In this retrospective exploratory study of symptomatic ICAS, angiography-derived fractional flow stratification (threshold 0.76) was associated with differences in functional outcomes between interventional and conservative treatment, whereas degree-of-stenosis stratification (DS% ≥70%) was not, but findings are exploratory and need prospective validation.
Key Findings
Results
Among patients with FF ≤ 0.76, a higher proportion of the interventional group than the conservative group had no worsening in mRS between discharge and 12 months.
No worsening in mRS occurred in 96.3% of the interventional group versus 78.6% of the conservative group (p = 0.017).
FF was derived from digital subtraction angiography using an angiography-based computational method.
The FF threshold of 0.76 was pre-specified.
Outcomes were assessed with mRS and NIHSS at discharge and 12 months.
Results
In a post hoc analysis of FF ≤ 0.76 patients, mRS improvement of at least one point was more frequent with intervention, but this difference was not robust to adjustment for discharge mRS.
Improvement of at least one mRS point occurred in 46.3% (interventional) versus 17.9% (conservative).
Discharge mRS scores differed between the treatment groups.
The difference in improvement was not statistically significant when the analysis was restricted to patients with discharge mRS ≥ 1.
Results
In patients with FF > 0.76, no significant differences in mRS or NIHSS improvement were observed between interventional and conservative strategies.
The reported p-values were > 0.05 for both mRS and NIHSS comparisons.
This contrasts with the FF ≤ 0.76 subgroup, where a difference in mRS non-worsening was seen.
Results
Stratification by degree of stenosis (DS% ≥ 70%) did not differentiate clinical outcomes between treatment groups.
This was in contrast to FF-based stratification, which was associated with outcome differences across treatment strategies in the FF ≤ 0.76 subgroup.
Conclusions
The authors conclude that FF may provide additional information for risk stratification in symptomatic ICAS and help identify subgroups for further evaluation, but the findings are exploratory.
The study was retrospective and exploratory, including symptomatic ICAS patients hospitalized between March 2019 and May 2024.
Patients were stratified by FF threshold of 0.76 and treatment modality (interventional vs conservative).
The authors state that validation in larger prospective studies is required.
What This Means
This study looked at patients who had symptoms from narrowed arteries inside the brain (intracranial atherosclerotic stenosis). The researchers used a computer method applied to standard angiogram images to estimate 'fractional flow,' a measure of how much the narrowing restricts blood flow. They then compared outcomes for patients who received an interventional procedure versus those treated conservatively, tracking disability and stroke severity scores at discharge and at 12 months.
In patients with low fractional flow (0.76 or below), nearly all who had an intervention (96.3%) did not get worse in disability over the year, compared with 78.6% of conservatively treated patients. Improvement in disability looked higher with intervention too (46.3% vs 17.9%), but the groups differed in disability at discharge, and the difference was not significant after restricting to patients with some disability at discharge. Among patients with higher fractional flow, treatment type made no significant difference. Sorting patients by how narrow the artery looked (70% or more stenosis) did not separate outcomes between treatments.
This research suggests that measuring blood flow through a narrowing, not just its visual tightness, might help identify which patients are more likely to benefit from intervention. However, the study was retrospective and exploratory, and treatment groups were not randomized, so the results cannot show that intervention caused better outcomes. Larger prospective studies are needed to confirm these findings.
Zheng W, Zou R, Wang M, Tang J, Chen R, Zheng C, et al.. (2026). Angiography-derived fractional flow and clinical outcomes in symptomatic intracranial atherosclerotic stenosis.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1944177