Prevention of the Rerupture of Collateral Artery Aneurysms on the Ventricular Wall by Early Surgical Revascularization in Moyamoya Disease: Report of Two Cases and Review of the Literature

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.

A Case of Moyamoya Disease With Spontaneous Regression of Posterior Choroidal Artery Aneurysm After Improvement in Obesity and Administration of an Antihypertensive Drug

A 24-year-old obese female (height = 162 cm, weight = 84 kg, and BMI = 32.0) developed transient dysarthria and left hemiparesis, which was diagnosed as moyamoya disease (MMD) after imaging studies. Cerebral angiography and single photon emission computed tomography studies revealed that the above symptoms were caused by hemodynamic insufficiency in the bilateral hemispheres with right-sided predominance, and a right-sided superficial temporal artery-middle cerebral artery bypass was performed. After the surgery, the patient was uneventful, but her obesity gradually worsened. Nineteen months after the bypass surgery, the MRI showed compensatory development of bilateral posterior choroidal arteries, and 29 months later, her weight was 87.9 kg and BMI was 33.5, further worsening her obesity, and the MRI showed an aneurysm formation on the right choroidal anastomosis. While considering the addition of revascularization surgery, as a result of obesity improvement (weight = 75 kg and BMI = 28.6) and blood pressure control as vascular risk management, the aneurysm spontaneously disappeared without bleeding on MRI five months after its confirmation. We report on the importance of vascular risk management in patients with MMD.

Parent artery occlusion for ruptured aneurysms in moyamoya vessels or on collaterals

Background

Aneurysms in moyamoya vessels or on collaterals are difficult to treat. Parent artery occlusion (PAO) via endovascular treatment (EVT) is often the last resort, but the safety and efficacy of this approach need to be evaluated.

Materials and methods

A retrospective study was performed on patients admitted to our hospital who were diagnosed with unilateral or bilateral moyamoya disease (MMD) associated with ruptured aneurysms in moyamoya vessels or on collaterals. These aneurysms were treated with PAO, and the clinical outcome was recorded.

Results

Eleven patients were aged 54.7 ± 10.4 years, and six patients were male (54.5%, 6/11). The aneurysms in 11 patients were single and ruptured, and the average size was 2.7 ± 0.6 mm. Three (27.3%, 3/11) aneurysms were located at the distal anterior choroidal artery, 3 (27.3%, 3/11) were at the distal lenticulostriate artery, 3 (27.3%, 3/11) were at the P2-3 segment of the posterior cerebral artery, 1 (9.1%, 1/11) was at the P4-5 segment of the posterior cerebral artery, and 1 was at the transdural location of the middle meningeal artery. Among the 11 aneurysms, PAO by coiling was performed on 7 (63.6%, 7/11), and Onyx casting was performed on 4 (36.4%, 4/11). Of 11 patients, 2 (18.2%, 2/11) suffered intraoperative hemorrhagic complications. During follow-up, all patients had good outcomes with a modified Rankin scale score of 0-2.

Conclusion

As a last resort, the application of PAO with coiling or casting Onyx for ruptured aneurysms in moyamoya vessels or on collaterals may be safe with an acceptable clinical outcome. However, patients with MMD may not always achieve expected health outcomes, and PAO for the aneurysm can bring only temporary relief.

Posterior Cerebral Artery Aneurysm Re-Rupture Following Revascularization for Moyamoya Disease

OBJECTIVES

Aneurysms associated with hemorrhagic moyamoya disease (MMD) are reported to stabilize or recede following revascularization.

CASE REPORT/RESULTS

A 29 year-old male with no past medical history presented obtunded with diffuse intraventricular hemorrhage and vascular imaging demonstrating bilateral MMD without any associated aneurysms. He underwent a delayed right-sided STA-MCA bypass and pial synangiosis, and was subsequently discharged on hospital day 24 with a modified Rankin Scale score (mRS) of 2. He returned eleven days later from a rehabilitation facility with recurrent IVH. A saccular 5 mm right P4 segment posterior cerebral artery aneurysm was seen on a diagnostic angiogram and embolized with Onyx glue.

