Acute PE: Advanced Risk Stratification

Beyond the Wells score

Critical Care · Seminar week 3 · released April 6, 2026 · includes a discussion video

PESI, sPESI, RV dysfunction, troponin, BNP: building a modern risk stratification framework. When to lyse, when to intervene, when to watch.

Learning Objectives

1. Interpret the novel AHA/ACC acute PE classification system and apply it to clinical scenarios
2. Utilize biomarkers (troponin, NT-proBNP, lactate) in risk stratification for PE
3. Compare and contrast initial anticoagulation options for high-risk PE patients
4. Evaluate indications for systemic thrombolysis and catheter-directed therapies
5. Discuss the role of PERT in improving patient outcomes in PE management
6. Plan post-acute management strategies including extended anticoagulation and CTEPH surveillance

Section 1: Introduction — The PE Landscape is Changing

Duration: 10 min | Content Tier: Teaching Point

%%FIG0%% Teaching Point: Pulmonary embolism remains one of the most common and lethal cardiovascular emergencies, and the way we classify and manage it has undergone a fundamental transformation. The 2024 international guideline review by Zuin et al. in the Journal of the American College of Cardiology reveals both harmony and significant dissonance among global guidelines for acute PE — and understanding these differences is essential for evidence-based practice (PMID: 39384264).

PE is not a single disease. It is a spectrum ranging from incidental subsegmental emboli discovered on CT scans performed for other reasons, to massive saddle emboli causing obstructive shock and cardiac arrest. The challenge for clinicians is not merely diagnosing PE — it is accurately stratifying its severity and matching the therapeutic intensity to the patient's risk.

Nuance: As populations age and chronic conditions become increasingly prevalent, the burden of venous thromboembolism is rising markedly. Lutsey and Zakai published a comprehensive epidemiological review in Nature Reviews Cardiology showing that approximately 1 in 12 individuals in Western populations will be diagnosed with VTE in their lifetime. Rates are lower in Asia, but data from other regions remain sparse. Approximately 20% of individuals who experience a VTE event die within one year, often from the provoking condition rather than the PE itself (PMID: 36258120).

Say Out Loud: "PE kills not because we can't diagnose it, but because we don't stratify it correctly. The same anticoagulant that saves a low-risk patient is insufficient for a patient with massive PE — and the thrombolytic that saves a massive PE patient may cause a fatal hemorrhage in a low-risk patient."

Audience Poll: How familiar are you with the recent AHA/ACC PE classification system?

• A) Very familiar — I use it routinely
• B) Somewhat familiar — I've read about it
• C) Not familiar — I still use the old massive/submassive/low-risk framework
• D) I didn't know the classification had changed

Why the Old Framework Was Insufficient

The traditional massive/submassive/low-risk classification, while clinically useful, created a false sense of clarity. The term "submassive" encompassed an enormous heterogeneity of patients — from those with trivial RV dysfunction and normal biomarkers to those teetering on the edge of hemodynamic collapse. This heterogeneity meant that two patients classified as "submassive" could have vastly different prognoses and treatment needs.

Decision Point: The updated classification systems address this by incorporating hemodynamic stability, RV function assessment (both echocardiographic and CT-based), and biomarker profiles into a more granular risk stratification framework. The key question for every PE patient is not "is this massive or submassive?" but rather "where does this patient sit on the continuum of risk, and what is the optimal therapeutic strategy?"

Section 2: PE Severity Classification — Categories A Through E

Duration: 10 min | Content Tier: MUST ACT

%%FIG1%% MUST ACT: The 2019 ESC Guidelines, which remain the most comprehensive international guidance, established a risk-stratified approach that has been refined by subsequent AHA/ACC recommendations. Understanding this classification is not academic — it directly determines whether your patient receives anticoagulation alone, escalated monitoring, or advanced interventions (PMID: 31504429).

