The rate of follow-up after an incomplete and negative lower extremity venous duplex ultrasound (I/N LEVDUS) has been shown to increase following a specific recommendation for follow-up in the ultrasound report. This was the main concluding finding of a study published in the Journal of Vascular Surgery: Venous and Lymphatic Disorders.
Authors Shelby Van Leuven (Oregon Health & Science University, Portland, USA) and colleagues write that LEVDUS examinations are commonly incomplete for reasons such as pain, oedema or the presence of overlying bandages. Additionally, they note that the likelihood of obtaining a follow-up examination after an I/N LEVDUS examination is low, but that rates of deep vein thrombosis (DVT) found in follow-up studies of initially I/N LEVDUS studies are similar to the rates of DVT found within initially complete LEVDUS examinations. In this prospective study, therefore, the investigators sought to describe the outcomes of appending a recommendation to obtain a follow-up LEVDUS study to preliminary and final reports of I/N LEVDUS.
The research team prospectively patients who had received an I/N LEVDUS examination for suspected DVT during the period of 1 January 2019 to 31 December 2019, and patients with I/N LEVDUS examinations who were potential candidates for anticoagulation therapy if new lower extremity venous thrombosis was found from 1 January 2020 to 31 March 2020. Patients with a known indication for anticoagulation were excluded from the study. Van Leuven et al define an I/N unilateral LEVDUS examination as “an examination in which DVT, proximal or distal, was not identified and, for any reason, the common femoral, profunda femoral, femoral, popliteal, or calf veins had not been examined.”
The investigators conducted the study at a single academic institution—the Oregon Health & Science University. Within the 2019 study period, the authors detail that 3,350 LEVDUS examinations were performed for suspected thrombosis. Of these examinations, 229 initial LEVDUS examinations (8.6%) were I/N for patients otherwise without an indication for anticoagulation. The average age of the patients without and with a repeat examination was 5118 and 5220 years, respectively (p=0.40), and there were slightly more female than male patients. There were no significant differences in demographics or venous thrombotic risk factors found between patient groups, with and without a follow-up examination after an initial I/N LEVDUS examination.
Van Leuven and colleagues report that the rate of follow-up examinations after an I/N LEVDUS examination improved by 43% after input of a specific recommendation for a follow-up study in the ultrasound report of the original incomplete study. Within the follow-up studies, they add, 23% of examinations presented DVT or superficial vein thrombosis.
The authors conclude that a specific recommendation for a follow-up was successful in improving the rate of repeat examinations, and in the detection of DVT and superficial vein thrombosis. They write: “Striving towards 100% compliance with the recommended follow-up if clinically indicated and decreasing the time to repeat examination are necessary to reduce missed diagnoses of thrombosis that may warrant medical treatment”.