Cerebrovascular Risk in Restless Legs Syndrome: Intima-Media Thickness and Cerebral Vasomotor Reactivity: A Case–Control Study

PURPOSE: Although some studies have suggested an association between cardiovascular disease and restless legs syndrome (RLS), the mechanisms underlying this relationship remain unclear. The intima-media thickness (IMT) and vasomotor reactivity are two simple, non-invasive tools to investigate preclinical atherosclerosis and microangiopathy, respectively. The aims of this study were to evaluate carotid IMT and to explore vasomotor reactivity in idiopathic RLS (iRLS) patients. PATIENTS AND METHODS: We enrolled 44 iRLS after exclusion of patients with secondary causes of RLS, history of vascular events, known uncontrolled vascular risk factors and other neurological disorders. Forty-four age and sex matched controls were therefore recruited. No significant differences in demographic data and vascular risk factors were found between the two groups. Carotid IMT was measured with a high-resolution B-mode ultrasound on the far-wall of common carotid artery, 10 mm and 30 mm to the carotid bulb. Vasomotor reactivity to hypo- and hypercapnia was assessed, by right middle cerebral artery transcranial Doppler, accordingly to the changes in peak systolic velocity, peak diastolic velocity and mean blood flow velocity. RESULTS: Mean IMT was significantly increased in patients with iRLS when measured immediately proximally to carotid bifurcation (0.73; sd=0.17), versus controls (0.65; sd=0.13); p=0.035. Patients showed higher cerebrovascular flow velocities (CBFVs) compared to controls. After multivariate analysis, age, hypertension and iRLS proved to be independent IMT predictors. CONCLUSION: Increased IMT and higher CBFVs in iRLS support the association of iRLS with vascular damage, possibly through enhanced atherogenesis and sympathetic hyperactivity. However, to clarify a causal relationship, further longitudinal assessment of these parameters is needed, trying to control all their physiological modifying factors.