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

RNF213 Mutation Associated with the Progression from Middle Cerebral Artery Steno-Occlusive Disease to Moyamoya Disease

Middle cerebral artery steno-occlusive disease (MCAD) has been recognized as a different clinical entity from moyamoya disease (MMD). Although MCAD can progress to MMD, the extent to which patients actually progress and the risk factors for this progression have not been fully elucidated. We retrospectively reviewed patients with MCAD who underwent RNF213 genotyping. Demographic features, RNF213 p.R4810K mutation, medical history, and longitudinal changes in angiography were analyzed. Sixty patients with 81 affected hemispheres were enrolled. During the follow-up period, 17 patients developed MMD, and the RNF213 p.R4810K mutation was the only factor significantly associated with progression to MMD (odds ratio, 16.1; 95% CI, 2.13-731; P = 0.001). The log-rank test demonstrated that patients with the mutation had a higher risk of progression to MMD (P = 0.007), stenosis progression (P = 0.010), and symptomatic cerebral infarction or hemorrhage (P = 0.026). In Cox regression analysis the p.R4810K mutation remained a significant factor after adjusting for age group (childhood or adult onset) at diagnosis (hazard ratio, 8.42; 95% CI, 1.10-64.4). Hemisphere-based analysis also showed that the mutation was associated with a higher risk of progression to the MMD hemisphere (P = 0.002), stenosis progression (P = 0.005), and cerebral infarction or hemorrhage (P = 0.012). The RNF213 p.R4810K mutation was identified as a risk factor for progression from MCAD to MMD. Genotyping for this mutation may contribute to risk stratification in MCAD.

"Transcallosal" periventricular anastomosis in moyamoya disease: the fourth periventricular anastomosis and a potential predictor of hemorrhage

OBJECTIVES

Choroidal anastomosis is a risk factor for hemorrhage in moyamoya disease. One variant of choroidal anastomosis, "transcallosal anastomosis," originates from the medial posterior choroidal artery, and penetrates the corpus callosum to reconstruct the pericallosal artery. We aimed to investigate the prevalence and the bleeding rate of transcallosal anastomosis using sliding thin-slab maximum intensity projection reformatted from magnetic resonance angiography (MRA).

MATERIALS AND METHODS

This study included 222 patients. We defined transcallosal anastomosis grades (0-2) and the stenosis of the anterior (ACA, 0-2), middle (MCA, 1-3), and posterior cerebral artery (PCA, 0-2) by MRA scores, independently by two coauthors.

RESULTS

Grade-2 transcallosal anastomosis was detected in 21 patients (9.5 %). There were no correlations of the incidence of transcallosal anastomosis with previous bypass surgery (P = 0.23). Multivariate analysis revealed a significantly higher incidence in hemorrhagic onset and younger age (odds ratio [OR] 3.77, and 0.97). Transcallosal anastomosis had statistically significant correlation with ACA and PCA scores (P = 0.01 and 0.03), but not with MCA scores (P = 0.1). In multivariate analysis, ACA scores 1 and 2 were significantly higher (OR, 15.44 and 11.17), and PCA score 1 was also higher (OR, 3.07), but PCA score 2 was not. Interrater agreement for judgment of transcallosal anastomosis grade was strong (κ = 0.89). Two patients with Grade-2 transcallosal anastomosis had late hemorrhage in the corpus callosum (bleeding rate: 2.5 % per year).

CONCLUSIONS

Transcallosal anastomosis may be associated with both advanced ACA and moderate PCA stenosis, and cause hemorrhage at the corpus callosum.

Recurrent hemorrhage risk associated with medial target medullary artery anastomosis from the periventricular collateral vessel in adult patients with moyamoya disease

BACKGROUND

Although the association between periventricular target collateral anastomosis and recurrent ipsilateral hemorrhage has been evaluated in adult patients with moyamoya disease (MMD), no studies have investigated the relationship between target anastomotic territory and recurrent ipsilateral hemorrhage. The goal of this study was to assess this association.

