Prognostic value of acylcarnitine-to-free carnitine ratio in ischemic stroke: associations with systemic inflammation and atherosclerosis.

BACKGROUND: Serum acylcarnitine-to-free carnitine (AC/FC) ratio has been proposed as an indicator of mitochondrial function and plays an important role in brain recovery. Although mitochondrial dysfunction promotes systemic inflammation and atherosclerosis, the prognostic value and pathophysiological implications of the AC/FC ratio in acute ischemic stroke (AIS) remain unclear. This study examined the association between the AC/FC ratio and prognosis as well as its relationship with systemic inflammation and atherosclerosis. METHODS: We enrolled consecutive patients with AIS admitted within 72 h of onset between October 2022 and November 2024. A favorable outcome was defined as a modified Rankin Scale score of 0-1 at 3 months. We determined the optimal AC/FC cutoff using receiver operating characteristic (ROC) analysis. Systemic inflammation and atherosclerosis were assessed using fibrinogen-to-albumin ratio (FAR) and ankle-brachial index (ABI). RESULTS: Of 463 screened patients, 285 were included (210 [74%] males; median age, 69 years), of whom 80 (28%) had unfavorable outcome. Poisson regression analysis with a robust variance estimator showed that an elevated AC/FC ratio was significantly associated with unfavorable outcome (PR 1.235, 95% CI 1.131-1.350, p < 0.001). Furthermore, higher FAR (PR 1.610, 95% CI 1.218-2.129, p = 0.001) and lower ABI (PR 0.268, 95% CI 0.099-0.727, p = 0.010) were associated with the AC/FC group above the optimal cutoff of 0.29 evaluated based on ROC analysis. CONCLUSIONS: An elevated serum AC/FC ratio was independently associated with unfavorable functional outcome in AIS and correlated with markers of systemic inflammation and atherosclerosis.