Moyamoya Arteriopathy

Disease specific urinary biomarkers in the central nervous system

Urinary biomarkers can diagnose and monitor pathophysiologic conditions in the central nervous system (CNS). However, focus is often on single diseases, with limited data on discriminatory capability of this approach in a general setting. Here, we demonstrate that different classes of CNS disease exhibit distinct biomarker patterns, evidence of disease-specific "fingerprinting." Urine from 218 patients with pathology-confirmed tumors or cerebrovascular disease, controls (n = 33) were collected. ELISA and/or bead-based multiplexing quantified levels of 21 putative urinary biomarkers. Analysis identified biomarkers capable of distinguishing each disease from controls and other diseases. Mann-Whitney U tests identified biomarkers with differential expression between disease types and controls (P ≤ 0.001). Subsequent receiver-operating characteristic (ROC) analyses revealed distinguishing biomarkers with high sensitivity and specificity. Areas under the curve (AUCs) ranged 0.8563-1.000 (P values ≤ 0.0003), sensitivities ranged 80.00-100.00%, and specificities ranged 80.95-100.00%. These data demonstrate proof-of-principle evidence that disease-specific urinary biomarker signatures exist. In contrast to non-specific responses to ischemia or injury, these results suggest that urinary biomarkers accurately reflect unique biological processes distinct to different diseases. This work can be used to generate disease-specific panels for enhancing diagnosis, assisting less-invasive follow-up and herald utility by revealing putative disease-specific therapeutic targets.

Comparison of Long-Term Effect Between Direct and Indirect Bypass for Pediatric Ischemic-Type Moyamoya Disease: A Propensity Score-Matched Study

Objectives: This study aimed to compare the postoperative risks and long-term effects between direct bypass surgery (DB) and indirect bypass (IB) surgery for pediatric patients with ischemic-type moyamoya disease (MMD). Method: Pediatric patients (under or equal to 18 years old) who were diagnosed as MMD and given surgical treatments at our center between 2009 and 2015 were retrospectively reviewed from a prospective database. Pediatric hemorrhagic-type MMD patients and those who did not undergo digital subtraction angiography (DSA) were excluded. Patients who underwent DB were matched with patients who underwent IB using 1:1 propensity score matching. Postoperative complications, recurrent ischemic stroke events and modified Rankin Scale (mRS) scores at the last follow-up were compared between the matched pairs. Results: A total of 223 pediatric patients were screened, and 138 patients (DB:34, IB:104) were considered for the propensity score match. Thirty four pairs were obtained. Nine patients had postoperative complications, including 6 (17.6%) in the DB group and 3 (8.8%) in the IB group (P = 0.476). The mean follow-up period was 71.9 ± 22.2 months for the DB group and 60.2 ± 24.3 months for the IB group (P = 0.041). Kaplan-Meier analysis showed a longer stroke-free time in the DB group than in the IB group (P = 0.025). At last follow-up, good neurological status (mRS ≤ 1) was achieved in 32 (94.1%) of the DB group and 34 (100.0%) of the IB group. MRS score at last follow-up were significantly lower than at time of admission (all pts: 1.09 ± 0.45 vs. 0.28 ± 0.51, P < 0.001; DB group: 1.12 ± 0.48 vs. 0.32 ± 0.59, P < 0.001; IB group: 1.06 ± 0.42 vs. 0.24 ± 0.43, P < 0.001). Conclusion: Both techniques were effective in improving the neurological status of pediatric ischemic-type MMD patients, and direct bypass surgery might be more superior in preventing recurrent ischemic strokes in the short-term.

Modified encephalo-duro-periosteal-synangiosis (EDPS) for the revascularization of anterior cerebral artery territory in moyamoya disease: A single-center experience

OBJECTIVES

Anterior cerebral artery (ACA) territory, a crucial area of intellectual development in children, is frequently involved in the progress of moyamoya disease (MMD). However, revascularization surgeries for this area are not as established as surgeries for middle cerebral artery (MCA) territory. This study aimed to describe our experience and study the effect of revascularizing ACA territory with periocranium and dural leaflets, which is referred to as 'encephalo-duro-periosteal-synangiosis (EDPS)'.

PATIENTS AND METHOD

Fourteen hemispheres of 9 MMD patients who had undergone EDPS from November 2015 till July 2017 in our hospital were retrospectively included. Clinical characteristics and procedure-related information were recorded. Cerebral perfusion was evaluated by computed tomography perfusion (CTP). Absolute and relative (r) CTP parameters of ROIs in ACA territory at the level of centrum semiovale and middle basal ganglia were calculated. Preoperative and postoperative parameters were compared.

