery (0.49 ± 0.11 vs. 0.55 ± 0.12, P < 0.01) and higher prevalence of CBNS (63.7% vs. 41.7%, P = 0.01). Comparing hemispheres with intracranial hemorrhage, patients with ipsilateral carotid artery CBNS had significantly higher prevalence of hemorrhage in posterior territories than patients without CBNS (57.1% vs. 23.1%, P = 0.05). Logistic regression revealed that CBNS was significantly associated with ipsilateral intracranial hemorrhage before (odds ratio = 2.45; 95% confidence interval, 1.19-5.05; P = 0.02) and after (odds ratio = 3.43; 95% confidence interval, 1.50-7.87; P < 0.01) adjusting for female sex, lenticulostriate anastomosis, and choroidal anastomosis.

CONCLUSIONS

CBNS is significantly associated with intracranial hemorrhage in the ipsilateral hemisphere in patients with MMD, particularly intracranial hemorrhage in posterior territories.

Visualization and Classification of Deeply Seated Collateral Networks in Moyamoya Angiopathy with 7T MRI

BACKGROUND AND PURPOSE

Collateral networks in Moyamoya angiopathy have a complex angioarchitecture difficult to comprehend on conventional examinations. This study aimed to evaluate morphologic patterns and the delineation of deeply seated collateral networks using ultra-high-field MRA in comparison with conventional DSA.

MATERIALS AND METHODS

Fifteen white patients with Moyamoya angiopathy were investigated in this prospective trial. Sequences acquired at 7T were TOF-MRA with 0.22 × 0.22 × 0.41 mm³ resolution and MPRAGE with 0.7 × 0.7 × 0.7 mm³ resolution. Four raters evaluated the presence of deeply seated collateral networks and image quality in a consensus reading of DSA, TOF-MRA, and MPRAGE using a 5-point scale in axial source images and maximum intensity projections. Delineation of deeply seated collateral networks by different imaging modalities was compared by means of the McNemar test, whereas image quality was compared using the Wilcoxon signed-rank test.

RESULTS

The relevant deeply seated collateral networks were classified into 2 categories and 6 pathways. A total of 100 collateral networks were detected on DSA; 106, on TOF-MRA; and 73, on MPRAGE. Delineation of deeply seated collateral networks was comparable between TOF-MRA and DSA (P = .25); however, both were better than MPRAGE (P < .001).

CONCLUSIONS

This study demonstrates excellent delineation of 6 distinct deeply seated collateral network pathways in Moyamoya angiopathy in white adults using 7T TOF-MRA, comparable to DSA.

[Characteristics of collateral circulation in adult moyamoya disease based on modified Suzuki staging]

OBJECTIVE

To investigate the characteristics of collateral circulation in adult moyamoya disease (MMD).

METHODS

The clinical data were collected from all adult patients with MMD undergoing digital subtractive angiography (DSA) in our department from 2006 to 2016. Based on the imaging findings, the patients were divided into ischemia group and bleeding group. A double-blind analysis was conducted of the CT or magnetic resonance imaging findings and the severity of the disease was graded using the modified Suzuki score (mSS). We classified the anastomotic networks in MMD into the superficial meningeal type and deep parenchymal type. The superficial meningeal type was further classified into the leptomeningeal and the durocortical networks, and the deep parenchymal networks into subependymal networks and the inner striatal and inner thalamic networks.

RESULTS

No significant difference was found in the distribution of mSS scores between the hemorrhage group and the ischemic group (Χ²=5.812, v=5, P=0.325), but the posterior communicating artery and internal carotid artery diameter ratio (Pcom/ICA ratio) was significantly greater in the hemorrhage group (t=2.119, v=108, P=0.036). The Pcom/ICA ratio differed significantly among the groups with different mSS scores (f=8.924, P=0.00), higher in groups with mSS scores of 3, 4 and 5. The incidence of anterior choroidal artery dilation differed significantly between hemorrhage and ischemic groups (Χ²=11.79, P=0.001). The incidences of durocortical networks (Χ²=0.327, P=0.567) and subependymal networks (Χ²=0.011, P=0.917) were comparable between hemorrhage group and ischemic groups, but the incidence of leptomeningeal networks (P=0.018) and inner striatal and inner thalamic networks (Χ²=7.551, P=0.006) differed significantly between the two groups.

CONCLUSION

The collateral circulation vascular system is an important component of cerebral blood flow in MMD patients and varies from patient to patient. Patients with MMD exhibit increased Pcom/ICA ratio with abnormal expansion of the anterior choroidal artery, and the leptomeningeal networks and the inner striatal and inner thalamic networks are independent risk factors for cerebral hemorrhage.

