Carotid and Vertebral Dissection — Is Anticoagulation Justified?
Carotid and Vertebral Dissection—Is Anticoagulation Justified?
Abstract & Commentary
By Alan Z. Segal, MD Dr. Segal is Assistant Professor, Department of Neurology, Weill-Cornell Medical College, Attending Neurologist, New York-Presbyterian Hospital. Dr. Segal is on the speaker's bureau of Boehringer Ingelheim.
Synopsis: There is a role for endovascular therapy, such as stenting, as reported in Stroke, in the setting of failed medical management with anticoagulants.
Source: Donnan GA, Davis SM. Controversies in Stroke: Extracranial Arterial Dissection. Stroke. 2005;36:2041-2042.
Dissections of carotid or vertebral arteries may produce stroke due to artery-to-artery embolism, as a result of clot formation at the site of the arterial intimal tear. If the arterial lumen is sufficiently obstructed, producing a so-called string sign, stroke may alternatively result due to impaired blood flow. Subarachnoid hemorrhage may complicate dissections that extend beyond the dural margin, as the arterial medial and adventitial walls weaken within the brain. A large subset of dissection patients, however, may present in a much less serious fashion. Many patients with carotid dissection may have only an incidental Horner's syndrome localized to the cervical sympathetic chain. Vertebral artery tears occurring with often minor neck trauma may also present without neurological signs, perhaps producing only pain. The advent of MRI imaging, particularly MRA of the neck, has permitted diagnosis of these vascular lesions when they previously may have gone undetected or would have required catheter-based angiography in order to be discovered. Because dissections may be so easily diagnosed, particularly in patients who are young and essentially well, they have become more common, and it has become more challenging to determine their optimal management.
Donnan and Davis presents a point-counter-point comparing the use of anti-platelet therapy (essentially aspirin) vs anticoagulation (heparin followed by coumadin). A recent Cochrane meta-analysis comparing these strategies showed no difference, although there was no data available from controlled trials. Real-life practice actually strongly slants towards anticoagulation. More than 80% of surveyed neurologists in Canada, reported using anticoagulation over anti-platelet treatment. Theoretically, anticoagulation might worsen dissection, since thinning the blood might promote enlargement of the extra-luminal clot and cause progressive intra-luminal compromise. Even more uncertain might be the use of tPA in patients with dissection. Such use has been reported in case reports, but has not been validated in large numbers of patients. Finally, there is a role for endovascular therapy, such as stenting, as our group recently reported in Stroke in the setting of failed medical management with anticoagulants.1
Commentary
Given the controversy and absence of controlled data, optimal management of carotid or vertebral dissection must be tailored to the individual patient. Patients with asymptomatic dissections, isolated to a Horner's syndrome (for carotid lesions), with no CNS signs and a negative MRI diffusion weighted image, could be managed with anti-platelet therapy alone. Aspirin may be used, but clopidogrel or combination anti-platelet therapy such as aspirin-clopidogrel or aspirin-dipyridamole are also reasonable empiric options. Patients with symptomatic dissections having TIA or stroke should be managed with anticoagulation, often intravenous or low molecular weight heparin followed by warfarin. Patients who fail medical management should be referred for stent procedures, or rarely for vascular or neurosurgical arterial repair. As with many clinical quandaries, a large-scale, randomized, controlled clinical trial is the only definitive way to clarify these issues.
Reference
1. Biondi A, Katz JM, Vallabh J, Segal AZ, Gobin YP. Progressive Symptomatic Carotid Dissection Treated with Multiple Stents. Stroke. 2005;36:e80.
There is a role for endovascular therapy, such as stenting, as reported in Stroke, in the setting of failed medical management with anticoagulants.Subscribe Now for Access
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