PULMONARY EMBOLISM
Wells Score | CTPA Gold Standard | Risk Stratify | Anticoagulate or Thrombolyse
PE RISK STRATIFICATION
Critical Must-Knows
- Wells score estimates PE probability - guides need for CTPA
- CTPA is gold standard (95% sensitive) - VQ scan if contrast contraindicated
- Risk stratification determines treatment: Massive = thrombolysis, Low-risk = anticoagulation only
- Thrombolysis saves lives in massive PE but 1-5% intracranial bleed risk
- IVC filters ONLY if anticoagulation absolutely contraindicated - NOT routine
Examiner's Pearls
- "PERC rule: If ALL 8 criteria negative AND low clinical suspicion, PE excluded (no D-dimer needed)
- "Massive PE = hemodynamic instability (SBP less than 90) - thrombolyse immediately
- "D-dimer negative with low Wells score excludes PE (99% NPV)
- "Postop PE is provoked - anticoagulate 3 months, NOT indefinite
Clinical Imaging
Imaging Gallery
Critical Exam Concepts
Massive PE Requires Thrombolysis
Massive PE = sustained hypotension (SBP less than 90 mmHg) or cardiac arrest. This is an emergency. Give alteplase 50-100mg over 2 hours IMMEDIATELY after confirming on CTPA. Mortality 30% if untreated vs 10% with thrombolysis.
IVC Filters are NOT Routine
IVC filters do NOT prevent PE or reduce mortality. Only use if absolute contraindication to anticoagulation (active bleeding, recent neurosurgery). PREPIC trial showed filters increase DVT without reducing PE death.
Risk Stratification Guides Treatment
Massive (high-risk): Thrombolysis. Submassive (intermediate): Anticoagulation, watch for deterioration. Low-risk: Anticoagulation, consider outpatient if PESI low risk. Do NOT thrombolyse submassive routinely.
CTPA is Gold Standard
CTPA has 95% sensitivity and 98% specificity for PE. Direct visualization of thrombus in pulmonary arteries. VQ scan only if contrast contraindicated (renal failure, severe allergy). Wells score determines who gets CTPA.
Quick Decision Guide
| Clinical Scenario | Wells Score | Next Step | Treatment |
|---|---|---|---|
| Low suspicion (all PERC negative) | Not needed | No further testing | PE excluded - no D-dimer needed |
| Moderate suspicion, low Wells (less than 4) | 0-3 (PE unlikely) | D-dimer first | If negative stop. If positive CTPA |
| High suspicion, high Wells (4+) | 4+ (PE likely) | Skip D-dimer, go to CTPA | If positive, anticoagulate |
| Massive PE (SBP less than 90, shock) | Not needed | CTPA if stable, or empiric thrombolysis if crashing | Alteplase 50-100mg over 2h + anticoagulation |
PEACH 3-3-1.5Wells Score for Pulmonary Embolism
Memory Hook:PEACH 3-3-1.5: Score less than 4 = PE unlikely (D-dimer), score 4+ = PE likely (CTPA). Remember Prior DVT, Elevated HR, Alternative unlikely, Cancer, Hemoptysis!
PERC 8PERC Rule (PE Rule-Out Criteria)
Memory Hook:If ALL 8 PERC criteria negative AND low clinical suspicion, PE excluded - NO D-dimer needed! Saves unnecessary testing.
H-R-SMassive vs Submassive vs Low-Risk PE
Memory Hook:H-R-S: High-risk needs thrombolysis, RV dysfunction needs monitoring, Stable can go home!
Overview and Clinical Significance
Why PE is Critical in Orthopaedic Surgery
Pulmonary embolism is the LEADING cause of preventable perioperative death in orthopaedic surgery. THA and TKA have 10-20% PE risk without prophylaxis. With modern prophylaxis, risk is 0.5-2% but still significant. Early recognition and treatment are life-saving.
