Variability in Venous Duplex Ultrasound Parameters in the United States

Introduction, Objectives, and/or Purpose: Standardization for venous duplex ultrasound exists in the form of minimum requirements put forth by accrediting bodies, such as the Intersocietal Accreditation Commission or the American College of Radiology. There are both technical and anatomical requirements specified in these documents. The technical requirements include image optimization and transducer selection. The anatomical requirements define the veins to be interrogated and measurement specific criteria, such as pulsed wave Doppler and grayscale calipered measurements. However, these documents allow for variability with respect to other parameters, such as patient position and method of augmentation. This study aimed to evaluate the variability in practice patterns associated with the performance of venous duplex ultrasound testing across the United States, specifically focused on those non-mandated parameters.

Methods: 550 credentialed sonographers participated in a one-time, 8 question, multiple choice survey regarding venous duplex ultrasound. The survey queried the type of institution, credentials of sonographer, equipment available to sonographer, time allotted for unilateral or bilateral study, patient positioning, reasoning for patient positioning, and method used to elicit reflux. Respondents replied to a link on the Society of Vascular Ultrasounds open forum as well as a social media platform dedicated to vascular ultrasound.

Results: 550 sonographers responded to the survey. The majority of sonographers carried the credentials of RVT/RVS, with some holding multiple titles. Seventy percent of the respondents worked in general vascular laboratories, with the remainder working in venous-focused vascular laboratories. To aid in patient positioning, reproducibility of augmentation, and ergonomics, equipment routinely utilized while scanning included a reversed Trendelenburg enabled adjustable table, a height adjustable stool for the sonographer with a low height capability, a raised platform to elevate the patient, and a height adjustable ultrasound machine in approximately 50% of laboratories. In contrast, less than 30% of laboratories had access to an automated rapid cuff augmentation device or an adjustable table with an attachable footboard. The highest percentage of allotted time for unilateral studies was 45 minutes in 41% of laboratories and 60 minutes for bilateral studies in 46%. Venous duplex ultrasound was performed in reversed Trendelenburg position in 41% of patients versus standing position in 40%. In 18% of laboratories, if reversed Trendelenburg position did not demonstrate reflux, the study was repeated in the standing position. In addition to laboratory protocol, the two most common reasons to support the choice of patient positioning included ergonomics in 50% and patient comfort in 42%. An automated rapid cuff augmentation device was used as the primary method of augmentation in only 22% of practices, with supplemental manual augmentation as needed.

Conclusion(s):

Conclusion: There is a lack of standardization of performance parameters in venous duplex ultrasound, which may lead to variation of the results from institution to institution. Validation of these non-standardized parameters is critically important to assure consistency in the results of venous duplex ultrasound studies from institution to institution.