II. Indications
- Deep Vein Thrombosis (DVT)
- Pulmonary Embolism (PE)
III. Precautions: Subsegmental Pulmonary Embolism Controversy
- CT Chest has False Positives and False Negatives
- False Positive Rate: 26% read initially as positive, were later over-read as negative
- False Negative Rate: 11% read initially as subsegmental, were later over-read as segmental
- Factors associated with a true positive sub-segmental Pulmonary Embolism
- High quality imaging
- Multiple filling defects
- Defects in proximal subsegmental vessels
- Same defect on multiple images or views
- Filling defect surrounded by contrast
- Symptomatic Pulmonary Embolism
- High pretest probability
- Unexplained positive D-Dimer
- Subsegmental Pulmonary Embolism treatment has mixed results on outcomes
- Some studies have shown worse outcomes with subsegmental Pulmonary Embolism treatment
- Other studies have shown subsegmental PE to have as significant outcomes as segmental PE
- Despite minor nature of subsegmental PE, recurrent Pulmonary Embolism may occur without Anticoagulation
- Approach
- Evaluate for Deep Vein Thrombosis with bilateral Lower Extremity DopplerUltrasound
- Consider other sources of VTE (Upper Extremity DVT, central-line associated DVT)
- Evaluate for risk of VTE progression or recurrence
- Hospitalized patients
- Decreased mobility
- Unprovoked VTE
- Hypercoagulable state including cancer
- Otherwise unexplained severe symptoms
- Poor cardiopulmonary reserve
- Consider surveillance instead of Anticoagulation if low risk criteria met (grade 2C evidence)
- Sub-segmental PE only (or suspicion for False Positive) AND
- No concurrent DVT AND
- No high risk criteria for progression or recurrence
- Evaluate for Deep Vein Thrombosis with bilateral Lower Extremity DopplerUltrasound
IV. Grading: Severity
- High Risk Pulmonary Embolism (Massive Pumonary Embolism)
- Pulmonary Embolism AND
- Systolic Blood Pressure <90 mmHg or >40 mmHg BP drop from baseline for at least 15 minutes OR
- Cardiac Arrest OR
- Vasopressors required
- Intermediate Risk Pulmonary Embolism (Submassive Pulmonary Embolism)
- Pulmonary Embolism and
- Right ventricular dysfunction (RV Strain)
- Serum Troponin elevation or
- ntBNP >900 pg/ml or (BNP >90 pg/ml) or
- Echocardiogram with right ventricular dilation or hypokinesis
- Low Risk Pulmonary Embolism
- Pulmonary Embolism and
- Normal right ventricular function and
- Hemodynamically stable
V. Management: Acute Stabilization
- Correct Hypoxia on presentation
- Hypoxia increases shunting, V/Q mismatch and greater right heart strain
- Supplemental Oxygen
- Refractory Hypoxia options
- High Flow Nasal Cannula
- Pulmonary dilators (inhaled nitric oxide or epoprostenol)
- Avoid Positive Pressure Ventilation (BiPap, CPAP, Mechanical Ventilation) if possible
- Intubation and RSI if needed should be performed with optimized first pass success
- Hypoxic patient will have little reserve and easily decompensate
- Correct Hypotension (target >90 mmHg)
- Small fluid challenges (e.g. 250 ml aliquots) are preferred to avoid further RV strain
- Consider Norepinephrine for refractory Hypotension
VI. Management: Massive Pumonary Embolism (Severe cardiovascular compromise)
- See Pulmonary Embolism Evaluation with Echocardiogram
- Indications (see grading above)
- Massive Pumonary Embolism
- Systemic Hypotension and shock (or Cardiac Arrest)
- Systolic Blood Pressure <90 mmHg for 15 min (or Vasopressors needed)
- Right ventricular Heart Failure
- Systemic Hypotension and shock (or Cardiac Arrest)
- Submassive Pulmonary Embolism
- Right ventricular dysfunction or Heart Failure
- Controversial for Thrombolytic use (evaluate on a case by case basis)
- Evidence as of 2017 does not support Thrombolytic use for submassive PE
- See Thrombolysis in Massive Pulmonary Embolism
- Reviews benefits and risks of Thrombolysis in Intermediate Risk PE
- Massive Pumonary Embolism
- Intervention options (includes Anticoagulation as above)