Safety of Extracranial-Intracranial Arterial Bypass in the Treatment of Moyamoya Disease

OBJECTIVE

The purpose of this study is to uncover the controversial problems and review the safety of extracranial-intracranial arterial bypass (EC-IC arterial bypass) in the treatment of moyamoya disease.

METHODS

Published randomized controlled clinical trials were searched from PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of science without date or language limitations until September 2016. Meta-analysis was performed as recommended by the Cochrane Collaboration of trials.

RESULTS

In total 2 studies were included by strict inclusion and exclusion criteria. The result of meta-analysis showed that surgical group had a greater reduction of the primary end points (OR [0.35], 95% CI [0.15, 0.84], I = 0%) than that of the nonsurgical group.

CONCLUSION

Surgical therapy significantly lowers incidence of the primary end points (including rebleeding attack; completed stroke resulting in significant morbidity; mortality from any medical cause and requirement for bypass surgery fora nonsurgical patient as determined by a registered neurologist) compared with nonsurgical therapy. High-quality randomized controlled trials are required to confirm this conclusion.

Natural History and Risk Factor of Recurrent Hemorrhage in Hemorrhagic Adult Moyamoya Disease

BACKGROUND

Recurrent hemorrhage is a serious neurosurgical problem in adult moyamoya disease (MMD) patients.

OBJECTIVE

To find the natural history and risk factors of recurrent hemorrhage in cases of adult hemorrhagic MMD.

METHODS

One hundred seventy-six adult MMD patients presenting with hemorrhage were enrolled. Patients' medical records and radiological images were retrospectively reviewed. Clinical and radiological features of recurrent hemorrhage, and related risk factors were analyzed. Poor neurological outcome was defined as a score on the modified Rankin Scale of 4 to 6. The hemisphere in which the initial hemorrhage occurred was considered as the affected one. The mean follow-up duration was 83 months.

RESULTS

The overall estimated rate of recurrent hemorrhage was 16.9%/person (95% confidence interval, 11.3%-24.8%) at 5 years and 26.3%/person (95% confidence interval, 18.5%-36.4%) at 10 years after the initial episode of hemorrhage. The affected hemisphere showed a higher recurrent hemorrhagic rate (11.7% vs 8.3%/hemisphere at 5 years, P = .09) after conservative treatment. As a result of recurrent hemorrhages, the number of patients with poor neurological outcome increased (first episode: 13.8%, second: 37.5%, third: 40.0%, fourth: 100%). The presence of intraventricular hemorrhage ( P = .05, hazard ratio = 3.32) and bilateral MMD ( P = .05, hazard ratio = 4.15) had a marginal significance for recurrent hemorrhage. Eight ischemic strokes (4.5%) including 4 postoperative infarctions were identified, and all ischemic strokes were minor stroke.

CONCLUSION

During the follow-up period, recurrent hemorrhagic events continued to increase and deteriorated the patients' neurological conditions. The presence of intraventricular hemorrhage was a significant risk factor of recurrent hemorrhage.

Angiographic features of hemorrhagic moyamoya disease with high recurrence risk: a supplementary analysis of the Japan Adult Moyamoya Trial

OBJECTIVE

In this paper, the authors set out to identify the angiographic features of moyamoya disease with posterior hemorrhage, which is a strong predictor of rebleeding.

METHODS

This cross-sectional study used the data set of the Japan Adult Moyamoya Trial (clinical trial registration no.: C000000166 [www.umin.ac.jp/ctr/index.htm]). The panel designed the ancillary measurement of angiography at onset, classifying the collateral vessels into 3 subtypes: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. The association between each collateral and the hemorrhage site (anterior vs posterior) was assessed in the hemorrhagic hemisphere by using multivariate adjustment for potential confounders, including age, sex, and involvement of the posterior cerebral artery (PCA). The association was confirmed through topographical analysis of bleeding points.

RESULTS

Among the 80 participants, 75 hemorrhagic hemispheres of 75 patients were analyzed. Lenticulostriate anastomosis was detected in 21 (28.0%) hemorrhagic hemispheres, thalamic anastomosis in 22 (29.3%), and choroidal anastomosis in 35 (46.7%). Choroidal anastomosis was a factor associated with posterior hemorrhage (OR 2.77 [95% CI 1.08–7.10], p = 0.034) and remained statistically significant after the multivariate adjustment (OR 2.66 [95% CI 1.00–7.07], p = 0.049). PCA involvement was also associated with posterior hemorrhage in both univariate and multivariate analyses. Topographical analysis revealed good correspondence between bleeding points associated with positive choroidal anastomosis and the anatomical distribution of the choroidal arteries, including the thalamus and the wall of the atrium.

CONCLUSIONS

Choroidal anastomosis and PCA involvement are characteristic of posterior hemorrhage in moyamoya disease. Choroidal anastomosis might be considered a potential source of posterior hemorrhage at high risk of rebleeding.

