Cardiology / Pulmonology
Pulmonary Embolism — Comprehensive Clinical Reference
Section 01
History + Diagnosis
Clinical Presentation
Symptoms (frequency)
- Dyspnea — most common (~80%); acute onset
- Pleuritic chest pain — ~40–50%; suggests peripheral/infarct PE
- Cough — ~20%; may be hemoptysis (infarct)
- Syncope/pre-syncope — suggests massive PE / RV failure
- Leg swelling/DVT sx — ~30% have concurrent DVT
Signs
- Tachycardia — HR >100 most common sign
- Hypoxia — SpO₂ <94%; A-a gradient widened
- Hypotension / Shock — SBP <90 mmHg → massive PE
- Tachypnea — RR >20
- Loud P2, RV heave, JVD — acute cor pulmonale
- Unilateral leg edema — DVT
Pre-test Probability — Wells Score
Wells Criteria for PE
Clinical signs/sx of DVT+3.0
PE more likely than alternative diagnosis+3.0
Heart rate > 100 bpm+1.5
Immobilization or surgery within 4 weeks+1.5
Prior DVT or PE+1.5
Hemoptysis+1.0
Malignancy (active Tx or Rx within 6 months)+1.0
≤4 Low/Moderate → D-dimer
>4 High → CTPA directly
Revised Geneva Score (Alternative)
Age > 65+1
Prior DVT or PE+3
Surgery / fracture within 1 month+2
Active malignancy+2
Unilateral lower limb pain+3
Hemoptysis+2
HR 75–94+3
HR ≥ 95+5
Pain on deep palpation + unilateral edema+4
Low 0–3 · Intermediate 4–10 · High ≥11
PERC Rule: If low pre-test probability AND all 8 PERC criteria negative → no further workup needed. Age <50, HR <100, SpO₂ ≥95%, no hemoptysis, no estrogen use, no prior DVT/PE, no leg swelling, no surgery/trauma within 4 weeks.
Biomarkers
| Marker | Role in PE | Threshold | Interpretation |
|---|---|---|---|
| D-dimer | Rule-out in low/moderate PTP | <500 ng/mL (age-adjusted: age×10 if >50y) | NPV ~97%; not useful in high PTP. Age-adjusted cutoff reduces unnecessary CTPA by ~12% |
| Troponin I/T (hs) | RV myocardial injury, prognosis | Any elevation | Elevated → intermediate-high or high risk; guides thrombolysis decision |
| BNP / NT-proBNP | RV pressure overload | BNP >90 pg/mL or NT-proBNP >500 pg/mL | RV dysfunction marker; elevated = intermediate-high or high risk |
| Lactate | Hemodynamic compromise | >2 mmol/L | Organ hypoperfusion; level correlates with in-hospital mortality in massive PE |
Diagnostic Algorithm (ESC 2019)
Suspected PE
↓
Hemodynamically Unstable?
SBP <90 or vasopressors
SBP <90 or vasopressors
↓
YES
Bedside Echo / CTPA
if available immediately
if available immediately
↓
RV overload confirmed?
↓
→ MASSIVE PE Protocol
(see management)
(see management)
NO
Assess Clinical PTP
(Wells or Geneva)
(Wells or Geneva)
↓
LOW / MODERATE PTP?
YES
D-dimer
(age-adjusted)
(age-adjusted)
↓
D-dimer negative?
