SAN DIEGO—With the availability of intensive medical therapy, carotid stenting or endarterectomy for the treatment of asymptomatic carotid stenosis may be beneficial only for a small percentage of patients, reported J. David Spence, MD, at the 2009 International Stroke Conference.
About 60% of revascularization procedures in the United States are performed for asymptomatic carotid stenoses. However, “most stenting and endarterectomy in asymptomatic patients is inappropriate,” said Dr. Spence, Professor of Neurology and Clinical Pharmacology and Director of the Stroke Prevention and Atherosclerosis Research Centre at the University of Western Ontario in London, Ontario, Canada.
Since implementing a new treatment paradigm at a Canadian stroke prevention clinic in 2003, Dr. Spence’s group has found that carotid plaques have stabilized or shrunk in size in most patients, and the development of microemboli has decreased markedly, limiting the number of patients with asymptomatic carotid stenosis who need revascularization to less than 5%.
The new treatment paradigm calls for adjustment of the intensity of medical therapy based on measurement of carotid plaque instead of risk factors. As a result, even patients who are already at goal levels for lipids and blood pressure would have their treatment intensified if the total plaque area progressed.
The study population consisted of 468 patients with asymptomatic carotid stenosis—199 who presented before the change in treatment paradigm in 2003 and 269 who presented after January 1, 2003. The incidence of microemboli and the number of clinical events (stroke, death, or carotid endarterectomy) during the two time periods were compared.
Before 2003, 12.6% of patients had microemboli detected on transcranial Doppler, compared with 3.7% after 2003. The risk for stroke in patients with microemboli was 10.3% at one year and 21.6% at two years. The corresponding risk for stroke in patients without microemboli was 1.4% at one year and 2.3% at two years.
Before 2002, the annual rate of plaque progression had been increasing. Since 2003, however, the rate of plaque progression has decreased markedly, and since 2005, “we have seen regression of plaque in 50% of patients, and regression on average in the entire clinic population,” said Dr. Spence.
In addition, the composite end point of stroke, death, myocardial infarction, or carotid endarterectomy decreased from 17.6% to 5.2% at two years following implementation of the treatment paradigm.
Revascularization Beneficial Only for Select Patients
Dr. Spence concluded that only patients with microemboli despite intensive medical therapy, which represents 3.7% of patients with asymptomatic carotid stenosis in his study, should be considered for endarterectomy or stenting.
These findings were supported by a study conducted at the Heart and Diabetes Institute in Melbourne, Australia. In a review of 11 randomized surgical trials, researchers found that among patients with asymptomatic severe proximal internal carotid artery stenosis, recent stroke rates with medical therapy alone were equivalent to rates with carotid surgery, angioplasty, or stenting.
—Wayne Kuznar