Pulmonary embolism (PE) is characterized by occlusion of pulmonary arterial blood flow, typically from a lower extremity DVT, with an incidence of ~60–120 per 100,000 per year and approximately 60,000–100,000 deaths annually in the US. [1] The 2026 AHA/ACC multi-society guideline introduces a new Category A–E classification system for severity-based management. [2-3]
1. History
- Onset and character of dyspnea: sudden vs. progressive, at rest vs. exertional — dyspnea is present in ~80% of cases [4]
- Chest pain: pleuritic in nature (60–70%), distinguish from pressure-type ACS pain [4]
- Hemoptysis (5–13%), syncope/presyncope, cough [1][4]
- Timing: acute onset is classic; ask about symptom duration and progression
- Triggers: recent travel (>4 hrs), surgery, immobilization, hospitalization, trauma
- Provoked vs. unprovoked: critical for long-term anticoagulation decisions
- Important negatives: absence of leg swelling/pain, no prior VTE, no recent immobilization, no estrogen use, no malignancy [1]
2. Alarm Features
- Hemodynamic instability: SBP <90 mmHg, persistent hypotension, cardiogenic shock [2-3]
- Syncope — may indicate massive PE with transient cardiac output failure
- Severe hypoxemia refractory to supplemental O₂
- Altered mental status, signs of end-organ hypoperfusion (elevated lactate, oliguria) [2-3]
- Cardiac arrest — PE is a common cause of PEA arrest
- Normotensive shock (AHA/ACC Category D): normal BP but elevated lactate, AKI, reduced cardiac index [2-3]
- The first 24–72 hours are the critical window for hemodynamic collapse in intermediate-high risk PE [2]
3. Medications
Medications that increase PE risk
- Combined oral contraceptives (adjusted RR ~3.5 vs. nonusers); risk varies by progestin type and estrogen dose [5-6]
- Hormone replacement therapy (oral estrogen-progestogen OR ~2.4 for VTE) [5]
- Depot medroxyprogesterone acetate (2–5.7× increased risk) [5]
- Tamoxifen, testosterone (in transfeminine persons), erythropoiesis-stimulating agents
- Antipsychotics, thalidomide/lenalidomide
Contraindicated medications
- Avoid estrogen-containing contraceptives after PE diagnosis
- DOACs contraindicated in pregnancy, breastfeeding, antiphospholipid syndrome (use VKA), and severe renal impairment (CrCl <15 mL/min) [2-3]
4. Diet
- No specific dietary triggers for PE
- Patients on warfarin require consistent vitamin K intake; DOACs have fewer dietary interactions [2]
- Rivaroxaban (15 mg and 20 mg doses) should be taken with the largest meal of the day to promote absorption [7]
- Adequate hydration during travel and immobilization periods for VTE prevention
5. Review of Systems
- Pulmonary: dyspnea, pleuritic chest pain, cough, hemoptysis
- Cardiovascular: palpitations, syncope, presyncope, exertional intolerance
- Lower extremity: unilateral leg swelling, pain, warmth, erythema (concurrent DVT in ~40% of PE patients) [4]
- Neurologic: lightheadedness, confusion (suggests hemodynamic compromise)
- Constitutional: anxiety, sense of impending doom
- GI: abdominal pain (rare, may indicate hepatic congestion from RV failure)
6. Collateral History and Family History
- Prior VTE in patient or first-degree relatives — strongest historical predictor
- Known thrombophilia: Factor V Leiden, prothrombin G20210A mutation, protein C/S deficiency, antithrombin deficiency, antiphospholipid syndrome [8]
- Active malignancy or recent cancer treatment [2-3]
- Recent hospitalization, surgery, or immobilization — collateral from family/caregivers may be essential in obtunded patients
- Medication history: estrogen use, anticoagulant compliance
7. Risk Factors
- Major transient: surgery (especially orthopedic), hospitalization, immobilization ≥3 days, major trauma [2-3]
- Minor transient: long-haul travel, oral contraceptives, pregnancy/postpartum, minor injury
- Persistent: active cancer, inflammatory disorders (IBD, SLE), chronic venous disease, inherited thrombophilia
- Patient-related: age, obesity (BMI ≥30 synergistically increases risk with OCP use — OR ~23.8), prior VTE, heart failure, COPD [5]
- Obesity + OCP is a particularly high-risk combination [5]
8. Differential Diagnosis
- Acute coronary syndrome — pressure-type chest pain, ST changes, troponin elevation (can also occur in PE)
- Pneumonia — fever, productive cough, focal consolidation
- Pneumothorax — sudden pleuritic pain, absent breath sounds, hyperresonance
- Acute heart failure/pulmonary edema — bilateral crackles, BNP elevation, cardiomegaly
- Pericarditis/tamponade — diffuse ST elevation, friction rub, Beck's triad
- Aortic dissection — tearing pain, pulse differential, widened mediastinum
