Vascular Disease: Venous Thromboembolism (VTE)

Venous Thromboembolism (VTE)

• VTE is a potentially fatal disorder and a significant health problem.
• VTE results from clot formation in the venous circulation, manifesting as deep vein thrombosis (DVT) or pulmonary embolism (PE).
• DVT is rarely fatal, but PE can cause death within minutes of symptom onset, before effective treatment is administered.

Learning Outcomes

• Students should understand the pathophysiology of VTE.
• Identify common vital/lab values used in assessing VTE.
• Recognize common risk factors for developing VTE.
• Compare and contrast different types of anticoagulation.
• Develop therapeutic plans, including efficacy and toxicity monitoring, for various patient populations with VTE.
• Formulate prevention strategies for different patient populations at high risk for DVT, consistent with clinical practice guidelines.

Vascular Disease

• VTE is presented as part of a larger vascular disease.
• This includes vascular disease of the veins, arteries, and lymphatic system, which lead to diseases such as IHD, ACS, stroke and TIA, coronary, cerebral, peripheral, renal, and mesenteric aorta.

Pathophysiology of Clots

• Arterial clots ("white clots") are platelet-rich and form in high-pressure environments.
• Antiplatelet agents are used to treat arterial clots.
• Venous clots ("red clots") are red blood cell-rich and form in low-pressure environments.
• Anticoagulant agents are used to treat venous clots.

Risk Factors for VTE

• Hypercoagulable State: malignancy, pregnancy, estrogen therapy, trauma or surgery (lower extremity, hip, abdomen or pelvis), inflammatory bowel disease, nephrotic syndrome, sepsis, thrombophilia
• Vascular Wall Injury: trauma or surgery, venepuncture, chemical irritation, heart valve disease, atherosclerosis, indwelling catheters
• Circulatory Stasis: atrial fibrillation, left ventricular dysfunction, immobility or paralysis, venous insufficiency or varicose veins, venous obstruction (tumour, obesity or pregnancy)

Presentation & Evaluation

• Presentation: Symptoms are often asymptomatic or non-specific, resembling other disease states. Objective testing is needed to confirm the diagnosis.
• Evaluation: Involves medical history, physical exams, and medication review.

Clinical Presentation: DVT & PE

• DVT Symptoms: unilateral swelling, warmth, discoloration, calf tenderness, pain, Homans sign
• PE Symptoms: shortness of breath, tachycardia, tachypnea, hemoptysis, anxiety, dyspnea, cough, chest pain

Assessment & Diagnosis

• DVT Diagnosis: Wells model, D-dimer, Doppler ultrasound, venography
• PE Diagnosis: Wells model, D-dimer, ECG, Chest X-ray, arterial blood gas, CT scan, ventilation/perfusion scan (V/Q scan), pulmonary angiography

D-Dimer

• A fibrin clot degradation product
• Elevated in patients with acute thrombosis, but not specific. Elevated in other conditions, such as trauma, pregnancy, cancer, surgery, and infection.

Wells Clinical Models (DVT & PE)

• These are clinical prediction rules used to evaluate the probability of DVT or PE and aid in clinical decision-making.

Goals of VTE Treatment

• Prevent thrombus extension and embolization
• Reduce recurrence risk
• Prevent long-term complications (e.g., post-thrombotic syndrome)
• Decrease the risk of PE complications (e.g., death, pulmonary hypertension, and impaired function)

Approaches to VTE Treatment

• Bridging Therapy: Injectable anticoagulants (UFH, LMWH, or fondaparinux) start with warfarin overlap for at least 5 days until therapeutic INR is achieved (INR 2-3), after which warfarin continues.
• Switching Therapy: Injects anticoagulant (UFH, LMWH, or fondaparinux) for at least 5 days, prior to switching to dabigatran or edoxaban for the appropriate duration.
• Monotherapy: Start with rivaroxaban or apixaban at a higher initial dose, then transition to a lower dose for an appropriate duration.

Acute VTE Management Options

• Flowchart for managing acute VTE, with considerations for various patient conditions, possible hospitalizations, and treatments (thrombolytics, IVC filters).

Parenteral Anticoagulants

• Factors such as heparin dosages, renal adjustments, and monitoring parameters are presented for several common agents (Heparin, Enoxaparin, Fondaparinux).

Oral Anticoagulants

• Various categories of oral anticoagulants, dosages, renal adjustments for specific conditions, and monitoring parameters are indicated for these agents (Warfarin, Rivaroxaban, Apixaban, Edoxaban, Dabigatrin).

Thrombolytics

• Only for high-risk patients with PE without hypotension/shock or specific clinical presentation characteristics (ecg findings, right ventricular dysfunction).
• Contra-indications include bleeding risk, and specific treatment regimens for high-risk PE (streptokinase, alteplase, urokinase).

Nonpharmacological Management of VTE

• Considerations for use of inferior vena cava filters (IVCF) placement, thrombectomy (e.g., catheter aspiration thrombectomy, thrombectomy [suctioning]), anti-embolic leg exercise.

VTE Prophylaxis

• Preventative measures to avoid VTE. Includes mechanical measures (e.g., early ambulation, graduated compression stockings, intermittent pneumatic compression), and pharmacologic measures (e.g., LMWH, UFH, dose adjustments, DOACS.)

Duration of Prophylaxis

• Optimal duration of VTE prophylaxis following surgical procedures is not standardized but is influenced by factors such as the type of surgery, patient risk factors, recovery, and bleeding risk.

General Approach to VTE Prophylaxis

• Flow chart for risk assessment and treatment options for VTE prophylaxis in various clinical contexts, focusing on medical and surgical procedures.

VTE & Bleeding Risk Assessment

• Charts presenting characteristics of patients that may increase the risk of VTE and/or bleeding, along with corresponding risk assessment points used to evaluate risk. Includes: renal, age, prior VTE, surgery, cancer, etc.

Non-Surgical Patients Prophylaxis Strategies

• Based on risk assessment of the patient, a choice between early ambulation as the sole prophylaxis measure, initiation of LMWH, or combined mechanics prophylaxis and LMWH to manage the risk of VTE.

Non-Orthopedic Surgical Prophylaxis Strategies

• Presents guidance for prophylaxis in various categories of risk levels, and types of surgery. Including strategies for prophylaxis where bleeding is a particular concern, as well as general surgical prophylaxis strategies.

Orthopedic Surgical Prophylaxis Strategies

• Presents guidance based on risk assessment and presents the use of LMWH, combined with mechanical prophylaxis, as a strategy for managing VTE in orthopedic surgeries.

Duration of Prophylaxis

• Offers duration guidance for prophylaxis in various categories of clinical settings and patient characteristics, including high-risk classifications and various types of surgery and illnesses.

Chest Guidelines Recommendation

• Recommendations for treatment and management for patients with VTE. Includes: treatment of VTE based on various risk levels, types of VTE, presence/absence of other health complications, and length of treatment plans. Further offers recommendations for anticoagulant treatments.

This quiz focuses on Venous Thromboembolism (VTE), a critical component of vascular disease. Students will explore the pathophysiology, risk factors, and management strategies for VTE. Understanding the implications of DVT and PE, as well as therapeutic plans and prevention strategies, is crucial for healthcare professionals.