Moyamoya Guidelines, UCSF Benioff Children’s Hospital San Francisco

Created 5/29/2014 and revised 3/1/21

Moyamoya Guidelines, UCSF Benioff Children’s Hospital San Francisco

Nalin Gupta, Corey Raffel, Heather Fullerton, Christine Fox, reviewed and approved by Michael Lawton and Kurtis Auguste. Revised with Prepare (Amanda Parker),Anesthesia (Atsuko Baba, David Rabinowitz) and PNCC group October 2017.

A. Pre-surgical work-up and medical management

1. Clinical indications for surgery

a. Ischemic events: TIAs or ischemic strokes

b. Hemorrhagic stroke

c. Headache or seizures (if thought to represent impaired brain perfusion)

2. Imaging indications (consider offering surgery even if asymptomatic)

a. Silent brain ischemic injury (typically deep borderzone injury) or evidence of hypoperfusion

b. High burden of deep moyamoya collaterals (risk of hemorrhagic stroke)

c. Progressive arteriopathy

3. Basic work-up (to guide surgical decisions)

a. MRI/A brain

b. Consider perfusion studies

4. Medical management:

a. Aspirin (3-5 mg/kg/day, maximum of 81 mg)

b. Counseling: Avoid hydration and high salt diet. Avoid anti-hypertensives. Steps if suspected TIA or stroke: lay patient flat, hydrate, call 911 if deficits persists

c. Consider fludrocortisone or midodrine to increase BP if having flow-related ischemia

5. Add “ICD-9 437.5 Moyamoya syndrome - avoid dehydration or lowering BP to prevent flow-related brain schemia” to Apex problem list. When available, add typical BP range and specific peri-anesthesia

recommendations (below).

6. Follow-up for patients not offered surgery: Repeat MRI/A in 6 months, then annually if stable

B. Peri-anesthesia management: special precautions to maintain adequate cerebral perfusion.

1. For known elective procedures: Pediatric Prepare Consult establishes peri-anesthesia plan with Neurovascular team (Christine Fox 443-0863 or Heather Fullerton 443-6930). If patient requires additional counseling regarding anesthesia risk, refer to Neurovascular clinic prior to procedure.

2. Establish peri-anesthesia BP goal: in general, use typical awake BP range. Aim to maintain during and as recovering from anesthesia until off medications that could lower blood pressure (for example, IV opiates).

3. For moderate risk patients (stenosis without active ischemia) with outpatient procedures:

a. Prepare clinic notifies IV access team of scheduled procedure; do not schedule as first case.

b. Prepare instructions: minimum 8 ml/kg clears (ok to drink more) midnight prior and 2 ml/kg again 2 hours prior to anesthesia.

c. On day of procedure, patient arrives in surgical preop (2nd floor). IV access team places IV in preop. Normal saline started at 1.5x maintenance rate. Recovery in PACU if pressors during procedure.

4. For high risk patients (e.g., active TIAs) or inpatient procedures:

a. Admit high-risk patients the day prior for IVF (Normal saline 1.5x maintenance rate) while NPO.

b. Direct primary attending communication of fluid and blood pressure goals prior to procedures with anesthesia (E1 502-0442). Post-operative admission to the PICU.

5. Anesthesiology recommendations:

a. At induction, ready with neo-synephrine (or other pressor). Consider arterial line for BP monitoring during major surgical procedures.

b. During anesthesia: IVF 1.5 maintenance. Avoid hyperventilation, maintain normocapnia (ETCO2 38-42).

c. Request PICU bed for recovery after general anesthesia; if no pressors may go to PACU at the discretion of anesthesiologist.

B. Revascularization Surgery (meets indications for surgery)

1. Pre-surgical imaging: Conventional angiogram with external carotid injections

2. Timing of surgery: If recent stroke or frequent/recent TIAs, consider urgent admission (from clinic if very active, or within days if less active) for angiogram and surgery

3. Preferred Surgical Procedures

a. STA-MCA bypass with temporalis muscle onlay (EMS)

• Procedure of choice for patients with adequate donor and recipient vessels

• Theoretical immediate benefit of direct bypass, plus onlay as back-up if direct bypass thrombosis

b. EDAMS (STA and temporalis muscle onlay)

• Consider in patients with inadequate donor or recipient vessels, minimally active disease, families reluctant to do direct bypass

c. Burr holes:

• Consider if recurrent stroke despite prior revascularization or for atypical vascular territory

4. Perioperative Management

a. Admit the day prior to surgery for IV fluids and to establish peri-operative BP goals (See “Peri anesthesia management”)

b. Continue daily aspirin (do not d/c for surgery)

c. Post-operative considerations:

• Continue aspirin post –operative (unless otherwise advised by neurosurgeon)

• Observe in PICU with frequent neurologic checks for minimum of 48 hours for TIAs

• Continue IV plus PO goal of 1.5 maintenance fluids for 3 days (longer if post-op ischemic events)

• After intracranial procedures, increase MAP goal by 5-10% for 3-5 days (longer if post-op ischemic events). Maintain with pressors as needed.

• BP monitoring with arterial line preferred while requiring IV opiate pain control.

• No routine post-op conventional angiograms

• No routine post-op brain imaging

d. If patient has a TIA:

i. Head of bed flat

ii. Give O2 via NC

iii. IV fluid bolus

iv. Monitor BP, consider moderate increase in MAP goals

5. Follow-up

a. MRI/MRA at 1 year and annually to follow surgical response to bypass, evidence of progressive ischemic brain injury, and evidence of posterior circulation progressive arteriopathy. MRA should be done with gadolinium unless a contraindication

b. No routine follow-up conventional angiograms

6. Indications to consider repeat surgery

a. No response to surgical bypass

b. On-going ischemic events or hemorrhage

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This information is meant to serve as an educational resource. Clinicians should use their own professional judgment in the care of any individual patient as the guidance contained in this document may not be appropriate for all patients or all situations.