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Updated: Jan 5, 2026

Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
A High Doppler Gradient: Obstruction or No Obstruction?: A Case Report
Yanick Baribeau1, Daawar Chaudhry1, Aidan Sharkey1
1From the Departments of Anesthesia, Critical Care and Pain Medicine.
Abstract:
The angle correction feature in ultrasound systems is used when there is difficulty accurately aligning the Doppler beam with the flow to be interrogated. The operator can manually "correct" the angle to the actual direction of flow. Subsequently, the machine corrects the peak velocity for the angle. We present a case of aortic valve replacement (AVR) in which falsely high transaortic gradients were obtained immediately after separation from cardiopulmonary bypass (CPB). We recommend that there be a more prominent notification when the angle correction feature is used with machine prompts confirming when a peak velocity is obtained using angle correction.
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