- Thrombolytic Therapy
- Surgical embolectomy
- Alternative management in massive PE when Thrombolysis is contraindicated or has failed
- Gulba (1994) Lancet 343:576-7 [PubMed]
- Intervention Radiology, catheter directed Thrombolysis
- Uses 75% less Thrombolytic than peripheral infusions with lower risk of bleeding and similar mortality
- Variable evidence and some studies have shown benefit while others have not
- Kuo (2015) Chest 148(3): 667-73 [PubMed]
- Piazza (2015) JACC Cardiovasc Interv 8(10): 1382-92 +PMID: 26315743 [PubMed]
- Other measures
- Avoid intubation if possible
- Intubation and ventilation is challenging to manage in Pulmonary Embolism
- VA-ECMO (Extracorporeal Membrane Oxygenation)
- Indicated in hemodynamic instability and Cardiogenic Shock refractory to other measures
- Best outcomes in massive Pulmonary Embolism are with early use of ECMO
- Consider pulmonary vasodilation agents
- See Pulmonary Arterial Hypertension Crisis
- Right Ventricular Afterload optimization (decrease pulmonary vascular resistance)
- These agents may exacerbate Left Ventricular Failure
- Agents
- Nitroglycerin 1 mg/ml inhaled/nebulized 5 mg (5 ml) over 15 minutes OR
- Inhaled Nitric Oxide (20 ppm)
- Advantages: No systemic effects and improves V-Q mismatch
- Risk of rebound, severe Pulmonary Arterial Hypertension if abruptly stopped
- Vasopressors
- Initiate early in Hypotension
- Avoid intubation if possible
- References
- Mattu and Swaminathan (2020) EM:RAP 20(11):2
- Jaff (2011) Circulation 123: 1788-830 [PubMed]
- Konstantinides (2017) J Am Coll Cardiol 69(12): 1536-44 +PMID:28335835 [PubMed]
VII. Management: General Measures
- Consider Thrombophilia work-up
- See Thrombophilia
- Reserve blood for tests prior to Anticoagulation
- Consider underlying malignancy in unprovoked PE
- Bed rest is not necessary
- Does not prevent new or fatal PE of bleeding
- Trujillo-Santos (2005) 127:1631-6 [PubMed]
VIII. Management: Anticoagulation
- See Anticoagulation in Thromboembolism
- Consider Heparin prior to imaging in high likelihood Pulmonary Embolism
- Reasonable in high risk cases
- Lack of study data to support as standard of care
- Risk of adverse outcome (i.e. bleeding complications)
IX. Management: Pregnancy
- See Pulmonary Embolism in Pregnancy
-
Anticoagulation
- Low Molecular Weight Heparin (except for peripartum use of Unfractionated Heparin)
- Contraindicated agents: Warfarin, Factor Xa Inhibitor (e.g. Rivoroxaban)
-
IVC Filter
- Indicated for Pulmonary Embolism within 4 weeks of estimated delivery date
-
Thrombolysis is absolutely contraindicated (EXCEPT in life threatening, massive PE)
- Risk of major bleeding 2.6%
- Consider in life-threatening massive Pulmonary Embolism if not near term
- Gartman (2013) Obstet Med 6:105-11 [PubMed]
X. Disposition: Outpatient Criteria
- Inpatient Anticoagulation until therapeutic and stable
- Inpatient management is default approach unless outpatient management criteria met
- Outpatient Anticoagulation management consideration (Exercise caution)
- Precautions
- Inpatient management is required for certain conditions
- Active cancer
- Pregnancy
- Pulmonary Embolism occurred while on therapeutic doses of Anticoagulation
- Oupatient management should only be considered if consistent with local expert opinion
- Must be supported by local protocols
- Requires patient Informed Consent
- Risk of major bleeding
- Risk of death up to 2% (if cancer patients excluded)
- Inpatient management is required for certain conditions
- Criteria for outpatient management (all criteria should be met)
- Patient must be able to comply with outpatient Anticoagulation
- Stable mental status without Dementia
- Medical literacy
- Social support
- Risk Stratification Tools with low risk assessment
- Pulmonary Embolism Severity Index (PESI) Score <66 (Class 1)
- As of 2015, PESI <86 (low risk) may be reasonable for discharge
- Hestia Criteria negative
