Evaluation of Moyamoya Disease in Sickle Cell Anemia Patients After Encephaloduroarteriosynangiosis

Moyamoya disease is a progressive cerebrovascular complication of sickle cell anemia characterized by collateral arterial formation in response to progressive stenosis of the large intracranial arteries. Despite chronic transfusions, moyamoya is associated with a high risk of stroke recurrence. Encephaloduroarteriosynangiosis (EDAS) is a surgical technique used to reestablish or augment cerebral perfusion in patients with moyamoya disease. However, evidence for its efficacy in SCA patients is limited. We initiated a prospective study to determine whether EDAS is safe and increases blood flow to ischemic areas of brain in SCA patients with moyamoya.

SCA patients who had complete or partial obstruction of the dICA with progression to moyamoya disease were eligible for EDAS. Progressive cognitive decline, dystonia and persistent seizures were also factors influencing eligibility. Seven SCA patients (age: median 16yrs, range 4–23yrs; sex: 5F/2M ) with moyamoya disease underwent encephaloduroarteriosynangiosis (EDAS) procedures between 3/2007 and 9/2010. All 7 patients were regularly transfused for a history of stroke or MRA-documented ICA stenosis. Complete or partial obstruction of the dICA with moyamoya changes was detected on MRA scans and confirmed by cerebral angiography. Bilateral (n = 2) or unilateral (n = 5) encephaloduroarteriosynangiosis procedures in which the superficial temporal artery is transplanted through a small craniotomy with dural and arachnoid opening and sutured to the pia were performed. Perfusion MR-weighted imaging was performed pre- and post-operatively to evaluate changes in relative cerebral blood volume and time to peak enhancement.

All patients have remained free of neurovascular complications and have had no new ischemic changes on MRI with an average follow-up of 26 months. All patients subjectively reported improvement in overall well-being. A decrease in the frequency of headaches (n=1), resolution of seizures (n=2) and improved gait (n=1) were also observed. Collateral anastomoses between external and internal carotid arteries were established by MRA in all patients. All 4 patients who had pre and post-procedure MRA perfusion imaging showed a reduction in the delay of time to peak enhancement in the affected territory after EDAS.

Our results indicate that EDAS is a safe and effective surgical procedure to re-establish blood flow to ischemic brain tissue in patients with SCA who develop moyamoya disease. MRA perfusion imaging may be a useful tool to evaluate improved perfusion status after EDAS. Further examination of neuropsychologic correlates, such as executive function, with EDAS procedures in these patients is presently underway.

Vichinsky:Novartis: Research Funding; Apotex: Research Funding.