Definition of Deep Vein Thrombosis (DVT)

Deep vein thrombosis (DVT) refers to the formation of blood clots in one or more deep veins, usually of the lower or upper extremities. 1

Key Characteristics of DVT

DVT has an estimated annual incidence of approximately 5 per 10,000 in the general population, with incidence increasing with advancing age 1
DVT typically starts distally below the knee but can extend proximally above the knee, potentially resulting in life-threatening pulmonary embolism 1
Pulmonary embolism can occur in 50-60% of patients with untreated DVT, with an associated mortality rate of 25-30% 1
Approximately one-third of patients with DVT do not have any symptoms, making clinical diagnosis challenging 1

Classic symptoms include local pain or tenderness, edema, and swelling of the affected extremity 1
Symptoms often are not apparent until there is involvement above the knee 1
The clinical diagnosis using risk-stratification scores (e.g., Wells score) alone has been less than ideal and typically requires additional testing 1
DVT can clinically mimic other conditions such as Baker cysts, cellulitis, lymphedema, and various musculoskeletal disorders 1

Post-thrombotic syndrome (PTS) is the most common long-term complication of DVT 1
PTS manifests as a spectrum of symptoms and signs of chronic venous insufficiency, ranging from minor leg swelling to severe complications such as:
- Chronic debilitating lower-limb pain
- Intractable edema
- Leg ulceration requiring intensive medical care 1
PTS increases healthcare costs and reduces quality of life 1

Diagnosis typically involves an algorithm combining:
- Pretest probability assessment (Wells score)
- D-dimer testing
- Compression ultrasonography 1
Ultrasound is widely recognized as the preferred initial imaging modality for diagnosing proximal DVT with high sensitivity (94.2%) and specificity (93.8%) 1
Complete duplex ultrasound (CDUS) is the preferred venous ultrasound test, which includes:
- Compression of deep veins from the inguinal ligament to the ankle
- Spectral Doppler waveforms of common femoral and popliteal veins
- Color Doppler imaging 1

The treatment of choice for DVT is anticoagulation to reduce the risk of:
- DVT extension
- Recurrent DVT
- Pulmonary embolism
- Post-thrombotic syndrome 1
Anticoagulant options include:
- Low-molecular-weight heparin
- Unfractionated heparin
- Vitamin K antagonists (e.g., warfarin)
- Direct oral anticoagulants (e.g., rivaroxaban) 2
For proximal (above-the-knee) DVT, the benefits of anticoagulation therapy generally outweigh the risks 1
For distal (below-the-knee) DVT, the role of anticoagulation remains more controversial, but serial imaging to exclude proximal extension is recommended if anticoagulation is not initiated 1

Prophylaxis can be both mechanical and pharmacological 1
Risk assessment is essential to identify appropriate prophylaxis regimens for different levels of risk 1
Implementation of VTE prevention clinical practice guidelines can improve compliance with appropriate prophylaxis in hospitalized patients 1

Patients with certain conditions like cancer, recent surgery, or thrombophilia may require specialized management approaches 1
Patients with recurrent DVT may need extended anticoagulation therapy 2
The location and extent of DVT are clinically important for determining appropriate treatment strategies 1