From the Guidelines
The patient with a D-dimer level of 1.22 should undergo further diagnostic imaging, such as compression ultrasonography for suspected deep vein thrombosis (DVT) or CT pulmonary angiography for suspected pulmonary embolism (PE), to determine the presence of venous thromboembolism (VTE) and guide subsequent management. The management approach for a patient with an elevated D-dimer level depends on the clinical context and pre-test probability for VTE. According to the American Society of Hematology 2018 guidelines for management of venous thromboembolism 1, a highly sensitive D-dimer assay is required, and a negative D-dimer rules out DVT and no additional testing or anticoagulation is required. However, in this case, the D-dimer level is elevated, so further diagnostic imaging is necessary. The European Society of Cardiology 2019 guidelines for the diagnosis and management of acute pulmonary embolism also recommend using recommended, validated diagnostic algorithms for PE, including standardized assessment of (pre-test) clinical probability and D-dimer testing 1. Some key points to consider in the management of patients with suspected VTE include:
- Clinical correlation is essential, as D-dimer can be elevated in many conditions besides VTE, including pregnancy, inflammation, malignancy, and infection.
- In elderly patients or those with comorbidities, age-adjusted D-dimer cutoffs may be used to improve specificity.
- If VTE is ruled out, the underlying cause of D-dimer elevation should be investigated based on the patient's clinical presentation.
- The American College of Physicians 2015 guidelines for evaluation of patients with suspected acute pulmonary embolism also recommend using age-adjusted D-dimer thresholds in patients older than 50 years to determine whether imaging is warranted 1.
- The American College of Radiology 2018 appropriateness criteria for suspected lower extremity deep vein thrombosis recommend imaging to definitively exclude DVT and properly document the extent of venous thrombosis, which is critical for proper therapeutic management of DVT 1. Given the elevated D-dimer level, further diagnostic imaging is necessary to determine the presence of VTE and guide subsequent management, and the choice of imaging modality will depend on the clinical presentation and pre-test probability of VTE.
From the Research
Management Approach for Elevated D-Dimer Level
The management approach for a patient with an elevated D-dimer level involves a combination of diagnostic tests and clinical evaluation to determine the underlying cause of the elevation.
- D-dimer testing is used as part of the clinical diagnosis algorithms for venous thromboembolism (VTE) 2.
- An extremely elevated D-dimer level is uniquely associated with severe disease, mainly including VTE, sepsis, and/or cancer 2.
- The approach to making a diagnosis currently involves an algorithm combining pretest probability, D-dimer testing, and compression ultrasonography 3.
Diagnostic Considerations
When interpreting D-dimer results, it is essential to consider the following:
- A normal D-dimer level (below a cutoff value of 500 micrograms/L) may allow the exclusion of pulmonary embolism (PE) 4.
- A plasma D-dimer concentration below 500 micrograms/L has a negative predictive value of 99% for PE 4.
- Elevated D-dimer levels can be associated with various conditions, including venous malformations, and can be useful in differential diagnosis 5.
Treatment and Prophylaxis
The treatment and prophylaxis of conditions associated with elevated D-dimer levels depend on the underlying cause:
- The mainstay of treatment for deep vein thrombosis (DVT) is anticoagulant therapy, which can include low-molecular-weight heparin, unfractionated heparin, and vitamin K antagonists 3.
- Prophylaxis for DVT can be mechanical and pharmacological, and the goals of treatment are to prevent extension of thrombi, pulmonary embolism, recurrence of thrombi, and the development of complications 3.