Pathogenesis of aneurysms on major vessels in moyamoya disease and management outcome

Outcomes and Complications of Endovascular Treatment in Patients with Moyamoya Disease: A Systematic Review

OBJECTIVE

The mainstream approach for preventing cerebrovascular events in hemorrhagic or ischemic moyamoya disease (MMD) is surgical revascularization, and the indications for endovascular treatment (EVT) for MMD are limited. This systematic review aimed to evaluate the outcomes and complications associated with EVT in patients with MMD.

METHODS

A comprehensive search was conducted in June 2024 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in the PubMed, Cochrane Library, and Web of Science databases, for patients with MMD treated with EVT.

RESULTS

Seventy-eight studies including 287 patients treated with EVT were identified. Target diseases included 255 aneurysms, 23 intracranial arterial stenoses, 4 extracranial arterial stenoses, 3 large vessel occlusioniks, and 2 dural arteriovenous fistulas. The outcomes of EVT for aneurysms in patients with MMD were comparable to those in patients without MMD. A significant association was observed between distal aneurysms and treatment failure (P < 0.001). The risk of rerupture in the group that received conservative treatment for ruptured aneurysms was higher than that in the group that received radical treatment (P < 0.001). EVT for intracranial arterial stenosis carried a higher risk of recurrence, while that risk did not differ between the angioplasty and stent placement groups, with a median recurrence-free survival of 4 and 3.5 months, respectively (P = 0.668).

CONCLUSIONS

For the patients with MMD, EVT of distal aneurysms would likely be unsuccessful because of the access difficulties. Furthermore, EVT for intracranial arterial stenosis often results in unsatisfactory treatment and has limited indications owing to the risk of complications.

Classification and treatment strategy for Moyamoya disease-related aneurysms

BACKGROUND

Moyamoya disease (MMD) is a cerebrovascular disorder characterized by progressive unilateral or bilateral stenosis of the distal internal carotid artery. As hemodynamic features in MMD patients alter, the comorbidity of intracranial aneurysm (IA) is sometimes observed clinically. We aim to investigate clinical characteristics and therapeutic strategies for the comorbidity of Moyamoya disease with intracranial aneurysms (MMD-IA).

METHODS

A total of 13 MMD-IA patients were recruited in this study and were manifested to be intracranial hemorrhage. We reviewed the surgical technique notes for all patients.

RESULTS

According to the locations of an aneurysm, MMD-IA could be divided into several categories: (1) MMD-IA at a circle of Willis-aneurysms usually located at the trunk of Willis circle; (2) MMD-IA at collateral anastomosis-aneurysms located at the distal end of collateral anastomosis; and (3) MMA-IA at basal ganglia region. In this report, aneurysms in 10 patients located at Willis circle, 2 at the pericallosal artery, and 1 at the basal ganglia region. Among them, endovascular embolism was performed among 5 patients. Aneurysm clipping was conducted among 7 patients. A patient with an aneurysm at the basal ganglia region just accepted revascularization treatment. All the treatments were successful. Follow-up studies, ranging from 6 to 24 months, demonstrated all patients received satisfactory curative effects.

CONCLUSION

Diverse clinical presentations could be observed among MMD-IA patients. Individualized neurosurgical treatments should be chosen according to the locations of the aneurysm.

Natural course and risk factors of moyamoya disease with unruptured intracranial aneurysm

Background and objective

The natural course and risk factors of moyamoya disease (MMD) associated with unruptured intracranial aneurysms involving stenosed parental arteries are scarcely studied. This study aimed to elucidate the natural course of MMD and its associated risk factors in patients with MMD with unruptured aneurysms.

Methods

Between September 2006 and October 2021, patients with MMD with intracranial aneurysms at our center were examined. The natural course, clinical features, radiological features, and follow-up outcomes after revascularization were analyzed.