The Five-Category Framework

The modern PE classification system divides patients into categories based on hemodynamic status, RV function, and biomarker elevation:

Category A — Low Risk (Outpatient Candidates):

• Hemodynamically stable
• No RV dysfunction on echo or CT
• Normal troponin and NT-proBNP
• PESI Class I-II or sPESI = 0
• These patients may be candidates for outpatient management with DOACs
• 30-day mortality: <1%

Category B — Intermediate-Low Risk:

• Hemodynamically stable
• RV dysfunction on imaging OR elevated biomarkers (but not both)
• Requires in-hospital monitoring
• Anticoagulation alone is usually sufficient
• 30-day mortality: 1-3%

Category C — Intermediate-High Risk:

• Hemodynamically stable
• RV dysfunction on imaging AND elevated biomarkers (both present)
• This is the critical decision-making zone — close monitoring in ICU/step-down
• Consider advanced therapies if clinical deterioration
• 30-day mortality: 5-15%

Category D — High Risk (Massive PE):

• Sustained hypotension (SBP <90 for >15 min) requiring vasopressors
• OR persistent bradycardia <40 with signs of shock
• Immediate reperfusion therapy indicated
• 30-day mortality: 25-65%

Category E — Cardiac Arrest:

• PE causing cardiac arrest or peri-arrest
• Immediate systemic thrombolysis or surgical embolectomy
• Mortality >65% without reperfusion therapy

Teaching Point: The category that generates the most controversy and clinical uncertainty is Category C — intermediate-high risk. These patients are hemodynamically stable at presentation but have evidence of significant RV strain. The IPER Registry data from Zuin et al. showed that hemodynamically stable PE patients presenting with chest pain or acute dyspnea (<24 hours) had significantly lower 30-day survival compared to asymptomatic patients — chest pain carried a hazard ratio of 3.21 (95% CI 2.16-4.78) for mortality, independent of RV dysfunction, troponin, and thrombolysis (PMID: 36350468).

Say Out Loud: "Category C is where the magic happens and where we earn our keep. These patients look stable but can decompensate rapidly. They need ICU-level monitoring, serial biomarkers, and a clear escalation plan."

Framework:

Audience Poll: Which severity category do you most frequently encounter in your practice?

• A) Low risk — most of my PEs go home
• B) Intermediate-low — admitted but straightforward
• C) Intermediate-high — the ones that keep me up at night
• D) Massive/arrest — the ones that define a career

Section 3: Biomarker Utility and Right Ventricular Assessment

Duration: 12 min | Content Tier: Nuance

%%FIG2%% Nuance: Biomarkers and imaging are not merely diagnostic — they are prognostic tools that drive therapeutic decisions. The key biomarkers in PE risk stratification are troponin (myocardial injury), NT-proBNP/BNP (ventricular strain), and lactate (tissue hypoperfusion). Understanding their temporal profiles and combined prognostic value is essential for accurate risk stratification.

Troponin — The Myocardial Injury Signal

Cardiac troponin elevation in PE reflects RV microinfarction from acute pressure overload. The mechanism is RV wall stress from sudden pulmonary hypertension, leading to supply-demand mismatch in the RV myocardium. Elevated troponin in the setting of acute PE identifies patients at higher risk of adverse outcomes, including death, hemodynamic collapse, and need for escalation.

Teaching Point: The PEITHO-2 study (Mavromanoli et al., 2023) provided landmark data on RV function recovery in intermediate-risk PE. In patients with documented RV dysfunction at baseline (84% of the cohort), echocardiographic parameters normalized within 6 days in approximately 65-75% of patients switched early to direct oral anticoagulants. However, nearly one in four patients continued to have evidence of RV dysfunction at 6 months (PMID: 36539534).

NT-proBNP — The Ventricular Strain Marker

NT-proBNP reflects RV pressure overload and volume distension. In the PEITHO-2 cohort, median NT-proBNP decreased from 1,448 pg/mL at baseline to 256.5 pg/mL on day 6 and 127 pg/mL at day 180. This dramatic drop in the first week provides a useful metric for monitoring treatment response.

