Management of “Moyamoya Angiopathy”
in children and in adults at the
Neurosurgery Department University Hospital Zürich
UniversitätsSpital Zürich, Switzerland

Professor Dr. med. Yasuhiro Yonekawa
PD Dr. med. Nadia Khan

Definition of Moyamoya angiopathy:

Moyamoya Angiopathy: encompasses both Moyamoya Disease and Moyamoya Syndrome

The word “Moyamoya”: Japanese word meaning “puff of smoke” describing the network of new vessel formation as a compensation to the decreased blood flow in both the brain hemispheres due to obstruction of the two main brain vessels the internal carotid arteries.

Commonly used terms:
Moyamoya Disease, Moyamoya Syndrome, Cerebral revascularisation

• Moyamoya disease: presence of obstruction (stenosis/occlusion) of the two main brain arteries the internal carotid arteries ICA within the skull vault (intracranially) on the angiography. Additional presence of new vessel formation/Moyamoya network of vessels.
  
• Moyamoya Syndrome: presence of other systemic diseases along with the intracranial Moyamoya findings.
  
• Cerebral/Brain revascularisation: to revascularise or to supply additional blood flow to brain areas with low flow due to obstruction of brain vessels/arteries
  
  Moyamoya in Children

• The Moyamoya angiopathy in children usually presents with 
• TIAS: transient ischemic attacks, which are sudden, repetitive loss of function either of muscle strength or sensation of one of the limbs (arm, leg, facial weakness)
  • epileptic attacks
  • headaches
    These symptoms usually appear when the child is under physical stress or under conditions of hyperventilation, blowing into musical instruments, physical exertion or under conditions of dehydration (warm days during the summer time, Fever). Therefore ample fluid intake on a daily basis is extremely important.  

Moyamoya in adults

In adult Moyamoya the common presentation is intracerebral bleeding in the region of the Moyamoya network. TIAs and headaches are also commonly seen.

Preoperative Examinations

- 6-vessel cerebral angiography and
- Water (H215O-PET) examinations

6-vessel cerebral angiography                                         H215O-PET
      
Angiography outlines the anatomy of the cerebral vasculature i.e. shows the location and extent of stenosis/occlusion of the cerebral vessels and the formation of the moyamoya network.
PET examination on the other hand demonstrates the perfusion reserves (pattern of blood flow).

Choice of Surgery
The direct and indirect method of revascularisation

- Direct EC-IC Bypass: STA-MCA, STA-ACA, OA-PCA

- Indirect Durasynangiosis, arteriosynangiosis

The Zürich pre- and post-surgical evaluation Protocol

Children with Moyamoya angiopathy are referred to us from all across Europe. To plan for surgery a number of presurgical examinations have to be performed before the decision of the most effective type and number of surgical procedure is made.
These investigations include a routine neurological examination, a routine blood test, ECG and if necessary a chest x-ray. The special investigations include a 6 –vessel cerebral angiography, a water-PET (H215O)-PET examination and a transcranial Doppler TCD. Depending on the extent of disease on angiography and the extent of perfusion deficits the number of revascularisation procedures to be performed is decided. We always advocate and perform a direct EC-IC bypass or end to side anastomosis of two vessels/arteries mainly the superficial temporal artery STA and a cortical vessel of either the anterior ACA, middle MCA or posterior PCA cerebral arteries. If these vessels are of too small a calibre an indirect revascularisation using the dura- or arteriosynangiosis technique is performed.

The logistics of a single hospitalisation is as follows:

Children below 10 years of age are admitted to the Kinderspital, Steinweisstrasse, Zürich on the PSU ward. Those of 10 years of age and above are admitted directly to the neurosurgical Department of the university hospital Zürich, Nordtrakt 1, 8091 Zürich on the wards M or N.
Admissions are organised for a Thursday and the preoperative examinations are carried out on the following Friday with surgery following on the Tuesday thereafter. Depending on the number of bypass operations to be performed the total hospital stay varies from 7-10 days to upto 2.5 weeks. Once the child has been successfully operated with an unremarkable postoperative in-patient stay a follow-up is carried out usually at 3-6 months with repeat clinical and angiography and PET examinations preferably at our Department in Zürich. After this initial follow-up a yearly TCD examination suffices. Repeat angiography and PET examinations are performed only if there is a steady, continuous increase in repeated TIAs occurrence of any new symptomatology.
We are in close contact with several neurologists, paediatricians all across Europe who have been referring patients to us for the past 6 years and continue taking on the responsibility of follow-ups of the children on a regular basis.

References:

1. Khan N, Yonekawa Y (2005) Moyamoya angiopathy in Europe. Acta Neurochir Suppl. 94:149-52.
   
2. Khan N, Schinzel A, Shuknecht B, Baumann F, Ostergaard JR, Yonekawa Y (2004) Moyamoya angiopathy with dolichoectatic internal carotid arteries, patent ductus arteriosus and pupillary dysfunction: a new genetic syndrome? Eur Neurol. 51(2):72-7.
   
3. Khan N, Schuknecht B, Boltshauser E, Capone A, Buck A, Imhof HG, Yonekawa Y (2003) Moyamoya disease and Moyamoya syndrome: experience in Europe; choice of revascularisation procedures. Acta Neurochir (Wien). 145(12):1061-71.
   
4. Yonekawa Y, Khan N (2003) Moyamoya disease. Adv Neurol. 92:113-8.
   
5. Muroi C, Yonekawa Y, Khan N, Pangalu A, Keller E (2003) Metabolic changes after H(2) 15O-positron emission tomography with acetazolamide in a patient with moyamoya disease: case report and review of previous cases. J Neurosurg Anesthesiol. 15(2):131-9.
   
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7. Weymann S, Yonekawa Y, Khan N, Martin E, Heppner FL, Schinzel A, Kotzot D (2001) Severe arterial occlusive disorder and brachysyndactyly in a boy: a further case of Grange syndrome? Am J Med Genet. 99(3):190-5.
   
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