Results

This study included 42 patients with MMD with intracranial aneurysms (42 aneurysms). The age distribution of MMD cases ranged from 6 to 69 years, with four children (9.5%) and 38 adults (90.5%). A total of 17 male and 25 female subjects were included (male-to-female ratio: 1:1.47). The first symptom was cerebral ischemia in 28 cases, and cerebral hemorrhage occurred in 14 cases. There were 35 trunk aneurysms and seven peripheral aneurysms. There were 34 small aneurysms (<5 mm) and eight medium aneurysms (5-15 mm). During the average clinical follow-up period of 37.90 ± 32.53 months, there was no rupture or bleeding from aneurysms. Twenty-seven of these patients underwent a cerebral angiography review, in which it was found that one aneurysm had enlarged, 16 had remained unchanged, and 10 had shrunk or disappeared. A correlation exists between the reduction or disappearance of aneurysms and the progression of the Suzuki stages of MMD (P = 0.015). Nineteen patients underwent EDAS on the aneurysm side, and nine aneurysms disappeared, while eight patients did not undergo EDAS on the aneurysm side and one aneurysm disappeared.

Conclusion

The risk of rupture and hemorrhage of unruptured intracranial aneurysms is low when the parent artery already has stenotic lesions, thus, direct intervention may not be necessary for such aneurysms. The progression of the Suzuki stage of moyamoya disease may play a role in the shrinkage or disappearance of the aneurysms, thereby decreasing the risk of rupture and hemorrhage. Encephaloduroarteriosynangiosis (EDAS) surgery may also help promote atrophy or even the disappearance of the aneurysm, thus reducing the risk of further rupture and bleeding.

Safety and effects of endovascular treatment of basilar tip aneurysms in patients with moyamoya diseases

The effect and safety of endovascular treatment of basilar tip aneurysms associated with moyamoya disease are unknown. This study was to investigate the safety and effect of endovascular treatment of basilar tip aneurysms associated with moyamoya disease. Patients with moyamoya disease concurrent with basilar tip aneurysms were retrospectively enrolled and treated with endovascular embolization. The clinical and angiographic data were analyzed. Thirty patients with a basilar tip aneurysm were enrolled, including 8 (26.67%) male and 22 (73.33%) female patients aged 38 to 72 years (mean 54.4 ± 8.15). Endovascular treatment was successfully performed in 29 (96.67%) patients but failed in 1 (3.33%). Immediately after embolization, aneurysm occlusion degree was Raymond-Roy grade I in 26 (89.66%), grade II in 2 (6.90%), and grade III in 1 (3.45%). Intraprocedural complications occurred in 2 (10%) patients, including aneurysm rupture in 1 (3.33%), leading to death of the patient, and stent thrombosis in 2 (6.67%) which was successfully treated with thrombolysis. At discharge, good clinical outcome (modified Rankin Scale 0-2) was achieved in 29 (96.67%) and death in 1 (3.03%). Follow-up was performed 6 to 26 months (median 15) in 27 (93.1%) patients. Aneurysm occlusion degree was Raymond-Roy grade I in 21 (77.78%) patients, grade II in 4 (14.81%), and grade III in 2 (7.41%), not significantly (P = .67) different from those immediately after embolization. Aneurysm recurrence was found in 4 patients (14.81%). The clinical outcome was modified Rankin Scale 0 to 2 in all 27 patients, not significantly different from that at discharge. Endovascular embolization can be performed safely and effectively for basilar tip aneurysms associated with moyamoya disease even though more advanced embolization techniques are necessary.

Endovascular treatment of main trunk aneurysms in the residual anterior circulation in moyamoya disease

BACKGROUND

Main trunk aneurysms in the residual anterior circulation in moyamoya disease (MMD) are uncommon, and in such cases, endovascular treatment (EVT) is a good choice.

MATERIALS AND METHODS

A retrospective study was performed on 35 consecutive patients admitted to our hospital who were diagnosed with MMD and main trunk aneurysms in the residual anterior circulation and were treated with EVT.