PE Epidemiology
- Incidence: 60-100 per 100,000 population annually
- Ortho surgery (with prophylaxis): 0.5-2%
- THA/TKA (without prophylaxis): 10-20%
- Peak: Days 3-7 postoperatively
- Mortality: 2-8% overall, 30% if massive PE untreated
- Fatal PE: Often first presentation (25% sudden death)
Consequences of PE
- Massive PE: 30% mortality if untreated, 10% with thrombolysis
- Submassive PE: 10-15% deterioration to massive
- Post-PE syndrome: Chronic dyspnea 50% at 1 year
- Chronic thromboembolic pulmonary hypertension (CTEPH): 2-4%
- Recurrent VTE: 10-30% over 5 years if inadequately treated
Pathophysiology
Mechanism of Pulmonary Embolism
PE results from venous thrombus (95% from lower limb DVT) embolizing to pulmonary circulation:
1. Thrombus Formation (Virchow's Triad):
- Venous stasis (immobility, surgery)
- Endothelial injury (surgical trauma, central lines)
- Hypercoagulability (inflammatory response, cancer, thrombophilia)
2. Embolization:
- Thrombus breaks off from DVT (usually proximal leg veins)
- Travels through IVC and right heart
- Lodges in pulmonary arteries (lobar, segmental, or subsegmental)
3. Hemodynamic Effects:
- Small PE: Minimal effect, may be asymptomatic
- Moderate PE: Ventilation-perfusion mismatch, hypoxia, tachycardia
- Massive PE: Acute RV failure from sudden afterload increase, cardiogenic shock
4. Gas Exchange Impairment:
- Dead space ventilation (ventilation without perfusion)
- Hypoxemia from V/Q mismatch
- Hyperventilation and hypocapnia (initially)
- Atelectasis from surfactant depletion
RV Failure in Massive PE
Massive PE causes acute RV failure because the thin-walled RV cannot generate sufficient pressure to overcome sudden increase in pulmonary vascular resistance. RV dilatation impairs LV filling (ventricular interdependence), reducing cardiac output and causing cardiogenic shock.
Orthopaedic Surgery Risk Factors
Why orthopaedic surgery is very high risk for PE:
- Prolonged immobility: Pre-op, intra-op (anesthesia), post-op
- Direct vascular trauma: Hip and knee surgery near large veins
- Bone marrow embolization: Fat and marrow emboli activate coagulation
- Cement polymerization: Thermal injury, microemboli
- Tourniquet use: Ischemia-reperfusion injury, endothelial damage
- Inflammatory response: Massive cytokine release activates coagulation cascade
Risk by Procedure (without prophylaxis):
- THA: 10-20% symptomatic PE, 0.5-1% fatal PE
- TKA: 10-20% symptomatic PE, 0.3-0.7% fatal PE
- Hip fracture surgery: 10-15% PE
- Spine surgery: 2-5% PE
- Arthroscopy: Less than 1% PE (but still occurs)
Classification
PE Risk Stratification Classification
Hemodynamic Classification (Primary):
- Massive (High-Risk): Sustained hypotension (SBP less than 90 mmHg for 15+ minutes), cardiac arrest, or cardiogenic shock
- Submassive (Intermediate-Risk): Normotensive BUT RV dysfunction on echo/CT OR elevated troponin/BNP
- Low-Risk: Normotensive, no RV dysfunction, normal biomarkers
Anatomical Classification:
- Saddle PE: Thrombus at bifurcation of main pulmonary artery
- Central PE: Main or lobar pulmonary arteries
- Segmental/Subsegmental PE: Peripheral branches
Temporal Classification:
- Acute PE: New thrombus, fresh clot
- Chronic thromboembolic disease: Organized thrombus, may lead to CTEPH
Clinical Presentation
PE Presentation is Highly Variable
25% of fatal PE present with sudden death without prior symptoms. Symptoms range from none (incidental finding) to sudden cardiovascular collapse. Maintain high index of suspicion in postoperative orthopaedic patients.
Symptoms (Nonspecific)
| Symptom | Frequency | Clinical Notes |
|---|---|---|
| Dyspnea (sudden onset) | 80-90% | Most common - often pleuritic |
| Pleuritic chest pain | 50-70% | Sharp, worse with inspiration (pleural irritation) |
| Cough | 40-50% | Dry or productive |
| Hemoptysis | 10-20% | Blood-streaked sputum (pulmonary infarction) |
| Syncope | 10-15% | Suggests massive PE with hypotension |
| Leg pain/swelling | 30-40% | Concurrent DVT |
Classic triad (dyspnea, pleuritic pain, hemoptysis) occurs in less than 20% of cases.
Signs
| Sign | Frequency | Significance |
|---|---|---|
| Tachypnea (RR greater than 20) | 70-80% | Most sensitive sign |
| Tachycardia (HR greater than 100) | 40-60% | Compensatory response to hypoxia |
| Hypoxemia (O2 sat less than 95%) | 50-70% | V/Q mismatch |
| Hypotension (SBP less than 90) | 5-10% | MASSIVE PE - RV failure |
| Elevated JVP | 20-30% | RV dysfunction |
| DVT signs (unilateral leg swelling) | 30-40% | Source of embolus |
Clinical Syndromes
Massive (High-Risk) PE
Definition: Sustained hypotension (SBP less than 90 mmHg for 15+ minutes) OR requiring inotropes OR cardiac arrest OR cardiogenic shock.