RESULTS

All EDPS procedures were technically successful with no postoperative complications. The mean operating time was 75.00 ± 22.53 min per hemisphere. Postoperative absolute cerebral blood flow (CBF), rCBF were significantly increased and absolute time to peak (TTP), rTTP, absolute mean transit time (MTT) were significantly reduced in ACA territory at centrum semiovale level (P = 0.002, 0.045, 0.007, 0.005 and 0.039 respectively). Improved outcomes were achieved in five patients, stabilization in three and one patient had deterioration out of intracerebral hemorrhage during follow-up.

CONCLUSION

EDPS is a simple but effective technique to revascularize ACA territory for MMD. EDPS significantly improved cerebral blood perfusion of frontal lobe in the majority of patients without increasing procedure-related risks.

Direct Bypass Surgery Vs. Combined Bypass Surgery for Hemorrhagic Moyamoya Disease: A Comparison of Angiographic Outcomes

Objective: Extracranial-intracranial bypass is currently recognized as the optimal treatment for hemorrhagic-type moyamoya disease (MMD) which reduces incidence of rebleeding. Recent studies have reported the advantage of combined bypass over direct bypass for the general MMD patients. However, the effect of direct bypass and combined bypass surgery specifically for hemorrhagic-type MMD had not been investigated yet. Methods: Hemorrhagic-type MMD patients who underwent direct and combined bypass surgery with complete clinical and radiological documentation from a multicenter cohort between 2009 and 2017 were retrospectively included. Surgical methods included superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis (direct bypass), combined STA-MCA bypass with encephalodurosynangiosis (EDS), and combined STA-MCA bypass with encephaloduroarteriosynangiosis (EDAS). Matsushima standard on follow-up catheter angiography was used to assess surgical outcome. Modified Rankin Scale, incidence of rebleeding and ischemia during follow-up were recorded. Rebleeding-free survival rates between direct and combined bypass were compared by Kaplan-Meier analysis. Results: Sixty eight hemorrhagic-onset MMD patients were included in this study, among which 71 hemispheres were treated with surgery (direct bypass: 17; bypass+EDS: 24; bypass+EDAS: 30). Forty six (64.8%) hemispheres had satisfactory revascularization (Matsushima level 2-3) and 26 (36.6%) had poor neoangiogenesis. Matsushima level was not significantly different between surgical groups (P = 0.258). Good neoangiogenesis from dural grafts was achieved in 26 (36.6%) hemispheres, and good neoangiogenesis from STA grafts was only seen in 4 (out of 30, 12.5%) hemispheres. Multivariate analysis showed bypass patency [P < 0.001, OR (95%CI): 13.41 (3.28-54.80)] and dural neoangiogenesis [P < 0.001, OR (95%CI): 13.18 (3.26-53.36)] both independently contributed to good angiographic outcome. During follow-up, incidences of rebleeding or ischemic events, and re-bleeding free survival rate were not significantly different between surgical groups (P = 0.433, P = 0.559, and P = 0.997). However, patients who underwent combined bypass surgery had significantly lower mRS at follow-up comparing to patients who underwent direct bypass (P = 0.006). Conclusion: Combined bypass surgery and direct bypass surgery offered similar revascularization for hemorrhagic MMD. Bypass patency and dural angiogenesis both contributed to revascularization independently. The potential of indirect bypass to grow new vessels in hemorrhagic-MMD patients was generally limited, but dural leaflets offered better neoangiogenesis than STA grafts and was therefore recommended for surgical revascularization of hemorrhagic MMD.

Time Course of Neoangiogenesis After Indirect Bypass Surgery for Moyamoya Disease : Comparison of Short-term and Long-term Follow-up Angiography

OBJECTIVE

Indirect bypass surgery, which induces spontaneous neoangiogenesis in ischemic brain tissue and improves cerebral blood flow, is an effective treatment for moyamoya disease (MMD). The time course of neoangiogenesis development has not yet been investigated. This study aimed to determine the critical period of neovascularization after indirect bypass in MMD patients.

METHODS

Patients with MMD who underwent indirect bypass surgery at Peking University International Hospital between January 2015 and October 2017 were retrospectively reviewed. Surgically treated hemispheres with short-term (3-6 months) and long-term (1 year) follow-up digital subtraction angiography (DSA) were included. The effects of revascularization were evaluated on lateral and anteroposterior views using angiography and compared between two follow-ups of the same hemisphere.

RESULTS

This study included 25 hemispheres from 24 MMD patients (mean age: 22.48 ± 14.83 years), among whom 13 were pediatric patients and 12 were adults. Qualitative measurements including the Matsushima scale and coverage of neoangiogenesis on anteroposterior views were not significantly different between the short term and long term (P = 0.083 and P = 0.157, respectively). Quantitative measurements including the greatest width and height of the area covered by neovascularization on lateral views of DSA and the greatest depth of neovascularization penetration on anteroposterior views (P = 0.488, 0.298 and 0.527, respectively) were also not significantly different. The mean count of newly formed veins was more at long-term than short-term follow-up (5.5 ± 2.5 vs. 5.1 ± 2.4, P = 0.005). Subgroup analysis of pediatric patients and adults yielded the same results as in the whole series.