RESULT

The 35 patients were aged 38-77 years (mean, 56.1 ± 8.8 years) and included 17 females (48.6%, 17/35). There were 29 cases (82.9%, 29/35) of hemorrhagic onset. In 35 patients, there were 38 main trunk aneurysms in the residual anterior circulation. Thirty-eight aneurysms underwent coiling; among them, coiling with stent assistance was used in the treatment of 6 (15.8%, 6/38) aneurysms. The immediate modified Raymond-Roy classification (MRRC) was grade I for all aneurysms. Among 35 patients, intraoperative bleeding occurred in 2 (5.7%, 2/35) patients. After EVT, immediate hemiplegia occurred in 4 (11.4%, 4/35) patients, and immediate coma occurred in 1 (2.9%, 1/35) patient. At discharge, in 35 patients, the Glasgow Outcome Scale (GOS) was five in 88.6% of them. Of 35 patients, 68.6% had follow-up data, GOS was five in 87.5% patients, and the MRRC was grade I for all aneurysms in the follow-up angiography.

CONCLUSION

For main trunk aneurysms in the residual anterior circulation in MMD, although EVT was accompanied by potential ischemic and hemorrhagic complications, which should be considered, EVT can still offer an acceptable prognosis in more than 85% of patients.

Clinical Features and Treatment Outcomes of Cerebral Arteriovenous Malformation Associated With Moyamoya Disease

BACKGROUND

Cerebral arteriovenous malformation (AVM) can rarely occur in conjunction with moyamoya disease (MMD). There is still no consensus on how to treat AVM when accompanied by MMD. In this study, we assessed the clinical features and suggested appropriate management when AVM was combined with MMD.

METHODS

From August 1994 to December 2020, 7 out of 4004 patients with MMD were found to have AVM. The Karnofsky Performance Scale (KPS) was used to evaluate the clinical outcomes of AVM and MMD. KPS greater than 80 was classified as a good outcome. In addition, the radiologic outcomes of the patients were evaluated.

RESULTS

The incidence of AVM with MMD was 1.7 per 1000 persons. Five patients underwent bypass surgery for MMD, and 5 patients underwent Gamma Knife surgery (GKS) for concurrent AVM. Postoperative perfusion magnetic resonance imaging and brain single photon emission computerized tomography showed improved cerebral hemodynamics in 4 out of 7 territories. Postoperative cerebral angiography showed good revascularization in 4 out of 8 territories. After GKS, 4 patients showed complete obliteration, and 1 patient showed a significantly decreased AVM size. Six patients showed favorable clinical outcomes (KPS 80-100), and 1 patient with delayed GKS for AVM had a poor outcome (KPS 20) due to AVM rupture.

CONCLUSIONS

In this study, AVM tended to occur where the angiographic stage of MMD was higher. When AVM is combined with MMD, MMD bypass surgery is recommended based on symptoms and cerebral perfusion status. For AVM, less invasive but effective treatments, such as GKS, should be implemented as soon as possible.

The angiographic presentation of European Moyamoya angiopathy

Background and purpose

Little is known about the angiographic presentation of Moyamoya angiopathy (MMA) in non-Asian patients.

Methods

Conventional cerebral angiograms from 155 Caucasian patients diagnosed as MMA were analyzed with respect to extracranial champagne bottle neck sign, Suzuki stages, collateral status, as well as presence of aneurysms and posterior cerebral artery stenosis.