Pathophysiological consideration of medullary streaks on FLAIR imaging in pediatric moyamoya disease

OBJECTIVE Medullary streaks detected on fluid-attenuated inversion recovery (FLAIR) imaging have been considered to be reflected ischemic regions in pediatric moyamoya disease. The purpose of this study was to evaluate these medullary streaks both clinically and radiologically and to discuss associated pathophysiological concerns. METHODS The authors retrospectively reviewed data from 14 consecutive pediatric patients with moyamoya disease treated between April 2009 and June 2016. Clinical and radiological features and postoperative imaging changes were analyzed. In 4 patients, hyperintense medullary streaks on FLAIR imaging (HMSF) at the level of the centrum semiovale were detected. RESULTS The HMSF were coincident with hyperintense medullary streaks on a T2-weighted image, though they were not completely coincident with the vasculature on either a T2*-weighted image or contrast-enhanced CT. Analysis revealed significantly higher values in terms of MR angiography scores, number of flow voids of the basal ganglia, and the presence of the medullary artery in the group with HMSF than in those without. In contrast, the presence of white matter damage was significantly less frequent in the HMSF group. All HMSF disappeared after surgery, and the mean apparent diffusion coefficient at the same level was significantly reduced postoperatively. CONCLUSIONS Although HMSF should be associated with collateral circulation in moyamoya disease, other factors may be involved, including stagnated cerebrospinal fluid or vasogenic edema that is relevant to the impaired state of the white matter. Findings in this study provide insight into the pathophysiological basis of the perivascular space in moyamoya disease.

Time-resolved 3D Rotational Angiography (4D DSA) of the Lenticulostriate Arteries: Display of Normal Anatomic Variants and Collaterals in Cases with Chronic Obstruction of the MCA

PURPOSE

The lenticulostriate arteries (LSA) and other perforators may play a role for collateral supply in cases with ischemia due to stenosis or occlusions of the middle cerebral artery (MCA). Purpose of this case series was to evaluate the potential of time-resolved 3D rotational angiography data sets (4D DSA) for detailed visualization of anatomic variants of LSA feeders and for display of local collaterals involving the LSA in cases with chronic MCA obstruction.

METHODS

Multiplanar and volume rendering reconstructions of 4D DSA data were computed in addition to standard postprocessing in 24 patients who had indications for 3D rotational angiography (3DRA) of the internal carotid artery (ICA) without pathologies of the ICA, middle cerebral artery (MCA) and anterior cerebral artery (ACA) main stems (n = 18) or with stenosis or chronic occlusion of the MCA (n = 6). For acquisition of 3DRA, we used a modified digital subtraction angiography (DSA) image acquisition protocol with an extended rotation angle of 260° and a prolonged scan time of 12 s on a Siemens Axiom Artis Zee biplane neuroangiography equipment. The 4D reconstructions of existing 3DRA data were computed on a dedicated workstation. Origin and course of LSA and other perforators were analyzed according to coronal multiplanar reconstructions (MPRs) with slice thicknesses between 6 and 28 mm.

RESULTS

In all cases 4D reconstructions of the LSA were technically feasible and evaluable. As expected, origin and course of LSA showed a wide range of variations: The most common pattern was a common trunk dividing into multiple ascending branches originating from the proximal M1 (n = 5) or the proximal A1 segment (n = 4). Alternatively, 8 patients showed several individual branches that directly originated from the proximal M1 segment of the MCA and occasionally from the A1 segment of the ACA. In patients with M1 stenosis or occlusion, 4 out of 6 cases had local collaterals with involvement of proximal LSA trunks and a network parallel to the obstructed vessel segment. The 4D reconstructions were found to be equivalent (n = 16) or superior to 3D reconstructions (n = 8).

CONCLUSION

The 4D DSA reconstructions provide a reliable display of normal LSA variants and connections to local collateral networks in cases with chronic MCA obstruction. The possibility to select a correct angiographic phase is advantageous compared to 3D DSA.

Reversible striatal hypermetabolism in chorea associated with moyamoya disease: a report of two cases

BACKGROUND

The pathophysiological mechanism of chorea as a presentation of pediatric moyamoya disease remains unknown, although ischemia is suspected as a likely cause. The authors describe two cases of pediatric moyamoya disease, both of which presented with hemichorea in the stable phase after successful bypass surgery.

CLINICAL PRESENTATION

Cerebral blood flow was almost normal in one case and decreased in the basal ganglia and watershed area in the other case due to infarcts occurring before surgery. In both cases, ¹⁸F-fluorodeoxyglucose positron emission tomography revealed elevated glucose metabolism in the corresponding side of the striatum, which reverted to normal after recovery from chorea. Magnetic resonance angiography revealed a dilated and extended lenticulostriate artery at the exact site of the hypermetabolic lesion.