↓
YES
PE excluded
No imaging needed
No imaging needed
NO
→ CTPA
HIGH PTP
→ CTPA directly
(skip D-dimer)
(skip D-dimer)
Section 02
Risk Factors
Virchow's Triad
Stasis
- Prolonged immobility / bed rest
- Long-haul travel (>8h)
- Heart failure / low EF
- Pregnancy / post-partum
- Obesity (BMI >30)
- Varicose veins
Endothelial Injury
- Major surgery (especially ortho/abdo/pelvic)
- Trauma / fracture
- Central venous catheter
- Prior DVT/PE
- Inflammatory conditions (IBD, vasculitis)
Hypercoagulability
- Active malignancy (especially mucin-secreting)
- Inherited: Factor V Leiden, Prothrombin G20210A
- Protein C / S deficiency
- Antithrombin deficiency
- Antiphospholipid syndrome (APS)
- OCP / HRT / tamoxifen
- Polycythemia vera, essential thrombocythemia
- Nephrotic syndrome
Caprini RAM — Surgical VTE Risk
| Points | Risk Factors | Score → Risk → PPx |
|---|---|---|
| 1 pt each | Age 41–60, Minor surgery, BMI>25, Swollen legs, Varicose veins, Hx of IBD, Sepsis within 1 mo, Serious lung disease, OCP/HRT, Pregnancy/post-partum, Unexplained stillbirth, Bedrest >72h, Immobilizing cast, Central line, Other risk factors |
0–1 → Very Low → Early ambulation
2 → Low → Pharmacological PPx or IPC alone
3–4 → Moderate → LMWH/UFH + IPC
≥5 → High → LMWH/UFH + IPC; consider extended PPx (28d) in high-bleed-risk cancer surgery
|
| 2 pts each | Age 61–74, Arthroscopic surgery, Malignancy, Laparoscopic surgery >45 min, Patient confined to bed >72h, Immobilizing cast | |
| 3 pts each | Age ≥75, Prior DVT/PE, Factor V Leiden, Prothrombin mutation, Lupus anticoagulant, Anticardiolipin Ab, Elevated homocysteine, HIT, Other congenital thrombophilia | |
| 5 pts | Stroke within 1 month, Elective arthroplasty (hip/knee), Hip/pelvis/leg fracture, Acute SCI |
Caprini score validated in surgical patients. Padua Prediction Score used for medical inpatients (see Prophylaxis section).
Section 03
Imaging
CTPA — Protocol & Acute Findings
CTPA Technical Protocol
- Scan: 64-slice or higher MDCT
- Contrast: 80–120 mL iodinated at 4–5 mL/s; pulmonary arterial phase (12–20s delay or bolus tracking at main PA)
- Window: Lung (W:1500/L:–600), Mediastinal (W:400/L:40)
- Coverage: Lung apex to base including proximal lower extremity (optional for DVT)
- PE-specific reconstructions: MPR coronal/sagittal, MIP (3–5mm slabs)
Acute PE — CT Findings
- Filling defect: Low-attenuation thrombus within opacified PA lumen — diagnostic
- Saddle embolus: Straddling bifurcation; highest mortality
- RV:LV ratio >0.9 (axial): RV dilation → high risk marker
- Interventricular septal deviation toward LV (D-sign)
- Contrast reflux into IVC/hepatic veins → elevated RA pressure
- Hampton's hump: Peripheral wedge-shaped opacity (infarct)
- Westermark sign (CXR): Regional oligemia (not on CT)
- Pulmonary arterial enlargement: Main PA >29mm suggests chronic/recurrent
Acute PE vs CTEPH — Imaging Differentiation
| Feature | Acute PE | CTEPH |
|---|---|---|
| Thrombus character | Convex filling defect; completely occludes lumen; acute angles with vessel wall | Eccentric; web-like or bandlike; obtuse angles; partial recanalization |
| Vessel calibre | Normal or mildly dilated proximal PA | Proximal PA dilation (>29mm), tortuous vessels, mosaic attenuation |
| Parenchymal changes | Peripheral infarct (Hampton's hump) | Mosaic perfusion (lobular), ground-glass areas, bronchial collaterals |
| Mediastinum | No hilar adenopathy; normal heart size (or acutely enlarged RV) | Bronchial artery hypertrophy, pericardial effusion (in severe cases) |
| RV morphology | Acute dilation (may be normal in submassive) | Hypertrophied RV wall >4mm, chronic dilation, sigmoid septum |
| V/Q scan pattern | Segmental/lobar perfusion defects; may normalise within weeks | Persistent segmental/lobar mismatches ≥3 months post-anticoagulation; V/Q more sensitive than CTPA for CTEPH |
| Pulmonary angiogram | Acute cutoff; vessel preserved distally | Web/spur/pouch defects; endarterectomy targets (proximal disease); PH on wedge pressure |
| Echo features | Acute RV pressure overload; McConnell's sign; absent RV hypertrophy | RV hypertrophy, pulmonic regurgitation, RVSP often >50 mmHg; tricuspid regurgitation |
| RHC (definitive Dx) | — | mPAP >25 mmHg, PVR >2 WU, PCWP ≤15 mmHg after ≥3 months of anticoagulation → CTEPH |
⚠ CTEPH requires: (1) ≥3 months therapeutic anticoagulation, (2) V/Q scan showing unresolved perfusion defects, (3) RHC confirming pre-capillary PH, and (4) imaging showing accessible proximal disease for surgical planning.
