Clinical applications of noninvasive carotid artery testing

The management of patients with cerebral transient ischemic attacks and carotid artery stenosis remains controversial. Noninvasive techniques help to determine which patients require surgical intervention without exposing the majority of patients to the risk and discomfort of invasive procedures. Measurement of ophthalmic artery pressure by ophthalmodynamometry or oculoplethysmography gives a representation of perfusion pressure in the internal carotid artery circulation. Doppler ultrasound studies can define the extent of obstruction to flow at the carotid artery bifurcation and assess collateral flow from the external carotid artery. Real time B-mode ultrasonography can detect nonobstructive ulcerated plaque in the carotid artery bifurcation. Employing these examinations in a test battery can identify hemodynamically significant lesions, which are more likely to precipitate a stroke. The information obtained from these studies can be utilized in patients with episodes of cerebral transient ischemic attacks, asymptomatic carotid artery bruits and vertebrobasilar insufficiency. Noninvasive carotid artery testing is also useful in screening patients with nonspecific symptoms, such as dizziness or light-headedness, which may be related to decreased flow in the carotid circulation. Noninvasive carotid artery testing can provide valuable anatomic and physiologic information required in the appropriate management of patients with cerebrovascular disease. It is of particular value in managing patients with heart disease who are at high risk for complications from invasive procedures.