Meta-Analysis of Stroke Studies Demonstrates the Benefits of Carotid Endarterectomy
DURHAM, N.C. -- Duke University Medical Center researchers have found that the long-term benefits of a neck artery-cleaning procedure, called an carotid endarterectomy, in preventing strokes outweigh the short-term risks of the procedure for patients with such symptoms of carotid blockage as "mini-strokes."
In a carotid endarterectomy, an incision is made in the neck, and the carotid artery is opened. The surgeon removes the blockage, and then closes the artery.
Blockages in the carotid are a major cause of transient ischemic attacks (TIA), or mini-strokes, which neurologists consider an important warning sign that a person is at high risk of a major stroke.
The findings stemmed from a statistical procedure known as "meta-analysis," in which the researchers combined and analyzed the results of three separate large multicenter trials examining the benefits of carotid endarterectomy. The results of the analysis were published Friday in the journal Neurology.
The Duke scientists' meta-analysis also found that the risks and benefits were the same for males and females, an analysis which had not previously been performed.
According to neurologist Dr. Larry Goldstein, who led the analysis, many physicians are reluctant to recommend the procedure. He cited a recent Duke survey that found one in five physicians seldom or never recommend carotid endarterectomies for symptomatic patients for whom clinical trials indicate it is clearly needed.
"There is a group of patients who would benefit from the surgery who may not be receiving it," Goldstein said. "Most of the care for this at-risk population is provided by internists and non-internist primary care physicians, so it is very important that they know about the particular groups of patients who should get the most benefit from the carotid endarterectomy procedure.
"Our meta-analysis of the data demonstrated that, while there is increased risk of stroke, non-fatal heart attack or death within 30 days of a carotid endarterectomy, there was a significant benefit after 30 days and a significant overall benefit," said Goldstein. Also participating in the study were Dr. Victor Hasselblad, Dr. David Matchar and Dr. Douglas C. McCrory. The study was funded in part by the federally sponsored Stroke PORT (Patient Outcomes Research Team), a large multicenter series of studies investigating clinical practice, costs and outcomes of preventive strategies for stroke that is supported by the Agency for Health Care Policy Research. Goldstein's research is also supported by the Veterans Administration.
The three trials, which were carried out in the United States and 14 European countries, were:
* The North American Symptomatic Carotid Endarterectomy Trial (NASCET), a 50-center study of 659 patients;
* The European Carotid Surgery Trial (ECST), an 80-center study of 778 patients;
* The VA Cooperative Study (VACS), a 13-VA Medical Center study of 193 patients.
"Despite the differences in the design of the three studies, we found a significant benefit of the procedure for those symptomatic patients who were experiencing TIAs, who had a significant blockage in the carotid that could be responsible for the symptoms, and who could tolerate the surgery," Goldstein said. "These results are robust and generalizable and add further validity to the individual studies."
The Duke researchers said the current meta-analysis provides compelling evidence that the procedure is warranted in patients who meet certain criteria -- those who experience TIAs, have significant narrowing of the carotid, and are without contraindications for surgery.
Comparison between the three studies had not been possible because of differences in study design and outcomes. However, Goldstein obtained standardized data from the principal investigators of the three studies.
"That these investigators would share the data that permitted us to carry out this analysis is truly noteworthy," Goldstein said. When the trials were combined, the Duke researchers had a total of 1,630 patients to include in their analyses.