Results

In 84 of 155 angiograms, the extracranial carotid artery was visualized, in 65 of them (77.4%), a champagne bottle neck sign was noted. Of the 278 analyzable hemispheres, 13.7%,11.2%, 37.8%, 27.3%, 8.6%, and 1.4% were classified as Suzuki stage I, stage II, stage III, stage IV, stage V, and stage VI, respectively. Among 280 hemispheres, in 53 hemispheres (18.9%) isolated basal collaterals (pathway I) and in 104 hemispheres (37.1%) choroidal and pericallosal collaterals (including basal collaterals, pathway II) were found. In 74 hemispheres (26.4%) ethmoidal collaterals (pathways III), and in 17 hemispheres (6.1%) vault collaterals were visualized. Patients with higher Suzuki stages IV–VI (p = 0.008) and ethmoidal collaterals (p < 0.001) suffered more often from cerebral hemorrhage. Transient ischemic attacks occurred more frequently in patients with Suzuki stage I to III (p < 0.001). In 10 of 155 patients (6.5%), the angiogram revealed a cerebral aneurysm. In 13 patients (8.4%), a stenotic P1 segment of the posterior cerebral artery was found.

Conclusions

This is so far the largest observational study about angiography in Caucasian European MMA patients. A comparison with Asian data indicates similarity of disease in Caucasian and Asian patients.

Clinical features of and risk factors for intracranial aneurysms associated with moyamoya disease

BACKGROUND

The clinical features of aneurysms associated with moyamoya disease (MMD) and risk factors for the formation and rupture of aneurysms are not well defined.

AIMS

In this study, we retrospectively analyzed clinical data of MMD patients and examined the potential risk factors for the formation and rupture of aneurysms in these patients.

METHODS

The medical records of all MMD patients in our hospital from April 2012 to May 2019 were reviewed. The logistic regression analysis was used to determine the independent association between various potential risk factors and the presence or rupture of intracranial aneurysms in MMD patients.

RESULTS

Of 2230 MMD patients, 182 (8.2%) cases had intracranial aneurysms. The mean age of onset in patients with aneurysms was 47.2 years, which was significantly higher when compared with those without aneurysms (p < 0.001). In logistic regression analysis, age of onset remained significantly associated with the presence of intracranial aneurysms, while female gender, hypertension, diabetes mellitus, and coronary artery disease were not. Besides, intracranial aneurysms were significantly associated with intracranial hemorrhage in MMD patients (odds ratio [OR] = 5.19; 95% confidence interval [CI], 3.80-7.09). About 60% aneurysms >5 mm in size, and 62.1% aneurysms with irregularly shaped morphology were ruptured. Aneurysms located in basilar tip, collateral or moyamoya vessels were more likely to present with rupture.

CONCLUSIONS

Age was an important risk factor for intracranial aneurysms formation in MMD patients. Aneurysms increased the risk of intracerebral hemorrhage in MMD patients, and their ruptures were correlated with aneurysms size, location, and morphology.

Clinical and Hemodynamic Features in Moyamoya Disease with Intracranial Aneurysms

OBJECTIVE

Intracranial aneurysms (IAs) are occasionally associated with moyamoya disease (MMD). The purpose of this study was to elucidate differences between patients with MMD with and without IAs and differences between patients with IAs at different locations.

METHODS

Between May 2012 and December 2017, consecutive patients with MMD were enrolled in a retrospective single-center study. IAs were classified as circle of Willis (CoW) or peripheral aneurysms according to the anatomic location. Clinical characteristics and hemodynamic parameters were collected and analyzed. A hemispheric analysis was performed for Suzuki stage and computed tomography perfusion parameters.

RESULTS

The study included 31 patients with MMD with IAs and 279 patients with MMD without IAs. The patients with IAs had more severe neurological dysfunction, more advanced Suzuki stage, and less hemodynamic dysfunction than the patients without IAs (P < 0.05). Of patients with MMD with IAs, 17 had CoW aneurysms, and 13 had peripheral aneurysms. Patients with CoW aneurysms were older and had more advanced Suzuki stage than patients with peripheral aneurysms (P < 0.05).

CONCLUSIONS

Patients with MMD with IAs had different clinical and hemodynamic features compared with patients with MMD without IAs. CoW aneurysms and peripheral aneurysms may occur at different stages of MMD, which may explain their differences in anatomical location, type of hemorrhage, and treatment strategy.