Clinical Features:
- Severe dyspnea, often unable to speak
- Hypotension, cold peripheries
- Altered mental status (confusion from poor perfusion)
- Cyanosis
- Elevated JVP, RV gallop
- ECG: Sinus tachycardia, S1Q3T3 pattern (25%)
Mortality: 30% if untreated, 10% with thrombolysis.
Management: THROMBOLYSIS (alteplase) + anticoagulation. Surgical embolectomy if thrombolysis contraindicated.
This is a medical emergency requiring immediate action.
Diagnostic Approach
Clinical Probability Assessment is First Step
Never order CTPA without first assessing pretest probability. Use PERC rule (very low suspicion) or Wells score (low to high suspicion) to determine who needs D-dimer vs CTPA. This reduces unnecessary radiation and contrast exposure.
PE Diagnostic Algorithm
Very low suspicion AND all PERC criteria negative? PE excluded, stop. Otherwise calculate Wells score for PE.
If Wells 0-3 (PE unlikely), check D-dimer. If NEGATIVE - PE excluded (99% NPV). If POSITIVE - proceed to CTPA.
If Wells 4+ (PE likely), skip D-dimer and go directly to CTPA. D-dimer has low utility when pretest probability is high.
CTPA is gold standard (95% sensitive). VQ scan if contrast contraindicated. If positive, risk stratify (massive/submassive/low-risk).
Check BP, echo (RV function), troponin, BNP. Classify as massive (thrombolyse), submassive (anticoagulate + monitor), or low-risk (anticoagulate +/- outpatient).
PERC Rule (PE Rule-Out Criteria)
If ALL 8 criteria are NEGATIVE AND clinical suspicion is LOW, PE is excluded (no D-dimer needed):
- Age less than 50 years
- Heart rate less than 100 bpm
- Oxygen saturation 95% or greater on room air
- No hemoptysis
- No estrogen use (OCP, HRT)
- No prior DVT or PE
- No unilateral leg swelling
- No surgery or trauma requiring hospitalization in past 4 weeks
Only use PERC if suspicion is LOW. If ANY criterion positive OR suspicion moderate/high, proceed to Wells score.
Wells Score for PE
| Clinical Feature | Points |
|---|---|
| Clinical signs of DVT (leg swelling + tenderness) | +3 |
| Alternative diagnosis less likely than PE | +3 |
| Heart rate greater than 100 bpm | +1.5 |
| Immobilization (3+ days) or surgery in past 4 weeks | +1.5 |
| Previous DVT or PE | +1.5 |
| Hemoptysis | +1 |
| Active cancer (treatment within 6 months or palliative) | +1 |
Interpretation:
- Score 0-3: PE unlikely (15% prevalence) - check D-dimer
- Score 4+: PE likely (40% prevalence) - skip D-dimer, go to CTPA
Investigations
D-dimer Testing
Principle: D-dimer is fibrin degradation product elevated in VTE. High sensitivity (95-98%) but low specificity (40-60%).
When D-dimer is Useful
- Low Wells score (less than 4)
- Negative D-dimer = PE excluded
- High negative predictive value (99%)
- Avoids unnecessary CTPA (radiation + contrast)
When D-dimer is NOT Useful
- High Wells score (4+) - go to CTPA
- Postoperative patients - often elevated
- Cancer, pregnancy, elderly - often elevated
- Positive D-dimer does NOT diagnose PE
Interpretation:
- Negative D-dimer + Low Wells: PE excluded, no CTPA needed
- Positive D-dimer: Proceed to CTPA (does NOT confirm PE)
- In postop ortho patients: Often falsely elevated - CTPA may be needed regardless
Age-adjusted D-dimer: In patients over 50, use cutoff of (age x 10) instead of 500 ng/mL to improve specificity.
Risk Stratification
Risk Stratification Determines Treatment
ALL confirmed PE patients must be risk stratified to determine if they need thrombolysis (massive), close monitoring (submassive), or standard anticoagulation (low-risk). This is NOT just for prognosis - it directly impacts treatment decisions.
