Abstract 3034: Does Untreated Peripheral Vascular Disease Create A Remote Ischemic Preconditioning Effect In Human Ischemic Stroke?

Abstract

Introduction: Despite promising success in animal models, neuroprotective strategies remain limited in clinical applications. There is a growing interest in endogenous mechanisms of ischemic protection in the human brain and their potential therapeutic application. In this study we investigated if a history of untreated peripheral vascular disease (PVD) could act as a form of “remote ischemic preconditioning” and induce tolerance to cerebral ischemic events in terms of clinical outcomes after ischemic stroke. Methods: We performed a retrospective review of a prospectively collected database of 1,473 patients who presented to our institution with ischemic strokes between October 2005 and February 2011. Patients with a history of peripheral vascular disease were identified. A balanced control group within the same database was determined by using a matching algorithm that considered the following characteristics: age, sex, ethnicity, history of hypertension, prior TIA’s, diabetes mellitus, tobacco use, and NIHSS at presentation. The groups were compared in terms of modified Rankin Scale (mRS) at discharge and mortality. Results: Forty-five patients were identified to have untreated PVD. Table 1 summarizes the demographic and risk factor proportions for each group. Age, gender, NIHSS at presentation and past medical history were comparable among the groups. Non-fatal outcomes were not significantly different in the case and control groups. There were 23 patients (51.1%) with a mRS of 3 or less with PVD compared to 22 patients (48.9%) in the control group and 18 patients (39%) with a mRS of 4 or 5 with PVD compared to 14 patients (31.1%) in the control group. However, the mortality rate was significantly different, with 4 deaths (8.9%) in the PVD group versus 10 deaths (22.2%) in the control group (Odds Ratio 0.85, 95% CI 0.7-1.0). Conclusions: In a retrospective cohort of patients and case-matched controls with ischemic stroke, a history of untreated peripheral vascular disease (PVD) is associated with a lower mortality rate secondary to stroke. PVD could act as a form of “remote ischemic preconditioning” and induce tolerance to cerebral ischemic events in terms of reduction of stroke-related mortality.