High Frequency of Intracranial Arterial Stenosis and Cannabis Use in Ischaemic Stroke in the Young

Background: Leading aetiologies of ischaemic stroke in young adults are cervico-cerebral arterial dissections and cardio-embolism, but the causes remain undetermined in a considerable proportion of cases. In a few reports, intracranial arterial stenosis has been suggested to be a potential cause of ischaemic stroke in young adults. The aim of our work was to evaluate the frequency, characteristics and risk factors of intracranial arterial stenosis in a prospective series of young ischaemic stroke patients. Methods: The study was based on a prospective consecutive hospital-based series of 159 patients aged 18-45 years who were admitted to our unit for an acute ischaemic stroke from October 2005 to December 2010. A structured questionnaire was used in order to assess common vascular risk factors such as hypertension, diabetes, hypercholesterolemia, use of tobacco, alcohol and illicit drugs, migraine, and, in women, oral contraceptive use. A systematic screening was performed, including the following: brain magnetic resonance imaging or, if not feasible, brain computed tomography scan, carotid and vertebral Duplex scanning and trans-cranial Doppler sonography, 3D time-of-flight magnetic resonance cerebral angiography or cerebral computed tomography angiography. Long-duration electrocardiography, trans-thoracic and trans-oesophageal echocardiography were performed and laboratory blood investigations were extensive. Urine samples were screened for cannabinoids, cocaine, amphetamine and methylene-dioxy-methamphetamine. When this initial work-up was inconclusive, trans-femoral intra-arterial selective digital subtraction angiography with reconstructed 3D images was performed. Results: In this series, 49 patients (31%) had intracranial arterial stenosis. Other defined causes were found in 91 patients (57%), including cardio-embolism in 32 (20%), cervical dissection in 23 (14%), extracranial atherosclerosis in 7 (4%), haematological disorders in 7 (4%), small vessel disease in 1, and isolated patent foramen ovale in 21 (13%); in 19 patients (12%), ischaemic stroke was related to an undetermined aetiology. Comparing risk factors between patients with intracranial arterial stenosis and those with other definite causes showed that there were only two significant differences: a lower age and a higher frequency of vasoactive substances (especially cannabis) in patients with intracranial arterial stenosis. All intracranial arterial stenosis in patients who used vasoactiv