PE Risk Stratification
| Category | Hemodynamics | RV Dysfunction | Biomarkers | Mortality | Treatment |
|---|---|---|---|---|---|
| Massive (High-Risk) | SBP less than 90 mmHg or shock or arrest | Usually present | Usually elevated | 30% untreated | THROMBOLYSIS + anticoagulation |
| Submassive (Intermediate) | SBP greater than 90 mmHg (normotensive) | Present (echo or CT) | Troponin or BNP elevated | 10-15% deterioration | Anticoagulation + close monitoring, rescue thrombolysis if deteriorates |
| Low-Risk | SBP greater than 90 mmHg (stable) | Absent | Normal | Less than 1% | Anticoagulation, consider outpatient if PESI low |
Assessing RV Dysfunction (for Submassive PE)
Echocardiography:
- RV dilatation: RV/LV diameter ratio greater than 0.9 (apical 4-chamber view)
- RV hypokinesis
- McConnell sign (RV free wall hypokinesis with apical sparing)
CT:
- RV/LV diameter ratio greater than 1.0 on axial images
Biomarkers:
- BNP greater than 90 pg/mL or NT-proBNP greater than 500 pg/mL
- Troponin I greater than 0.4 ng/mL
If ANY of the above present with normotensive patient = submassive PE.
Management Algorithm
Start Anticoagulation Immediately
Once PE is diagnosed (or strongly suspected while awaiting CTPA), start anticoagulation immediately. Delays increase mortality. Choice of agent depends on hemodynamic status, bleeding risk, and renal function.
Anticoagulant Options for PE
| Agent | Advantages | Disadvantages | Australian Context |
|---|---|---|---|
| Rivaroxaban/Apixaban (DOACs) | Oral from day 1, no monitoring, no LMWH lead-in | Cost, renal impairment, limited reversal | PBS approved, first-line |
| LMWH + Warfarin | Cheap, reversible, familiar | LMWH injections, INR monitoring, drug interactions | Traditional approach, still used |
| IV Unfractionated Heparin | Reversible (short half-life), can use in renal failure | IV access needed, monitoring (aPTT), HIT risk | Used in massive PE, perioperatively |
| LMWH alone | No monitoring, predictable | Injections, expensive long-term | Cancer-associated PE |
Direct Oral Anticoagulants (First-Line for Stable PE)
Rivaroxaban:
- 15mg BD for 21 days, then 20mg daily
- No LMWH lead-in needed
- Reduce to 15mg daily if CrCl 30-50
- Avoid if CrCl less than 30
Apixaban:
- 10mg BD for 7 days, then 5mg BD
- No LMWH lead-in needed
- Reduce to 2.5mg BD if 2 of: age greater than 80, weight less than 60kg, creatinine greater than 133
- Avoid if CrCl less than 30
Advantages: Oral from day 1, predictable, no monitoring, easier than warfarin, similar efficacy, lower bleeding risk.
Use for: Low-risk and submassive PE (after ruling out need for thrombolysis).
Do NOT use for: Massive PE (use IV heparin initially), CrCl less than 30, active bleeding, mechanical valve, antiphospholipid syndrome.
Treatment Duration
| VTE Type | Duration | Rationale |
|---|---|---|
| Provoked (surgery) | 3 months | Transient risk factor removed, low recurrence risk (1-3% annually) |
| Unprovoked first | 3-6 months minimum | Assess bleeding vs recurrence risk. May extend if low bleeding risk |
| Recurrent unprovoked | Indefinite | High recurrence risk (15% annually if stopped) |
| Active cancer | Indefinite (while active) | Ongoing hypercoagulable state, high recurrence |
Post-Surgical PE is Provoked
PE occurring after orthopaedic surgery is PROVOKED (transient risk factor). Treat for 3 months only. Lower recurrence risk (1-3% annually) vs unprovoked PE. Do NOT anticoagulate indefinitely.
Thrombolysis for Massive PE
Thrombolysis Saves Lives in Massive PE
Massive PE has 30% mortality if treated with anticoagulation alone vs 10% with thrombolysis. If patient has sustained hypotension (SBP less than 90 mmHg) or cardiogenic shock, give alteplase 50-100mg IV over 2 hours IMMEDIATELY after confirming PE on CTPA.
