Carotid Occlusion Surgery Study (COSS)

The purpose of this study is 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 positron emission tomography (PET).

Study Overview

• Status: Terminated
• Conditions: Stroke; Ischemic Attack, Transient; Cerebral Infarction
• Intervention / Treatment: Procedure: extracranial-intracranial bypass surgery; Drug: best medical therapy

Detailed Description

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.

This bypass surgery is considered experimental because it is not generally performed for this condition and it is unknown whether it leads to a decrease, an increase or no change in the risk of stroke. In order to determine if people fit into this second group of people who may benefit from the bypass operation they need to have a test called a PET scan. The PET scan measures the amount of blood that is getting to the brain and the amount of oxygen that the brain is using. The PET scan uses radioactive oxygen and water and is experimental (not approved by the United States Food and Drug Administration). If the PET scan shows that less blood is getting to the brain, there will be a 50-50 chance (like a coin toss) of receiving the bypass surgery or not. There will then be follow-up visits to the clinic one month later and then every three months for two years to check on the appropriate medical treatment that everyone will receive and to determine who has had a stroke.

The study hypothesis is that extracranial-intracranial bypass surgery when added to best medical therapy can reduce by 40 percent subsequent stroke within two years in participants with recent TIA ('ministroke") or stroke (</= 120 days) due to blockage of the carotid artery and reduced blood flow to the brain measured by PET.

• Study Type: Interventional
• Enrollment (Actual): 700
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • Missouri
    • St. Louis, Missouri, United States, 63110
      • Washington University School of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Vascular imaging demonstrating occlusion of one or both internal carotid arteries.
• Transient ischemic attack (TIA) or ischemic stroke in the hemispheric carotid territory of one occluded carotid artery.
• Most recent qualifying TIA or stroke occurring within 120 days prior to projected performance date of PET.
• Modified Barthel Index > 12/20 (60/100).
• Language comprehension intact, motor aphasia mild or absent.
• Age 18-85 inclusive.
• Competent to give informed consent.
• Legally an adult.
• Geographically accessible and reliable for follow-up.

Exclusion Criteria:

• Non-atherosclerotic carotid vascular disease. Blood dyscrasias: Polycythemia vera ,essential thrombocytosis, sickle cell disease (SS or SC).
• Known heart disease likely to cause cerebral ischemia (echocardiography not required). This includes the following conditions ONLY: 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: Atrial fibrillation, patent foramen ovale, atrial septal aneurysm.
• Other non-atherosclerotic condition likely to cause focal cerebral ischemia.
• Any condition likely to lead to death within 2 years.
• Other neurological disease that would confound follow-up assessment.
• Pregnancy.
• Subsequent cerebrovascular surgery planned which might alter cerebral hemodynamics.
• Any condition which in the participating surgeon's judgment makes the subject an unsuitable surgical candidate.
• Participation in any other experimental treatment trial.
• Participation within the previous 12 months in any experimental study that included exposure to ionizing radiation.
• Acute, progressing or unstable neurological deficit. Neurological deficit must be stable for 72 hours prior to the performance of PET.
• If supplemental arteriography is required, allergy to iodine or x-ray contrast media, serum creatinine > 3.0 mg/dl or other contraindication to arteriography.
• If aspirin is to be used as antithrombotic therapy in the perioperative period, those with allergy or contraindication to aspirin are ineligible.
• Medical indication for treatment with anticoagulant drugs, ticlopidine, clopidogrel or other antithrombotic medications such that these medications cannot be replaced with aspirin in the perioperative period as deemed necessary by the COSS neurosurgeon if the participant is randomized to surgical treatment.
• 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).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Surgical group; Assigned to undergo extracranial-intracranial arterial bypass in addition to best current practice medical therapy	Procedure: extracranial-intracranial bypass surgery; Surgical anastomosis of a superficial temporal artery branch to a middle cerebral artery branch through a small craniectomy plus best current practice medical therapy; Other Names: EC-IC Arterial Bypass; STA-MCA Bypass
Active Comparator: Non-surgical group; Receives best current practice medical therapy	Drug: best medical therapy; best current practice medical therapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Surgical Group:Ipsilateral Ischemic Stroke in 2 Yrs From Randomization and All Stroke & Death Through 30d Post-surgery; Non-surgical Group:Ipsilateral Ischemic Stroke in 2 Yrs From Randomization and All Stroke & Death Through 30d Post-randomization	2 yr Kaplan-Meier estimates of the proportions.Proportions expressed as percentages for reporting purposes. Ipsilateral ischemic stroke is defined as the clinical diagnosis of a focal neurological deficit due to cerebral ischemia clinically localizable within the internal carotid artery territory distally to the symptomatic occluded internal carotid artery that lasts for more than 24 hours. All stroke is defined as the clinical diagnosis of a focal deficit due to ischemia or hemorrhage clinically localizable to the brain that lasts for more than 24 hours. Death is of any cause.	within 2 yrs of randomization