Decision Point: The combination of both elevated troponin AND elevated NT-proBNP identifies the intermediate-high risk group (Category C) who warrant ICU-level monitoring and consideration of advanced therapies. Chen et al. demonstrated that cardiac troponin T and NT-proBNP easily distinguished low-risk from submassive PE (AUC 0.84 and 0.88, respectively) and from massive PE (AUC 0.89 for both markers). Importantly, in patients with RV dysfunction, the predicted short-term mortality by PESI or BOVA scores was lower than observed mortality by a two-fold magnitude — suggesting these composite scores may underestimate risk in the presence of RV strain (PMID: 31375993).

Lactate — The Tissue Perfusion Alarm

Lactate elevation in PE reflects inadequate cardiac output and tissue hypoperfusion. An initial lactate >2 mmol/L should prompt consideration of higher-risk classification. Serial lactate trending upward despite initial treatment is an ominous sign demanding immediate reassessment.

Echocardiographic Assessment of RV Function

MUST ACT: The bedside echocardiogram is the single most important diagnostic and prognostic tool in acute PE after CTPA. RV dysfunction on echo independently predicts adverse outcomes and is superior to composite scoring systems for risk stratification in the PERT setting (Chen et al., PMID: 31375993).

Key echocardiographic findings in significant PE:

• RV dilation: RV/LV ratio >1.0 in the apical 4-chamber view
• RV free wall hypokinesis: with apical sparing (McConnell's sign)
• Septal flattening or bowing: D-shaped LV in short-axis
• Tricuspid regurgitation: with elevated RVSP
• TAPSE <16 mm: reduced tricuspid annular plane systolic excursion
• IVC dilation: with reduced respiratory variation

Nuance: Gao et al. developed a predictive nomogram combining NT-proBNP, cardiac troponin I, and CT ventricular diameter ratios that achieved excellent discrimination for RV dysfunction (AUC 0.881 in the training dataset). This tool highlights the power of combining biomarkers with imaging parameters for risk prediction (PMID: 33509132).

Audience Poll: Do you routinely use NT-proBNP in PE risk assessment?

• A) Yes, on every PE patient
• B) Only when I'm on the fence about severity
• C) Rarely — I rely on echo and clinical assessment
• D) I didn't realize it was useful in PE

Section 4: Initial Management — Anticoagulation Selection

Duration: 10 min | Content Tier: Teaching Point

%%FIG3%% Teaching Point: The initial anticoagulation decision in acute PE depends on the patient's risk category, renal function, body weight, bleeding risk, and potential need for escalation to advanced therapies. The 2021 CHEST Guideline update (Stevens et al.) generated 29 guidance statements covering antithrombotic management of VTE from initial management through secondary prevention (PMID: 34352278).

Direct Oral Anticoagulants — The New Standard

MUST ACT: For the majority of PE patients (Categories A and B), DOACs are now the preferred initial anticoagulation strategy. Both apixaban and rivarelbaan can be started without a heparin lead-in (the "single-drug approach"), simplifying initial management and enabling earlier discharge.

• Apixaban: 10 mg BID for 7 days, then 5 mg BID
• Rivaroxaban: 15 mg BID for 21 days, then 20 mg daily
• Advantages: predictable pharmacokinetics, no monitoring required, lower bleeding risk than warfarin, outpatient-friendly
• Contraindications: severe renal impairment (CrCl <15-25 mL/min depending on agent), active major bleeding, pregnancy, antiphospholipid syndrome

Unfractionated Heparin vs. LMWH

Decision Point: For Category C and D patients who may require escalation to thrombolysis or interventional procedures, the anticoagulant choice matters strategically:

Unfractionated Heparin (UFH):

• Short half-life (~90 min) — can be stopped and reversed quickly
• Titratable to aPTT targets
• Preferred when thrombolysis, embolectomy, or catheter-directed therapy is being considered
• Preferred in severe renal failure and extreme obesity
• Disadvantages: requires continuous IV infusion, monitoring, HIT risk

Low Molecular Weight Heparin (LMWH):

• More predictable pharmacokinetics than UFH
• Weight-based dosing without routine monitoring
• Lower HIT risk than UFH
• Preferred for initial treatment when advanced interventions are unlikely
• Disadvantages: renal clearance, difficult to reverse fully, less titratable

Nuance: The choice between UFH and LMWH often comes down to a practical question: "Is this patient likely to need a procedure in the next 24-48 hours?" If yes, use UFH. If no, LMWH or a DOAC is preferred.

