What are some high‑yield pulmonary embolism examination questions suitable for a fellowship‑level exam?

High-Yield Pulmonary Embolism Examination Questions for Fellowship

Risk Stratification and Hemodynamic Assessment

The most critical initial step in PE management is determining hemodynamic stability, which dictates whether systemic thrombolysis is indicated. 1

Question 1: Defining High-Risk PE

• High-risk PE is defined by sustained hypotension (systolic BP <90 mmHg for >15 minutes), obstructive shock requiring vasopressors, or cardiac arrest. 2
• Candidates must recognize that this classification mandates immediate systemic thrombolysis unless absolute contraindications exist. 1, 2
• A common pitfall is confusing intermediate-risk PE (RV dysfunction without hypotension) with high-risk PE—only the latter requires primary thrombolysis. 1, 2

Question 2: Clinical Presentation Patterns

• Three cardinal presentations must be recognized: (1) sudden collapse with elevated JVP indicating massive PE, (2) pulmonary hemorrhage syndrome with pleuritic pain/hemoptysis, and (3) isolated dyspnea without cough or sputum. 1, 3
• The isolated dyspnea pattern is frequently missed, particularly in elderly patients and those with pre-existing cardiorespiratory disease. 1, 3
• Tachypnea (respiratory rate >20/min) occurs in most cases and should trigger immediate suspicion. 1, 3

Question 3: Pre-Test Probability Assessment

• Major risk factors that score +1 point include: recent immobilization/surgery, lower limb trauma/surgery, clinical DVT, prior VTE, pregnancy/postpartum, and major medical illness. 1
• PE is rare in patients <40 years without risk factors; oral contraceptives are only a minor risk factor. 1
• When clinical probability is high (Wells score ≥7), anticoagulation must be initiated immediately without waiting for imaging. 2, 4

Diagnostic Algorithms and Imaging

Question 4: Role of D-Dimer Testing

• D-dimer testing should never be used in high clinical probability settings—it delays treatment and is unsafe. 2
• D-dimer is only appropriate for low-risk DVT patients or moderate-risk PE patients to rule out disease. 4
• In suspected massive PE, D-dimer is useless and diagnosis relies on clinical probability plus bedside echocardiography. 5

Question 5: Imaging Strategy for Unstable Patients

• CTPA is first-line imaging but should be performed within 1 hour for high-risk PE. 2
• When transport is unsafe for hemodynamically unstable patients, bedside echocardiography demonstrating RV dysfunction is sufficient to proceed with thrombolysis when clinical probability is high. 2
• If CTPA reports single subsegmental PE, discuss findings with radiology and seek second opinion to avoid misdiagnosis. 1

Anticoagulation Management

Question 6: Initial Anticoagulation Choice

• For hemodynamically stable patients, LMWH or fondaparinux is preferred over unfractionated heparin (UFH). 2, 4
• For hemodynamically unstable patients, use weight-adjusted UFH: 80 U/kg IV bolus followed by 18 U/kg/h infusion, targeting aPTT 1.5-2.5× control. 2, 3
• LMWH dosing: enoxaparin 1 mg/kg SC every 12 hours. 2

Question 7: UFH Monitoring and Adjustment

• aPTT should be measured 4-6 hours after initiation; sub-therapeutic anticoagulation in the first 24 hours increases recurrent VTE risk. 2
• Adjustment algorithm: 2
  • aPTT <35 sec: 80 U/kg bolus, increase infusion by 4 U/kg/h
  • aPTT 35-45 sec: 40 U/kg bolus, increase by 2 U/kg/h
  • aPTT 46-70 sec: no change (therapeutic)
  • aPTT 71-90 sec: decrease by 2 U/kg/h
  • aPTT >90 sec: stop for 1 hour, then decrease by 3 U/kg/h

Question 8: Long-Term Anticoagulation Selection

• NOACs (apixaban, rivaroxaban, edoxaban, dabigatran) are preferred over warfarin for eligible patients. 1, 2
• Absolute contraindications to NOACs: severe renal impairment, pregnancy/lactation, antiphospholipid antibody syndrome, mechanical heart valves. 2
• Apixaban and rivaroxaban can be started immediately without parenteral bridging; edoxaban and dabigatran require ≥5 days of LMWH first. 4

Question 9: Duration of Anticoagulation

• Provoked PE (surgery/trauma): 3 months then stop. 2
• Unprovoked first PE: ≥3 months; strongly consider indefinite therapy due to lifelong recurrence risk. 1, 2
• Recurrent VTE or cancer-associated PE: indefinite anticoagulation. 2
• All patients must be re-evaluated at 3-6 months to balance bleeding versus recurrence risk. 1, 2

Reperfusion Therapy

Question 10: Thrombolysis Indications and Dosing

• Systemic thrombolysis is first-line therapy for high-risk PE (Class I, Level B). 1, 2
• Alteplase dosing: 100 mg IV over 90 minutes for stable patients; 50 mg IV bolus for cardiac arrest. 2
• Routine thrombolysis is NOT recommended for intermediate-risk PE; reserve rescue thrombolysis only for hemodynamic deterioration. 2, 4
• Thrombolysis reduces short-term mortality (RR 0.61; 95% CI 0.40-0.94), corresponding to 13 fewer deaths per 1,000 treated. 2

Question 11: Alternative Reperfusion Options

• Surgical pulmonary embolectomy is indicated when thrombolysis is contraindicated or has failed. 1, 2
• Catheter-directed therapy is considered when: absolute contraindications to systemic thrombolysis exist, systemic thrombolysis failed, or experienced interventional expertise is available. 2
• VA-ECMO may bridge patients with refractory circulatory collapse to recovery or definitive intervention. 2

Supportive Care and Common Pitfalls

Question 12: Hemodynamic Support in Massive PE

• Avoid aggressive fluid boluses—they worsen right ventricular failure. 2
• Use norepinephrine or dobutamine for hypotension; provide oxygen for hypoxemia. 2
• Untreated hemodynamically unstable PE carries 90-day mortality ~50%, justifying aggressive thrombolysis despite bleeding risks. 2

Question 13: IVC Filter Indications

• IVC filters are reserved for absolute contraindication to anticoagulation or recurrent PE despite therapeutic anticoagulation. 2, 4
• Routine filter use is not recommended (Class III, Level A). 2
• Use retrievable filters when possible, with retrieval as soon as anticoagulation becomes feasible. 4

Follow-Up and Long-Term Complications

Question 14: Post-PE Surveillance

• All PE patients require scheduled follow-up; do not lose patients to follow-up. 1
• At 3-6 months, assess for persistent dyspnea/functional limitation to screen for chronic thromboembolic pulmonary hypertension (CTEPH). 1, 2
• Evaluate for VTE recurrence, occult malignancy (in unprovoked cases), and bleeding complications. 1, 2
• Routine follow-up imaging is not recommended in asymptomatic patients but may be considered in those with CTEPH risk factors. 1

Question 15: Special Populations

• Pregnant patients: utilize formal diagnostic pathways including CTPA or V/Q scan—both can be used safely during pregnancy. 1
• Cancer patients: LMWH is preferred over warfarin for ≥6 months; continue while cancer is active. 2, 4
• More frequent clinical assessment is needed in cancer patients due to higher recurrence and bleeding risk. 4