Deep-Venous Thrombosis and Pulmonary Thromboembolism¶
Chapter 290 | Part 6: Disorders of the Cardiovascular System
KEY CLINICAL POINTS¶
- Venous thromboembolism (VTE) includes deep-venous thrombosis (DVT) and pulmonary embolism (PE), causing significant morbidity and mortality.
- Risk factors for VTE include cancer, obesity, immobility, hormonal therapies, and genetic mutations (e.g., factor V Leiden).
- Diagnosis of PE involves clinical scoring (Wells score), d-dimer testing, and imaging (CT pulmonary angiography).
- Anticoagulation is the mainstay of treatment, with DOACs (rivaroxaban, apixaban) preferred over warfarin in most cases.
- Post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension (CTEPH) are long-term complications.
1. DEFINITION & OVERVIEW¶
Venous thromboembolism (VTE) encompasses deep-venous thrombosis (DVT) and pulmonary embolism (PE). DVT involves clot formation in deep veins, while PE occurs when thrombi embolize to the pulmonary circulation. VTE is a leading cause of preventable mortality, with PE contributing to ~100,000 deaths annually in the U.S.
Table 290-1: Inflammation-Linked Conditions That Can Trigger PE or DVT¶
| Condition |
|---|
| Ulcerative colitis |
| Crohn’s disease |
| Rheumatoid arthritis |
| Psoriasis |
| Type 2 diabetes mellitus |
| Obesity/metabolic syndrome |
| Hypercholesterolemia (elevated LDL) |
| Lipoprotein(a) |
| Pneumonia |
| Acute coronary syndrome |
| Acute stroke |
| Condition |
|---|
| Cigarette smoking |
| Sepsis/septic shock |
| Erythropoiesis-stimulating agents |
| Blood transfusion |
| Cancer |
1.1 Pathophysiology¶
VTE arises from Virchow’s triad: venous stasis, hypercoagulability, and endothelial injury. Inflammation and genetic factors (e.g., factor V Leiden, prothrombin gene mutation) exacerbate thrombogenesis. PE causes acute right ventricular (RV) overload, leading to hemodynamic instability and potential cardiogenic shock.
1.2 Classification¶
PE is classified as massive (high-risk), submassive (intermediate-risk), or low-risk based on hemodynamic status and RV dysfunction. DVT is categorized by location (e.g., calf vs. proximal) and risk of embolization.
2. EPIDEMIOLOGY¶
PE mortality in the U.S. decreased from 6 per 100,000 in 2000 to 4.5 per 100,000 in 2017. Socioeconomic disparities persist, with higher PE hospitalization rates in disadvantaged communities. African Americans have higher PE mortality compared to Caucasians. VTE incidence is rising among younger adults, with median age at death decreasing from 73 to 68 years between 2000 and 2018.
Table 290-2: Clinical Decision Rules for DVT and PE¶
| Clinical Variable | DVT Score | PE Score |
|---|---|---|
| Active cancer | 1 | 1.0 |
| Paralysis/paresis/recent cast | 1 | 1.5 |
| Bedridden >3 days or surgery <12 weeks | 1 | 1.5 |
| Tenderness along deep veins | 1 | 0 |
| Entire leg swelling | 1 | 0 |
| Unilateral calf swelling >3 cm | 1 | 0 |
| Pitting edema | 1 | 0 |
| Collateral superficial veins | 1 | 0 |
| Alternative diagnosis ‡ DVT | -2 | 0 |
| Signs/symptoms of DVT | 0 | 3.0 |
| Alternative diagnosis < PE | 0 | 3.0 |
| Heart rate >100/min | 0 | 1.5 |
| Immobilization >3 days/surgery <4 weeks | 0 | 1.5 |
| Prior PE/DVT | 0 | 1.5 |
| Hemoptysis | 0 | 1.0 |
| Clinical Variable | DVT Score | PE Score |
|---|---|---|
| Cancer | 0 | 1.0 |
2.1 Demographics¶
African-American males are more prone to malignant hypertension and kidney failure. Socioeconomic disadvantage correlates with higher PE hospitalization rates, even after adjusting for age and comorbidities.
3. ETIOLOGY & PATHOPHYSIOLOGY¶
VTE is driven by inflammation, hypercoagulability, and endothelial dysfunction. Genetic factors (e.g., factor V Leiden, prothrombin gene mutation) and acquired conditions (e.g., antiphospholipid syndrome) increase risk. Inflammation from infections (e.g., COVID-19) or malignancies exacerbates thrombogenesis via cytokine storms and endothelial injury.
Table 290-3: Differential Diagnosis of DVT and PE¶
| DVT | PE |
|---|---|
| Ruptured Baker’s cyst | Pneumonia, asthma, COPD |
| Muscle strain/injury | Congestive heart failure |
| Cellulitis | Pericarditis |
| Acute postthrombotic syndrome | Pleurisy (viral syndrome) |
| Rib fracture, pneumothorax | Acute coronary syndrome |
| Anxiety | Vasovagal syncope |
3.1 Prothrombotic States¶
Factor V Leiden (resistance to protein C) and prothrombin gene mutation (increased plasma prothrombin) are the most common genetic risk factors. Antiphospholipid syndrome (APS) is an acquired thrombophilic disorder associated with recurrent thrombosis.
