To the Editor:
Cervical artery dissection is an important cause of stroke in young patients. While the recent literature has focused on the pathophysiology,1 little attention has been given to acute treatment. Based on stroke patterns, recent work has opined that heparin is a “logical” treatment for carotid territory dissection,2 although this has been challenged.3 To investigate the treatment preferences of stroke experts in extracranial cervical artery dissection, we developed a single-page questionnaire. Members of the Canadian Stroke Consortium (CSC),4 a group consisting of neurologists with a subspeciality interest in stroke, were asked to fill out the questionnaire at their annual general meeting in 1999. In addition, the questionnaire was mailed out once to members who did not attend the meeting.
The CSC had 96 members at the time of this meeting, of whom 43 were present at the meeting. Of 49 survey responses received, 1 was excluded because of incomplete information, leaving 48 completed surveys (50% response rate) for this analysis. All of the respondents were neurologists, and the average number of years in practice was 13.4±1.1 (SEM). Physicians working at academic facilities (30) composed 61% of the total; those at community facilities, 37% (18 physicians); and not stated, 2% (1 physician). The average number of acute strokes seen per year per center was 357±30. The mean estimated number of dissections per center per year was 11±1. The centers were characterized by the availability of neuroimaging technology. All centers had duplex ultrasonography. Acute CT was available in 98%, conventional selective cerebral angiography in 90%, CT angiography in 75%, and MRI and MR angiography (MRA) in 71% of centers.
The preferred initial diagnostic modality for suspected carotid dissection was fairly evenly divided among angiography (31.3%), MRA (31.3%), and duplex (37.5%). For suspected vertebral dissection, angiography was favored (56.3%) over duplex (35.4%), MRA (6.3%), and CTA (2.1%). Although 92% of respondents believed that the gold standard test for any cervical artery dissection was conventional selective cerebral angiography, only 56% believed that all patients should undergo the gold standard test for diagnosis.
The preferred treatment for extracranial dissection was immediate anticoagulation. The favored underlying pathophysiology was distal embolism from clot in the dissected artery (Table⇓). Logistic regression analysis identified no variable (years in practice, province of practice, community versus teaching hospital, number of stroke cases admitted per year, availability of imaging technology, or favored underlying mechanism) that was predictive of treatment choice. Once the diagnosis was made, the mean time on treatment was 5.2±0.5 months. Patients were seen in follow-up after discharge in a mean of 2.3±0.2 months. Two thirds (67%) felt that patients should be re-imaged at follow-up, and the preferred modality was MRA (58%). Few (6%) would re-image with conventional selective arterial angiography.
Although there is little direct evidence supporting anticoagulation in extracranial cervical artery dissection, this lack of evidence has not dissuaded the majority of Canadian stroke neurologists from empirically anticoagulating their patients. This is consistent with recent literature which claims that the etiology of stroke after dissection is arteroembolic in more than 90% of cases.3 It remains possible that anticoagulation is not helpful; this is particularly relevant in light of increasing evidence that heparin is not generally useful in acute stroke treatment.5 6 The Stroke Group at the Cochrane Collaboration is working on a review of anticoagulation in extracranial internal carotid artery dissection that may provide more information.
A randomized trial of anticoagulation versus antiplatelet therapy in stroke secondary to acute cervical artery dissection, with definitive outcomes such as recurrent stroke or death, may be impractical due to the necessary size of such a trial.7 However, it remains an important question. Surrogate outcomes that would change practice—such as neurological disability, artery patency rate after 3 to 6 months of anticoagulation, transcranial Doppler analysis of high-intensity transient signals, cerebral blood flow measurement, and quality of life—need to be considered. Because stroke patients with dissection are most often young and likely to be intensively investigated, a multicenter collaboration using the outcomes described should be possible.
- Copyright © 2000 by American Heart Association
Grau AJ, Brandt T, Buggle F, Orberk E, Mytillineos J, Werle E, Conradt C, Krause M, Winter R, Hacke W. Association of cervical artery dissection with recent infection. Arch Neurol.. 1999;56:851–856.
Lucas C, Moulin T, Deplanque D, Tatu L, Chavot D, and the DONALD Investigators. Stroke patterns of internal carotid artery dissection in 40 patients. Stroke.. 1998;29:2646–2648.
Bounds JA, Lucas C, Deplanque D, Moulin T, Tatu L, Chavot D. Carotid dissection: pathophysiology of stroke and treatment implications. Stroke.. 1999;30:1149–1150. Letter.
Canadian Stroke Consortium Web site. Available at http://www.strokeconsortium.ca. Accessed October 1999.
Swanson RA. Intravenous heparin for acute stroke: what can we learn from the megatrials? Neurology.. 1999;52:1746–1750.
Gubitz G, Counsell C, Sandercock P, Signorini D. Anticoagulants for acute ischaemic stroke (Cochrane review). In: The Cochrane Library, Issue 3, 1999. Oxford, UK: Update Software.
Bounds JA. Carotid dissection: pathophysiology of stroke and treatment implications. Stroke.. 1999;30:1149. Letter.