CONCLUSIONS

Distal posterior circulation artery aneurysmal rupture is a rare cause of hemorrhagic MMD. This case demonstrates the capacity of these aneurysms to re-rupture following revascularization and underscores the importance of treating the aneurysms directly.

Treatment of ruptured aneurysms of the choroidal collateral system in moyamoya disease: a systematic review and data analysis

OBJECTIVE

Moyamoya disease (MMD) is a chronic, progressive steno-occlusive condition of the distal internal carotid arteries of unknown etiology. Collateral arterial networks typically develop in MMD, bypassing the steno-occlusion. Aneurysms arising on the collateral networks are a known source of hemorrhage. The choroidal collateral system is the most common location for collateral pathway aneurysms in MMD and associated hemorrhage. The authors performed data collection and analysis to further elucidate the best treatment approaches for ruptured aneurysms of the choroidal collateral system in MMD, which as yet remain unclear.

METHODS

A comprehensive data collection and analysis of case reports and case series with ruptured choroidal collateral artery aneurysms (CCAAs) was performed. PRISMA guidelines for systematic reviews were followed and the Medline, Embase, and Scopus databases were searched for relevant studies. A database was created including patients with ruptured CCAA in MMD. Original data from case series were included whenever possible. A previously unreported case of a ruptured choroidal artery aneurysm in MMD treated by the authors was also included.

RESULTS

The database comprised 72 patients with ruptured CCAA in MMD. The most common clinical symptoms were headache, nausea, and vomiting (39%). Initially, a conservative treatment approach was chosen in 29% of cases but led to rehemorrhage in 40% of cases; 63% of these rehemorrhages occurred during the first 35 days. Endovascular treatment seemed a safe option for aneurysm exclusion, mainly through parent vessel sacrifice, but had a treatment failure rate of 21%, due to inadequate access. Aneurysm treatment with revascularization as the initial treatment strategy led to aneurysm regression in 82% with no reported rehemorrhage. Aneurysm exclusion through open surgery was effective but was associated with a relatively high complication rate (25%). Outcome after rupture of CCAA was poor, with 41% of patients deceased or permanently disabled. Overall, patient outcomes were better in the endovascular and revascularization treatment group than in the conservative treatment group.

CONCLUSIONS

Rupture of CCAA in MMD is associated with high morbidity and rerupture rate requiring urgent treatment.

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.

Development and natural course of lateral posterior choroidal artery aneurysms arising from fragile choroidal collaterals in moyamoya disease: illustrative cases

BACKGROUND

Choroidal collaterals are a risk factor for hemorrhagic stroke, even in the nonhemorrhagic hemisphere, among patients with moyamoya disease (MMD). Peripheral choroidal aneurysms rupture in fragile collaterals; however, the development and natural course of these aneurysms remain elusive.

OBSERVATIONS

A 51-year-old woman, who had experienced a right cerebral hemorrhage 3 years earlier, presented with asymptomatic minor bleeding from a left lateral choroidal artery aneurysm in a predeveloped choroidal anastomosis. Although the aneurysm spontaneously thrombosed within 2 months, the choroidal collaterals persisted. After bypass surgery, the choroidal anastomosis regressed, and neither a de novo aneurysm nor a hemorrhagic stroke occurred. A 75-year-old woman with MMD, who had experienced a left frontal infarction 6 years earlier, experienced recurrent right intraventricular hemorrhage from a ruptured lateral choroidal artery aneurysm that developed in the choroidal anastomosis. The aneurysm spontaneously regressed 3 days after the rebleeding with no recurrence over the following 7 years.

LESSONS

Choroidal artery aneurysms may develop in the choroidal anastomosis and rupture in the nonsurgical or contralateral hemispheres. Patients with MMD who have a history of hemorrhagic or ischemic stroke and impaired cerebral blood flow require careful observation. Although aneurysms may rapidly regress spontaneously, bypass surgery can stabilize hemodynamic stress and prevent further hemorrhage.

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.

