Cerebrovascular Reactivity to L-Arginine in Patients with Lacunar Infarctions

Abstract

Background: It is well known that endothelial dysfunction plays an important role in the pathogenesis of many cardiovascular disorders. The aim of this study was to test the hypothesis that specific, marked endothelial dysfunction of cerebral arteries is present in patients with lacunar cerebral infarctions. Methods: Cerebrovascular reactivity to L-arginine, which reveals the function of the cerebral endothelium, was investigated in patients with lacunar infarctions (20 patients, 11 male and 9 female, aged 60.9 ± 7.3 years), 21 age- and gender-matched asymptomatic patients with similar cardiovascular risk factors (all patients had arterial hypertension) and 21 age- and gender-matched healthy controls. The mean arterial velocity (v_m) in both middle cerebral arteries was measured by transcranial Doppler sonography during a 15-min baseline period, a 30-min intravenous infusion of L-arginine and a 15-min interval after L-arginine infusion. Arterial blood pressure, heart rate and CO₂ were measured continuously. Results: The measured v_m increase during L-arginine infusion in the patients with lacunar infarctions (13.4 ± 9.1%) was significantly lower compared to the healthy controls (20.5 ± 9.9%) but similar to that obtained in the patients with cardiovascular risk factors (11.5 ± 8.9%). Conclusions: Our results showed that cerebrovascular reactivity to L-arginine, which demonstrates cerebral endothelial function, is significantly impaired in patients with cardiovascular risk factors. Importantly, we found that patients with lacunar infarctions do not show any additional impairment of cerebral endothelial function.