Five-Year Stroke Risk and Its Predictors in Asymptomatic Moyamoya Disease: Asymptomatic Moyamoya Registry (AMORE)
Authors: Kuroda Satoshi , Yamamoto Shusuke , Funaki Takeshi , Fujimura Miki , Kataoka Hiroharu , Hishikawa Tomohito , Takahashi Jun , Endo Hidenori , Nariai Tadashi , Osato Toshiaki , Saito Nobuhito , Sato Norihiro , Hori Emiko , Ito Yoichi M. , Miyamoto Susumu , Inaji Motoki , Morita Kenichi , Maruyama Daisuke , Nakagawara Jyoji , Hashimura Naoki , Hamano Eika , Iihara Koji , Hashimoto Nobuo , Honjo Kaori , Nakamura Hirohiko , Kashiwazaki Daina , Imai Hideaki , Miyawaki Satoru , Hongo Hiroki , Yoshida Kazumichi , Kikuchi Takayuki , Mineharu Yohei , Isozaki Makoto , Kikuta Kenichiro , Araki Yoshio , Kanamori Fumiaki , Date Isao , Ono Junichi , Machida Toshio , Mase Mitsuhito , Katano Hiroyuki , Yamaguchi Koji , Kawamata Takakazu , Tominaga Teiji , Uchino Haruto , Tokairin Kikutaro , Ito Masaki , Houkin Kiyohiro , Chida Kohei , Ogasawara Kuniaki , Nagata Izumi , Horie Nobutaka , Oka Hidehiro , Kumabe Toshihiro , Itoh Yoshiaki , Abe Takato , Oki Koichi , Takahashi Shinichi , Suzuki Norihiro 
Published: May 2023

Background:
Long-term outcomes are unknown in patients with asymptomatic moyamoya disease. In this report, we aimed to clarify their 5-year risk of stroke and its predictors.

Methods:
We are conducting a multicenter, prospective cohort study (Asymptomatic Moyamoya Registry) in Japan. Participants were eligible if they were 20 to 70 years, had bilateral or unilateral moyamoya disease, experienced no episodes suggestive of TIA and stroke; and were functionally independent (modified Rankin Scale score 0–1). Demographic and radiological information was collected at enrollment. In this study, they are still followed up for 10 years. In this interim analysis, we defined the primary end point as a stroke occurring during a 5-year follow-up period. Independent predictors for stroke were also determined, using a stratification analysis method.

Results:

Between 2012 and 2015, we enrolled 109 patients, of whom 103 patients with 182 involved hemispheres completed the 5-year follow-up. According to the findings on DSA and MRA, 143 hemispheres were judged as moyamoya disease and 39 hemispheres as questionable manifestations (isolated middle cerebral artery stenosis). The patients with questionable hemispheres were significantly older, more often male, and more frequently had hypertension than those with moyamoya hemisphere. Moyamoya hemispheres developed 7 strokes, including 6 hemorrhagic and 1 ischemic stroke, during the first 5 years. The annual risk of stroke was 1.4% per person, 0.8% per hemisphere, and 1.0% per moyamoya hemisphere. Independent predictor for stroke was Grade-2 choroidal anastomosis (hazard ratio, 5.05 [95% CI, 1.24–20.6];
P
=0.023). Furthermore, microbleeds (hazard ratio, 4.89 [95% CI, 1.13-21.3];
P
=0.0342) and Grade-2 choroidal anastomosis (hazard ratio, 7.05 [95% CI, 1.62–30.7];
P
=0.0093) significantly predicted hemorrhagic stroke. No questionable hemispheres developed any stroke.

Conclusions:
The hemispheres with asymptomatic moyamoya disease may carry a 1.0% annual risk of stroke during the first 5 years, the majority of which are hemorrhagic stroke. Grade-2 choroidal anastomosis may predict stroke, and the microbleeds and Grade-2 choroidal anastomosis may carry the risk for hemorrhagic stroke.

Registration:

URL:
https://www.clinicaltrials.gov
; Unique identifier: UMIN000006640.