2023 American Academy of Neurology Abstract Website

Objective:

This study was undertaken to clarify the clinic-radiological characteristics and prospective follow-up of apparently “asymptomatic” MMA, if it is truly asymptomatic or not.

Background:

“Asymptomatic” Moyamoya Angiopathy (MMA) has been defined as absence of ischemic or hemorrhagic episodes in MMA patients. An ambiguous definition has led to its variable adaptation in the limited studies in the past.

Design/Methods:

Of the 122 angiographically proven MMA in our center over last 6 years, 6 patients had an initial diagnosis of “asymptomatic” MMA following evaluation by atleast one post-graduate doctor. These 6 cases were then further scrutinized by 3 different neurologists for epidemiological, clinical, radiological characteristics and subsequent follow-up. Data were analyzed using descriptive statistics.

Results:

The mean age at diagnosis was 23.7±13.14 years. 3 of the 6 patients had undergone brain imaging for evaluation of non-migraine-like headache, 1 for dizziness, 2 as a part of familial screening for MMA. 4 of the 6 patients had specific triggers for aggravation of symptoms. Brain imaging revealed old vascular insults and ivy sign in 5 of 6 patients(83.3%), cerebral microbleeds in 1 of 6 patients(16.7%), and mean suzuki staging3.6±0.82. 4 of the 6 patients who underwent cerebral perfusion study, all having hypoperfusion. Revascularization surgery was done in 2 of the 6 patients, rest were managed conservatively. None of the patients had any new onset neurological deficit or radiological progression over a mean follow-up period of 22.3±20.22 months.

Conclusions:

Subtle “paroxysmal events” often precipitated by specific triggers might be indicative of transient cerebral hypoperfusion in an apparently “asymptomatic” MMA and are likely indicative of ischemic symptoms, and warrants for a more precise definition to avoid misclassification of “asymptomatic” MMA.