Indications for Thrombolysis
Absolute indication (Massive PE):
- Sustained hypotension (SBP less than 90 mmHg for 15+ minutes) AND confirmed PE
- Cardiac arrest due to PE
- Cardiogenic shock
Relative indication (Submassive PE - controversial):
- Normotensive BUT severe RV dysfunction AND deteriorating clinically
- PEITHO trial showed routine thrombolysis in submassive PE reduces hemodynamic collapse (2% vs 5%) but increases major bleeding (11% vs 2%) and stroke (2% vs 0.2%)
- Current recommendation: Anticoagulation for submassive, rescue thrombolysis only if deteriorates
Thrombolytic Agents
| Agent | Dose | Notes |
|---|---|---|
| Alteplase (tPA) | 100mg IV over 2 hours OR 50mg bolus (if arrest) | First-line, most evidence |
| Tenecteplase | 30-50mg IV bolus (weight-based) | Single bolus, easier administration |
| Streptokinase | 1.5 million units over 2 hours | Rarely used (antigenic, allergic reactions) |
Give heparin concurrently (bolus + infusion as per protocol).
Contraindications to Thrombolysis
Contraindications
| Absolute | Relative |
|---|---|
| Active bleeding | Recent minor bleeding (less than 10 days) |
| Intracranial hemorrhage (ever) | Recent major surgery (10-14 days) |
| Ischemic stroke within 3 months | Ischemic stroke greater than 3 months ago |
| Neurosurgery or head trauma within 3 months | Major trauma |
| Brain tumor, arteriovenous malformation | CPR greater than 10 minutes |
| Pregnancy, first week postpartum | |
| Uncontrolled hypertension (SBP greater than 180) |
If absolute contraindication: Consider surgical embolectomy or catheter-directed thrombolysis.
Complications of Thrombolysis
| Complication | Incidence | Management |
|---|---|---|
| Major bleeding | 10-15% | Stop thrombolytic, transfuse, consider reversal (cryoprecipitate, TXA) |
| Intracranial hemorrhage | 1-5% | STOP thrombolytic, reverse, neurosurgical consultation |
| Minor bleeding | 20-30% | Local pressure, monitor |
| Allergic reaction (streptokinase) | 5-10% | Antihistamines, steroids, switch to alteplase |
Intracranial hemorrhage is the most feared complication - occurs in 1-5%. Risk higher in elderly, uncontrolled HTN, prior stroke.
Management Algorithm
Surgical and Interventional Options
Surgical Pulmonary Embolectomy
Indication: Massive PE with absolute contraindication to thrombolysis OR failed thrombolysis.
Procedure:
- Median sternotomy
- Cardiopulmonary bypass
- Direct removal of thrombus from pulmonary arteries via pulmonary arteriotomy
Outcomes:
- Mortality 30-50% (very sick patients)
- Success depends on speed of intervention
- Reserved for last resort
Availability: Only at tertiary cardiac surgery centers.
IVC Filters - Evidence and Indications
IVC Filters Do NOT Prevent PE Death
The PREPIC trial clearly showed IVC filters do NOT reduce PE mortality. They prevent recurrent PE in the first 2 weeks but INCREASE the risk of DVT long-term. Only use if absolute contraindication to anticoagulation.
Indications for IVC Filter
Absolute indications (very narrow):
- Acute VTE with absolute contraindication to anticoagulation (active bleeding, recent intracranial hemorrhage, recent neurosurgery)
- Recurrent VTE despite therapeutic anticoagulation (documented compliance + therapeutic levels)
Relative indications (controversial, generally NOT recommended):
- Free-floating IVC or iliofemoral thrombus (no good evidence)
- Very limited cardiopulmonary reserve where any PE would be fatal (debated)
NOT indicated:
- Primary prophylaxis in high-risk patients (ortho surgery, trauma) - use chemical prophylaxis instead
- PE with contraindication to thrombolysis (can still anticoagulate)
Evidence Against Routine IVC Filters
PREPIC Trial (1998):
- RCT of IVC filter + anticoagulation vs anticoagulation alone in DVT patients
- Filter group: Lower PE at 12 days (1.1% vs 4.8%)
- BUT: Increased DVT at 2 years (21% vs 12%)
- NO difference in mortality at 2 years or 8 years
Implication: Filters prevent early PE but cause more DVT. Net benefit is ZERO. Only use if cannot anticoagulate at all.
Types of IVC Filters
| Type | Indication | Notes |
|---|---|---|
| Retrievable (removable) | Temporary contraindication to anticoagulation | Should be removed within 2-4 weeks once anticoagulation starts |
| Permanent | Permanent contraindication to anticoagulation | Rarely needed |
Always use retrievable filters and set removal date. Many are left in permanently by mistake.