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
All Stroke	2 yr Kaplan-Meier estimates of the proportions. All stroke is defined as the clinical diagnosis of a focal deficit due to ischemia or hemorrhage clinically localizable to the brain that lasts for more than 24 hours	within 2 yrs of randomization
Disabling Stroke	2 yr Kaplan-Meier estimates of the proportions. Disabling stroke is defined as a modified Barthel Index of <12/20 at the first scheduled return visit more than 3 months after the stroke occurred	within two years after randomization
Fatal Stroke	2 yr Kaplan-Meier estimates of the proportions. Fatal stroke is a stroke that in the investigator's opinion led directly to the participants death within 30 days of occurrence	within 2 years after randomization
Death	2 yr Kaplan-Meier estimates of the proportions. Death of any cause	within 2 years after randomization
Modified Rankin 0-1	Proportion with modified Rankin score, dichotomized 0 or 1 vs 2-6.The modifed Rankin (0-6) describes the degree of functional disability. A lower score indicates less functional disability.	at 2 years after randomization or end of trial. Worst case imputed for death and missing values
Modified Rankin 0-2	Proportion with Modified Rankin score at 2 yrs, dichotomized 0-2 vs 3-6. The modifed Rankin (0-6) describes the degree of functional disability. A lower score indicates less functional disability.	at 2 years after randomization or end of trial. Worst case imputed for death and missing values
Modified Barthel Index 19-20	Modified Barthel Index dichotomized 19-20 vs <= 18. The modifed Barthel Index(0-20) describes the degree of independence in day-to-day self-care activities. A higher score indicates greater independence.	at 2 years after randomization or end of trial. Worst case imputed for death and missing values
Summary SS-QOL Score	Summary Stroke Specific Quality of Life score (1-4) askes how self-reported overall quality of life compares with with that before stroke. A higher score indicates is better.	at 2 years after randomization or end of trial. Worst case imputed for death and missing values
Ipsilateral Ischemic Stroke in 2 Yrs From Randomization and All Stroke & Death Through 30d Post-surgery; Non-surgical Group:Ipsilateral Ischemic Stroke in 2 Yrs From Randomization and All Stroke & Death Through 30d Post-randomization	2 yr Kaplan-Meier estimates of the proportions.Proportions expressed as percentages for reporting purposes. Ipsilateral ischemic stroke is defined as the clinical diagnosis of a focal neurological deficit due to cerebral ischemia clinically localizable within the internal carotid artery territory distally to the symptomatic occluded internal carotid artery that lasts for more than 24 hours. All stroke is defined as the clinical diagnosis of a focal deficit due to ischemia or hemorrhage clinically localizable to the brain that lasts for more than 24 hours. Death is of any cause.	within 2 years of randomization

Other Outcome Measures

Outcome Measure	Time Frame
Any Stroke or Death Within 30 Days After Surgery	within 30 days after surgery

Collaborators and Investigators

• Sponsor: University of North Carolina, Chapel Hill
• Collaborators: Washington University School of Medicine; National Institute of Neurological Disorders and Stroke (NINDS); University of Iowa
• Investigators: Principal Investigator: William J. Powers, M.D., University of North Carolina, Chapel Hill

Publications and helpful links

General Publications

• Grubb RL Jr, Derdeyn CP, Fritsch SM, Carpenter DA, Yundt KD, Videen TO, Spitznagel EL, Powers WJ. Importance of hemodynamic factors in the prognosis of symptomatic carotid occlusion. JAMA. 1998 Sep 23-30;280(12):1055-60. doi: 10.1001/jama.280.12.1055.
• Derdeyn CP, Gage BF, Grubb RL Jr, Powers WJ. Cost-effectiveness analysis of therapy for symptomatic carotid occlusion: PET screening before selective extracranial-to-intracranial bypass versus medical treatment. J Nucl Med. 2000 May;41(5):800-7.
• Adams HP Jr, Powers WJ, Grubb RL Jr, Clarke WR, Woolson RF. Preview of a new trial of extracranial-to-intracranial arterial anastomosis: the carotid occlusion surgery study. Neurosurg Clin N Am. 2001 Jul;12(3):613-24, ix-x.
• Grubb RL Jr, Powers WJ, Derdeyn CP, Adams HP Jr, Clarke WR. The Carotid Occlusion Surgery Study. Neurosurg Focus. 2003 Mar 15;14(3):e9. doi: 10.3171/foc.2003.14.3.10.
• Grubb RL Jr, Powers WJ, Clarke WR, Videen TO, Adams HP Jr, Derdeyn CP; Carotid Occlusion Surgery Study Investigators. Surgical results of the Carotid Occlusion Surgery Study. J Neurosurg. 2013 Jan;118(1):25-33. doi: 10.3171/2012.9.JNS12551. Epub 2012 Oct 26.
• Powers WJ, Clarke WR, Grubb RL Jr, Videen TO, Adams HP Jr, Derdeyn CP; COSS Investigators. Extracranial-intracranial bypass surgery for stroke prevention in hemodynamic cerebral ischemia: the Carotid Occlusion Surgery Study randomized trial. JAMA. 2011 Nov 9;306(18):1983-92. doi: 10.1001/jama.2011.1610. Erratum In: JAMA. 2011 Dec 28;306(24):2672. Obviagele, Bruce [corrected to Ovbiagele, Bruce].

Study record dates

Study Major Dates

• Study Start: July 1, 2002
• Primary Completion (Actual): June 1, 2010
• Study Completion (Actual): June 1, 2010

Study Registration Dates

• First Submitted: January 8, 2002
• First Submitted That Met QC Criteria: January 8, 2002
• First Posted (Estimate): January 9, 2002

Study Record Updates

• Last Update Posted (Estimate): March 27, 2012
• Last Update Submitted That Met QC Criteria: March 24, 2012
• Last Verified: March 1, 2012

More Information

Terms related to this study

• Keywords: stroke; cerebral infarction; transient ischemic attack (TIA); carotid arteries
• Additional Relevant MeSH Terms: Ischemia; Pathologic Processes; Necrosis; Cardiovascular Diseases; Vascular Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Brain Ischemia; Stroke; Brain Infarction; Infarction; Ischemic Attack, Transient; Cerebral Infarction
• Other Study ID Numbers: R01NS042167; R01NS041895 (Other Grant/Funding Number: NINDS)