V/Q Scan + Echo Roles
V/Q Scintigraphy
- Preferred over CTPA when: contrast allergy, renal impairment (eGFR <30), pregnancy (lower fetal radiation)
- PIOPED II criteria: High probability (≥2 large mismatched segments) → PPV 85–90%
- Normal scan: Effectively excludes PE (NPV ~96%)
- CTEPH: V/Q more sensitive (97%) than CTPA (~51%) for detecting CTEPH — preferred screening modality
- Limitation: Non-diagnostic in ~60% if underlying lung disease
Echocardiography (TTE/TEE)
- Not diagnostic for PE but confirms RV compromise → guides risk stratification
- McConnell's sign: Hypokinesis of RV free wall with preserved apex (60–77% specific for acute PE)
- 60/60 sign: RVOT acceleration time <60ms + TR gradient 30–60 mmHg → acute PE
- RV:LV ratio >0.9 (apical 4-chamber) → intermediate-high risk
- Use in unstable patients: Bedside echo if CTPA not immediately available; if RV overload + no other explanation → treat as PE
Section 04
Management
Risk Stratification (ESC 2019 + sPESI)
| Risk Class | Criteria | 30-day Mortality | Initial Strategy |
|---|---|---|---|
| MASSIVE / HIGH RISK | Hemodynamic instability: SBP<90 for ≥15min, or vasopressor use, or cardiac arrest | >15% | Immediate systemic thrombolysis or surgical/catheter embolectomy |
| INTERMEDIATE-HIGH | Normotensive + BOTH RV dysfunction (echo/CT) AND troponin elevation | 3–15% | Anticoagulate → monitor closely → rescue thrombolysis if deterioration |
| INTERMEDIATE-LOW | Normotensive + one of: RV dysfunction OR elevated troponin (not both) | 1–3% | Anticoagulate; hospital admission; reassess |
| LOW RISK | sPESI = 0 AND no RV dysfunction AND no troponin elevation | <1% | Early discharge or outpatient Tx (DOAC preferred) |
sPESI Score (Simplified PESI)
Age >80 years+1
Cancer+1
Chronic cardiopulmonary disease+1
HR ≥ 110 bpm+1
SBP < 100 mmHg+1
SpO₂ < 90%+1
sPESI = 0 → Low risk → possible outpatient Tx
sPESI ≥ 1 → Higher risk → admission
Low risk = sPESI 0 AND no RV dysfunction on echo/CT AND troponin negative. All three criteria must be met for early discharge.
Massive PE — Step-by-Step Protocol
MASSIVE PE — Hemodynamic Instability Confirmed
↓
Immediate stabilization:
O₂/intubate if needed · IV access ×2 · Bedside echo · Activate PERT if available
O₂/intubate if needed · IV access ×2 · Bedside echo · Activate PERT if available
↓
Absolute contraindications to thrombolysis?
Recent stroke <3mo · Active intracranial bleed · Head trauma <3mo · GI bleed active · Aortic dissection
Recent stroke <3mo · Active intracranial bleed · Head trauma <3mo · GI bleed active · Aortic dissection
NO contraindications
Systemic thrombolysis
Alteplase 100mg IV over 2h
Hold heparin during infusion; restart when aPTT <80s
Alteplase 100mg IV over 2h
Hold heparin during infusion; restart when aPTT <80s
↓
Hemodynamic improvement?
YES
Transition to therapeutic anticoagulation
LMWH → DOAC or warfarin
LMWH → DOAC or warfarin
NO / Deterioration
Repeat alteplase 50mg bolus
OR surgical embolectomy
OR catheter-directed Tx
OR surgical embolectomy
OR catheter-directed Tx
YES — Contraindicated
PERT team / Catheter-directed therapy
or Surgical embolectomy
or Surgical embolectomy
↓
Consider VA-ECMO as bridge
in refractory cardiogenic shock
in refractory cardiogenic shock
⚠ Avoid aggressive fluid resuscitation in massive PE: RV is preload-dependent but volume overload worsens RV dilation and septal shift → cardiogenic shock. Limit to 500mL isotonic bolus; use vasopressors (norepinephrine preferred) to maintain MAP. Dobutamine if RV dysfunction without hypotension.