VTE Prophylaxis in Orthopaedic Surgery
VTE Prophylaxis is Mandatory
All orthopaedic surgery patients require VTE prophylaxis unless absolute contraindication. The goal is to reduce VTE risk from 10-20% to 0.5-2%. Use mechanical (TED stockings, intermittent pneumatic compression) PLUS chemical prophylaxis (LMWH, fondaparinux, rivaroxaban, or aspirin).
Risk Assessment
High-risk procedures (require extended prophylaxis):
- Total hip arthroplasty (THA): 28-35 days
- Total knee arthroplasty (TKA): 10-14 days
- Hip fracture surgery: 28-35 days
- Spine surgery (multilevel, malignancy): 10-14 days
Moderate-risk procedures:
- Arthroscopy: 7-10 days if other risk factors (age greater than 40, obesity, prior VTE)
- Upper limb surgery: Generally low risk, prophylaxis only if additional risk factors
Prophylaxis Options
| Agent | Dose | Duration | Australian Context |
|---|---|---|---|
| Enoxaparin (LMWH) | 40mg SC daily (20mg if weight less than 50kg or CrCl less than 30) | 28-35d THA, 10-14d TKA | PBS approved, widely used |
| Rivaroxaban | 10mg PO daily | 28-35d THA, 10-14d TKA | PBS approved, oral convenience |
| Apixaban | 2.5mg PO BD | 28-35d THA, 10-14d TKA | PBS approved, oral |
| Fondaparinux | 2.5mg SC daily | 28-35d | PBS approved, synthetic pentasaccharide |
| Aspirin | 100mg PO daily | 28-35d (after initial LMWH) | Cheaper, ASA trial showed non-inferiority after initial LMWH |
| Warfarin | Target INR 2-3 | Rarely used now | Replaced by DOACs |
Mechanical prophylaxis:
- TED stockings (graduated compression stockings)
- Intermittent pneumatic compression (IPC) devices
- Early mobilization
Use BOTH mechanical AND chemical unless contraindication.
Timing of Prophylaxis
First dose:
- LMWH/fondaparinux: 12 hours post-op (NOT pre-op if neuraxial anesthesia planned - epidural hematoma risk)
- Rivaroxaban/apixaban: 6-10 hours post-op (once hemostasis achieved)
- Aspirin: Post-op day 1
Neuraxial anesthesia (spinal/epidural) considerations:
- LMWH given pre-op requires 12-24 hour gap before neuraxial
- LMWH given post-op requires 12 hour gap before catheter removal
- DOACs require 24 hour gap before neuraxial
Contraindications to Chemical Prophylaxis
Absolute:
- Active bleeding
- Severe bleeding risk (e.g., bleeding peptic ulcer, recent intracranial hemorrhage)
- HIT with thrombosis (cannot use heparin-based agents)
Relative:
- Recent neurosurgery or ophthalmologic surgery (balance risk vs benefit)
- Platelets less than 50,000 (relative, depends on bleeding risk)
- Severe renal impairment (avoid LMWH/fondaparinux, use UFH or reduce dose)
If contraindication: Use mechanical prophylaxis alone, consider IVC filter if very high risk (NOT routinely recommended).
Complications and Long-Term Sequelae
Acute Complications of PE
| Complication | Incidence | Management |
|---|---|---|
| Death (massive PE) | 10-30% | Thrombolysis reduces to 10% |
| Cardiogenic shock | 5-10% | Thrombolysis, inotropes, consider ECMO |
| Cardiac arrest | 2-5% | CPR, thrombolysis, consider ECMO |
| Recurrent PE | 5-10% if inadequate anticoagulation | Ensure therapeutic anticoagulation, consider IVC filter if recurrent despite therapy |
| Bleeding from anticoagulation | 1-3% major bleed annually | Reversal agents, transfusion |
Chronic Complications
Chronic Thromboembolic Pulmonary Hypertension (CTEPH):
- Incidence: 2-4% of PE survivors
- Pathophysiology: Unresolved thrombus causes chronic pulmonary artery obstruction and pulmonary hypertension
- Presentation: Progressive dyspnea, exercise intolerance, right heart failure
- Diagnosis: RV systolic pressure greater than 25 mmHg on echo, confirmed by right heart catheterization + V/Q scan showing perfusion defects
- Treatment: Pulmonary thromboendarterectomy (surgical removal of organized thrombus) OR balloon pulmonary angioplasty OR pulmonary vasodilators (sildenafil, riociguat)
