Clinical Review

Decision Making in Venous Thromboembolism


 

References

Imaging

After application of a clinical prediction rule, the mainstay of diagnosis of VTE is imaging. For DVT the use of ultrasonography is considered the gold standard, with both high sensitivity (89–100%) and specificity (86–100%), especially when the DVT is located proximally [37–39].We generally recommend compression ultrasound starting with the proximal veins but expanding to include the whole leg if the proximal studies are negative [40–42].Other diagnostic options include computed tomography (CT) venography, which is not first line as it is highly invasive and exposes the patient to iodine-based contrast dyes, and magnetic resonance venography (MRV), which offers superb visualization for diagnosis of pelvic vein thrombosis but is limited because of availability and cost issues.

Helical CT pulmonary angiography (CTPA) is the diagnostic test of choice in PE, with high sensitivity (96%) and specificity (95%), and has replaced conventional ventilation perfusion (VQ) scanning or other methods such as magnetic resonance pulmonary angiography in most settings [43,44].CTPA should be avoided in patients who have severe chronic kidney disease or a contrast allergy, and is often avoided in patients who are pregnant due to potential risk of radiation exposure, and in such situations VQ scanning may be employed.

Algorithmic Approach to Workup

Our general practice is to apply the Wells clinical prediction rule ( Table 2 for DVT and Table 3 for PE), as this system is likely the most familiar to a large number of clinicians and a score can be obtained promptly but accurately based on easily accessible data from history and exam. We generally use the simplified modified criteria presented in the Tables. Once the clinical prediction rule has been applied, we use 2 risk-based algorithms for further evaluation ( Figure 1 and Figure 2 ) [45,46]. In general, we initially perform a D-dimer test for low-risk patients, while we advocate for prompt imaging in high-risk patients to avoid delays in treatment should VTE be diagnosed. Once a diagnosis of VTE is established, treatment should be started promptly. One exception may be isolated
distal DVT, where it is reasonable to defer treatment in favor of serial ultrasound testing to rule to rule out proximal extension unless the patient is significantly symptomatic with the distal DVT alone [40].

Of note, there are multiple clinical situations in which the application of a clinical prediction rule followed by D-dimer testing and/or imaging cannot be “standardized” with such algorithms. These include situations where D-dimer may be falsely positive (as above), situations in which alternative imaging strategies should be used to avoid contrast exposure in workup of PE (as above), and workup of suspected upper extremity DVT. Upper extremity ultrasound comprises about 10% of all DVT and frequently occurs in the setting of risk factors such as central venous catheters or pacemakers; specific upper-extremity risk-assessment rules have been developed [47,48].

D-dimer is generally not as useful in workup of upper extremity DVT (given high prevalence of factors that lead to false-positive DVT) and we generally perform compression ultrasonography up front in patients in whom we have high clinical suspicion for upper extremity DVT. In all such clinical situations above, workup should be individualized in accordance with patient factors and careful physician assessment.

Acute Treatment Options

Pages

Recommended Reading

Using Patient Navigators to Help Adults with Sickle Cell Disease Obtain a Primary Care Home
Journal of Clinical Outcomes Management
Emotional Distress, Barriers to Care, and Health-Related Quality of Life in Sickle Cell Disease
Journal of Clinical Outcomes Management
Transition Readiness Assessment for Sickle Cell Patients: A Quality Improvement Project
Journal of Clinical Outcomes Management
Using Quality Improvement Methods to Implement an Individualized Home Pain Management Plan for Children with Sickle Cell Disease
Journal of Clinical Outcomes Management
Improving Care of Patients with Sickle Cell Disease and Sickle Cell Trait: The Hemoglobinopathy Learning Collaborative Series
Journal of Clinical Outcomes Management
A Quality Improvement Initiative to Improve Emergency Department Care for Pediatric Patients with Sickle Cell Disease
Journal of Clinical Outcomes Management