In 2026, the American College of Cardiology (ACC) and the American Heart Association (AHA) Joint Committee on Clinical Practice Guidelines published a report on the evaluation and management of acute pulmonary embolism (PE).¹ The report carries endorsements from multiple professional societies, including ACEP. The comprehensive 75-page document contains some key recommendations for emergency clinicians.

Elevated D-dimer Thresholds Are “in” for Diagnostic Evaluation

Unsurprisingly, the AHA/ACC guideline endorses the use of the Pulmonary Embolism Rule-out Criteria (PERC) for ultra-low-pretest probability patients, obviating the need for a D-dimer for some. However, for intermediate risk patients, those with a pre-test probability of  less than 50 percent (e.g., Wells ≤6), the guideline endorses age-adjusted D-dimer and the YEARS algorithm (elevated D-dimer of up to 1,000 ng/mL threshold for those with negative YEARS criteria).

Despite the common refrain that clinician gestalt is as good as clinical decision tools, randomized controlled trials have demonstrated that PERC and the YEARS algorithm are safe and result in reduced chest imaging compared with usual care alone.^2,3 What emergency clinicians should note, and is in the supporting text for these recommendations, is that these recommendations are for individuals not on therapeutic anticoagulation. Anticoagulated patients were excluded from all major studies evaluating clinical decision tools and D-dimer, and there are some data suggesting that anticoagulants could result in a falsely low D-dimer.

What is most notable about the new AHA/ACC recommendations for diagnostic evaluation is that clinicians finally have professional society-backed guidance for the evaluation of pregnant patients with suspected PE. Previously, chest imaging was required to exclude PE in pregnant patients based on a lack of evidence on alternative strategies with abysmal yield (0–5 percent of scans positive for PE).⁴ The guideline endorses the use of the pregnancy-adapted YEARS algorithm in pregnant patients, previously detailed in ACEP Now.⁵ Of course, the real-world utility of YEARS in pregnant patients depends on the stewardship of emergency clinicians only applying it to patients for whom they would have otherwise ordered chest imaging.

More Granular Risk Stratification of PE

Pulmonary embolism is best characterized as a spectrum of disease from asymptomatic to lethal. Prior risk stratification schema inadequately captured the spectrum. The new AHA/ACC risk stratification schema expands on the European Society of Cardiology’s classification, with categories A (asymptomatic) to E (cardiorespiratory failure). Novelly, this finally accounts for hypoxemia and respiratory failure with a respiratory modifier. It also introduces a category to capture pre-cardiopulmonary failure, Category D. This category is marked by poor perfusion including persistently elevated lactate, altered mental status, poor urine output, and transient hypotension. The full risk stratification scheme can be found in Figure 1, along with treatment recommendations.

There are a few key nuances to recommendations for proper risk stratification. Category C represents the former “intermediate risk” group, marked by right ventricular (RV) dilation and elevated biomarkers. Importantly, the guidelines recommend the use of echo, including point-of-care ultrasound, over CT to identify an abnormal RV, owing to the poor specificity of CT for RV dysfunction.^6,7 In addition, although the guidelines recommend troponin and/or brain natriuretic peptide for Category C (elevated severity score) patients, there is no guidance on thresholds for abnormal biomarkers.

Clinicians will need to thoughtfully evaluate a patient’s comorbidities (e.g., chronic kidney disease or heart failure), baseline values, and concurrent illnesses to properly attribute elevations to the PE. Lastly, Category D requires close clinician attention. For example, Category D2, deemed normotensive shock, appears to state lactate >2 mmol/L qualifies, yet the supporting text is more granular, defining this category as a persistently elevated lactate accompanied by transient hypotension.

Figure 1: AHA/ACC Acute PE Clinical Guidelines. (Click to enlarge. Credit: Dr. Westafer)

Treatment

Over the past decade, there has been substantial interest in adjunct treatments for higher risk PEs—from thrombolytics to catheter-based therapies. Despite this, anticoagulation remains the mainstay of treatment, and the guideline gives a strong recommendation that nearly all patients requiring parenteral anticoagulation should be started on low-molecular-weight heparin instead of unfractionated heparin.

Stabilization and Supportive Care

Stabilization and supportive care are also critical, including prior to transport. Although a small volume trial of fluids (500-1000 mL) are acceptable for patients that clinicians believe have a reduced preload, vasopressors and/or inotropes are recommended for those in categories D2 through E2.

Patients with acute PE and RV dysfunction (Categories C2-E) rely on a compensatory increase in sympathetic activity to maintain perfusion. A number of studies have shown a higher risk of cardiovascular collapse in patients with RV dysfunction, even if apparently hemodynamically stable, when undergoing sedation and intubation.^8–10 Additionally, invasive mechanical ventilation can decrease RV preload and increase RV afterload, further worsening RV failure and sometimes resulting in cardiac arrest. As a result, alternatives to mechanical ventilation are recommended and, if intubation is clinically indicated, clinicians should anticipate cardiovascular collapse and prepare for this with vasopressors, inotropes, and extracorporeal membrane oxygenation (ECMO) if available.

The AHA/ACC guidelines usher in the new era of advanced treatments for the sickest patients with PE (Categories C3-E), including catheter-directed treatments (CDT: thrombolysis and mechanical thrombectomy). As in prior guidelines, these guidelines recommend systemic thrombolysis in addition to anticoagulation for the sickest patients (Category E). The guideline notes that either systemic thrombolysis or CDT may be considered in Categories D1-E1, although CDT procedures carry a lower bleeding risk and may be preferred.

