From the Guidelines
The recommended approach for screening and diagnosis of Venous Thromboembolism (VTE) involves a combination of clinical assessment, risk stratification, and appropriate diagnostic testing, with the most recent guidelines suggesting the use of D-dimer as the initial test for patients at low VTE risk and imaging for those at high risk 1.
Key Considerations
- Clinicians should first evaluate patients using validated clinical prediction rules such as the Wells score or Geneva score to determine the pretest probability of VTE.
- For patients with low pretest probability, a negative D-dimer test can safely rule out VTE without further imaging, as suggested by the American Society of Hematology 2018 guidelines 1.
- However, patients with moderate to high pretest probability or positive D-dimer should undergo imaging studies, with compression ultrasonography being the first-line imaging test for suspected deep vein thrombosis (DVT) and CT pulmonary angiography (CTPA) being preferred for suspected pulmonary embolism (PE) 1.
Diagnostic Testing
- D-dimer levels can be elevated in many conditions, including pregnancy, inflammation, cancer, and advanced age, potentially reducing specificity, and age-adjusted D-dimer cutoffs can improve specificity without compromising safety 1.
- Point-of-care ultrasound may be useful in emergency settings for rapid assessment, and ventilation-perfusion (V/Q) scanning is an alternative for patients with contraindications to CTPA 1.
Risk Stratification
- The concept of a posttest probability threshold has high utility for clinical decision-making, with a threshold of <2% being considered acceptable for safely excluding the diagnosis of VTE 1.
- Modern diagnostic techniques have evolved to detect PE at a subsegmental level and ultrasound capable of detecting DVT within calf veins, but the clinical relevance of such findings is controversial and potentially contributes to the concept of overdiagnosis of VTE 1.
From the Research
VTE Diagnosis Screening
- The recommended approach for screening and diagnosis of Venous Thromboembolism (VTE) involves a combination of clinical scoring systems, such as Wells' score, and D-dimer assay 2.
- A multifaceted approach to VTE prevention, including regular audits with feedback, electronic reminders systems, prescribing tools, and continuing education, can increase thromboprophylaxis usage and decrease pulmonary embolism (PE) rates 3.
- Risk assessment models can help decide which patients should receive prophylaxis and match VTE risk with the appropriate intensity of prophylaxis 4.
Screening Tools
- Standardized VTE risk assessment tools, such as Caprini, Padua, and IMPROVE, can accurately identify high-risk patients who benefit most from prevention 5.
- The use of these tools can lead to significant benefits, including lower VTE rates, shorter hospital stays, fewer deaths, and better use of preventive strategies matched to estimated clot risk 5.
Prevention Strategies
- Low molecular weight heparins, such as enoxaparin and dalteparin, provide effective means of preventing DVT in high-risk, critically ill, or postoperative patients, without causing a significant increase in the risk of bleeding or other side effects 2.
- Guidelines recommend the use of parenteral anticoagulants, such as low molecular weight heparins, for 6 to 14 days, but advise against extended-duration thromboprophylaxis after hospital discharge 6.