Role of Immune Indices, NLR, SII, PLR and SIRI in Predicting Post-Mechanical Thrombectomy (MT) outcomes
Yasmin Ghochani1, Chloe Villars2, Kevin Gramajo-Aponte2, Sookyung Oh3, Brenton Maisel3, Andrew Lee1, Masaki Nagamine1, Jay Shah1, Wengui Yu1, Mohammad Shafie1
1Vascular Neurology, 2School of Medicine, 3Neurology, University of California, Irvine
Objective:
We retrospectively reviewed MT cases at our institution to assess whether immune indices predict clinical/radiographic features and post-MT outcomes.
Background:
MT is an established treatment for acute ischemic stroke (AIS). With expanding eligibility windows and improved devices, outcome prediction and patient selection are crucial. Increasing evidence implicates systemic and intra-/peri-thrombus inflammation in AIS prognosis. Among systemic immune indices, neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), platelet-to-lymphocyte ratio (PLR), and systemic inflammation response index (SIRI) predict AIS outcomes, but their role in MT remains unclear.
Design/Methods:
We studied 68 MT patients treated between 9/2023-12/2024 at UC-Irvine. Demographics and clinical variables were summarized using means. Indices: NLR = neutrophils/lymphocytes (L), SII = (platelets × neutrophils)/L, SIRI = (neutrophils × monocytes)/L, PLR = platelets/L. Predictive values were calculated against TICI, mRS, LOS, and hemorrhagic transformation (HE) using 2×2 tables and reported 95% CIs. Thresholds were defined by ROC-derived Youden index or clinical cutoffs. Fisher’s exact test with FDR correction assessed significance.
Results:
Several indices showed significant predictive value (FDR <0.05). For poor reperfusion (TICI ≤2b), NLR ≥2.28, SII ≥470, and SIRI ≥0.92 yielded moderate PPVs (47–51%) and good NPVs (76–82%); raw p-values (0.027–0.045) trended toward significance after FDR (0.060). For HE (PH1/PH2), all indices were predictive, with NPVs 96–100%. NLR (≥3.64), PLR (≥265), and SIRI (≥1.33) predicted prolonged LOS >7 days (PPVs 65–100%). At discharge, NLR (≥4.7), SII (≥721), and SIRI (≥1.1) predicted discharge mRS ≥3 (PPVs 86–93%), though NPVs were low; 90-day mRS results trended similarly, with SIRI showing strongest NPV (86%).
Conclusions:
Elevated immune indices were consistently associated with HE and longer hospitalization, with trends toward poor reperfusion and functional outcomes, whereas lower values strongly excluded adverse events such as parenchymal hematoma. These leukocyte-based indices may improve MT candidate selection, as inflammation likely contributes substantially to AIS pathogenesis and treatment response.
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