Anticoagulation — Drug Comparison
| Drug | Dose | Monitoring | Notes |
|---|---|---|---|
| UFH (Heparin) | 80 U/kg bolus IV → 18 U/kg/hr infusion; adjust to aPTT 60–100s Or weight-based nomogram | aPTT q6h until therapeutic, then daily; CBC | Preferred in: massive PE (pre-thrombolysis), renal failure, potential surgery, active bleed risk needing rapid reversal |
| Enoxaparin (Clexane) | 1 mg/kg SC q12h OR 1.5 mg/kg SC once daily Reduce to 1 mg/kg/day if eGFR <30 | Anti-Xa (target 0.5–1.0 IU/mL peak for BID dosing); CBC for HIT | Standard for intermediate-risk. Avoid if eGFR <15 or severe obesity (BMI>40, use anti-Xa) |
| Fondaparinux (Arixtra) | Weight-based: <50kg: 5mg; 50–100kg: 7.5mg; >100kg: 10mg SC once daily | No routine monitoring; avoid if eGFR <30 | No HIT risk; not reversed by protamine. Alternative to LMWH if HIT suspected |
All parenteral agents: UFH or LMWH must be started immediately on clinical suspicion (before imaging) if bleeding risk is acceptable. DOAC monotherapy (rivaroxaban or apixaban) can replace parenteral agent + VKA — no overlap needed.
| Drug | Dose (PE treatment) | Key Consideration | Preferred Scenario |
|---|---|---|---|
| Rivaroxaban (Xarelto) | 15mg BD × 21 days → 20mg OD with food | No loading parenteral needed; avoid if eGFR<15 | DOAC of choice in most unprovoked or provoked PE (non-cancer) |
| Apixaban (Eliquis) | 10mg BD × 7 days → 5mg BD | No loading parenteral needed; fewest GI side effects | Preferred in GI-intolerant patients; also safer if borderline renal function |
| Dabigatran (Pradaxa) | Parenteral lead-in 5–10 days required → 150mg BD (110mg BD if >75y or bleeding risk) | Needs parenteral bridge; reversible with idarucizumab | If reversal agent availability is a priority |
| Edoxaban (Lixiana) | Parenteral lead-in required → 60mg OD (30mg if <60kg, eGFR 15-50, or P-gp inhibitor) | QD dosing; needs parenteral bridge | Convenient once-daily after lead-in |
| Warfarin (Coumadin) | Target INR 2.0–3.0; overlap heparin minimum 5 days AND until INR >2 for 24h | INR monitoring; multiple drug interactions; dietary vitamin K consistency | Mechanical valves, severe renal failure (eGFR<15), pregnancy, APLS (triple-positive) |
| Scenario | Duration | Drug Recommendation |
|---|---|---|
| First provoked PE (major transient risk factor — surgery, trauma) | 3 months only | DOAC preferred |
| First unprovoked PE (no identifiable cause) | Minimum 3 months → reassess bleeding vs recurrence risk → often extended or indefinite | DOAC (rivaroxaban 10mg OD or apixaban 2.5mg BD extended-dose after 6 months) |
| Cancer-associated PE (CAT) | Minimum 6 months → continue while cancer active or on chemotherapy | LMWH (dalteparin) historically preferred; DOACs now comparable (edoxaban/rivaroxaban acceptable if no GI tract malignancy — higher GI bleed risk) |
| Antiphospholipid syndrome (APS) | Indefinite | Warfarin INR 2–3 (triple-positive APS: INR 3–4 or warfarin preferred; DOACs inferior in triple-positive) |
| Second unprovoked VTE | Indefinite | DOAC (low-dose rivaroxaban 10mg OD or apixaban 2.5mg BD) |
| Thrombophilia (inherited: Factor V Leiden heterozygous, single mutation) | As per clinical context (3 months if provoked) | DOAC |
Catheter-Directed Therapy (CDT) / EKOS / Mechanical
| Technique | Mechanism | Indications | Notes |
|---|---|---|---|
| Catheter-Directed Thrombolysis (CDT) | Low-dose tPA infused directly into clot via multi-side-hole catheter | Submassive (intermediate-high) PE with RV dysfunction AND bleeding risk for systemic lysis; massive PE if systemic lysis CI | Typical dose: alteplase 0.5–1 mg/hr per catheter × 12–24h. Less bleeding than systemic. Requires ICU monitoring |
| EKOS (Ultrasound-Accelerated Thrombolysis) | Ultrasound energy + CDT → fibrin disaggregation → faster drug penetration | Same as CDT; used in bilateral PE with bilateral catheters | SEATTLE II trial: RV:LV ratio reduced from 1.55→1.13 at 48h. Not proven superior to CDT alone in RCTs but widely used |
| Aspiration Embolectomy (FlowTriever, AngioVac) | Mechanical suction removes thrombus without thrombolytics | Massive or intermediate-high PE when thrombolytics absolutely contraindicated | FlowTriever FLARE trial: RV:LV ratio improved; no lytic needed. Growing evidence base |
| Rheolytic/Fragmentation | Mechanical disruption + aspiration | Large central thrombus | Risk of distal embolization and hemolysis; less commonly used now |
PERT (Pulmonary Embolism Response Team) — multidisciplinary team (pulm, cards, IR, CT surgery) for intermediate-high and high-risk PE — improves decision-making and reduces delay to definitive therapy.
