Age-dependent associations of peripheral immune-inflammatory indices with cerebrovascular remodeling after revascularization in ischemic moyamoya disease

Objective Peripheral immune-inflammatory activity may influence postoperative vascular remodeling in Moyamoya disease (MMD), but the relevant pathways may differ by developmental stage. We investigated age-dependent associations of blood cell-derived inflammatory indices with two complementary imaging outcomes: collateralization angiogenesis ratio (CAR) and arterial residual volume (ARV). Methods This retrospective observational study included 108 patients with ischemic MMD who underwent revascularization (76 adults and 32 pediatric patients). Associations of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), neutrophil-to-platelet ratio (NPR), and platelet-to-albumin ratio (PAR) with CAR and ARV were screened using Spearman correlations with Benjamini–Hochberg false-discovery-rate correction. Standardized multivariable linear models used HC3 robust standard errors and adjusted for age, sex, Suzuki stage, and follow-up. Effect modification was evaluated using cohort-by-marker and continuous age-by-marker interactions. Results CAR and ARV did not differ between adults and pediatric patients (P = 0.583 and P = 0.853, respectively) and were uncorrelated within either cohort, supporting their interpretation as distinct remodeling dimensions. In unadjusted analyses, pediatric NPR correlated inversely with CAR (ρ=−0.431, P = 0.014), whereas adult PLR correlated inversely with ARV (ρ=−0.242, P = 0.035); neither association survived false-discovery-rate correction. After adjustment, pediatric NPR remained inversely associated with CAR (standardized β=−0.380, 95% CI −0.652 to −0.108; P = 0.006). The adult PLR–ARV association was borderline (β=−0.255, 95% CI −0.512 to 0.002; P = 0.052). PLR showed significant age-dependent effect modification: the PLR pediatric-cohort interaction was positive (β=0.547, 95% CI 0.112 to 0.981; P = 0.014), and the PLR continuous-age interaction was negative (β=−0.264, 95% CI −0.485 to −0.043; P = 0.019), indicating that the PLR–ARV relationship became more negative with increasing age. Conclusions In this exploratory analysis, peripheral inflammatory indices were associated with different postoperative remodeling pathways according to developmental stage. The age-dependent PLR–ARV relationship was the most consistent interaction signal, whereas the adjusted pediatric NPR–CAR association suggests a potentially localized collateralization mechanism. However, these exploratory findings require validation in larger, prospectively characterized cohorts.