- See Hestia Criteria
- Bova Score stage 1 (low risk)
- Simplified PESI (sPESI) with no positive criteria (score 0)
- Pulmonary Embolism Severity Index (PESI) Score <66 (Class 1)
- Reassuring appearance with normal Vital Signs
- Hemodynamically stable and normotensive
- No Hypoxia (Oxygen Saturation >90%)
- No intervention needed (e.g. no thromobolysis or embolectomy)
- Troponin normal
- No signs of right ventricular strain
- Echocardiogram without right strain pattern (right ventricle dilatation, D-Sign, hypokinesis)
- Troponin Normal
- Brain Natriuretic Peptide (BNP) normal or unchanged from baseline
- No contraindicating conditions (cancer, pregnancy)
- No significant comorbidities (e.g. chronic lung disease)
- No Anticoagulation increased risks
- Recent significant bleeding, active bleeding or high risk of bleeding
- Severe liver disease
- Severe renal disease (Creatinine Clearance <30 ml/min)
- Platelet Count >70k
- History of Heparin Induced Thrombocytopenia
- No intractable pain
- Expected need for IV Analgesics >24 hours (e.g. required at least 2 IV doses in ED)
- Patient must be able to comply with outpatient Anticoagulation
- References
- Paripati (2023) Crit Dec Emerg Med 37(7): 18-9
- Aujesky (2011) Lancet (2011) 378(9785): 41-8 [PubMed]
- Otero (2010) Thromb Res 126(1):e1-5 [PubMed]
- Vinson (2012) Ann Emerg Med 60(5): 651-62 [PubMed]
- Kearon (2016) Chest 149(2): 315-52 [PubMed]
- Zondag (2011) J Thromb Haemost 9(8): 1500-7 +PMID:21645235 [PubMed]
- Precautions
XI. Disposition: ED Observation Unit Protocol
- Background
- In some regions, these low risk patients are discharged home instead of to observation unit
- Indications
- Low risk PESI Score (Class I to II, PESI <86) or low risk on sPESI or Bova Score AND
- Hemodynamically stable (normal Blood Pressure)
- Contraindications to ED observation unit
- Right ventricular strain on Echocardiogram
- Troponin Increased
- Brain Natriuretic Peptide (BNP)
- New Hypoxemia requiring Oxygen Supplementation
- Dyspnea or increased work of breathing
- Extensive DVT into the iliac or pelvic vessels or free floating thrombus
- Heart related hospitalization in last 30 days (CHF exacerbation, CAD)
- Unable to be compliant with medical regimen (e.g. homeless, chemical abuse)
- Diagnostics
- Telemetry
- Echocardiogram (consider as evaluation for right heart strain)
- Bilateral Lower Extremity DopplerUltrasound (consider)
- Hypercoagulable state evaluation in unprovoked Venous Thromboembolism
-
Anticoagulation (choose one)
- See Anticoagulation in Thromboembolism
- Warfarin and Low Molecular Weight Heparin (e.g. Lovenox)
- Direct Oral Anticoagulant or DOAC (e.g. Rivaroxaban, Apixaban, Edoxaban)
- Low Molecular Weight Heparin (e.g. Lovenox) alone
- Indicated in pregnancy or severe Thrombophilia (or when Warfarin or DOACs contraindicated)
- Discharge goals
- Systolic Blood Pressure >100 mmHg
- Heart Rate <110 bpm
- No Supplemental Oxygen required
- Negative Troponin
- Education
- Anticoagulant safety (Trauma prevention, bleeding signs/symptoms)
- Anticoagulation clinic close follow-up (Warfarin)
- Discharge
- Follow-up (e.g. primary care, hematology, cardiology or vascular) within 72 hours
- Anticoagulation clinic follow-up for Warfarin within days
- Efficacy
- Successful discharge home in 75% of cases (25% require hospital admission)
- References
- Davenport and Baugh (2018) Crit Dec Emerg Med 32(7): 15-24
- Bledsoe (2010) Crit Pathw Cardiol 9(4): 212-5 [PubMed]
XII. Prevention
- See DVT Prevention
- See DVT Prophylaxis
- See DVT Prevention in Travelers
-
Inferior Vena Cava Filter Indications
- Pulmonary Embolism despite Anticoagulation
- Contraindication to Anticoagulation
XIII. References
- Orman and Mattu in Herbert (2015) EM:Rap 15(12): 8-10
- Vibhakar (2015) Crit Dec Emerg Med 29(9): 2-8
- Kearon (2016) Chest 149(2):315-52 [PubMed]
- Konstantinides (2020) Eur Heart J 41(4):543-603 [PubMed]
- Wilbur (2012) Am Fam Physician 86(10):913-9 [PubMed]