METHODS

Consecutive adult MMD patients who had experienced initial intracranial hemorrhage and undergone conservative treatment were included. Two readers assessed angiographic results to identify the target anastomotic territory (medial medullary artery, lateral medullary artery, multiple medullary arteries, or nonmedullary artery) responsible for the hemorrhage. Cox proportional hazard regression models were used to estimate the risk of recurrent hemorrhage.

RESULTS

In the 36 hemispheres with initial hemorrhage, the target anastomotic territory was in the anastomotic territory of the medial medullary artery in 10 (27.8%), lateral medullary artery in 15 (41.7%), multiple medullary arteries in 2 (5.6%), and a nonmedullary artery in 9 (25.0%) hemispheres. During 45.1 ± 40.0 months of follow-up, recurrent ipsilateral hemorrhage occurred in 44.4% (16/36) of hemispheres. The target anastomotic territories responsible for the recurrent event were in the anastomotic territory of the medial medullary artery in 9 (56.3%) hemispheres, lateral medullary artery in 6 (37.5%) hemispheres, and multiple medullary arteries in 1 (6.3%) hemisphere. The anastomotic territory of the medial medullary artery was associated with recurrent hemorrhage before (HR = 2.94; 95% CI, 1.07-8.08; p = 0.037) and after (HR = 6.65; 95% CI, 1.32-33.60; p = 0.022) adjustments were made for confounding factors.

CONCLUSIONS

The incidence of recurrent ipsilateral hemorrhage varies with the target anastomotic territory in adult patients with MMD. Medial target medullary artery anastomosis is a significant risk factor for recurrent ipsilateral hemorrhage.

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.

Different subtypes of collateral vessels in hemorrhagic moyamoya disease with p.R4810K variant

Background

The aim of this study was to investigate the hemorrhgic sites and collateral vessels in hemorrhagic MMD with the p.R4810K variant.

Methods

Hemorrhage sites were classified as either anterior or posterior. Collateral vessels were classified into three subtypes according to origin: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. Hemorrhage sites and collateral vessels were compared between patients with wild-type p.R4810K variant (GG) and patients with heterozygous p.R4810K variant (GA) after 1:1 propensity score matching.

Results

A total of 130 hemorrhagic MMD patients were included in present study, 21 pairs (42 hemorrhagic hemispheres) were obtained after 1:1 propensity score. In GA group, 16 hemispheres (76.2%) presented anterior hemorrhage, and 5 hemispheres (23.8%) presented with posterior hemorrhage. In GG group, 13 hemispheres (61.9%) presented anterior hemorrhage, and 8 hemispheres (38.1%) presented with posterior hemorrhage. No significant differences were found in hemorrhagic sites between two matched groups (P > 0.05). Of 21 hemispheres in GA group, 10 (47.6%) exhibited lenticulostriate anastomosis, 6 (28.6%) thalamic anastomosis, and 6 (28.6%) choroidal anastomosis. Of 21 hemispheres in GG group, 3 (14.3%) exhibited lenticulostriate anastomosis, 5 (23.8%) thalamic anastomosis, and 9 (42.9%) choroidal anastomosis. There was significant difference in lenticulostriate anastomosis between two matched groups (P = 0.045). After adjustment the age, sex, and PCA involvement, we found that lenticulostriate anastomosis was associated with p.R4810K variant (OR, 5.995; 95% CI, 1.296–27.737; P = 0.022).

Conclusion

Lenticulostriate anastomosis might be associated with p.R4810K variant. Whereas hemorrhagic sites, thalamic anastomosis, and choroidal anastomosis might not be associted withp.R4810K variant.

Neuroendoscope-Assisted Aneurysm Trapping for Ruptured Intraventricular Aneurysms in Moyamoya Disease Patients

BACKGROUND

Intracranial hematomas associated with abnormal collateral vessels are observed in certain populations of adult patients with moyamoya disease (MMD). Of these, intraventricular hematomas resulting from rupture of intraventricular aneurysms, which are formed along an abnormal peripheral choroidal artery, are sometimes detected and could be severe. No appropriate treatment option for these ruptured aneurysms has been well established to date. Therefore in this report, we describe the case of an MMD patient with an intraventricular hematoma resulting from a ruptured intraventricular aneurysm arising along the abnormal collateral vessels near the lateral ventricular wall, which was successfully treated using a neuroendoscope.