Multiple flow-related intracranial aneurysms in the setting of contralateral carotid occlusion: Coincidence or association?

The prevalence of intracranial aneurysms (IAs) is higher in patients with internal carotid artery (ICA) stenosis, likely due to alterations in intracranial hemodynamics. Severe stenosis or occlusion of one ICA may result in increased demand and altered hemodynamics in the contralateral ICA, thus increasing the risk of contralateral IA formation. In this article, we discuss a relevant case and a comprehensive literature review as it pertains to the association of ICA stenosis and IA. Our patient was a 50-year-old female with a chronic asymptomatic right ICA occlusion who presented with diffuse subarachnoid hemorrhage. Emergent angiography revealed left-sided A1-A2 junction, paraclinoid, left middle cerebral artery (MCA) bifurcation, and left anterior temporal artery aneurysms. Brisk filling of the right anterior circulation through the anterior communicating artery was also identified, signifying increased demand on the left ICA circulation. Complete obliteration of all aneurysms was achieved with coil embolization and clipping. For our literature review, we searched the PubMed and EMBASE databases for case reports and case series, as well as references in previously published review articles that described patients with concurrent aneurysms and ICA stenosis. We selected articles that provided adequate information about the case presentations to compare aneurysm and patient characteristics. Our review revealed a higher number of patients with multiple aneurysms contralateral (25%) to rather than ipsilateral to (6%), the ICA stenosis. We discuss the pathogenesis and management of multiple flow-related IA in the context of the existing literature related to concurrent ICA stenosis and IA.

Clinical Features and Outcomes of Intracranial Aneurysm Associated with Moyamoya Disease

Background and Purpose

Moyamoya disease (MMD) is a rare form of intracranial stenoocclusive disease that can be associated with intracranial aneurysms. We evaluated the clinical features and outcomes of MMD-associated aneurysms while focusing on their locations.

Methods

Between January 1998 and December 2018 there were 1,302 adult and pediatric patients diagnosed as MMD at a single institution. These patients included 38 with 44 MMD-associated aneurysms. The MMD-associated aneurysms were classified into two groups based on their locations: major-artery aneurysms and non-major-artery aneurysms. The clinical and radiological data for patients with MMD-associated aneurysms were reviewed retrospectively.

Results

The 44 MMD-associated aneurysms comprised 28 in major arteries and 16 in nonmajor arteries. All of the major-artery aneurysms were initially unruptured lesions, and follow-up angiography showed that 23 (82.1%) had an improved or stable status and 5 (17.9%) had a worse status. The non-major-artery aneurysms comprised 10 ruptured and 6 unruptured lesions, and follow-up angiography showed that 11 (68.8%) had improved or were stable and 5 (31.2%) had worsened. At the latest follow-up, there were four cases of unfavorable outcome: two initial hemorrhagic insults, one treatment-related morbidity, and one repeated-hemorrhage case.

Conclusions

MMD-associated aneurysms occurred in 3.3% of the MMD cohort in this study, of which 63.6% were major-artery aneurysms and 36.4% were non-major-artery aneurysms. The major-artery group included 17.9% that became angiographically worse, while 31.2% were growing or hemorrhaging in the non-major-artery group.

Treatment strategies of ruptured intracranial aneurysms associated with moyamoya disease

OBJECTIVE

The purpose of this study was to present our experience in the management of ruptured intracranial aneurysms associated with moyamoya disease (MMD), and to discuss their treatment strategies and the timing of revascularization surgery.

PATIENTS AND METHODS

Thirteen patients who had ruptured intracranial aneurysms associated with MMD were enrolled in this study. Different treatment strategies were adopted based on the location of the aneurysms. Their clinical and radiologic features, treatment selection and outcomes were retrospectively reviewed.

