New Guideline for Scoring Pulmonary Embolism Severity: What to Know

Grading the new grades for PE risk

In February 2026, the American Heart Association and American College of Cardiology issued a new guideline on the evaluation and management of acute pulmonary embolism, with many other societies’ endorsements. PulmCCM is not affiliated with any specialty society.

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The guidance included a novel severity scoring or staging system that grades pulmonary embolism from “A” (nearly benign) to “E” (probably lethal).

The AHA’s model proposes to help triage more low-risk patients to outpatient management and guide the use of invasive or risky therapies like systemic thrombolytics and catheter-based interventions.

Of course, anyone proposing a new scoring system for any medical condition would do well to have read the oncologist researcher Florian Markowetz’s landmark 2024 monograph in Precision Oncology on the subject:

Markowetz delivers on his sardonic title with an unsparing takedown of most prediction models (including his own) and the researchers who produce them (including himself), arguing that such rubrics usually benefit their creators more than patients or their doctors.

But this isn’t some CV-padding manuscript in a third-rate journal by junior faculty struggling to publish or perish; it’s the AHA with nine other societies, publishing in Circulation! Let’s suspend our skepticism, examine the new AHA scoring system for PE on its own terms, and ask: Is this useful?

Grade “A” and “B” PE: Send Them Home?

Pulmonary embolism’s wide spectrum of possible outcomes—ranging from asymptomatic and probably benign to rapidly lethal—makes it an unsettling diagnosis for patients and physicians alike.

Research suggests clinical conservatism spawned by this variability has led to many thousands of unnecessary or overly long hospitalizations for patients with asymptomatic and otherwise low-risk pulmonary embolism.

The new guideline classifies asymptomatic PE as category “A”, and advises that they can “safely be discharged home from the emergency room and do not need to be hospitalized.”

This was one of the top-line “Take Home Messages” of the document—but in the actual guideline text, the authors weaken that statement.

There (p. e20), they lump category A together with category “B” PEs, which are symptomatic but with low clinical risk scores (either PESI I-II, simplified PESI = 0, or Hestia = 0; Bova < 4 is also mentioned).

It’s “reasonable” to manage “select” patients with category “A” or “B” on an outpatient basis, the authors advise, if they have low risk scores “and it aligns with patient goals.”

All discharged patients must have anticoagulation medication access (preferably a DOAC) and “rapid, reliable, expert follow-up in place,” the latter of which may not be arranged by the end of the average ED visit.

Grade “C” PEs, Sliced Thinly

Grade “C” PEs have both symptoms and elevated risk scores (PESI III-IV, simplified PESI ≥1, or Bova >4 ), but have preserved blood pressure and no shock.

They should be hospitalized, receive low molecular weight heparin, and undergo measurement of the right ventricle (by CT and/or echo), troponin, and brain natriuretic peptide, along with lactate.

Category C PE is further subdivided into 3 subcategories:

• C1: with normal RV function and biomarkers

• C2: Either an abnormal RV or elevated biomarker(s)

• C3: With both an elevated RV and biomarker(s)

The panel did not address the clinical uncertainty regarding the indications for invasive catheter-based therapies (catheter-directed thrombolysis or mechanical thrombectomy) in the “C” category, which includes patients categorized in earlier European schemes as “intermediate-risk” (RV dysfunction without biomarker elevations) and “intermediate-high risk” (RV dysfunction plus biomarker elevations).

For “C1” patients, catheter-based treatments were discouraged as “No Benefit,” but this was already uncontroversial.

For “C2” and “C3” patients, the benefits of invasive therapies were described as “unclear,” but the panel left the door open for routine intervention by also giving a weak 2b recommendation (“Benefit ≥ Risk”) to both CDT and MT.

Grade “D” PEs: Things Get Dicey

Category “D” PEs are those with incipient cardiopulmonary failure: either transient hypotension (“D1”) or normotensive shock (“D2”).

Besides anticoagulation with low molecular weight heparin and vasopressors when needed, the AHA guidelines now endorse either systemic thrombolysis or catheter-based therapies (CDT or MT), each with a 2b (weak, “may be considered”) recommendation in this category of patients.

Grade “E” PEs: Extreme Risk

Category “E” represents PEs with persistent hypotension, either without (E1) or with (E2) refractory shock or cardiac arrest.

In line with usual practice, the panel suggests systemic thrombolysis for either “E1” or “E2”—but interestingly, with only a moderate 2a (“we suggest”) recommendation.

For the first time, both mechanical thrombectomy and catheter-directed thrombolysis were indirectly endorsed as reasonable alternatives to systemic thrombolysis for patients with PE and hypotension (“E1”). Although the panel did not compare CDT / MT to systemic thrombolysis, it gave both invasive therapies a 2a recommendation—the same as for systemic thrombolysis for category “E1” PE.

“R” For Respiratory Complications

Patients with more severe PE (“C”, “D”, and “E”) with respiratory symptoms and signs crossing a certain threshold tailored to each category receive an “R+” (or “R-” for lacking that degree of respiratory failure):

• C: O₂ <90% and/or RR ≥30 and/or need supplemental O₂

• D: >6 L nasal cannula or NRB mask

• E: hypoxemic respiratory failure or ventilatory failure

Grading the New PE Grading System

Pulmonary embolism presents with a very wide spectrum of hemodynamic involvement, symptoms, and risk.

From a practical standpoint the new system will help triage patients more effectively and enable clearer communication among clinicians by creating an objectively describable “shared reality”.

For low risk patients, it will likely enable more discharges from the ED and shorter hospitalizations (i.e., next-day or even same-day discharge) for those who are admitted.

(By the way, regarding category “A”, how does an asymptomatic patient end up in the ED and undergo a CT angiogram of the chest that happens to diagnose an incidental PE?)

Among more severely affected patients, the refinement of categories “C” through “E” will permit the collection and analysis of more detailed and granular observational data, and help standardized randomized trial enrollment.

But the new system’s most immediate and far reaching effect will be its tacit endorsement of invasive procedures in all but the mildest PEs requiring hospitalization (“C1”).

So, to answer our original question: is it useful? Yes: the new severity scoring system will help standardize management and care coordination for acute PE, especially among less-experienced clinicians.

And it will be extremely useful if you happen to be an interventionalist performing catheter-based treatments.

References

Creager MA, Barnes GD, Giri J, 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. Published online February 19, 2026. doi:https://doi.org/10.1161/cir.0000000000001415

‌Watson NW, Carroll BJ, Krawisz A, Schmaier A, Secemsky EA. Trends in Discharge Rates for Acute Pulmonary Embolism in U.S. Emergency Departments. Annals of Internal Medicine. Published online January 30, 2024. doi:https://doi.org/10.7326/m23-2442

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