Patient follow-up after negative lower extremity bedside ultrasound for deep venous thrombosis in the ED

Prevalence and predictors of alternative diagnoses on whole-leg ultrasound negative for acute deep venous thrombosis

Background

To investigate the prevalence, spectrum, and predictors of alternative diagnoses explaining leg symptoms in patients negative for suspected acute deep venous thrombosis (DVT), which can be detected with whole-leg ultrasound.

Methods

We retrospectively analyzed a cohort of 789 patients (median age 70 years, 50.6% women) evaluated with a whole-leg ultrasound examination for suspected acute DVT within one year. All findings in the radiology report were analyzed and electronic chart review was performed to collect clinical information.

Results

Ultrasound was negative for acute DVT in 531 patients (67.3%). Among these, alternative diagnoses explaining leg symptoms were seen in 349 patients (65.7%). The most frequent alternative diagnoses were chronic venous insufficiency (147 patients, 27.7%), followed by lymphedema (48 patients, 9.0%) and chronic post-thrombotic changes (41 patients, 7.7%). Patients with alternative diagnoses were older (median 71 vs. 66 years, p = 0.0226), as well as more likely to present with leg swelling (39.5% vs. 23.1%, p = 0.0002), difference in leg circumference (25.5% vs. 14.8%, p = 0.0055) and redness (7.7% vs. 2.7%, p = 0.0213) than patients without alternative diagnosis. Independent predictors of finding alternative diagnoses on whole-leg ultrasound were older age (odds ratio 1.014 per year, p = 0.0119), leg swelling (OR 1.949, p = 0.0020) and history of previous DVT (OR 2.235, p = 0.0154).

Conclusions

Alternative diagnoses explaining leg symptoms can be detected on whole-leg ultrasound in two thirds of patients with no evidence of acute DVT. Our data supports performing a comprehensive ultrasound evaluation beyond the venous system, particularly, in older patients, who present with leg swelling and a past history of DVT.

Ultrasound for Lower Extremity Deep Venous Thrombosis

Venous ultrasound is the standard imaging test for patients suspected of having acute deep venous thrombosis (DVT). There is variability and disagreement among authoritative groups regarding the necessary components of the test. Some protocols include scanning the entire lower extremity, whereas others recommend scans limited to the thigh and knee supplemented with serial testing. Some protocols use gray-scale ultrasound alone, whereas others include Doppler interrogation. Point-of-care ultrasound is recommended in some settings, and there is heterogeneity of these protocols as well. Heterogeneity of recommendations can lead to errors including incorrect application of guidelines, confusion among requesting physicians, and incorrect follow-up. In October 2016, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to evaluate the current evidence to develop recommendations regarding ultrasound protocols for DVT and the terminology used to communicate results to clinicians. Recommendations were made after open discussion and by unanimous consensus.

The panel recommends a comprehensive duplex ultrasound protocol from thigh to ankle with Doppler at selected sites rather than a limited or complete compression-only examination. This protocol is currently performed in many facilities and is achievable with standard ultrasound equipment and personnel. The use of these recommendations will increase the diagnosis of calf DVT and provide better data to explain the presenting symptoms. The panel recommends a single point-of-care protocol that minimizes underdiagnoses of proximal DVT.

The panel recommends the term chronic postthrombotic change to describe the residual material that persists after the acute presentation of DVT to avoid potential overtreatment of prior thrombus.

Adoption of a single standardized comprehensive duplex ultrasound and a single point-of-care examination will enhance patient safety and clinicians’ confidence.

Non-thrombotic abnormalities on lower extremity venous duplex ultrasound examinations

Introduction

Emergency physician-performed compression ultrasonography focuses primarily on the evaluation of the proximal veins of the lower extremity in patients with suspected deep venous thrombosis (DVT). A detailed sonographic evaluation of lower extremity is not performed. The objective of this study was to determine the prevalence of non-thrombotic findings on comprehensive lower extremity venous duplex ultrasound (US) examinations performed on emergency department (ED) patients.

