Cardiology > Venous Thromboembolism (VTE)  

Background

Venous thromboembolism (VTE) is a spectrum of disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE). It results from the formation of thrombi in the venous system, most commonly in the deep veins of the lower extremities, which may dislodge and embolize to the pulmonary arteries. This condition is associated with significant morbidity and mortality if undiagnosed or untreated. 

II) Classification/Types

By Anatomic Location: 

• • Deep Venous Thrombosis (DVT): 

• • • Proximal DVT: Thrombi in popliteal, femoral, or iliac veins (higher risk of embolization) 

• • • Distal DVT: Thrombi in calf veins (less likely to embolize) 

• • Pulmonary Embolism (PE): 

• • • Subsegmental 

• • • Segmental 

• • • Lobar 

• • • Massive or saddle PE 

By Clinical Presentation: 

• • Provoked (secondary): Associated with transient risk factors (e.g., surgery, trauma, immobility) 

• • Unprovoked (idiopathic): No identifiable risk factor 

• • Recurrent VTE 

By Onset: 

• • Acute VTE 

• • Chronic VTE (includes post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension) 

III) Pathophysiology 

VTE arises from Virchow’s triad: 

• • Venous stasis (e.g., immobility, prolonged travel, heart failure) 

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

• • Hypercoagulability (e.g., cancer, inherited thrombophilias, pregnancy, OCP use) 

Thrombus formation begins in areas of slow or turbulent blood flow, particularly in valve sinuses of deep veins. If the thrombus propagates and embolizes, it can lodge in the pulmonary arteries, resulting in ventilation-perfusion mismatch and right heart strain. 

IV) Epidemiology

• • Sex: Slightly more common in men overall; PE more common in women during pregnancy/postpartum 

• • Age: Risk increases markedly with age (>60 years) 

• • Geography: Higher incidence in hospitalized patients worldwide 

• • Comorbidities: Common in cancer, obesity, heart failure, and post-surgical states 

Etiology

I) Causes

• • Surgery (especially orthopedic and abdominal) 

• • Trauma/fractures 

• • Cancer (especially pancreatic, gastric, brain, and lung) 

• • Prolonged immobility or travel 

• • Pregnancy/postpartum 

• • Hormone therapy (e.g., oral contraceptives, HRT) 

• • Inherited thrombophilias (e.g., Factor V Leiden, Protein C/S deficiency) 

• • Antiphospholipid syndrome 

• • Central venous catheters 

II) Risk Factors

• • Age >60 years 

• • Recent surgery or hospitalization 

• • Malignancy 

• • Prior history of VTE 

• • Obesity 

• • Estrogen use 

• • Smoking 

• • Long-distance travel 

• • Nephrotic syndrome 

Clinical Presentation

I) History (Symptoms)

• • DVT: 

• • • Unilateral leg swelling, pain, redness 

• • • Heaviness or tightness in the limb 

• • • Calf tenderness 

• • PE: 

• • • Sudden onset dyspnea 

• • • Pleuritic chest pain 

• • • Cough or hemoptysis 

• • • Syncope (in massive PE) 

• • • Anxiety or sense of impending doom 

II) Physical Exam (Signs)

Vital Signs: 

• • Tachycardia 

• • Hypoxia 

• • Hypotension (in massive PE) 

• • Fever (low-grade) 

Extremities (DVT): 

• • Unilateral swelling 

• • Warmth and erythema 

• • Positive Homan’s sign (nonspecific) 

• • Superficial collateral veins (chronic cases) 

Cardiopulmonary (PE): 

• • Tachypnea, crackles 

• • Accentuated P2 heart sound 

• • Right ventricular heave or JVD (massive PE) 

Differential Diagnosis (DDx)

• • Cellulitis 

• • Ruptured Baker’s cyst 

• • Superficial thrombophlebitis 

• • Heart failure 

• • Pneumonia 

• • Acute coronary syndrome 

• • Pericarditis 

• • Costochondritis 

• • Musculoskeletal strain 

Diagnostic Tests

Initial Tests: 

Compression Ultrasound (for DVT): 

• • First-line test for suspected DVT 

• • High sensitivity for proximal DVT 

CT Pulmonary Angiography (CTPA): 

• • Gold standard for PE 

• • Visualizes emboli in pulmonary arteries 

Ventilation-Perfusion (V/Q) Scan: 

• • For patients with contraindications to contrast 

• • Normal scan excludes PE 

ECG: 

• • Sinus tachycardia (most common) 

• • S1Q3T3 pattern (rare, suggests massive PE) 

• • Right heart strain findings 

Chest X-ray: 

• • Often normal in PE 

• • May show Westermark sign or Hampton hump (rare) 

Echocardiogram: 

• • Right ventricular dysfunction 

• • McConnell’s sign (regional RV dysfunction in PE) 

D-Dimer: 

• • Sensitive but nonspecific 

• • Negative test rules out DVT/PE in low-risk patients (Wells score ≤1) 

Labs: 

• • ABG: hypoxemia, respiratory alkalosis 

• • Troponin and BNP: may be elevated in PE with RV strain 

Treatment

I) Medical Management

Anticoagulation (Mainstay): 

• • Initial therapy: 

• • • LMWH, unfractionated heparin (UFH), or fondaparinux 

• • • Direct oral anticoagulants (DOACs): apixaban, rivaroxaban 

• • Long-term therapy: 

• • • Continue for 3 months minimum 

• • • Extended therapy in unprovoked or recurrent VTE 

Thrombolytics (e.g., alteplase): 

• • Indicated in massive PE with hemodynamic instability 

Inferior Vena Cava (IVC) Filter: 

• • For patients with contraindications to anticoagulation 

• • May reduce PE risk but increases long-term DVT risk 

Analgesics and Compression Therapy (for DVT): 

• • Leg elevation, compression stockings 

• • Encourage early ambulation 

II) Interventional/Surgical:

• • Catheter-directed thrombolysis or thrombectomy: 

• • • Reserved for massive or submassive PE with right heart strain 

• • Surgical embolectomy: 

• • • For select patients with life-threatening PE and failed lysis 

Patient Education, Screening, Vaccines

• • Importance of medication adherence and monitoring 

• • Recognize symptoms of recurrence (leg swelling, dyspnea, chest pain) 

• • Avoid prolonged immobility; take breaks during travel 

• • Maintain healthy weight and hydration 

• • Graduated compression stockings for DVT 

• • Screen for inherited thrombophilia in select cases 

Vaccinations: 

• • Influenza 

• • Pneumococcal 

• • COVID-19 

Consults

• • Hematology: Recurrent VTE, suspected hypercoagulable states 

• • Cardiology: For RV dysfunction or hemodynamic compromise 

• • Pulmonology: In submassive/massive PE 

• • Vascular Surgery: If thrombectomy or IVC filter needed 

• • Pharmacy: Anticoagulant management and education 

• • Primary Care/Internal Medicine: Long-term monitoring and chronic disease optimization 

Follow-Up

• • Anticoagulation monitoring: INR for warfarin; renal function for DOACs 

• • Duration of therapy: 

• • 3 months minimum for provoked 

• • Indefinite in high-risk unprovoked or recurrent VTE 

• • Monitor for complications: 

• • Post-thrombotic syndrome (DVT) 

• • Chronic thromboembolic pulmonary hypertension (PE) 

• • Regular reassessment of risk vs benefit of continued anticoagulation 

• • Patient education reinforcement at each visit