Cardiology > Deep Venous Thrombosis  

Background

Deep venous thrombosis (DVT) refers to the formation of a thrombus (blood clot) within the deep veins of the body, most commonly in the lower extremities. DVT is part of the broader spectrum of venous thromboembolism (VTE), which includes pulmonary embolism (PE) when the clot embolizes to the lungs. If left untreated, DVT can lead to life-threatening PE, chronic venous insufficiency, or post-thrombotic syndrome. 

II) Classification/Types

By Location: 

• • Proximal DVT: Involves the popliteal, femoral, or iliac veins (higher risk of PE) 

• • Distal DVT: Confined to the calf veins (e.g., posterior tibial, peroneal veins) 

By Provocation: 

• • Provoked DVT: Triggered by identifiable risk factors (e.g., surgery, trauma, immobility) 

• • Unprovoked DVT: No apparent transient risk factor; may indicate underlying malignancy or thrombophilia 

By Clinical Presentation: 

• • Symptomatic DVT: Classic leg symptoms like swelling or pain 

• • Asymptomatic DVT: Incidental finding on imaging 

III) Pathophysiology 

DVT develops due to Virchow’s triad: 

Venous stasis (e.g., immobility, long flights) 

Endothelial injury (e.g., trauma, surgery) 

Hypercoagulability (e.g., cancer, thrombophilia, OCP use) 

The thrombus forms most commonly near venous valve cusps in areas of slow flow, potentially propagating and embolizing to the pulmonary circulation. 

IV) Epidemiology

• • Sex: Slightly more common in men; hormone-related risk higher in women (pregnancy, OCPs) 

• • Age: Incidence increases sharply with age 

• • Geography: Higher rates in developed countries, especially in hospitalized and post-surgical patients 

• • Comorbidities: Cancer, obesity, recent surgery, pregnancy, autoimmune disorders 

Etiology

I) Causes

• • Surgery (especially orthopedic, pelvic, or abdominal) 

• • Trauma 

• • Prolonged immobilization or long-distance travel 

• • Malignancy 

• • Hormonal therapy (OCPs, HRT) 

• • Pregnancy and postpartum state 

• • Inherited thrombophilia (e.g., Factor V Leiden, prothrombin gene mutation) 

• • Central venous catheters (upper extremity DVT) 

II) Risk Factors

• • Age >60 

• • Prior history of VTE 

• • Cancer (especially pancreas, lung, stomach) 

• • Obesity 

• • Smoking 

• • Nephrotic syndrome 

• • Antiphospholipid syndrome 

• • Prolonged hospitalization or ICU stay 

• • Air travel >4 hours without movement 

Clinical Presentation

I) History (Symptoms)

• • Unilateral leg swelling or edema 

• • Leg pain, tenderness, or heaviness 

• • Calf or thigh tightness 

• • Warmth and redness of the affected limb 

• • Symptoms of PE (dyspnea, chest pain, syncope) may be the initial clue in occult DVT 

• • Often asymptomatic, especially in distal DVT 

II) Physical Exam (Signs)

Vital Signs: 

• • Usually normal unless PE is present 

• • Tachycardia or low-grade fever in some cases 

Extremity Exam: 

• • Unilateral leg swelling (measure calf circumference) 

• • Tenderness along deep venous system 

• • Warmth, erythema, and superficial venous distension 

• • Homan’s sign (calf pain with dorsiflexion) is neither sensitive nor specific 

Pulmonary Signs: 

• • • Tachypnea or hypoxia if PE has occurred 

Differential Diagnosis (DDx)

• • Cellulitis 

• • Lymphedema 

• • Baker’s cyst 

• • Chronic venous insufficiency 

• • Superficial thrombophlebitis 

• • Muscle strain or hematoma 

• • Compartment syndrome 

• • Popliteal (cystic) mass or tumor 

 
Diagnostic Tests

Initial Tests: 

• • Compression Duplex Ultrasonography (first-line): 

• • • Detects non-compressible veins 

• • • Highly sensitive/specific for proximal DVT; less so for calf DVT 

• • D-Dimer: 

• • • Sensitive but nonspecific 

• • • Useful in low-pretest probability to rule out DVT 

Confirmatory/Additional Tests: 

• • Venography (gold standard): Rarely used; invasive 

• • CT Venography or MRI Venography: 

• • Used for pelvic/abdominal DVT or upper extremity DVT 

Wells Criteria for DVT: 

• • Clinical prediction tool to guide testing and management 

• • Score stratifies patients into low, moderate, or high pre-test probability 

Treatment

I) Medical Management

Initial Anticoagulation (within 24 hours of diagnosis): 

• • Low molecular weight heparin (LMWH) 

• • Unfractionated heparin (UFH) (preferred in renal dysfunction) 

• • Direct oral anticoagulants (DOACs): Rivaroxaban, apixaban, dabigatran 

Long-term Anticoagulation (3–6 months minimum): 

• • Provoked DVT: 3 months 

• • Unprovoked DVT: 6 months or indefinite depending on bleeding risk 

Cancer-associated DVT: 

• • LMWH or DOACs preferred 

IVC Filter (rare): 

• • Considered in patients with contraindication to anticoagulation or recurrent PE despite therapy 

Compression Stockings: 

• • May reduce risk of post-thrombotic syndrome 

II) Thrombolysis or Thrombectomy (in select cases):

• • Consider catheter-directed thrombolysis for extensive proximal DVT with limb threat (phlegmasia cerulea dolens) 

• • Surgical thrombectomy for severe cases unresponsive to medical therapy 

Patient Education, Screening, Vaccines

• • Emphasize medication adherence and follow-up 

• • Signs of bleeding (e.g., melena, hematuria, easy bruising) with anticoagulants 

• • Importance of early mobilization after surgery or hospitalization 

• • Use graduated compression stockings and leg elevation 

• • Avoid prolonged immobility—frequent movement during travel 

• • Smoking cessation 

• • Discuss potential need for screening for thrombophilia in unprovoked or recurrent DVT 

• • Vaccinations (as part of general health maintenance): 

• • Influenza 

• • COVID-19 

• • Pneumococcal if other comorbidities exist 

 
Consults

• • Hematology: For thrombophilia workup or complex coagulopathies 

• • Vascular Surgery: If thrombolysis or thrombectomy is considered 

• • Interventional Radiology: For catheter-directed therapies 

• • Oncology: If DVT is unprovoked and malignancy suspected 

• • Internal Medicine/Primary Care: For anticoagulation monitoring and chronic disease management 

Follow-Up

• • Regular outpatient monitoring of anticoagulation (if on warfarin) (INR 2–3 target) 

• • Periodic re-evaluation for bleeding risks or change in therapy 

• • Evaluate for post-thrombotic syndrome (leg pain, swelling, discoloration) 

• • Repeat DVT imaging not routinely indicated unless symptoms worsen or recur 

• • Consider long-term anticoagulation in high-risk individuals (e.g., cancer, multiple DVTs) 

• • Educate patients on recurrence signs and when to seek immediate care