(Based on 2026 AHA/ACC 2026 AHA/ACC Mult society Guideline: Evaluation & Management of Acute Pulmonary Embolism (PE)

(Ref: Circulation. March 24, 2026:153: e977-e1051)

Adil Abbasi, MD FACP

Learning Objectives

• Understand the physiology-based classification of acute PE (Categories A–E)
• Apply diagnostic algorithms using clinical probability and D-dimer
• Interpret PESI, sPESI, and Hestia criteria in clinical practice
• Integrate RV function, biomarkers, and hemodynamics into risk stratification
• Select appropriate anticoagulation strategies (DOAC, LMWH, UFH)
• Determine inpatient vs outpatient management
• Recognize complications and long-term outcomes
• Apply evidence-based decisions for thrombolysis and thrombectomy
• Determine appropriate duration of anticoagulation

1. Introduction and Conceptual Framework

Acute pulmonary embolism (PE) represents a heterogeneous clinical spectrum, ranging from incidental findings to cardiogenic shock and death.

Historically, PE was classified as:

• Massive
• Sub-massive
• Low risk

However, this approach was imprecise and anatomically focused.

Key Paradigm Shift based on 2026 Guidelines

• Moves from clot burden → physiologic impact 
• Introduces dynamic risk classification (A–E) 
• Emphasizes continuous care pathway:

Suspect → Diagnose → Stratify → Treat → Disposition → Follow-up

2. Pathophysiology of Severity

PE severity depends on hemodynamic consequences, not clot size.

Pathophysiologic Cascade

• Pulmonary artery obstruction
• ↑ Pulmonary vascular resistance
• RV pressure overload
• RV dilation and dysfunction
• ↓ LV preload
• ↓ Cardiac output

Clinical Consequences: Hypotension ~ Shock ~ Death

Key Concept

• Right ventricular (RV) dysfunction = primary determinant of outcome 

3. Clinical Classification: AHA/ACC Categories (A–E)

Table 1. Clinical Categories

Core Interpretation:

• A–B → Outpatient 
• C → Admit 
• D → ICU + escalation 
• E → Immediate reperfusion 

4. Clinical Risk Assessment Tools

4.1 PESI (Pulmonary Embolism Severity Index)

Variables:

• Age, male sex
• Cancer, heart failure, lung disease
• HR >110, SBP <100
• RR ≥30, Temp <36°C
• Altered mental status
• O2 sat <90%

Table 2. PESI Risk Classes

4.2 sPESI (Simplified PESI)

Variables:

• Age >80
• Cancer
• Cardiopulmonary disease
• HR ≥110
• SBP <100
• O2 sat <90%

Interpretation:

• 0 → low risk; ≥1 → higher risk

4.3 Hestia Criteria

Used to determine outpatient eligibility.

Includes:

• Hemodynamic instability
• Oxygen requirement
• Bleeding risk
• Severe pain
• Social factors

Key Rule: All negative → safe for outpatient care 

4.4 Diagnostic Probability Tools

 5. Diagnostic Approach to Suspected PE

Stepwise Algorithm

Step 1: Clinical Probability

• Wells / Geneva

Step 2: PERC (very low risk)

• If negative → no testing 

Step 3: D-dimer

• Negative → excludes PE 
• Positive → imaging

Step 4: Imaging

• CTPA = gold standard 
• V/Q scan if contraindications

6. Right Ventricular (RV) Assessment

6.1 CT Findings

6.2 Echocardiography Findings

Critical Concept: RV dysfunction = most important prognostic marker 

7. Biomarkers in PE - Table: Biomarker Roles

8. Integrated Risk Stratification

Table: Combined Assessment

Key Concept: Risk = clinical + imaging + biomarkers + vitals 

9. Anticoagulation Strategy

Core Principle

• DOAC = first-line 
• LMWH preferred over UFH 
• UFH reserved for unstable patients 

9.1 DOAC (First-line)

Examples: Apixaban; Rivaroxaban

Advantages: No monitoring; Lower bleeding risk

Apixaban and Rivaroxaban DO NOT require Enoxaparin

Dabigatran and Edoxaban require Enoxaparin first

Must give: Enoxaparin (Lovenox) or IV heparin for 5–10 days first, then switch to oral DOAC

9.2 LMWH (e.g., Enoxaparin)

Use in: Stable hospitalized patients and Cancer-associated PE

9.3 UFH (Critical Indications)

Use UFH when:

• Category D–E (unstable)
• Planned procedures
• Severe renal failure
• ICU setting
• High bleeding risk

10. Inpatient Management

Category-Based Approach

11. Duration of Anticoagulation

Core Rule

• Minimum = 3 months 

Table: Duration of treatment by Scenario

12. Reperfusion Therapy (Thrombolysis vs Thrombectomy)

Stepwise Decision

Step 1: Hypotension?

• YES → Thrombolysis immediately (Category E) 

Step 2: No hypotension

• Evaluate for deterioration

Step 3: Category C

• Anticoagulation only

Step 4: Category D

• Consider escalation

Table: Reperfusion Options

13. Complications of PE

Complication  Management

Long-Term Complications

Final Summary (Core Concepts)

• PE management is physiology-based 
• Risk stratification is multidimensional 
• RV dysfunction is the central determinant 
• DOACs are first-line therapy 
• UFH is for unstable patients 
• Minimum anticoagulation = 3 months 
• Reperfusion = only for high-risk or deteriorating patients 
• Follow-up is mandatory for all patients