- COPD/asthma exacerbation — wheezing, known history [9]
- Pleural effusion, musculoskeletal chest pain, anxiety/panic attack
- Cannot-miss mimics: PE can present identically to STEMI (ST elevation on ECG from RV strain) [10]
9. Past Medical History
- Prior VTE (DVT or PE) — strongest individual risk factor
- Malignancy — active or treated within 6 months
- Thrombophilia — inherited or acquired (antiphospholipid syndrome)
- Heart failure, COPD — increase PESI score and mortality risk
- Recent surgery — especially hip/knee replacement, abdominal/pelvic surgery
- Chronic kidney disease — affects anticoagulant choice and dosing
- Liver disease — affects anticoagulant metabolism and bleeding risk
10. Physical Exam
Vital signs
- Tachycardia (HR >100 in 65–70%), tachypnea (RR >20), hypoxemia (SpO₂ <94%) [4]
- Hypotension (SBP <90) — defines high-risk/massive PE
- MAP <80 mmHg is a predictor of 48-hour clinical deterioration [2-3]
Focused exam
- Lungs: decreased breath sounds, pleural friction rub; often clear
- Cardiac: accentuated P2, parasternal heave/RV lift, JVD, tricuspid regurgitation murmur [2-3]
- Lower extremities: unilateral edema, calf tenderness, Homan's sign (low sensitivity)
- Skin: cyanosis (suggests severe hypoxemia)
- 20–25% of patients with PE, including large clot burden, may have a completely normal exam [11]
11. Lab Studies
- D-dimer: 97–100% NPV at threshold of 500 ng/mL; use only in low/intermediate pretest probability patients [1]
- Age-adjusted cutoff (age × 10 μg/L for patients >50 years) safely reduces imaging [2]
- YEARS algorithm: D-dimer threshold of 1000 μg/L if no YEARS criteria present [2]
- D-dimer has limited utility in cancer patients [7]
- Troponin I/T: elevated in RV strain; prognostic, not diagnostic [3][7]
- NT-proBNP/BNP: marker of RV dysfunction and adverse outcomes [7]
- CBC, BMP, PT/aPTT: baseline before anticoagulation [7]
- Lactate: elevated suggests tissue hypoperfusion (normotensive shock) [2]
- ABG: hypoxemia with respiratory alkalosis (classic but nonspecific); A-a gradient often elevated
12. Imaging
- CT Pulmonary Angiography (CTPA): gold standard — wide availability, excellent diagnostic performance, also assesses RV size and identifies alternative diagnoses [3][12]
- V/Q scan: appropriate when CTPA is contraindicated (contrast allergy, severe renal insufficiency); best combined with SPECT [3]
- Echocardiography: not diagnostic for PE but critical for RV function assessment — look for RV dilation, McConnell's sign, TAPSE reduction, septal bowing, elevated RVSP [3]
- Lower extremity venous duplex ultrasound: useful if DVT suspected; positive DVT in setting of PE symptoms may obviate CTPA in select cases [3]
- Chest X-ray: often normal or nonspecific; useful to exclude pneumothorax, pneumonia, effusion. Classic findings (Hampton's hump, Westermark's sign) are uncommon
- Imaging is unnecessary if PERC-negative in low-probability patients or if D-dimer is negative in low/intermediate probability [1][13]
13. Special Tests
Clinical decision tools
- Wells Score for PE: stratifies into low/intermediate/high probability (or PE likely/unlikely) [1][13]
- Revised Geneva Score: fully objective scoring system [1][13]
- PERC (Pulmonary Embolism Rule-Out Criteria): if all 8 criteria met in low-probability patients, no further testing needed [1]
- PESI / sPESI: risk stratification after PE diagnosis for disposition decisions [2-3]
- Hestia Criteria: bedside tool to identify patients safe for outpatient management [14]
- Bova Score: predicts 30-day complications in hemodynamically stable PE [supported calculator]
Point-of-care
- Bedside echocardiography: rapid RV assessment in unstable patients
- Point-of-care ultrasound (POCUS): DVT assessment, RV dilation, IVC assessment
- Whole-blood D-dimer assays available in some EDs
14. ECG
ECG is insensitive for PE but may raise suspicion and help with risk stratification: [15-16]
- Sinus tachycardia: most common finding (~31%) [17]
- S1Q3T3 pattern: classic but present in only ~15% of cases [17]
- T-wave inversion in V1–V3: best ECG predictor of RV dysfunction and massive/submassive PE (18% prevalence) [17-18]
- Right bundle branch block (new or incomplete): ~14% [17]
- Right axis deviation, clockwise rotation (transition zone shift)
- P pulmonale (right atrial enlargement): rare
- ST elevation in right precordial leads: can mimic STEMI [10]
- Normal ECG in 20–25% of confirmed PE, including large clot burden [11]
- Classical ECG findings have minimal independent diagnostic accuracy and should not be used alone to rule in or rule out PE [16]