Assessment of the cortical artery using computed tomography angiography for bypass surgery in moyamoya disease

Computed tomography angiography (CTA) is often used to assess the vascular status in moyamoya disease. The purpose of the study is to identify the characteristics of cortical arteries (M4) of moyamoya disease on CTA; the clinical significance of which is also discussed. A total of 38 hemispheric sides of 27 patients with moyamoya disease were included in this study. The number of M4 was visualized on CTA using cortical surface imaging and compared between the moyamoya disease group and the non-moyamoya disease group or the control group. Then, the clinical and radiological factors associated with the number of M4, the distribution of M4, and collateral circulation were examined. The number of M4 was lower in the moyamoya disease group than in the non-moyamoya disease group and in the control group (p < 0.05). There are few predictive clinical factors of the number of M4 except male sex. The prefrontal artery, precentral artery, central artery, and angular artery had a significantly higher prevalence in moyamoya disease (p < 0.05). The durocortical and periventricular anastomosis had a significantly higher prevalence in moyamoya disease (p < 0.05). The prevalence and distribution pattern of cortical arteries in moyamoya disease differed from that of the non-moyamoya disease group, and the distribution patterns of M4 might be influenced by collateral circulation. It is thus essential to recognize M4 to assess the recipient artery so as to ensure superficial temporal artery-middle cerebral artery bypass.

Periventricular anastomosis in moyamoya disease: detecting fragile collateral vessels with MR angiography

OBJECT

The authors’ aim in this paper was to determine whether periventricular anastomosis, a novel term for the abnormal collateral vessels typical of moyamoya disease, is reliably measured with MR angiography and is associated with intracranial hemorrhage.

METHODS

This cross-sectional study sampled consecutive patients with moyamoya disease or moyamoya syndrome at a single institution. Periventricular anastomoses were detected using MR angiography images reformatted as sliding-thin-slab maximum-intensity-projection coronal images and were scored according to 3 subtypes: lenticulostriate, thalamic, and choroidal types. The association between periventricular anastomosis and hemorrhagic presentation at onset was evaluated using multivariate analyses.

RESULTS

Of 136 eligible patients, 122 were analyzed. Eighteen (14.8%) patients presented with intracranial hemorrhage with neurological symptoms at onset. Intra- and interrater agreement for rating of the periventricular anastomosis score was good (κw = 0.65 and 0.70, respectively). The prevalence of hemorrhagic presentation increased with the periventricular anastomosis score: 2.8% for Score 0, 8.8% for Score 1, 18.9% for Score 2, and 46.7% for Score 3 (p < 0.01 for trend). Univariate analysis revealed that age (p = 0.02) and periventricular anastomosis score (p < 0.01) were factors tentatively associated with hemorrhagic presentation. The score remained statistically significant after adjustment for age (OR 3.38 [95% CI 1.84–7.00]).

CONCLUSIONS

The results suggest that periventricular anastomosis detected with MR angiography can be scored with good intra- and interrater reliability and is associated with hemorrhagic presentation at onset in moyamoya disease. The clinical utility of periventricular anastomosis as a predictor for hemorrhage should be validated in further prospective studies.

Significance of the Hemorrhagic Site for Recurrent Bleeding: Prespecified Analysis in the Japan Adult Moyamoya Trial

BACKGROUND AND PURPOSE

The primary results of the Japan Adult Moyamoya Trial revealed the statistically marginal superiority of bypass surgery over medical treatment alone in preventing rebleeding in moyamoya disease. The purpose of this analysis is to test the prespecified subgroup hypothesis that the natural course and surgical effects vary depending on the hemorrhagic site at onset.

METHODS

The hemorrhagic site, classified as either anterior or posterior, was the only stratifying variable for randomization. Statistical analyses were focused on the assessment of effect modification according to the hemorrhagic site and were based on tests of interaction.

RESULTS

Of 42 surgically treated patients, 24 were classified as anterior hemorrhage and 18 as posterior hemorrhage; of 38 medically treated patients, 21 were classified as anterior and 17 as posterior. The hazard ratio of the primary end points (all adverse events) for the surgical group relative to the nonsurgical group was 0.07 (95% confidence interval, 0.01-0.55) for the posterior group, as compared with 1.62 (95% confidence interval, 0.39-6.79) for the anterior group (P=0.013 for interaction). Analysis within the nonsurgical group revealed that the incidence of the primary end point was significantly higher in the posterior group than in the anterior group (17.1% per year versus 3.0% per year; hazard ratio, 5.83; 95% confidence interval, 1.60-21.27).

CONCLUSIONS

Careful interpretation of the results suggests that patients with posterior hemorrhage are at higher risk of rebleeding and accrue greater benefit from surgery, subject to verification in further studies.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/ctr/index.htm. Unique identifier: C000000166.