Peripheral endothelial dysfunction measured by EndoPAT and functional outcomes after acute ischemic stroke

EndoPAT-derived reactive hyperemia index (RHI) is used to assess peripheral endothelial dysfunction, but its clinical value after acute ischemic stroke remains uncertain. We aimed to evaluate whether low RHI was associated with functional outcomes, early neurological deterioration (END), 3-month clinical events, and incremental outcome prediction.

This was a retrospective analysis of a prospectively maintained single-center acute stroke registry. Patients were followed through discharge and 3 months after the index stroke. Among 373 patients with a final diagnosis of acute ischemic stroke, 357 had valid RHI measurements and were included in the EndoPAT analysis. Low RHI was defined as RHI ≤1.67. Logistic regression models were adjusted for age, sex, TOAST subtype, premorbid modified Rankin Scale (mRS), initial NIHSS, and vascular risk factors. Receiver operating characteristic analyses compared conventional outcome models with and without continuous RHI.

Low RHI was present in 152 patients (42.6%). Poor discharge outcome occurred in 49/149 patients with low RHI and 51/204 with normal RHI (32.9% vs 25.0%; P = 0.104). Low RHI was associated with poor discharge outcome after full adjustment (adjusted odds ratio 1.82, 95% CI 1.04-3.18; P = 0.036). Poor 3-month outcome occurred in 36/141 patients with low RHI and 35/191 with normal RHI (25.5% vs 18.3%; P = 0.113) and was not significant after adjustment (adjusted odds ratio 1.55, 95% CI 0.84-2.85; P = 0.158). Low RHI was not associated with END or 3-month clinical events. Adding continuous RHI minimally changed AUC for discharge outcome (0.792 to 0.793) and 3-month outcome (0.771 to 0.776).

Low pre-discharge RHI was associated with poor discharge functional outcome, but showed limited association with longer-term outcome, clinical events, or incremental prediction. These findings support interpreting RHI as an in-hospital clinical marker, not as an independent prognostic test.