Implementation and Rationale for a Unified Clinical and Imaging Protocol for Evaluation and Treatment of Moyamoya Angiopathy: A Single Institutional Experience

Abstract

Moyamoya disease (MMD) is a complex and incompletely-understood cerebrovascular pathological entity that requires thorough clinical and imaging evaluation. Moyamoya is rare, thereby making the establishment of an effective, thorough and interdisciplinary patient evaluation protocol challenging, even within specialized referral centers. Nevertheless, implementation of such a protocol is crucial in order to provide the best possible evaluation and treatment for MMD patients. Here, we describe our institution's implementation of, rationale for, and experience with a comprehensive multidisciplinary collaboration and evaluation strategy for adult patients with moyamoya. This evaluation course consists of, first of all, a thorough clinical and laboratory evaluation with a vascular neurologist. This is followed by a comprehensive imaging assessment which evaluates angiographic and parenchymal features, in addition to cerebrovascular functionality. Finally, appropriate referrals are made to consulting services as indicated, which includes vascular neurosurgery. These steps are described in detail herein.

European Stroke Organisation (ESO) Guidelines on Moyamoya angiopathy Endorsed by Vascular European Reference Network (VASCERN)

“…The incomplete knowledge on the natural course of MMA, as well as the unknown pathophysiology and the heterogeneity of the disease, especially between East Asians and Western populations, has limited, so far, the development of shared management strategies. 9,10,19,[35][36][37] Surgical revascularization is considered the only treatment able to prevent ischaemic and haemorrhagic strokes. 38,40 However, indication on the best type of revascularization and the timing of surgery as well as on patient management in the presurgical and follow-up phases are lacking.…”

“…12,33,34 Although these techniques are currently used not only to assess the disease severity but also to establish indication to surgery, they are not validated, and no standardised indications are provided for pre-operative and outcome patient assessment. 35–37…”

“…12,33,34 Although these techniques are currently used not only to assess the disease severity but also to establish indication to surgery, they are not validated, and no standardised indications are provided for pre-operative and outcome patient assessment. [35][36][37] To date, no treatment limiting the progression of the occlusive arterial lesions is available for MMA patients and strategies aiming at reducing the risk of further cerebrovascular events employ surgical revascularization techniques. [38][39][40] The surgical methods are mainly divided into direct revascularization, in which the superficial temporal artery (STA) -a branch of the external carotid artery (ECA) -is directly anastomosed with the middle cerebral artery (MCA) or the anterior cerebral artery (ACA), and indirect revascularization (synangiosis procedures) in which tissues encompassing ECA branches (dura mater, temporal muscle, galeal tissue, or superficial temporal artery) are placed in contact with the surface of the ischaemic brain.…”