CONCLUSION

After indirect bypass surgery, the major time window of arterial neoangiogenesis development was within 6 months after surgery. The general effect of revascularization was very similar in the short and long term; therefore, a follow-up angiography scheduled at 6 months after surgery is recommended. Growth of veins might continue after 6 months.

The management of childhood cancer survivors at risk for stroke: A Delphi survey of regional experts

BACKGROUND

Evidence is not available to guide management of childhood cancer survivors (CCS) at risk for radiation-associated cerebral vascular disease (CVD) and stroke. We propose to use a consensus-based methodology to describe the collective opinion of regional experts for the care of these patients and identify areas of controversy.

PROCEDURE

Thirty physicians from the New England region who care for CCS participated in a Delphi panel querying their management approach (imaging, laboratory tests, medications, counseling, referrals) to a CCS treated with cranial radiation formatted as five clinical scenarios (asymptomatic, small- and large-vessel CVD, transient ischemia, stroke) in three rounds of anonymous questionnaires. Consensus defined as ≥90% agreement.

RESULTS

Response rate was 100% for all three rounds. Panelists reached consensus on laboratory tests to assess stroke risk factors, stroke risk and prevention counseling, brain imaging to monitor survivors with known CVD, and acute care for stroke symptoms. Only 67% panelists agreed with MRI screening asymptomatic survivors with no history of CVD, 87% endorsed aspirin as stroke prevention for large-vessel CVD and 57% for small-vessel CVD. There was no consensus on specialty referrals. Overall, panelists practicing at large institutions and neurology subspecialists were more likely to advocate for screening, interventions, and referrals.

CONCLUSIONS

Despite lack of evidence to guide stroke prevention in CCS treated with cranial radiation, a panel of regional physicians reached consensus on managing most clinical scenarios. Controversial areas requiring further study are surveillance imaging for asymptomatic survivors, aspirin for stroke prevention, and indications for specialty referral.

Novel imaging approaches to cerebrovascular disease

Imaging techniques available to the physician treating neurovascular disease have substantially grown over the past several decades. New techniques as well as advances in imaging modalities continuously develop and provide an extensive array of modalities to diagnose, characterize, and understand neurovascular pathology. Modern noninvasive neurovascular imaging is generally based on computed tomography (CT), magnetic resonance (MR) imaging, or nuclear imaging and includes CT angiography, CT perfusion, xenon-enhanced CT, single-photon emission CT, positron emission tomography, magnetic resonance angiography, MR perfusion, functional magnetic resonance imaging with global and regional blood oxygen level dependent imaging, and magnetic resonance angiography with the use of the noninvasive optional vessel analysis software (River Forest, Ill). In addition to a brief overview of the technique, this review article discusses the clinical indications, advantages, and disadvantages of each of those modalities.

Reduction in Overt and Silent Stroke Recurrence Rate Following Cerebral Revascularization Surgery in Children with Sickle Cell Disease and Severe Cerebral Vasculopathy

BACKGROUND

Children with sickle cell disease (SCD) and moyamoya may benefit from indirect cerebral revascularization surgery in addition to chronic blood transfusion therapy for infarct prevention. We sought to compare overt and silent infarct recurrence rates in children with SCD undergoing revascularization.

METHODS

This was a retrospective cohort study of all children with SCD and moyamoya treated at two children's hospitals. Clinical events and imaging studies were reviewed.

RESULTS

Twenty-seven children with SCD and confirmed moyamoya receiving chronic transfusion therapy were identified, of whom 12 underwent indirect cerebral revascularization. Two subjects had postoperative transient ischemic attacks and another had a subarachnoid blood collection, none of which caused permanent consequences. Two subjects had surgical wound infections. Among these 12 children, the rate of overt and silent infarct recurrence decreased from 13.4 infarcts/100 patient-years before revascularization to 0 infarcts/100 patient-years after revascularization (P = 0.0057); the postrevascularization infarct recurrence rate was also significantly lower than the overall infarct recurrence of 8.87 infarcts/100 patient-years in 15 children without cerebral revascularization (P = 0.025).

CONCLUSIONS

The rate of overt and silent infarct recurrence was significantly lower following indirect cerebral revascularization. A prospective study of cerebral revascularization in children with SCD is needed.

The collateral circulation in pediatric moyamoya disease

PURPOSE

The descriptions of collateral circulation in moyamoya have so far been a mixture of topography-based and vessels' source-based analyses. We aimed to investigate the anatomy and systematize the vascular anastomotic networks in pediatric moyamoya disease.

