Ultrasound of Neck May Indicate Who Will Have a Stroke

November 12, 2012

Ultrasound of Neck May Indicate Who Will Have a Stroke

The results of a two year study have just been published in the journal Neurology. The study investigated 435 people who have severe ACS. ACS is asymptomatic carotid stenosis, this is a condition where the carotid arteries in the neck narrow. It is called asymptomatic because no symptoms are seen or felt by the patient. Because carotid arteries feed the brain with its blood supply it is important to recognize that when they become narrow it increases the risk of stroke. Presently the medical community is undecided about the best methods to identify high risk individuals who will need surgery or stenting. Inserting a stent can open the artery and lower the risk of stroke.

The study suggests that two non invasive tests should be used to determine those with increased risk of stroke and hence higher probability of surgery too. The two tests were ultrasound and Doppler ultrasound. The quality and make up of the plaque in the carotid arteries can be evaluated by ultrasound and Doppler ultrasound can identify microemboli, this is the name for tiny blood clots or particles. These can come away from the arteries and travel to the brain causing a stroke. These tests are only part of the appraisal stage to evaluate patients for ACS. They must be used in addition to taking a thorough medical history and a full neurological examination.

Calculating the Risk of Having a Stroke

Throughout the two year study just over 2% (10 people) had a stroke and around 5% (20 people) had mini strokes (transient ischemic attacks).

Known facts relating to the risk of stroke are that people with fatty plaque in their carotid arteries are more than six times more likely to have a stroke than those people without this type of plaque. Fatty plaques have been proven to be more dangerous. If the person has indications of microemboli and has fatty plaque then their risk of a stroke rises to more than 10 times that of people without these two conditions.

The new study indicates that the risk of a having a stroke is 8% per year for people who have fatty plaque and indicate the presence of microemboli. But if the person tests negative on both tests the risk of stroke falls to less than 1% per year. The findings are all in addition to the other known stroke risk factors such as diabetes, smoking, high blood pressure and vascular disease.

Differing Views on Screening

There are differing views on the worth of the Doppler ultrasound amongst the medical professionals. Some practitioners say that the Doppler test should be adopted as standard when dealing with patients with ACS. They say that if the study’s findings have confirmed that both types of ultrasound can identify patients with a high risk of stroke then patients should be screened as part of their standard treatment.

Other professionals accept that if an ACS patient does have a stroke it is devastating but then go on to say that even ACS sufferers have a relatively low chance of having a stroke. They go on to explain that with better management techniques dealing with lowering cholesterol and blood pressure the incidence of stroke has been declining over the years anyway.

Medical professionals all tend to agree that further research is required, some say that ultrasounds should not become common practice until some more study takes place, others think that the research findings are strong enough to carry out ultrasound testing already. Tatjana Rundek, MD, professor of neurology at the University of Miami, Miller School of Medicine in Florida, already uses both types of ultrasound when evaluating ACS patients. She says, “These individuals have a disease but don’t have symptoms yet, so this field is a sort of divided. We would love to select patients at the highest risk for stroke for surgery.” She goes on to say, “It is not enough to know the percent of [narrowing]. We need to know the composition of the plaque and what it looks like and the potential for embolization”.

Because most of the patients will remain without symptoms (asymptomatic) and not suffer a stroke the difficulty of finding people who are the highest risk should not be underestimated. These are the people that probably should have some form of surgery. Even with today’s improvements in drugs and management, medication is probably not enough for these people.

Presently ultrasound is used routinely to evaluate plaque composition. The Doppler ultrasound causes issues within the medical community because it is time consuming and there is a belief that interpretation of the results can vary depending on the staff member who is carrying out the test.

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