15. Assessment
The 2026 AHA/ACC guideline introduces 5 clinical categories (A–E) for severity stratification: [2-3]
- Category A: Asymptomatic/incidental PE — safe for ED discharge
- Category B: Symptomatic, low-risk (sPESI <1, Hestia <1) — early discharge candidates
- Category C: Symptomatic, elevated severity score (sPESI ≥1) ± biomarker/RV dysfunction
- Category D: Pre-cardiopulmonary failure (normotensive shock, transient hypotension, approaching ventilatory support)
- Category E: Cardiopulmonary failure — persistent hypotension, cardiogenic shock, cardiac arrest
A respiratory modifier (R) is added when significant hypoxemia, tachypnea, or supplemental O₂ requirement is present. [2-3]
16. Treatment Plan
Initial stabilization (all categories)
- Supplemental O₂ to maintain SpO₂ >90%
- IV access, continuous monitoring
- Empiric anticoagulation is reasonable in high pretest probability while awaiting imaging [2]
Anticoagulation — the cornerstone of PE treatment: [2-3][19]
Key anticoagulation pearls:
- DOACs are recommended over VKAs unless contraindicated (antiphospholipid syndrome, severe CKD, pregnancy) [2-3]
- LMWH is preferred over UFH for parenteral therapy (lower recurrent VTE, less HIT) [2-3]
- UFH is preferred when advanced therapies (thrombolysis, catheter intervention, surgery) are anticipated [12]
- The COBRRA trial (2026) showed apixaban had lower clinically relevant bleeding than rivaroxaban in acute VTE [20]
Advanced therapies (Category D–E): [2-3]
- Systemic thrombolysis: alteplase 100 mg IV over 2 hours (standard dose); low-dose regimens (25–50 mg) may have similar efficacy with less bleeding [2]
- Indicated for Category E (hemodynamic collapse/cardiogenic shock); may be considered for Category D
- Rescue thrombolysis is beneficial for patients who decompensate on anticoagulation alone [2]
- Catheter-directed therapy (CDT): catheter-directed thrombolysis or mechanical thrombectomy — considered when systemic thrombolysis is contraindicated or as alternative [21]
- Surgical embolectomy: for massive PE with thrombolysis contraindication or failure
- ECMO: bridge therapy in refractory cardiogenic shock or cardiac arrest [2]
- PERT activation is recommended for Category C3 and above [2-3]
IVC filter: only when anticoagulation is absolutely contraindicated or PE recurs despite therapeutic anticoagulation [1]
17. Disposition
Per the 2026 AHA/ACC guidelines: [2-3]
- ED discharge (outpatient management):
- Category A (asymptomatic/incidental PE)
- Category B (symptomatic, low-risk: sPESI <1, Hestia 0) — if adequate outpatient follow-up, medication access, and stable home circumstances [2][14][22]
- Admit to floor/telemetry:
- Admit to step-down/ICU:
- Category C3 (elevated troponin AND RV dysfunction) — close monitoring for first 24–72 hours [2]
- Category D (pre-cardiopulmonary failure)
- ICU admission:
- Transfer to higher-level center if advanced therapies (catheter intervention, surgical embolectomy, ECMO) are needed but unavailable locally [3]
Specialist consultation triggers: PERT activation for Category C3 and above; hematology for thrombophilia workup; oncology if cancer-associated PE
18. Follow-Up / Return Precautions
- Initial follow-up within 48 hours to 7 days after diagnosis — focus on medication adherence, patient education, and barrier assessment [2-3]
- Dedicated visit at ~3 months: discuss anticoagulation duration, assess for ongoing symptoms, evaluate for thrombophilia/cancer screening if indicated [2-3]
- Screen for CTEPD at every visit for at least 1 year — one-third to one-half of PE patients report persistent dyspnea; CTEPD with PH complicates 2.3–4% of acute PEs [2-3]
- Anticoagulation duration: [2-3][12]
- Provoked by major transient risk factor: 3 months, then stop
- Unprovoked or persistent risk factor: extended/indefinite anticoagulation recommended
- After 3–6 months of full-dose therapy, consider reduced-dose apixaban (2.5 mg BID) or rivaroxaban (10 mg daily) for extended phase [12]
Return precautions — counsel patients to return immediately for:
- New or worsening shortness of breath
- Chest pain, hemoptysis
- Lightheadedness, syncope, or near-syncope
- Unilateral leg swelling or pain (recurrent DVT)
- Signs of bleeding: blood in urine/stool, unusual bruising, prolonged bleeding from cuts
- Expected recovery: symptoms typically improve over days to weeks; persistent dyspnea beyond 3 months warrants further evaluation for CTEPD [2-3]
References
1. Acute Pulmonary Embolism: A Review. — Freund Y, Cohen-Aubart F, Bloom B. The Journal of the American Medical Association. 2022.
