a Departments of Medicine, King Abdulaziz International Medical Research Center, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia;b Cardiology, King Abdulaziz Medical City, King Abdulaziz International Medical Research Center, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia;c College of Medicine, King Saud bin Abdulaziz University of Health Sciences, Riyadh, Saudi Arabia;d Departments of Anaesthesia and Intensive Care, Stoke Mandeville Hospital, Aylesbury, Buckinghamshire, United Kingdom;e Division of Cerebrovascular Disorders, Cleveland Clinic Neurological Institute, Cleveland Clinic Foundation, Ohio, USA;f Department of Cardiovascular Medicine, Heart & Vascular Institute, Cleveland Clinic, Ohio, USA