What is the appropriate management for an adult patient with suspected embolism and thrombosis, considering potential risk factors for clotting such as cardiovascular disease?

Management of Embolism and Thrombosis

For confirmed venous thromboembolism (deep vein thrombosis or pulmonary embolism), immediately initiate anticoagulation with low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH), followed by transition to oral anticoagulation for a minimum of 3 months. 1, 2

Immediate Assessment and Risk Stratification

Hemodynamic Status Evaluation

• Assess for massive PE immediately: Look for hypotension (systolic BP <90 mmHg), persistent hypotension requiring vasopressors, cardiogenic shock, collapse, unexplained hypoxia, engorged neck veins, and right ventricular gallop. 1, 2
• Check vital signs: Tachycardia, tachypnea (respiratory rate >20/min), hypoxia (O2 saturation <90%), and altered mental status indicate higher mortality risk. 1
• Calculate PESI score to stratify 30-day mortality risk: Class I-II (≤85 points) have <3.5% mortality; Class III-V (>85 points) have 7-24% mortality. 1

Imaging Strategy

• For massive PE with hemodynamic instability: Obtain CTPA or bedside echocardiography within 1 hour to confirm diagnosis and assess right ventricular dysfunction. 1, 2
• For non-massive PE: Imaging should ideally occur within 24 hours. 1
• McConnell sign on echocardiography (RV free wall hypokinesis with apical sparing) is highly specific for acute PE and justifies emergency treatment when CT is not immediately available. 2

Anticoagulation Protocol

Initial Parenteral Therapy

For hemodynamically stable patients (most cases):

• Start LMWH immediately without waiting for imaging confirmation if clinical suspicion is high. 1, 3
• LMWH is preferred over UFH for stable patients due to equal efficacy, lower bleeding risk, and feasibility of outpatient management. 1, 3
• Continue parenteral anticoagulation for minimum 5 days before transitioning to oral agents. 1, 4

For hemodynamically unstable patients or specific contraindications:

• Use UFH instead of LMWH if the patient has severe renal insufficiency (CrCl <30 mL/min), hemodynamic instability, high bleeding risk, or morbid obesity. 3
• UFH dosing: 5,000-10,000 units IV bolus, followed by continuous infusion at 1,300 units/hour (or weight-adjusted 80 units/kg bolus, then 18 units/kg/hour). 1, 2
• Monitor APTT: Check 4-6 hours after starting, then 6-10 hours after each dose adjustment, maintaining APTT at 1.5-2.5 times control (45-75 seconds). 1

Transition to Oral Anticoagulation

Direct oral anticoagulants (DOACs) - Preferred option:

• Dabigatran 150 mg twice daily after 5-10 days of parenteral anticoagulation (reduce to 75 mg twice daily if CrCl 15-30 mL/min). 4
• Rivaroxaban or apixaban can be started immediately without parenteral overlap in stable patients. 3, 5
• DOACs have equal efficacy to warfarin with lower bleeding risk, particularly lower intracranial hemorrhage. 3, 5

Warfarin - Alternative option:

• Start warfarin 5-10 mg daily while continuing heparin. 1
• Continue heparin for minimum 5 days AND until INR is 2.0-3.0 for 24 hours. 1
• Target INR 2.0-3.0 throughout treatment course. 1
• Monitor INR every 1-2 days initially, then adjust frequency based on stability. 1

Thrombolytic Therapy Decision

Indications for Thrombolysis

Administer thrombolytic therapy immediately if:

• Hemodynamic instability (hypotension, cardiogenic shock) with confirmed or highly suspected PE. 1, 2
• Cardiac arrest due to massive PE. 2
• In life-threatening massive PE with obstructive shock, ignore relative contraindications to thrombolysis as mortality risk exceeds bleeding risk. 2

Thrombolytic Dosing Regimens

• Alteplase 100 mg IV over 2 hours (standard regimen). 1, 2
• Alteplase 50 mg IV bolus for cardiac arrest, reassess at 30 minutes. 2
• Alternative accelerated regimen: 0.6 mg/kg over 15 minutes (maximum 50 mg) - equally effective with similar bleeding risk. 2
• Streptokinase: 250,000 units over 20 minutes, then 100,000 units/hour for 24 hours (plus hydrocortisone to prevent circulatory instability). 1

Absolute Contraindications to Thrombolysis

• Active or recent hemorrhage (within 3 weeks). 2
• Recent stroke (within 3 months). 2
• Current gastrointestinal bleeding. 2
• Recent major surgery or trauma. 1

However, in truly life-threatening PE with obstructive shock, these contraindications should be overridden. 2

Duration of Anticoagulation

Minimum Treatment Duration

• All patients require minimum 3 months of therapeutic anticoagulation. 2, 3, 6

Extended Anticoagulation Decision Algorithm

Provoked VTE with transient risk factors (surgery, trauma, immobilization):

• Stop anticoagulation at 3 months - recurrence risk is low. 2, 3

Unprovoked VTE (no identifiable trigger):

• Continue anticoagulation beyond 3 months, consider indefinite therapy - recurrence risk is 10% per year off anticoagulation. 2, 3
• Reassess bleeding risk annually. 3

Active cancer:

• Use LMWH indefinitely (preferred over warfarin or DOACs due to superior efficacy). 3

Recurrent VTE:

• Indefinite anticoagulation required. 2

Special Populations and Situations

Pregnancy

• LMWH throughout pregnancy and 6 weeks postpartum - warfarin and DOACs are contraindicated. 3

Severe Renal Insufficiency (CrCl <30 mL/min)

• Use UFH or warfarin - most DOACs are contraindicated except dabigatran 75 mg twice daily (if CrCl 15-30 mL/min). 4, 3

Outpatient vs. Inpatient Management

• Up to 50% of PE patients can be managed as outpatients if hemodynamically stable, low PESI score (Class I-II), adequate home support, and no high bleeding risk. 1, 3
• All DVT patients without PE can be managed outpatient with LMWH or DOACs. 3

Common Pitfalls to Avoid

• Never delay anticoagulation while awaiting imaging if clinical suspicion is moderate-to-high - start heparin immediately. 1
• Do not use inferior vena cava filters as primary treatment when anticoagulation is feasible - filters do not reduce mortality and increase DVT risk. 3
• Do not give thrombolytics to hemodynamically stable patients - bleeding risk outweighs benefit in this population. 1
• Do not stop heparin prematurely when transitioning to warfarin - continue until INR therapeutic for 24 hours. 1
• Do not use DOACs in patients with mechanical heart valves - they are contraindicated and increase thrombotic risk. 4