CASE DESCRIPTION

A 53-year-old female with MMD presented with an intraventricular hematoma. The patient had already undergone bilateral, combined direct/indirect cerebral revascularization surgery 3 years prior. Digital subtraction angiography revealed an aneurysm along the abnormal collateral choroidal artery near the posterior horn of the left lateral ventricle. A neuroendoscopic technique was applied to approach and treat the aneurysm; this was performed successfully by trapping using aneurysm clips without intraoperative or postoperative complications.

CONCLUSIONS

Neuroendoscopic aneurysm trapping using aneurysm clips is a treatment option for an intraventricular aneurysm that causes an intraventricular hematoma in patients with MMD. This technique is minimally invasive and offers good visibility of the surgical field.

Location-based treatment of intracranial aneurysms in moyamoya disease: a systematic review and descriptive analysis

We conducted a systematic review of the literature to evaluate the efficacy of various treatment modalities for intracranial aneurysms (IA) in patients with moyamoya disease (MMD) based on anatomical location of IA. A comprehensive review of studies documenting single cases or series of MMD patients with concomitant IA was conducted. Aneurysms were classified into two primary anatomical categories: those of the Circle of Willis (CoW) and those of peripheral "moyamoya" collateral vessels. Conservative, endovascular, and open surgical treatment modalities and their outcomes between each anatomical subgroup were descriptively compared. A total of 124 studies consisting of 275 patients with 313 IA were included. Of all IA, 59.6% were located on CoW vessels, 33.7% on peripheral vessels, and 6.7% in "other" locations. Of all CoW IA, 87.2% treated with endovascular techniques had no or minimal deficit at follow-up as compared with 56.7% of those treated with open surgery. Ninety-five percent of patients with peripheral aneurysms treated with endovascular therapy had no or minimal deficit, in contrast to open surgery (69.6%). Of peripheral IA treated conservatively with or without revascularization, 65.7% had spontaneous resolution as compared with 12.0% IA of the CoW. Our results support the use of endovascular techniques for direct treatment of both CoW and peripheral IA. Aneurysms of peripheral vessels respond well to indirect treatment through surgical revascularization as opposed to CoW aneurysms. The quality of evidence is limited due to heterogeneity of included studies and IA management in MMD patients should be considered in a case-specific manne.

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.

Identification of the Bleeding Point in Hemorrhagic Moyamoya Disease Using Fusion Images of Susceptibility-Weighted Imaging and Time-of-Flight MRA

BACKGROUND AND PURPOSE

The location of intracerebral hemorrhage in Moyamoya disease is a prognostic factor for rebleeding and the degree of preventive effects obtainable with bypass surgery. We evaluated whether the bleeding point and responsible vessel were detectable using fusion images of SWI and time-of-flight MRA performed during chronic-phase hemorrhage.

MATERIALS AND METHODS

We retrospectively enrolled 42 patients with hemorrhagic Moyamoya disease (48 hemorrhagic events). Fusion images of SWI and MRA were made using workstations, and we defined the bleeding point as the point at which the signal of an abnormally extended artery on MRA overlapped the hypointense area on SWI. Two independent raters identified the bleeding point, and classified the location and responsible vessels.

RESULTS

The bleeding point was detectable at a frequency of 79.2% by rater 1. Agreement for the presence of a bleeding point was high (interrater κ = 0.83; 95% CI, 0.65-1; intrarater κ = 0.86; 95% CI, 0.68-1). The frequency of a periventricular location of the bleeding point was 65.8% by rater 1, and agreement on the location was again high (interrater κ = 0.92; 95% CI, 0.82-1; intrarater κ = 0.85; 95% CI, 0.72-0.99). The choroidal artery was the most frequent responsible vessel (57.9% by rater 1), and agreement on the responsible vessel was high (interrater κ = 0.84; 95% CI, 0.69-1; intrarater κ = 0.90; 95% CI, 0.78-1).

CONCLUSIONS

Detection of the bleeding point in hemorrhagic Moyamoya disease using SWI and MRA fusion images offers highly reproducible results.