However, according to Goldstein, they do not provide the same level of detail as does angiography. In the Duke study, the charts of 569 consecutive patients during a three-year period who received all three tests at an academic medical center and a community hospital were reviewed. After reviewing the charts, the researchers found that if the decision to operate were based solely on DU, about 29 percent of the patients would be misclassified, while 18 percent with MRA were misclassified. Misclassification rates dropped to 8 percent if both tests were used and showed the same degree of blockage. The majority of the errors reported were related to the tests' ability to help physicians determine the degree and extant of blockage in the artery.
Endarterectomy is an effective operation when performed in selected patients by skilled surgeons.
If the patient's primary physician is concerned about the risks of angiography or the surgery, the patient should be referred to a center that does many of these procedures, since studies show high-volume centers have the lowest complication rates. In performing a carotid endarterectomy, surgeons make an incision in the neck, and the carotid artery is split open lengthwise. The surgeon removes the atherosclerotic plaque or blood clots impeding the flow of blood to the brain. Patients experiencing a TIA from a narrowing of the carotid artery may experience temporary loss or blurring of vision in one eye, numbness or weakness in the arm or leg on one side of the body, or have trouble speaking or understanding. Dr. Dean C.C. Johnston, who also contributed to the study during a fellowship at Duke, was supported by Canada's health system.