Clinical features, surgical treatment, and outcome of intracranial aneurysms associated with moyamoya disease

The objective of this study was to elucidate the clinical features, surgical treatment, and outcome of intracranial aneurysms associated with moyamoya disease. We retrospectively reviewed a consecutive cohort of 79 moyamoya disease patients with 98 intracranial aneurysms at Beijing Tiantan Hospital. Clinical features, radiological findings, and outcomes were analyzed. Prevalence of intracranial aneurysms in patients with moyamoya disease was 3.9%. The mean age at diagnosis was 39.0 ± 12.4 years, with 1 peak distribution in patients from 40 to 50 years of age. The ratio of women to men was 1.00:1.03. Familial occurrence was 2.5%. The initial symptom was hemorrhage or ischemia in 56 (70.9%) and 23 patients (30.4%), respectively. Most patients presented with Suzuki stage 3 or 4. Seventy-nine cases had 98 aneurysms. Of the 98 aneurysms, sixteen aneurysms (16.3%) were treated by microsurgery and 7 by endovascular procedures, 13 aneurysms were conservatively managed, the remaining 62 were treated with revascularization alone. After a median nine-month angiographic follow-up, 18 aneurysms received clipped or embolized were completed occlusion, 18 aneurysms received conservative treated or coating were remained stable. Of the remaining 63 aneurysms that were treated with revascularization alone, 59 of 63 aneurysms remained stable, and 2 were obliterated, whereas 1 aneurysm ruptured during the follow-up. Hemorrhage was the most common symptom in intracranial aneurysms associated with moyamoya disease. Revascularization surgery may improve cerebral circulation, decreases hemodynamic stress and prevent the rupture of intracranial aneurysms.

Transcallosal, transchoroidal clipping of a hypothalamic collateral vessel aneurysm in Moyamoya disease

Peripheral collateral vessel aneurysms in Moyamoya disease (MMD) remain difficult to treat due to their deep location, small size, and vascular fragility. We report the case of an aneurysm localized in the hypothalamus, which was rapidly increasing in size with repeated hemorrhage despite revascularization surgery. Aneurysm clipping was performed to prevent further progress and rerupture with favorable outcome. To our best knowledge, this is the first description of a hypothalamic aneurysm in MMD being clipped via a transcallosal, transchoroidal approach through the third ventricle.

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.

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.

Efficacy of Direct Revascularization Surgery for Hemorrhagic Moyamoya Syndrome As a Late Complication of Cranial Irradiation for Childhood Craniopharyngioma

Moyamoya syndrome (MMS) is an uncommon late complication after cranial irradiation. Its hemorrhagic presentation from the associated pseudo-aneurysm is extremely rare, and the optimal management strategy is undetermined. We herein report a 36-year-old man who developed intraventricular hemorrhage from a pseudo-aneurysm at the extended left anterior choroidal artery as an abnormal collateral of MMS 30 years after surgical removal and cranial irradiation for childhood craniopharyngioma. Catheter angiography confirmed the diagnosis of MMS, and multiple pseudo-aneurysms were evident at the ipsilateral abnormal choroidal collateral, one of which was considered to be a source of bleeding. The patient underwent left superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis with indirect pial synangiosis based on the observation that the development of choroidal collateral may be associated with a high rebleeding risk in hemorrhagic moyamoya disease. The patient was discharged without neurological deficit, and postoperative magnetic resonance angiography confirmed the STA-MCA bypass to be patent. Catheter angiography 1 year after revascularization surgery revealed the complete disappearance of the pseudoaneurysms with the apparently patent STA-MCA bypass. The patient did not exhibit any cerebrovascular events during the follow-up period of 16 months. In conclusion, hemorrhagic MMS with choroidal collateral as a dangerous anastomosis was effectively managed by STA-MCA anastomosis. Although long-term follow-up is necessary to evaluate our strategy, the favorable disappearance of pseudoaneurysms after revascularization surgery in the present case strongly suggests that STA-MCA anastomosis has a potential role for preventing rebleeding in MMS after cranial irradiation.