Although the language in the guideline is subtle, the guideline notes that the benefit of either CDT or systemic thrombolysis in lower risk patients with RV dysfunction (Category C3) patients is unclear. For patients that do receive systemic thrombolysis, a reduced dose is reasonable, although we still do not have data to suggest an ideal dose. Of note, there is a strong recommendation against systemic thrombolysis or CDT in patients with lower risk PEs (Categories A-C1), regardless of thrombus location or size.

Disposition

For the past decade, essentially every professional society guideline on PE has recommended that patients with low-risk PE be treated in the outpatient setting.^11,12 Despite this, only a small proportion of patients with acute PE in the United States are treated as outpatients.¹³ The new guidelines continue to affirm that patients with subclinical or symptomatic PE with low clinical severity score (i.e., categories A and B) can be treated in the outpatient setting.

Although the guideline states that patients in categories C3 and D may be transferred for advanced therapies, they give this one of the lowest levels of recommendations based on limited data.

Key Learning Points

1. Use clinical decision tools and adjusted D-dimer thresholds for the diagnosis of PE in patients with less than 50 percent probability of PE (Wells score less than 6).
2. Low-risk patients (Categories A/B) may be managed in the outpatient setting.
3. Low molecular weight heparin is the anticoagulant of choice for most patients requiring parenteral anticoagulation.
4. Avoid sedation and mechanical ventilation, if possible; anticipate cardiovascular collapse if intubation is imminent.
5. Pulmonary embolism response teams and catheter-directed procedures may be reasonable in higher risk patients, although one strategy over another cannot be recommended based on available data.

Dr. Barreto-Vazquez is a third-year emergency medicine resident at Baylor College of Medicine and future Toxikon toxicology fellow at the University of Illinois at Chicago. Main areas of interests are in toxicology, critical care, and social determinants of health.

Dr. Westafer (@LWESTAFER) is an assistant professor in the departments of emergency medicine and healthcare delivery and population science at UMass Chan Medical School, Baystate, and co-host of FOAMcast.

References

1. Members WC, Creager MA, Barnes GD, et al. 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. Circulation. 2026;153(12). doi:10.1161/CIR.0000000000001415
2. Freund Y, Cachanado M, Aubry A, et al. Effect of the Pulmonary Embolism Rule-Out Criteria on Subsequent Thromboembolic Events Among Low-Risk Emergency Department Patients: The PROPER Randomized Clinical Trial. JAMA. 2018;319(6):559-566. doi:10.1001/JAMA.2017.21904
3. Freund Y, Chauvin A, Jimenez S, et al. Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism: A Randomized Clinical Trial. JAMA. 2021;326(21):2141. doi:10.1001/JAMA.2021.20750
4. Goyal SK, Wang JJ, McCandlish JA, et al. Ten-Year Trend in Advanced Imaging Utilization for Suspected Pulmonary Embolism in Pregnancy. Journal of the American College of Radiology. 2024;21(4):549-557. doi:10.1016/J.JACR.2023.08.045
5. Westafer LM. Decoding Pulmonary Embolism Evaluation in Pregnancy. ACEPNow. May 12, 2022. Accessed May 6, 2026. https://www.acepnow.com/article/decoding-pulmonary-embolism-evaluation-in-pregnancy/
6. Lyhne MD, Giordano N, Dudzinski D, et al. Concordance between CTPA and echocardiography in identification of right ventricular strain in PERT patients with acute pulmonary embolism. Emergency Radiology 2023 30:3. 2023;30(3):325-331. doi:10.1007/S10140-023-02130-Z
7. Girardi AM, Turra EE, Loreto M, et al. Diagnostic accuracy of multiorgan point-of-care ultrasound compared with pulmonary computed tomographic angiogram in critically ill patients with suspected pulmonary embolism. PLoS One. 2022;17(10 October). doi:10.1371/journal.pone.0276202
8. Goldberg JB, Spevack DM, Ahsan S, et al. Comparison of Surgical Embolectomy and Veno-arterial Extracorporeal Membrane Oxygenation for Massive Pulmonary Embolism. Semin Thorac Cardiovasc Surg. 2022;34(3):934-942. doi:10.1053/j.semtcvs.2021.06.011
9. Rosenberger P, Shernan SK, Shekar PS, et al. Acute hemodynamic collapse after induction of general anesthesia for emergent pulmonary embolectomy. Anesth Analg. 2006;102(5):1311-1315. doi:10.1213/01.ANE.0000208970.14762.7F
10. Manchec B, Liu B, Tran T, et al. Sedation with Propofol During Catheter-Directed Thrombolysis for Acute Submassive Pulmonary Embolism Is Associated with Increased Mortality. Journal of Vascular and Interventional Radiology. 2019;30(11):1719-1724. doi:10.1016/j.jvir.2019.08.009
11. Kearon C, Akl EA, Ornelas J, et al. Antithrombotic Therapy for VTE Disease: CHEST Guideline and Expert Panel Report. Chest. 2016;149(2):315-352. doi:10.1016/J.CHEST.2015.11.026
12. Wolf SJ, Hahn SA, Nentwich LM, Raja AS, Silvers SM, Brown MD. Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department with Suspected Acute Venous Thromboembolic Disease (Executive Summary). Ann Emerg Med. 2018;71(6):783-784. doi:10.1016/s0196-0644(18)30401-3
13. Westafer LM, Shieh MS, Pekow PS, Stefan MS, Lindenauer PK. Outpatient Management of Patients Following Diagnosis of Acute Pulmonary Embolism. Academic Emergency Medicine. 2021;28(3):336-345. doi:10.1111/ACEM.14181/FULL