Abstract 2790: Persistent Impairment of Endothelial Function in the Brachial Artery is a Predictor of Future Ischemic Stroke in Patients with Coronary Artery Disease
Although endothelial dysfunction is a predictor of ischemic stroke, it remains unclear whether reversibility of endothelial dysfunction in response to risk-factor reduction has prognostic value. This study examined whether changes in endothelial vasomotor function in response to optimized therapy for atherosclerotic cardiovascular diseases (CVD) may predict ischemic stroke in patients with coronary artery disease (CAD).
Methods: This study included 202 consecutive patients with newly diagnosed CAD who had an impairment of flow-mediated dilation (FMD) of the brachial artery at baseline. After enrollment, all patients had individualized, optimized therapies including medications and life style changes based on AHA guidelines to reduce risk factors for CVD. FMD (expressed as percent dilation from baseline brachial artery diameter) during reactive hyperemia was measured by high-resolution ultrasound at entry and after 6 months. Impairment of FMD was defined as < 5.5% (mean minus 1 SD of FMD in 100 age- and sex-matched normal subjects in our hospital). Patients were prospectively followed for ≤ 36 months or until occurrence of an ischemic stroke, defined as focal neurological symptoms lasting > 24 hours for which computed tomography or magnetic resonance imaging showed corresponding ischemic infarction but not cerebral hemorrhage.
Results: FMD was persistently impaired (< 5.5%) in 79 (39%) patients after 6 months, whereas it was improved (FMD ≥ 5.5%) in the remaining 123 (61%) patients. Baseline FMD was comparable between the 2 groups of the patients (2.9 ± 0.2 vs.3.0 ± 0.1%, respectively, p = ns). During mean follow-up of 33 ± 2 months, stroke events occurred in 12 (15%) of 79 patients with persistently impaired FMD and in 5 (4%) of 123 patients with improved FMD (p < 0.01 by chi-square test). In multivariate Cox hazards analysis, persistent impairment of FMD predicted stroke independently of baseline FMD and traditional CVD risk factors (hazard ratio 3.1, 95% CI 1.5 – 9.7, p < 0.01).
Conclusions: Persistent impairment of endothelial function despite optimized therapies to reduce CVD risk factors predicts ischemic stroke in patients with CAD. Periodic measurement of FMD may be useful for stratification of stroke risk in these patients.