Venous Thromboembolism (VTE)

• Venous Thromboembolism (VTE) is the sum of Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE).
• DVT is a blood clot formed in deep veins, typically in the legs or lower extremities, and involves phlebitis, the inflammation of vessels.
• PE occurs when a clot travels to the lungs and is life-threatening.
• DVT can lead to PE if a clot dislodges and travels to the lungs..

Causes of DVT - Virchow's Triad

• Virchow's Triad outlines the three main causes of DVT: venous stasis, vessel wall injury, and hypercoagulability.
• Venous stasis is the stasis of blood flow in veins and can be caused by heart failure, shock, immobility, anesthesia, paralysis, or abdominal tumors, where bed rest reduces blood flow in the legs by 50%.
• Vessel wall injury is damage to the blood vessel lining and can be caused by fractures, dislocations, IV medications that irritate the endothelial lining, and vascular diseases like atherosclerosis or varicose veins.
• Hypercoagulability is an increased tendency for blood clotting caused by oral contraceptives, malignancies, sudden withdrawal from anticoagulants, and blood disorders.

DVT Symptoms

• Symptoms of DVT include edema and swelling due to inhibited venous outflow, warmth over the affected area due to pooled blood, pain in the calf when the foot is dorsiflexed (Homan’s sign), and tenderness of the area.
• Superficial Thrombophlebitis also displays symptoms such as pain, tenderness, redness, and warmth over the vein.
• Treatment for superficial thrombophlebitis includes bed rest, leg elevation, and pain or anti-inflammatory medications, though there is a risk of clot dislodging and causing PE.

DVT Assessment

• Identify patients at high risk which include those post-op, obese, or undergoing pelvic surgery.
• Assess for limb pain, feelings of heaviness, swelling, ankle engorgement, tenderness, and temperature increase.
• Use a form to identify patient DVT risk (mild, moderate, or high) to determine proper treatment.

DVT Prevention

• Mobilization/early ambulation and ROM exercises are beneficial.
• TED stockings provide compression.
• Intermittent Pneumatic Compression Devices (IPCDs) are useful.
• Low-dose anticoagulation with Heparin or Lovenox can prevent DVT.
• It's important to avoid putting post-surgery patients on complete bed rest; they should be mobilized.

Medical Management

• The goal of medical management is to prevent the thrombus from growing or fragmenting and prevent recurrence.
• Anticoagulation therapy does not dissolve existing thrombi but prevents new ones from forming.

Anticoagulant Medications

• Heparin (Unfractionated) has an immediate action with a half-life of about 1 hour and requires PTT monitoring (1.5-2x normal).
• Complications of Heparin include bleeding such as monitoring stool, urine, and IV sites.
• The antidote for Heparin is protamine sulfate.
• If PTT is too high, the Heparin dose should be stopped for 1 hour and restarted at a lower dose.
• If PTT is too low, the Heparin dose should be increased to prevent emboli.
• Lovenox is a low molecular weight heparin (LMWH) and permits daily dosing without lab monitoring.
• Lovenox carries a lower risk of heparin-induced thrombocytopenia.
• Warfarin (Coumadin) is an oral anticoagulant that takes 2-3 days to take effect and requires PT & INR monitoring and should maintain 2.0-3.0 (moderate risk) and 2.5-3.5 (high risk).
• The antidote for Warfarin is Vitamin K and avoid high-Vitamin K foods.

Heparin to Warfarin Transition

• Heparin and Warfarin should be given together for 2–3 days to prevent clotting until Warfarin takes effect.

Thrombolytic Therapy

• Thrombolytic Therapy breaks down existing clots, unlike Heparin/Warfarin.
• It is best given within 3 days of clot formation and reduces post-thrombotic syndrome risk + chronic venous insufficiency but increases bleeding risk.
• Not everyone can get Thrombolytic Therapy; there are certain factors such as no high BP, no recent surgery/trauma/bleeding, or within first 3 days.

Nursing Care of Thrombolytic Therapy

• Bedrest (5-7 days) is necessary to prevent embolization.
• Elevating the affected extremity reduces swelling.
• Apply TEDs to the unaffected leg.
• Administer analgesics for pain and warm compresses reduce pain.
• Ambulation is preferred over prolonged sitting or standing.

Pulmonary Embolism

• Occurs when a clot breaks off and lodges in the pulmonary artery.
• Origins include: DVT, pelvic veins, right heart (AFib).
• Symptoms of PE are dependent upon clot size and lung area affected which include dyspnea, chest pain, anxiety, fever, tachycardia, cough, diaphoresis, hemoptysis (coughing up blood), syncope (fainting), and tachypnea (rapid breathing).

Risk Factors for Pulmonary Embolism

• Risk factors include: Surgery, trauma, pregnancy, heart failure, hypercoagulable states, immobility.

Massive PE

• Manifests as severe dyspnea, substernal pain, weak pulse, hypotension, and shock.
• Often leads to high mortality, with death usually occurring within 1 hour of symptom onset and rapid recognition & treatment is therefore critical.

PE Diagnostic Tests

• Chest X-ray (CXR) shows normal results or show infiltrates, atelectasis, pleural effusion.
• EKG shows sinus tachycardia
• Arterial Blood Gases (ABG) shows hypoxemia (low o2) & hypocapnia (low CO2 due to hyperventilation).
• D-dimer assay detects clot fragments (elevated in PE).

PE Prevention

• Early ambulation + leg exercises is a preventative measure as well as TED stockings and SCDs, and low-dose anticoagulants (Heparin, Lovenox).

PE Emergency Management

• Oxygen therapy counteracts pulmonary vasoconstriction.
• Dobutamine (Beta-agonist) increases cardiac output.
• IV Morphine reduces pain & respiratory distress.
• Initiate Anticoagulation Therapy with Heparin and transitioning to Warfarin (Coumadin), and INR must be 2.0-2.5 before stopping Heparin. Give Heparin and Coumadin together for 2-3 days.
• Thrombolytic Therapy for PE can be achieved via tPA (Tissue Plasminogen Activator), Streptokinase.
• Patients who are hypotensive and have severe hypoxemia using O2 supplements can use TPA drugs.
• Contraindications of this therapy include: Stroke (last 2 months), recent surgery, trauma, active bleeding, and severe hypertension (>180) and there is a need to monitor closely for bleeding.

Surgical Interventions for PE

• Surgical interventions for PE include: Embolectomy, removal of clot; transvenous catheter embolectomy involving suction; and an Inferior Vena Cava (IVC) Filter which prevents future PE in high-risk patients.
• Note that very dangerous procedures for excessive bleeding + clot can travel.