Reaffirmation of the importance of follow-up ultrasound studies in patients with high D-dimers and clinical suspicion of vein thrombosis

Abstract

Background: Venous thromboembolism is a common disease seen in the emergency department and a cause of high morbidity and mortality, constituting a major health problem. Objectives: To assess the potential benefit of follow-up ultrasound of patients who attended the emergency department with suspected superficial venous thrombosis or deep venous thrombosis and were found to have an initial negative whole-leg (or arm) ultrasound study. Methods: This retrospective study included patients aged 18 years or older who were consecutively referred to a thrombosis clinic from the emergency department, with abnormal D-dimer test and moderate to high pre-test probability of deep venous thrombosis (Well's score ≥ 1), but a negative whole-leg (or arm) ultrasound. Demographic characteristics, symptom duration, laboratory and ultrasound data were recorded. At one-week follow-up, an experienced physician repeated ultrasound, and recorded the findings. Results: From January 2017 to April 2018, 54 patients were evaluated. The mean age was 66.8 years (SD 15.0) and 63% were women. The average D-dimer was 2159.9 (SD 3772.0) ng/mL. Ultrasound abnormalities were found in 12 patients (22.2%; 95% confidence interval of 12.5 to 36.0%), with 4 patients having proximal deep venous thrombosis, distal deep venous thrombosis in 2 patients and superficial venous thrombosis in 6 patients. We did not find any significant differences in demographic characteristics, venous thromboembolism risk factors or laboratory parameters between patients with negative and positive follow-up ultrasound. Conclusions: These preliminary findings suggest that a negative whole-leg (or arm) ultrasound in addition to an abnormal D-dimer in moderate to high deep venous thrombosis pretest probability patients, might be an insufficient diagnostic approach to exclude suspected deep venous thrombosis or superficial venous thrombosis. Confirmation of this higher than expected prevalence would support the need to repeat one-week ultrasound control in this population.