Carotid Occlusion Surgery Study (COSS)

Overview
The overall purpose of this research is to determine if a surgical operation called "Extracranial-Intracranial Bypass" can reduce the chance of a subsequent stroke in someone who has complete blockage in one main artery in the neck (the carotid artery) that supplies blood to the brain and has already suffered a small stroke. This surgery involves taking an artery from the scalp outside the skull, making a small hole in the skull and then connecting the scalp artery to a brain artery inside the skull. In this way the blockage of the carotid artery in the neck is bypassed and more blood can flow to the brain. In some people natural bypass arteries develop and the brain is already getting plenty of blood. These people have a low risk of stroke if they take medicine. In other people, no natural bypass arteries develop so less blood flows to their brains. This second group has a much higher risk of stroke while taking medicine, as high as 25-50% within the next two years. It is this second group of people who may benefit from having the bypass operation and who are the candidates for this study.

Purpose
To determine if extracranial-intracranial bypass surgery when added to best medical therapy can reduce the subsequent risk of ipsilateral stroke in high-risk patients with recently symptomatic carotid occlusion and increased cerebral oxygen extraction fraction measured by PET.

Eligibility

Inclusion criteria

• Patient must have vascular imaging demonstrating occlusion of one internal carotid artery.
• Patient must have vascular imaging demonstrating less than 50% stenosis of the contralateral carotid artery.
• Patient must have had a transient ischemic attack (TIA) or ischemic stroke in the hemispheric carotid territory of the occluded carotid artery.
• Patient's most recent qualifying TIA or stroke occurring within 120 days prior to projected performance date of PET.
• Patient's Modified Barthel Index > 12/20 (60/100).
• Patient must have language comprehension intact, motor aphasia mild or absent.
• Patient must be between the age of 18-85 and legally an adult.
• Patient must be competent to give informed consent.
• Patient must be geographically accessible and reliable for follow-up.

Exclusion criteria

• Patient must not have non-atherosclerotic carotid vascular disease.
• Patient must not have blood dyscrasias: Polycythemia vera, essential thrombocytosis, sickle cell disease (SS or SC).
• Patient must not have a known heart disease likely to cause cerebral ischemia (echocardiography not required). This includes the following conditions ONLY: Atrial fibrillation, Prosthetic valve, Infective endocarditis, Left atrial or ventricular thrombus, Sick sinus syndrome, Myxoma, Cardiomyopathy with ejection fraction <25%. This is an all-inclusive list. The following conditions are NOT EXCLUSIONS: patent foramen ovale, atrial septal aneurysm.
• Patient must not have other non-atherosclerotic condition likely to cause focal cerebral ischemia.
• Patient must not have the following medical conditions: Cancer (other than skin), Renal Failure (BUN and/or creatinine > twice normal upper limit), Congestive Heart Failure, Myocardial Infarction within 6 months, Liver disease, Pulmonary disease constituting an anesthetic risk.
• Patient must not have any condition likely to lead to death within 2 years.
• Patient must not have other neurological disease that would confound follow-up assessment.
• Patient must not be pregnant.
• Patient must not have subsequent cerebrovascular surgery planned which might alter cerebral hemodynamics.
• Patient must not have any condition which in the participating surgeon's judgment makes the subject an unsuitable surgical candidate.
• Patient must not be a participant in any other experimental treatment trial.
• Patient must not have participated within the previous 12 months in any experimental study that included exposure to ionizing radiation.
• Remediable medical conditions. Patients with the following conditions can become eligible if the exclusion criterion no longer applies within 120 days of onset of the most recent qualifying event: Uncontrolled diabetes mellitus (FBS > 300 mg%/16.7 mmol/L), Uncontrolled hypertension (systolic BP>180, diastolic BP >110), Unstable angina, Uncontrolled hypotension (diastolic BP < 65).
• Patient must not have acute, progressing or unstable neurological deficit. Neurological deficit must be stable for 72 hours prior to the performance of PET.
• Patient must not have an allergy to iodine or X-ray contrast media.

Study design
This is a Phase III randomized, multicenter treatment study.

Location & contact
Mario Zuccarello, MD (Principal investigator)
University of Cincinnati Medical Center
231 Albert Sabin Way
Cincinnati, OH 45219
Telephone: 513-558-3590
Fax: 513-558-7702
Email: suzanne.kempisty-cliver@uc.edu 

More information
More info is available for this study .
Start date: 02/03/2004
Close date: upon enrollment of 93 people.
Sponsor: National Institute of Neurological Disorders and Stroke (NINDS)
Study ID number: 1   UO1 NS42167-01, UC#02-4-30-11