Section 05
Prophylaxis
Post-Operative VTE Prophylaxis
| Surgery Type | Caprini Risk | PPx Strategy | Duration |
|---|---|---|---|
| General/Abdominal/Pelvic (benign) | Moderate (3–4) | Enoxaparin 40mg SC OD or UFH 5000U SC TDS + IPC | 7–10 days |
| Cancer surgery (abdominal/pelvic) | High (≥5) | Enoxaparin 40mg SC OD + IPC | 28 days extended (reduces VTE by 60% vs 7 days) |
| Total Hip Replacement (THR) | High (5 pts each) | Rivaroxaban 10mg OD or Apixaban 2.5mg BD or LMWH + IPC | 35 days |
| Total Knee Replacement (TKR) | High | Rivaroxaban 10mg OD or Apixaban 2.5mg BD | 12–14 days |
| Hip fracture surgery | High (5 pts) | LMWH or rivaroxaban + IPC; start preop if delay >12h | 28–35 days |
| Intracranial neurosurgery | High — bleed risk | IPC alone until hemostatic; add pharmacological PPx when safe (24–48h post-op) | Until ambulatory |
| Spine surgery | Moderate–High | IPC + early mobilization; LMWH when hemostatic | Until ambulatory |
| Laparoscopic surgery <30 min (low-risk) | Very Low–Low | Early ambulation alone | — |
⚠ Timing: Start pharmacological PPx 12h pre-op or 12h post-op (spinal anesthesia: min 12h gap for LMWH, 24h for rivaroxaban from last dose before neuraxial procedure). IPC should be applied in OR from induction.
Medical Inpatient — Padua Prediction Score
Padua Score Items
Active cancer+3
Prior VTE (excl. superficial thrombosis)+3
Reduced mobility ≥3 days+3
Known thrombophilic condition+3
Recent (<1 month) trauma / surgery+2
Age ≥70+1
Heart / respiratory failure+1
Acute MI or ischemic stroke+1
Acute infection / rheumatological disorder+1
Obesity (BMI ≥30)+1
Ongoing hormonal treatment+1
Action Thresholds
Padua ≥ 4 → HIGH risk → Pharmacological PPx
Padua < 4 → LOW risk → Early mobilization only
Drug Options
- Enoxaparin 40mg SC OD — first-line (Clexane)
- UFH 5000U SC TDS — if eGFR <30
- Fondaparinux 2.5mg SC OD — if HIT or LMWH-intolerant
- Betrixaban 160mg → 80mg OD — extended (FDA-approved, limited local availability)
Check IMPROVE Bleed Score before pharmacological PPx. Withhold if: active bleeding, platelets <50k, high-risk procedure within 12h.