3.2 Inflammatory Triggers¶
Infections (e.g., pneumonia, sepsis), malignancies, and autoimmune diseases (e.g., lupus) drive inflammation, leading to endothelial activation and thrombosis. COVID-19 is associated with elevated DVT and PE rates due to cytokine storms and endothelial dysfunction.
4. CLINICAL FEATURES¶
PE presents with unexplained dyspnea, chest pain, syncope, or hemoptysis. DVT manifests as calf pain, swelling, or erythema. Massive PE is associated with hypotension, tachycardia, and signs of right heart failure. Submassive PE may present with RV dysfunction without hypotension.
4.1 Complications¶
Post-thrombotic syndrome (PTS) causes chronic venous insufficiency, leg swelling, and ulcers. Chronic thromboembolic pulmonary hypertension (CTEPH) develops in ~2% of PE patients, leading to progressive dyspnea and right heart failure.
5. DIFFERENTIAL DIAGNOSIS¶
DVT must be differentiated from cellulitis, muscle strain, or Baker’s cyst rupture. PE must be distinguished from pneumonia, heart failure, myocardial infarction, or pulmonary embolism mimics (e.g., pleuritis, pneumothorax).
6. INVESTIGATIONS & DIAGNOSIS¶
Diagnosis combines clinical scoring (Wells score), d-dimer testing, and imaging. CT pulmonary angiography (CTPA) is the gold standard for PE. Venous ultrasonography is first-line for DVT. Ventilation/perfusion (V/Q) scans are used in patients with contraindications to contrast.
Table 290-4: Anticoagulation of VTE¶
| Agent | Dosing | Notes |
|---|---|---|
| Unfractionated heparin | Bolus + infusion (aPTT 2–3× normal) | Monitor aPTT |
| Enoxaparin | 1 mg/kg BID | Renal function adjustment |
| Dalteparin | 200 U/kg QD or 100 U/kg BID | Renal adjustment |
| Tinzaparin | 175 U/kg QD | Renal adjustment |
| Fondaparinux | 2.5 mg QD | Renal adjustment |
| Rivaroxaban | 15 mg BID for 3 weeks fi 20 mg OD | CrCl adjustment |
| Apixaban | 10 mg BID for 7 days fi 5 mg BID | CrCl ‡15 mL/min |
| Dabigatran | 150 mg BID for 5 days fi 110 mg QD | CrCl adjustment |
| Edoxaban | 60 mg OD for CrCl >50 mL/min | CrCl adjustment |
6.1 Diagnostic Algorithms¶
For low-risk PE (d-dimer normal), no imaging is required. For high-risk PE, immediate CTPA is performed. In ambiguous cases, MR venography or echocardiography may be used. The Wells score guides initial testing (Table 290-2).
7. MANAGEMENT & TREATMENT¶
Anticoagulation is the cornerstone of therapy. DOACs (rivaroxaban, apixaban) are preferred over warfarin in most cases. Fibrinolysis or catheter-directed thrombolysis is used for massive PE or submassive PE with hemodynamic instability. Surgical embolectomy is reserved for refractory cases.
Table 290-5: Take-Home Points from ESC 2019 PE Guidelines¶
| Point |
|---|
| Avoid ‘provoked’ vs. ‘unprovoked’ terminology for PE/DVT |
| Extended anticoagulation is recommended for first PE with persistent risk factors |
| DOACs are preferred over warfarin for most patients |
7.1 Anticoagulation Strategies¶
DOACs (rivaroxaban, apixaban, edoxaban) are first-line for most patients. Warfarin is used in patients with antiphospholipid syndrome (APS) or mechanical heart valves. Heparin bridging is required for warfarin initiation.
7.2 Thrombolytic Therapy¶
Alteplase (tPA) is administered as a continuous IV infusion for massive PE. Catheter-directed thrombolysis is used for submassive PE with RV dysfunction. Fibrinolysis carries a 10% risk of major bleeding, including intracranial hemorrhage.
8. PROGNOSIS & COMPLICATIONS¶
PE mortality is ~10% for massive PE, but 5-year survival exceeds 50% with effective anticoagulation. PTS affects ~50% of PE patients, with persistent dyspnea and reduced exercise capacity. CTEPH occurs in ~2% of PE patients and may require pulmonary thromboendarterectomy.
8.1 Long-Term Outcomes¶
Post-PE syndrome includes chronic dyspnea, fatigue, and reduced exercise tolerance. CTEPH is a progressive condition requiring surgical intervention. Recurrent VTE risk is higher in patients with cancer, obesity, or inherited thrombophilias.
9. SPECIAL CONSIDERATIONS¶
Pregnancy requires LMWH or DOACs (apixaban, rivaroxaban) for anticoagulation. Elderly patients may require dose adjustments for DOACs. Socioeconomic disparities in PE outcomes persist, with higher mortality in disadvantaged communities. Patients with cancer require extended anticoagulation beyond 3 months.
10. KEY POINTS & CLINICAL PEARLS¶
- VTE is a leading cause of preventable mortality.
- Use the Wells score and d-dimer to guide PE diagnosis.
- DOACs are preferred over warfarin for most patients.
- Massive PE requires immediate anticoagulation or thrombolysis.
- Post-thrombotic syndrome and CTEPH are long-term complications.
- Socioeconomic disparities affect PE outcomes.