453-122 | Carotid Doppler Ultrasound: Beyond Stenosis-Carotid Doppler Ultrasound: Beyond Stenosis

Carotid Doppler Ultrasound: Beyond Stenosis

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Carotid Doppler ultrasound is frequently performed to evaluate carotid artery stenosis in patients with abnormal physical examination findings or stroke-like symptoms. However, abnormal Doppler spectral waveforms can be encountered in scenarios unrelated to stenosis, and understanding the hemodynamic properties of the vessels is crucial. This article aims to increase awareness of these less common scenarios. <br /><br />The normal carotid artery has a smooth intima seen as a hyperechoic line with an adjacent hypoechoic media layer, and the outer line represents the adventitia. The common carotid artery (CCA) supplies the internal and external carotid arteries and has waveform features of both branch vessels, with the CCA waveform resembling the internal carotid artery (ICA) waveform. The ICA waveform demonstrates a low-resistive pattern with continuous forward flow throughout the cardiac cycle, while the external carotid artery (ECA) waveform exhibits a high-resistive arterial flow pattern with absent or decreased diastolic flow.<br /><br />The article also discusses the sonographic findings associated with aortic stenosis (AS), including the tardus-parvus waveform characterized by a delayed upstroke and rounded peak. Decreased peak velocity and prolonged acceleration time are quantitative measures suggesting the presence of AS. Pulsus bisferiens, which refers to the presence of two systolic peaks, is often seen in conditions such as aortic regurgitation and hypertrophic cardiomyopathy. <br /><br />The article further explores the Doppler spectral waveforms in scenarios involving cardiac assist devices, such as intra-aortic balloon pumps (IABPs) and left ventricular assist devices (LVADs). IABPs can result in altered peak systolic velocities and increased flow during diastole, necessitating careful attention to color Doppler images to identify areas of stenosis. LVADs render the patient pulseless and produce low-velocity, low-resistive carotid spectral waveforms. Accurate assessment of carotid artery stenosis in LVAD patients requires visual inspection and repeated ultrasound after device removal or cardiac transplantation.<br /><br />Lastly, the article discusses carotid-internal jugular fistula, a complication occurring after trauma or iatrogenic injury during central line placement. Ultrasound can identify the abnormal connection and show turbulent, low-resistive waveforms.<br /><br />In summary, familiarity with the normal and abnormal spectral waveforms encountered in carotid Doppler ultrasound is essential for accurate interpretation and diagnosis in various clinical scenarios.

Keywords

Carotid Doppler ultrasound

carotid artery stenosis

abnormal Doppler spectral waveforms

hemodynamic properties

normal carotid artery

common carotid artery

internal carotid artery

external carotid artery

aortic stenosis

cardiac assist devices