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VENOUS THROMBOEMBOLISM - MANAGEMENT
Deep vein thrombosis is a frequent manifestation of venous thromboembolism in which there is a blood clot blocking a deep vein.
Clinical findings are important to the diagnosis of deep vein thrombosis but are poor predictors of the presence or severity of thrombosis.
Pulmonary embolism is the blockage of the blood vessels in the lungs usually due to blood clots from the veins, especially veins in the legs and pelvis.
Dyspnea, pleuritic chest pain, syncope and tachypnea occur in most cases of pulmonary embolism.
Massive pulmonary embolism has the prime symptom of dyspnea and systemic arterial hypotension, that requires pressor support, is the predominant sign.

Definition

Venous Thromboembolism (VTE)

  • Most commonly manifested as pulmonary embolism (PE) and deep venous thrombosis (DVT), and is associated with significant morbidity and mortality
    • ⅓ of patients present with symptoms of DVT and ⅔ with PE 
    • Also manifests as superficial vein thrombosis (SVT), a less severe form of DVT 
  • One of the most common life-threatening cardiovascular diseases in the US and with increasing incidence and mortality rates in Asia
  • All patients admitted for major trauma, surgery or acute medical illness should be assessed for risk of VTE and bleeding before starting prophylaxis of VTE 
    • Studies show that appropriate VTE prophylaxis should be given to surgical patients in Asia who are at risk for VTE

Deep Vein Thrombosis (DVT)

  • Frequent manifestation of VTE in which there is a blood clot blocking a deep vein
  • Patients are generally asymptomatic with a calf DVT but becomes symptomatic with proximal extension of the DVT and venous outflow obstruction

Pulmonary Embolism (PE)

  • Blockage of the blood vessels in the lungs usually due to blood clots from the veins, especially the veins in the legs and pelvis

Pathogenesis

  • Virchow’s triad theorizes 3 factors contributing to the development of VTE: Hypercoagulability, endothelial damage, and stasis
  • Hypercoagulability has been associated with factor V Leiden mutation and prothrombin gene mutation
    • Cancer also produces a hypercoagulable state due to the procoagulant activity produced by malignant cells and also secondary to effects of chemotherapeutic agents
  • Major contributing risk factors include history of trauma, surgical procedures, spinal cord injury, long bone fractures, and previous VTE 

Signs and Symptoms

Deep Vein Thrombosis (DVT)

  • Localized tenderness along the distribution of the deep venous system
  • Unilateral or entire leg is swollen
  • Calf swelling >3 cm compared to asymptomatic leg (measured 10 cm below tibial tuberosity)
  • Pitting edema is greater in the symptomatic leg
  • Collateral superficial veins (non-varicose)
  • Erythema
  • Warmth
  • Superficial thrombophlebitis with a palpable cord over a superficial vein
  • Phlegmasia cerulea dolens (blue leg) - deoxygenated hemoglobin in the stagnant veins causes a cyanotic hue in the leg
  • Phlegmasia alba dolens (pale leg) - pallor in the edematous legs because the interstitial tissue pressure has exceeded capillary perfusion pressure

Pulmonary Embolism (PE)

  • Suspicion of PE is usually raised by the clinical symptoms
    • Clinical findings are nonspecific and should not be the only criteria to diagnose PE
  • Dyspnea, pleuritic chest pain, syncope and tachypnea [respiratory rate (RR) ≥20/minute] occur in most cases of PE
    • Dyspnea is the most frequent symptom, while tachypnea is its most frequent sign
    • Other signs and symptoms that may be present: Tachycardia [heart rate (HR) >100/minute], cough and hemoptysis, fever, diaphoresis, nonpleuritic chest pain, apprehension, rales, increasing pulmonic component of the 2nd heart sound, wheezing, hypotension, cyanosis, pleural rub, raised jugular venous pressure
    • PE should be suspected in cases of postoperative hypoxemia

Pleuritic Chest Pain

  • Pleuritic chest pain with or without dyspnea is one of the most frequent presentations of PE
    • May suggest a small embolism located distally near the pleura that also causes pleural irritation

Isolated Dyspnea

  • Isolated dyspnea may occur suddenly or progressively (over several weeks)
    • Usually due to a more central PE (not affecting the pleura)
    • May be associated with substernal angina-like chest pain that probably is representing right ventricular (RV) ischemia
    • Worsening dyspnea may be the only symptom that indicates PE in patients with preexisting heart failure (HF) or pulmonary disease

Syncope or Shock

  • Syncope or shock is the hallmark sign of central PE and usually results in severe hemodynamic repercussions
    • Signs of hemodynamic compromise and reduced heart flow are also usually present (eg systemic arterial hypotension, oliguria, cold extremities and/or clinical signs of acute right heart failure)

Massive Pulmonary Embolism

  • Dyspnea is usually the prime symptom and systemic arterial hypotension that requires pressor support is the predominant sign
    • Persistent hypotension is defined as a systolic blood pressure (SBP) <90 mmHg or a pressure drop of <40 mmHg for >15 minutes (or needing inotropic support) not caused by new-onset arrhythmia, hypovolemia or sepsis; or absence of pulse or sustained heart rate <40 beats/minute (bpm) with signs or symptoms of shock
  • Syncope and altered mentation
  • Renal insufficiency, hepatic dysfunction
  • Severe respiratory distress or hypoxemia (eg cyanosis)

Risk Factors

Transient or Reversible Provoking 

  • Surgery within the past 4 weeks (eg hip or knee replacement) 
  • Major trauma
  • Immobilization for at least 3 days
  • Bedridden for >3 days 
  • Estrogen therapy
  • Pregnancy/postpartum
  • Lengthy travel, eg airline flight >8 hours

Persistent Provoking 

  • Active cancer
  • Active autoimmune disease
  • Antiphospholipid antibody syndrome
  • Chronic inflammatory states, eg inflammatory bowel disease 

Other Risk Factors   

  • Increasing age
  • Past medical history or family history of VTE
  • Spinal cord injury 
  • Lower limb fracture
  • Myocardial infarction or hospitalization for atrial flutter/fibrillation or heart failure within the past 3 months 
  • Congestive heart failure or respiratory failure 
  • Obesity
  • Varicose veins
  • Blood transfusion and erythropoiesis-stimulating agents
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