2. 2026 AHA/ACC/ACCP/ACEP/CHEST/SCAI/SHM/SIR/SVM/SVN Guideline for the Evaluation and Management of Acute Pulmonary Embolism in Adults: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. — Writing Committee Members*, Creager MA, Barnes GD, et al. Circulation. 2026.
3. 2026 AHA/ACC/ACCP/ACEP/CHEST/SCAI/SHM/SIR/SVM/SVN Guideline for the Evaluation and Management of Acute Pulmonary Embolism in Adults: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. — Creager MA, Barnes GD, Giri J, et al. Journal of the American College of Cardiology. 2026.
4. Venous Thromboembolism. — Khan F, Tritschler T, Kahn SR, Rodger MA. Lancet. 2021.
5. Sex Hormone Influences on Venous Thrombotic and Cardiovascular Risk. — Skeith L, Bates SM. The New England Journal of Medicine. 2026.
6. Contraception Selection, Effectiveness, and Adverse Effects: A Review. — Teal S, Edelman A. The Journal of the American Medical Association. 2021.
7. Cancer-Associated Venous Thromboembolic Disease. — Updated 2026-05-05. National Comprehensive Cancer Network.
8. Combined Hormonal Contraception and the Risk of Venous Thromboembolism: A Guideline. — Practice Committee of the American Society for Reproductive Medicine. Electronic address: ASRM@asrm.org, et al. Fertility and Sterility. 2017.
9. 2026 GOLD Report and Pocket Guide: Global Strategy for Prevention, Diagnosis, and Management of COPD – 2026 Report. — Global Initiative for Chronic Obstructive Lung Disease. 2025.
10. Massive Pulmonary Embolism Presenting With Hemoptysis and S1Q3T3 ECG Findings. — Islamoglu MS, Dokur M, Ozdemir E, Unal OF. BMC Cardiovascular Disorders. 2021.
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12. International Clinical Practice Guideline Recommendations for Acute Pulmonary Embolism: Harmony, Dissonance, and Silence. — Zuin M, Bikdeli B, Ballard-Hernandez J, et al. Journal of the American College of Cardiology. 2024.
13. Comparison of International Guideline Recommendations for the Diagnosis of Pulmonary Embolism. — Falster C, Hellfritzsch M, Gaist TA, et al. The Lancet. Haematology. 2023.
14. Evidence-Based Risk Stratification of Patients With Acute Pulmonary Embolism: Communication From the ISTH SSC Subcommittee on Predictive and Diagnostic Variables in Thrombotic Disease. — Talerico R, de Wit K, Barco S, et al. Journal of Thrombosis and Haemostasis : JTH. 2026.
15. 2015 ACR/ACC/AHA/AATS/ACEP/ASNC/NASCI/SAEM/SCCT/SCMR/SCPC/SNMMI/STR/STS Appropriate Utilization of Cardiovascular Imaging in Emergency Department Patients With Chest Pain: A Joint Document of the American College of Radiology Appropriateness Criteria Committee and the American College of Cardiology Appropriate Use Criteria Task Force. — Rybicki FJ, Udelson JE, Peacock WF, et al. Journal of the American College of Cardiology. 2016.
16. EXPRESS: Classical ECG Findings in Pulmonary Embolism Have Minimal Diagnostic Accuracy: A Cross-Sectional Study. — Smaniotto MF, Alencar E Silva GPS, Heringer JN, et al. Journal of Investigative Medicine : The Official Publication of the American Federation for Clinical Research. 2025.
17. Prevalence of Electrocardiographic Abnormalities in Patients With Acute Pulmonary Embolism: A Systematic Review and Meta-Analysis. — Krintratun S, Srichuachom W, Wongtanasarasin W. Journal of Clinical Medicine. 2025.
18. Differentiating electrocardiographic indications of massive and submassive pulmonary embolism: A cross‐sectional study in Southern Iran from 2015 to 2020. — Bahreini Z, Kamali M, Kheshty F, et al. Clinical Cardiology. 2024.
19. Pulmonary Embolism. — Kahn SR, de Wit K. The New England Journal of Medicine. 2022.
20. Bleeding Risk with Apixaban vs. Rivaroxaban in Acute Venous Thromboembolism. — Castellucci LA, Chen VM, Kovacs MJ, et al. The New England Journal of Medicine. 2026.
21. Catheter-Directed Therapies for the Treatment of High Risk (Massive) and Intermediate Risk (Submassive) Acute Pulmonary Embolism. — Harvey JJ, Huang S, Uberoi R. The Cochrane Database of Systematic Reviews. 2022.
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