Special Populations
| Population | Strategy | Notes |
|---|---|---|
| Pregnancy | LMWH throughout pregnancy (adjusted-dose); discontinue 24h pre-delivery | DOACs contraindicated; warfarin teratogenic in T1 and fetal bleeding risk T3; LMWH does not cross placenta |
| ICU / Critical illness | UFH 5000U SC BD-TDS + IPC (if not contra); LMWH if no AKI | Anti-Xa monitoring preferred in ICU due to variable absorption |
| Cancer (outpatient chemotherapy) | LMWH or rivaroxaban/apixaban if Khorana score ≥2 | Khorana ≥2 = high risk for CAT; CASSINI/AVERT trials support DOAC prophylaxis in high-Khorana patients |
| Long-haul travel (>8h) | Compression stockings; hydration; ambulation q2h; consider LMWH in very high-risk individuals | Pharmacological PPx not routinely recommended for low–moderate risk travelers |
| Bariatric surgery | Extended LMWH 10–14 days; dose by anti-Xa (standard prophylactic doses subtherapeutic in obesity) | BMI-based LMWH dosing: 0.5mg/kg enoxaparin OD; ASMBS recommends anti-Xa monitoring |
Section 06
Surgical & Interventional Roles
Surgical Embolectomy — Acute PE
Indications (ESC Class I/IIa)
- Massive PE with absolute contraindication to thrombolysis
- Failed systemic thrombolysis (hemodynamic deterioration after alteplase)
- Right heart thrombus in transit (especially "ball thrombus" in RA with paradoxical embolism risk)
- Massive PE requiring surgical correction of concurrent cardiac defect (e.g. ASD allowing paradoxical embolism)
Technique
- Median sternotomy, CPB (cardiopulmonary bypass)
- Bilateral pulmonary arteriotomy → direct thrombus extraction
- No cardiac arrest needed in most cases if perfusion maintained on CPB
- Operative mortality: 6–8% in expert centers (vs ~50% in massive PE without treatment)
Pre-Op Considerations
- ECMO as bridge to surgery in refractory shock
- Avoid aggressive volume loading — worsen RV failure
- Avoid vasodilators (worsen systemic hypotension)
- Coordinate with cardiac surgery URGENTLY — time to CPB is critical
Pulmonary Endarterectomy (PEA) — CTEPH
Pulmonary Endarterectomy is the CURATIVE treatment for CTEPH with accessible proximal disease. 5-year survival >90% in experienced centers (International CTEPH Registry).
Selection Criteria
- Confirmed CTEPH (mPAP >25, PVR >2 WU, PCWP ≤15) on RHC
- Proximal accessible disease on CTPA / PA angiogram (main, lobar, segmental PA level)
- ≥3 months adequate anticoagulation prior to surgery
- PVR <1000–1200 dynes/s/cm⁻⁵ (<12–15 WU) — very high PVR = high surgical risk
- Patient fitness: no severe comorbidity precluding CPB + DHCA
Technique & Outcomes
- Median sternotomy, CPB, Deep Hypothermic Circulatory Arrest (DHCA) at 20°C
- Endarterectomy plane: between adventitia and media — removes organized thrombus + remodeled intima
- Bilateral; typically 20-minute arrest periods alternating sides
- 30-day mortality: 2.2–5% in high-volume centers
- Functional class improvement: WHO FC IV → FC I/II in >70%
When PEA is Not Feasible — Medical and BPA Options
| Option | Indication | Drug/Procedure | Evidence |
|---|---|---|---|
| Riociguat (Adempas) | Inoperable CTEPH or residual PH post-PEA | 1mg TDS → titrate to 2.5mg TDS | CHEST-1 trial: 6MWD +46m, PVR −246 dyn·s·cm⁻⁵ vs placebo (Class I, LOE B) |
| Balloon Pulmonary Angioplasty (BPA) | Inoperable CTEPH (distal disease), or high surgical risk | Sequential sessions of balloon dilation of segmental/subsegmental vessels | Experienced centers: PVR reduction ~50%, functional improvement. Complications: reperfusion pulmonary edema, hemoptysis (~5%) |
| Lung transplantation | Last resort: bilateral disease, very distal disease, failed BPA + medical therapy | Single or bilateral lung transplant | Rare; reserved for patients failing all other options |
IVC Filter — Indications & Types
⚠ IVC filters do NOT replace anticoagulation. They reduce risk of recurrent PE but increase DVT risk. Remove as soon as anticoagulation is possible (retrievable filter preferred).
Indications (Class IIa–IIb)
- Absolute CI to anticoagulation in confirmed PE/DVT (active life-threatening bleed, recent major surgery with uncontrolled hemorrhage)
- Recurrent VTE despite therapeutic anticoagulation
- Free-floating ileofemoral thrombus in patient undergoing major surgery (temporary filter)
- Prophylaxis in very high-risk surgical patients who cannot receive pharmacological PPx (controversial; not routine)
Filter Types & Retrieval
- Permanent: Greenfield, Simon Nitinol — placed if anticoagulation permanently contraindicated
- Retrievable: Günther Tulip, OptEase, Celect — remove within 2–6 weeks (or up to 3 months per manufacturer); restart anticoagulation ASAP
- Complications: Filter migration, IVC thrombosis, penetration, strut fracture — especially with long dwell time
- PREPIC-2 trial: Retrievable filters + anticoagulation vs anticoagulation alone — no difference in recurrent PE or mortality at 3 months; higher DVT rate in filter group