- Screen for CTEPH if persistent dyspnea 3-6 months post-PE
Post-PE Syndrome:
- Chronic dyspnea without pulmonary hypertension
- Incidence: 50% at 1 year
- Cause: Deconditioning, anxiety, subclinical RV dysfunction
- Management: Pulmonary rehabilitation, exercise training
Recurrent VTE:
- 10% first year (unprovoked), 1-3% annual (provoked)
- Prevention: Appropriate duration anticoagulation
- Risk factors for recurrence: Unprovoked PE, residual thrombus, thrombophilia, cancer
Postoperative Care
Post-PE Monitoring
Inpatient Monitoring by Severity:
- Massive PE: ICU admission, continuous monitoring
- Submassive PE: HDU/step-down for 24-48 hours
- Low-risk PE: Ward care or outpatient if PESI Class I-II
Clinical Monitoring:
- Vital signs every 4-6 hours
- Oxygen saturation target greater than 94%
- Watch for deterioration (dropping BP, worsening dyspnea)
Anticoagulation Monitoring:
- DOACs: No routine monitoring required
- Warfarin: INR target 2-3, weekly until stable
- LMWH: Anti-Xa levels if renal impairment or extreme weight
Outcomes
PE Outcomes Summary
Short-Term Mortality:
- Massive PE untreated: 30%
- Massive PE with thrombolysis: 10%
- Submassive PE: 3-15%
- Low-risk PE: Less than 1%
Recurrence Rates:
- Provoked PE (post-surgery): 1-3% annual after stopping anticoagulation
- Unprovoked PE: 10-15% annual if anticoagulation stopped
Long-Term Sequelae:
- CTEPH: 2-4% of PE survivors
- Post-PE syndrome: 50% have persistent dyspnea at 1 year
- Bleeding from anticoagulation: 1-3% major bleed annually
Evidence Base
PEITHO Trial - Thrombolysis in Submassive PE
- RCT of 1006 patients with submassive PE (normotensive + RV dysfunction)
- Tenecteplase vs placebo (both groups received heparin)
- Thrombolysis reduced hemodynamic decompensation (2.6% vs 5.6%, p=0.015)
- BUT increased major bleeding (11.5% vs 2.4%) and stroke (2.4% vs 0.2%)
- No mortality difference at 30 days
PREPIC Trial - IVC Filters in DVT
- RCT of 400 DVT patients: IVC filter + anticoagulation vs anticoagulation alone
- Filter reduced early PE (1.1% vs 4.8% at 12 days)
- BUT increased DVT at 2 years (20.8% vs 11.6%)
- NO difference in mortality at 2 years (16.9% vs 15.6%)
- 8-year follow-up confirmed no mortality benefit
EINSTEIN PE Trial - Rivaroxaban vs Warfarin
- RCT of 4832 patients with acute PE
- Rivaroxaban (15mg BD x21d then 20mg daily) vs LMWH + warfarin
- Non-inferior for recurrent VTE (2.1% vs 1.8%)
- Similar major bleeding (1.1% vs 2.2%)
- Oral from day 1 without LMWH bridging
ACCP Guidelines - Antithrombotic Therapy for VTE
- DOACs recommended over warfarin for non-cancer PE (Grade 2B)
- Thrombolysis recommended for massive PE (Grade 2B)
- Thrombolysis NOT routinely recommended for submassive PE (Grade 2C)
- Provoked PE: 3 months anticoagulation (Grade 1B)
- IVC filters only if contraindication to anticoagulation (Grade 1B)
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Post-THA PE Suspected (~2-3 min)
"A 70-year-old woman develops sudden onset dyspnea and pleuritic chest pain on day 5 after total hip arthroplasty. Vitals: BP 130/80, HR 110, RR 24, SpO2 92% on room air. How would you assess and manage?"
Scenario 2: Massive PE Decision-Making (~3-4 min)
"A 65-year-old man collapses 3 days after hip fracture surgery. On arrival to ED, BP 75/40, HR 130, RR 30, SpO2 85% on high-flow oxygen. CTPA shows large bilateral PE with RV/LV ratio of 1.5. He had neurosurgery for subdural hematoma 6 weeks ago. What is your management?"
Scenario 3: Submassive PE and VTE Prophylaxis (~3-4 min)
"A 55-year-old woman has confirmed PE on CTPA 1 week after TKA. She is normotensive (BP 125/75) but echo shows RV/LV ratio 1.1 and troponin is elevated. She was on rivaroxaban 10mg daily for prophylaxis but admits she stopped taking it 3 days ago. How do you manage? Also, what prophylaxis protocol should have been used?"
