Cardiovascular

Associations of nine composite inflammatory indices with clinical outcomes after mechanical thrombectomy for acute ischemic stroke: a single-center retrospective study.

Yuan M, He H, et al. • Frontiers in neurology • 2026

PubMed 42745732 DOI 10.3389/fneur.2026.1874021

TL;DR

The SII, NLR and PLR may serve as consistent biomarkers of post-MT hemorrhagic transformation, unfavorable outcomes and all-cause mortality, with particularly robust associations in patients with cardioembolic stroke.

Key Findings

Results

SII, NLR, and PLR were each significantly associated with hemorrhagic transformation after mechanical thrombectomy.

SII: OR 1.487, 95% CI 1.206–1.843, p-FDR = 0.001
NLR: OR 1.592, 95% CI 1.292–1.977, p-FDR < 0.001
PLR: OR 1.457, 95% CI 1.182–1.806, p-FDR = 0.001
Associations were significant whether indices were treated as continuous (z-scored) or categorical (tertile) variables
Blood sampling for all indices was performed before the MT procedure

Results

SII, NLR, and PLR were each significantly associated with unfavorable functional outcome (modified Rankin Scale score > 2) at 90-day follow-up.

SII: OR 1.662, 95% CI 1.293–2.178, p-FDR < 0.001
NLR: OR 1.648, 95% CI 1.291–2.148, p-FDR < 0.001
PLR: OR 1.707, 95% CI 1.319–2.267, p-FDR < 0.001
Multivariable analyses with false discovery rate correction were used to account for multiple comparisons
Continuous indices were standardized to z-scores prior to analysis

Results

SII, NLR, and PLR were each significantly associated with all-cause mortality after mechanical thrombectomy.

SII: HR 1.392, 95% CI 1.218–1.591, p-FDR < 0.001
NLR: HR 1.284, 95% CI 1.111–1.484, p-FDR = 0.001
PLR: HR 1.413, 95% CI 1.240–1.609, p-FDR < 0.001
Hazard ratios were derived from multivariable analyses with FDR correction

Results

Subgroup analyses revealed significant interactions of SII and NLR with all-cause mortality specifically in patients with cardioembolic stroke.

p for interaction for SII with mortality = 0.029
p for interaction for NLR with mortality = 0.004
These interactions indicated 'particularly robust associations in patients with cardioembolic stroke'
The paper concludes that 'closer monitoring may be required for cardioembolic stroke patients with elevated systemic inflammatory burden'

Results

Of nine composite inflammatory indices examined, only SII, NLR, and PLR showed consistent significant relationships across all three clinical outcomes.

Nine indices tested: SII, systemic inflammation response index, pan-immune-inflammation value, NLR, PLR, lymphocyte-to-monocyte ratio, neutrophil-to-platelet ratio, C-reactive protein-to-lymphocyte ratio, and neutrophil percentage-to-albumin ratio
Only SII, NLR, and PLR were subjected to further subgroup analyses based on their consistent significance
FDR correction was applied to control for multiple comparisons across all nine indices and three outcomes

Methods

The study included 508 patients with acute ischemic stroke who underwent mechanical thrombectomy at a single center.

Median age was 73 years (IQR 64–78)
233 patients (45.9%) were female
Median National Institutes of Health Stroke Scale (NIHSS) score was 15 (IQR 12–19), indicating moderate-to-severe stroke severity
This was a retrospective, single-center study design

What This Means

This research suggests that three blood-based inflammatory markers — the Systemic Immune-Inflammation Index (SII), the Neutrophil-to-Lymphocyte Ratio (NLR), and the Platelet-to-Lymphocyte Ratio (PLR) — measured before a stroke procedure called mechanical thrombectomy (a treatment to remove blood clots from blocked arteries) are consistently linked to worse outcomes. Specifically, patients with higher values of these markers were more likely to experience bleeding in the brain after the procedure, have poor functional recovery at 90 days, and die from any cause. The study looked at nine different inflammatory indices in 508 stroke patients and found that these three stood out as the most reliably predictive across all three types of bad outcomes. The research also found that the associations between these inflammatory markers and death were especially strong in patients whose strokes were caused by clots coming from the heart (cardioembolic stroke). This suggests that inflammation plays a particularly important role in outcomes for this subgroup of patients. These markers are calculated from routine blood tests, making them potentially easy and inexpensive to use in clinical practice. This research suggests that measuring pre-procedure inflammatory markers like SII, NLR, and PLR could help doctors identify stroke patients at higher risk of complications and death after mechanical thrombectomy. Patients with cardioembolic stroke and high inflammatory burden may warrant especially close monitoring. However, because this was a single-center retrospective study, further research in larger and more diverse populations would be needed to confirm these findings before they could be widely applied clinically.

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Citation

Yuan M, He H, Zheng L, Tang Y, Tang S, Duan J, et al.. (2026). Associations of nine composite inflammatory indices with clinical outcomes after mechanical thrombectomy for acute ischemic stroke: a single-center retrospective study.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1874021

Key Findings

What This Means

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