RESULTS

Among the five patients with major artery aneurysms in anterior circulation, three were embolized and two clipped. Among the five patients with major artery aneurysms in posterior circulation, three were treated by endovascular coiling. Among the three peripheral aneurysms, one was treated by endovascular embolization, one by aneurysmectomy, and the other one by revascularization alone. For the patients whose aneurysms were treated by endovascular embolization or surgery, a staged revascularization was performed on day 28 to day 87 after the first operation. For the two patients with aneurysms untreated directly, the timing of revascularization was 20 days and 54 days after hemorrhage, respectively. During the follow-up recurrent intracranial hemorrhage occurred in a patient, but not caused by the previous aneurysm. No other patients suffered recurrent intracranial hemorrhage or ischemic stroke. Complete occlusion was achieved in all the 11 aneurysms that had been clipped or embolized. Of the remaining three aneurysms that had not been directly treated, one disappeared spontaneously, whereas the other two remained stable. The direct and indirect bypasses were confirmed patent in the 11 patients who had undergone revascularization.

CONCLUSION

Our current treatment strategies and timing of revascularization may provide a benefit for the patients with MMD accompanied by ruptured intracranial aneurysms.

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.

Intracranial Aneurysms in White Patients with Moyamoya Disease: A U.S. Single-Center Case Series and Review

BACKGROUND

Intracranial aneurysms (IA) are associated with moyamoya disease (MMD). There are no clinically tested treatment guidelines. Reporting of cases is vital to better understand the underlying pathophysiology and potential ethnic predispositions and improve patient selection for intervention.

METHODS

Records of all patients diagnosed with MMD with concomitant IA who presented to our institution were retrospectively reviewed. Data related to demographic, clinical, MMD characteristics, aneurysm characteristics, surgical intervention, and follow-up were collected from the records of each patient. Aneurysm location was categorized into circle of Willis (CoW) aneurysms (originating from the CoW or its major branches) and peripheral aneurysms (arising from choroidal or lenticulostriate arteries).

RESULTS

Ten patients were found to have a total of 14 IA. All patients were white. Ten aneurysms (71%) were classified as CoW aneurysms and 4 (29%) were classified as peripheral. Seven of 10 CoW aneurysms (70%) were located in the anterior circulation, whereas 3 (30%) were located in the posterior circulation. Aneurysms of anterior and posterior circulations were most commonly treated with coil embolization, whereas peripheral artery aneurysms were most commonly treated with either cerebral revascularization alone or aneurysm excision.

CONCLUSIONS

Revascularization surgery seems to be an effective method of indirectly treating IA in patients with MMD. Previous literature in addition to our series shows that endovascular embolization is safe and efficacious in treating IA of most locations in patients with MMD. The use of open microsurgery for direct aneurysm treatment in this population poses many challenges.

The prospects and pitfalls in the endovascular treatment of moyamoya disease-associated intracranial aneurysms

Moyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the distal internal carotid artery and simultaneous formation of collateral vasculature. The fragile alteration and increased hemodynamic stress in the intra- and extracranial vasculature would conjointly result in the formation of intracranial aneurysms in MMD patients. According to our classification, the MMD-associated aneurysms are divided into the major artery aneurysms (MAAs) and non-MAAs. The non-MAAs are further subdivided into the distal choroidal artery aneurysms, moyamoya vessel aneurysms, transdural collateral aneurysms, and anastomosis aneurysms. Currently, endovascular treatment (EVT) has become the main stream for the MMD-associated aneurysms. There is no difference to EVT for the MMD-associated MAAs of the non-stenosed major arteries with that in the non-MMD patients. While it is a big challenge to perform EVT for MMD-associated aneurysms in the stenosed arteries. Generally speaking, the parent arteries of the non-MAAs are slim, and super-selective catheterization is technically difficult. Most of the times, parent artery occlusion with liquid embolic agents or coils can only be performed. The vasculature in MMD patients is fragile; perioperative management and meticulous intraoperative manipulation are also very important to avoid complications during EVT. In spites of the complications, the EVT can bring good outcome in selected cases of MMD-associated aneurysms.