Objective We performed a systematic review and meta-analysis to determine the association of fluid-attenuated inversion recovery (FLAIR) hyperintense arteries (FLAIR-HAs) on brain MRI and prognosis after acute ischaemic stroke (AIS).
Methods We searched Medline, Embase and Cochrane Central Register of Controlled Trials for studies reporting clinical or imaging outcomes with presence of FLAIR-HAs after AIS. Two researchers independently assessed eligibility of retrieved studies and extracted data, including from the Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED). Outcomes were unfavourable functional outcome (primary, modified Rankin scale scores 3–6 or 2–6), death, intermediate clinical and imaging outcomes. We performed subgroup analyses by treatment or types of FLAIR-HAs defined by location (at proximal/distal middle cerebral artery (MCA), within/beyond diffusion-weighted imaging (DWI) lesion) or extent.
Results We included 36 cohort studies (33 prospectively collected) involving 3577 patients. FLAIR-HAs were not associated with functional outcome overall (pooled risk ratio 0.87, 95% CI 0.71 to 1.06), but were significantly associated with better outcome in those receiving endovascular therapy (0.56, 95% CI 0.41 to 0.75). Contrary to FLAIR-HAs at proximal MCA or within DWI lesions, FLAIR-HAs beyond DWI lesions were associated with better outcome (0.67, 95% CI 0.57 to 0.79). FLAIR-HAs favoured recanalisation (1.21, 95% CI 1.06 to 1.38) with increased risk of intracerebral haemorrhage (2.07, 95% CI 1.37 to 3.13) and early neurological deterioration (1.93, 95% CI 1.30 to 2.85).
Conclusions FLAIR-HAs were not associated with functional outcome overall but were associated with outcome after endovascular therapy for AIS. FLAIR-HAs were also associated with early recanalisation or haemorrhagic complications, and early neurologic deterioration.
PROSPERO registration number CRD42019131168.
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Contributors Conception and design: ZZ, GM, RASS, JMW, RIL, CSA; literature search and data extraction: ZZ, AM, SY, CD; analysis and interpretation of data: all authors; initial drafting of manuscript: ZZ, AM, CD, CSA; critical revision of the manuscript for intellectual content: all authors; final approval of the manuscript: all authors.
Funding The Enhanced Control of Hypertension and Thrombolysis Stroke Study trial is supported by grants from the National Health and Medical Research Council of Australia (project grant numbers 1020462 and 1101113), the Stroke Association of the UK (TSA 2012/01 and 2015/01), the Ministry of Health and the National Council for Scientific and Technological Development of Brazil (CNPQ: 467322/2014-7, 402388/2013-5), the Ministry for Health, Welfare and Family Affairs of the Republic of Korea (HI14C1985) (for the alteplase-dose arm) and a research grant from Takeda for conduct of the study in China. The work was done by the authors with no involvement of the funder in the design or conduct of the study; collection, management, analysis or interpretation of the data; preparation, review or approval of the manuscript; or decision to submit the manuscript for publication.
Competing interests GM reports grants from The Stroke Association. AMD reports personal fees from Medtronic and Daiichi Sankyo (outside the work). JMW reports grants from The Stroke Association and UK Medical Research Council. CSA reports honorarium from Takeda, Boehringer Ingelheim and Amgen.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information except the data in Table 1 and individual participant data from ENCHANTED which are available upon reasonable request.