METHODS

From a series of 25 consecutive complete angiographic studies of newly diagnosed children with moyamoya, 14 children had moyamoya disease and 11 were diagnosed with moyamoya syndrome, i.e., moyamoya angiopathy with some additional concomitant systemic disease. We retrospectively analyzed the arterial branches supplying the moyamoya anastomotic networks, their origin, course, location, and connections with the recipient vessels.

RESULTS

We describe four types of anastomotic networks in children with moyamoya disease, two superficial-meningeal and two deep-parenchymal. As superficial-meningeal, we defined the leptomeningeal and the durocortical networks. Apart from the previously described leptomeningeal network observed in the convexial watershed zones, we report on the basal temporo-orbitofrontal leptomeningeal network. The second superficial-meningeal network is the durocortical network, which can be basal or calvarian in location. We define as deep-parenchymal networks the nonpreviously described subependymal network and the inner striatal and inner thalamic networks. The subependymal network is fed by the intraventricular branches of the choroidal system and diencephalic perforators, which at the level of the periventricular subependymal zone, anastomose with medullary-cortical arteries as well as with striatal arteries. The inner striatal and thalamic networks are constituted by intrastriatal connections among striatal arteries and intrathalamic connections among thalamic arteries when the disease compromises the origin of one or more sources of their supply.

CONCLUSION

The previously inexplicitly described "moyamoya abnormal network" in pediatric moyamoya disease can be described as a composition of four anastomotic networks with distinct angioarchitecture. A better understanding of the collateralization in moyamoya may help in defining a new staging system of the disease with clinical relevance.

Intraoperative MRI for neurosurgical and general surgical interventions

PURPOSE OF REVIEW

The use of intraoperative magnetic resonance imaging (IMRI) during surgeries and procedures has expanded in the last decade. Not only is it becoming more commonly used for a variety of adult and pediatric neurosurgical procedures, but also its use has expanded to other types of surgeries. Along with using IMRI for removing tumors of the spinal cord, surgeons are now using it for other types of surgical operations of the kidney and liver. The increased utilization during the intraoperative period warrants the anesthesia provider to assure that patients and staff are unharmed because of increased risk of the powerful magnet.

RECENT FINDINGS

Recent literature is reviewed regarding the expansive use of IMRI in the operating and procedure room. Safety issues and anesthetic implications are also addressed.

SUMMARY

IMRI is becoming increasingly more popular, especially with neurosurgeons, but its use is also expanding to other types of surgeries. Because of the increased use, the anesthesia provider must be aware of the dangers that it imposes to those involved and take necessary safety precautions. This will help assure that no one is harmed during the operation or procedure.

Selective and superselective angiography of pediatric moyamoya disease angioarchitecture: the anterior circulation

The angioarchitecture of the so-called moyamoya vessels in children has not been explicitly analyzed. We aimed to investigate the precise anatomy of the vascular anastomotic networks in patients with childhood moyamoya disease. Six children diagnosed with moyamoya disease for the first time underwent an angiographic investigation with selective and superselective injections. We recorded the arterial branches feeding the moyamoya anastomotic networks, their connections and the recipient vessels. Depending on the level of the steno-occlusive lesion, the feeding vessels included the medial striate arteries, the perforators of the choroidal segment of the carotid, the uncal artery, the medial and lateral branches of the intraventricular segment of the anterior choroidal artery, perforators of the communicating segment, the superior hypophyseal arteries, the prechiasmal branches of the ophthalmic artery, the ethmoidal arteries and the dural branches of the cavernous carotid. Through connections, which are described, the recipient vessels were the lateral striate arteries and the middle cerebral, the medial striate arteries and the anterior cerebral, medullary arteries around the ventricular system, anterior temporal branches of the middle cerebral, orbitofrontal and frontopolar branches of the anterior cerebral, as well as other cortical branches of the anterior and middle cerebral territories. The use of high quality selective and superselective angiography enabled us to clearly demonstrate for the first time aspects of the microangiographic anatomy of the moyamoya anastomotic network previously only vaguely or incompletely described.

Recent advances in moyamoya disease: pathophysiology and treatment

Moyamoya disease is a progressive intracranial arteriopathy characterized by bilateral stenosis of the distal portion of the internal carotid artery and the proximal anterior and middle cerebral arteries, resulting in transient ischemic attacks or strokes. The pathogenesis of moyamoya disease remains unresolved, but recent advances have suggested exciting new insights into a genetic contribution as well as into other pathophysiological mechanisms. Treatment that may halt progression of the disease or even reverse the intracranial arteriopathy is yet to be found. There are strong indications that neurosurgical intervention, through direct, indirect, or combined revascularization surgery, can reduce the risk of ischemic stroke and possibly also cognitive dysfunction by improving cerebral perfusion, although randomized clinical trials have not been performed. Many questions regarding the indication for and timing of surgery remain unanswered. In this review, we discuss recent developments in the pathogenesis and treatment of moyamoya disease.