MCQ Practice Points
Wells Score Interpretation
Q: A patient has Wells score of 2 for PE. What is the next step? A: D-dimer. Wells less than 4 = PE unlikely, check D-dimer. If negative, PE excluded. If positive, CTPA.
Massive vs Submassive PE
Q: What defines massive PE? A: Sustained hypotension (SBP less than 90 mmHg for 15+ minutes) OR cardiac arrest OR cardiogenic shock. Massive PE requires thrombolysis. Submassive PE is normotensive BUT has RV dysfunction.
Thrombolysis Indication
Q: What is the indication for thrombolysis in PE? A: Massive PE (hemodynamic instability). PEITHO trial showed NO benefit for routine thrombolysis in submassive PE, only increased bleeding.
IVC Filter Evidence
Q: What did the PREPIC trial show about IVC filters? A: Filters reduce early PE but increase DVT and do NOT reduce mortality. Only use if absolute contraindication to anticoagulation.
Australian Context
Australian Practice Considerations
PBS Anticoagulants:
- Rivaroxaban 10mg: PBS listed for VTE prophylaxis post-arthroplasty
- Rivaroxaban 15mg/20mg: PBS listed for VTE treatment
- Apixaban 2.5mg/5mg: PBS listed for prophylaxis and treatment
- Enoxaparin: PBS listed for prophylaxis and treatment
VTE Prophylaxis Guidelines:
- Follow NHMRC VTE Prevention Guidelines
- THA: 28-35 days prophylaxis
- TKA: 10-14 days prophylaxis
- Hip fracture surgery: 28-35 days
Thrombolysis Availability:
- Alteplase and tenecteplase available in major EDs
- Catheter-directed therapy: Major tertiary centers only
PULMONARY EMBOLISM
High-Yield Exam Summary
Wells Score for PE (PEACH 3-3-1.5)
- •Prior DVT/PE +1.5, Elevated HR (greater than 100) +1.5
- •Alternative diagnosis unlikely +3, Cancer active +1, Hemoptysis +1
- •Clinical DVT signs +3, Surgery/immobilization (4 weeks) +1.5
- •Score less than 4 = PE unlikely (D-dimer), score 4+ = PE likely (CTPA)
Diagnostic Algorithm
- •PERC rule: If ALL 8 negative + low suspicion, PE excluded (no D-dimer)
- •Low Wells (less than 4): D-dimer - if negative stop, if positive CTPA
- •High Wells (4+): Skip D-dimer, go to CTPA
- •CTPA gold standard (95% sensitive), VQ scan if contrast contraindicated
Risk Stratification
- •Massive (High-Risk): SBP less than 90 or shock or arrest � THROMBOLYSE
- •Submassive (Intermediate): Normotensive BUT RV dysfunction (echo/CT) or elevated troponin/BNP � Anticoagulate + monitor
- •Low-Risk: Normotensive, no RV dysfunction � Anticoagulate, consider outpatient if PESI low
- •RV dysfunction: RV/LV ratio greater than 0.9 (echo) or greater than 1.0 (CT)
Treatment - Anticoagulation
- •First-line: DOACs (rivaroxaban 15mg BD x21d then 20mg OR apixaban 10mg BD x7d then 5mg BD)
- •No LMWH lead-in with rivaroxaban/apixaban
- •Massive PE: IV heparin initially (UFH bolus 80 units/kg, infusion 18 units/kg/h)
- •Duration: Provoked (surgery) = 3 months, Unprovoked = 3-6 months minimum
Thrombolysis
- •Indication: Massive PE ONLY (SBP less than 90 or shock)
- •Agent: Alteplase 100mg IV over 2h (or 50mg bolus if arrest)
- •Reduces mortality from 30% to 10% in massive PE
- •Complications: Major bleed 10-15%, intracranial hemorrhage 1-5%
- •PEITHO trial: Do NOT routinely thrombolyse submassive PE (more bleeding, no mortality benefit)
IVC Filters and VTE Prophylaxis
- •IVC filter ONLY if absolute contraindication to anticoagulation (NOT routine)
- •PREPIC trial: Filters reduce early PE but increase DVT, NO mortality benefit
- •THA prophylaxis: Rivaroxaban 10mg daily OR enoxaparin 40mg daily for 28-35 days
- •TKA prophylaxis: Rivaroxaban 10mg daily OR enoxaparin 40mg daily for 10-14 days