Methods

We performed a retrospective six-year review of an academic ED’s records of adult patients who underwent a comprehensive lower extremity duplex venous US examination for the evaluation of DVT. The entire US report was thoroughly reviewed for non-thrombotic findings.

Results

We detected non-thrombotic findings in 263 (11%, 95% CI [9.5–11.9%]) patients. Among the non-thrombotic findings, venous valvular incompetence (81, 30%) was the most frequent, followed by cyst/mass (41, 15%), lymphadenopathy (33, 12%), phlebitis (12, 4.5%), hematoma (8, 3%), cellulitis (1, 0.3%) and other (6, 2.2%).

Conclusion

In our study, we detected a variety of non-thrombotic abnormalities on comprehensive lower extremity venous duplex US examinations performed on ED patients. Some of these abnormalities could be clinically significant and potentially be detected with point-of-care lower extremity US examinations if the symptomatic region is evaluated. In addition to assessment of the proximal veins for DVT, we recommend sonographic evaluation of the symptomatic area in the lower extremity when performing point-of-care ultrasound examinations to identify non-thrombotic abnormalities that may require immediate intervention or close follow up.

Fatal pulmonary embolization after negative serial ultrasounds

BACKGROUND

Isolated distal deep vein thrombosis (DVT) is not traditionally viewed as a potentially life-threatening condition. There are conflicting recommendations regarding its evaluation and treatment, and wide variability in clinical practice. The presentation of this case highlights the fatal potential of this condition.

CASE REPORT

This is the report of a previously healthy young woman who presented to the emergency department with calf pain concerning for a DVT. She received two radiologist-performed duplex ultrasound examinations of the affected extremity, both of which were negative, but suffered a sudden cardiac arrest several hours after the second study. Autopsy attributed the death to DVT and pulmonary embolism. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the risk for fatal pulmonary embolization, even after normal serial ultrasound examinations to exclude DVT.

[Epidemiology and management of isolated distal deep venous thrombosis]

Isolated distal deep-vein thromboses (DVT) are infra-popliteal DVT without involvement of proximal veins or pulmonary embolism (PE). They can affect deep calf (tibial anterior, tibial posterior, or peroneal) or muscular (gastrocnemius or soleal) veins. They represent half of all lower limbs DVT. Proximal and distal DVTs differ in terms of risk factor profile, proximal DVT being more frequently associated with chronic risk factors and distal DVT with transient ones. Their natural history (rate of spontaneous proximal extension) is debated leading to uncertainties on the need to diagnose and treat them with anticoagulant drugs. In the long term, the risk of venous thromboembolic recurrence is lower than that of proximal DVT and their absolute risk of post-thrombotic syndrome is unknown. French national guidelines suggest treating with anticoagulants for 6 weeks a first episode of isolated distal DVT provoked by a transient risk factor and treating for at least 3 months unprovoked or recurrent or active cancer-related distal DVT. The use of compression stockings use is suggested in case of deep calf vein thrombosis. Ongoing therapeutic trials should provide important data necessary to establish an evidence-based mode of care, especially about the need to treat distal DVT at low risk of extension with anticoagulants.

Distal DVT: worth diagnosing? Yes

Much of the argument for or against diagnosis of distal deep vain thrombosis (DVT) depends on the extra effort that has to be spent on it. This review presents the data on ultrasound of paired calf veins and calf muscle veins (distal ultrasound) in terms of protocols, feasibility, reliability and expected findings. In summary, provided there is adequate and anatomically sound training of sonographers, distal ultrasound is a valid, 4-minute procedure, which can easily be added to the examination of proximal veins. The second part of the review refers to the pathophysiology of ascending DVT, which is the most common type. Adequate patient care in terms of benefit, harm and cost includes a single non-invasive examination followed by risk adopted treatment allocation. This concept ideally should be valid for any type of DVT. The data extending this concept to distal DVT can only be derived from studies that look closely at this entity (i.e. in fact diagnose distal DVT). Even before these data are available, diagnosing distal DVT at least doubles the number of symptomatic patients in which signs and symptoms can be ascribed to a definitive diagnosis, which in itself is a benefit for patient care.