The HIT Challenge

Case Integration: Consider a 62-year-old man presenting with massive PE and a documented history of heparin-induced thrombocytopenia. Neither UFH nor LMWH can be used. Options include:

• Argatroban: direct thrombin inhibitor, hepatically metabolized, titratable, can be used with thrombolysis
• Bivalirudin: direct thrombin inhibitor, shorter half-life, predominantly enzymatic clearance
• Fondaparinux: factor Xa inhibitor, minimal cross-reactivity with HIT antibodies, but not reversible and renally cleared

Say Out Loud: "For most PE patients, start a DOAC. For the sick ones where you might need to escalate, start heparin. For the rare HIT patient, know your alternatives cold — argatroban in the ICU, fondaparinux on the floor."

Audience Poll: What is your preferred initial anticoagulation for intermediate-high risk PE?

• A) UFH drip — I want the option to escalate
• B) LMWH — reliable and effective
• C) DOAC — simpler, and I can always switch if needed
• D) It depends entirely on the clinical scenario

Section 5: Advanced Interventions — Thrombolysis and Catheter-Directed Therapies

Duration: 15 min | Content Tier: MUST ACT

%%FIG4%% MUST ACT: For patients with massive PE (Category D) or cardiac arrest from PE (Category E), reperfusion therapy is potentially life-saving. The choice between systemic thrombolysis, catheter-directed therapy (CDT), and surgical embolectomy depends on institutional resources, patient characteristics, and clinical urgency.

Systemic Thrombolysis

Systemic thrombolysis remains the most accessible reperfusion therapy and the treatment of choice for massive PE when immediate intervention is needed. Alteplase (tPA) is the most commonly used agent:

• Standard dose: Alteplase 100 mg IV over 2 hours
• Accelerated regimen: Alteplase 0.6 mg/kg (max 50 mg) IV over 15 minutes — preferred in peri-arrest
• Half-dose regimen: Alteplase 50 mg IV over 2 hours — emerging evidence for reduced bleeding with preserved efficacy

Teaching Point: The IPER Registry data (Zuin et al., 2023) provided important insights into PE outcomes based on clinical presentation at admission. In 1,365 hemodynamically stable patients, symptom phenotype at admission independently predicted 30-day mortality. Chest pain carried an HR of 3.21 and recent-onset dyspnea an HR of 2.12 for mortality — independent of RV dysfunction, troponin, and thrombolysis administration. This suggests that clinical presentation may provide additional prognostic information beyond traditional risk stratification variables (PMID: 36350468).

Nuance: The question of systemic thrombolysis in intermediate-high risk PE (Category C) remains the most contentious issue in PE management. The landmark PEITHO trial showed that tenecteplase reduced hemodynamic decompensation in intermediate-risk PE but increased major bleeding (including intracranial hemorrhage). Current guidelines recommend reserving systemic thrombolysis for Category C patients who show signs of clinical deterioration — hemodynamic instability, worsening RV function, rising lactate, or declining clinical status despite anticoagulation.

Catheter-Directed Therapies

Teaching Point: Catheter-based interventions have emerged as a middle ground between anticoagulation alone and systemic thrombolysis. The 2024 international guideline review by Zuin et al. noted that catheter-based interventions for PE have been "blessed" by multiple major societies, though the evidence base remains limited compared to systemic therapies (PMID: 39384264).

Types of catheter-directed therapies:

1. Catheter-directed thrombolysis (CDT): Low-dose tPA delivered directly into the pulmonary arteries via catheter. Typical dose: 1 mg/hr per catheter for 12-24 hours (total 12-24 mg bilateral). The ULTIMA, SEATTLE II, and OPTALYSE PE trials demonstrated significant RV recovery with lower systemic bleeding than full-dose systemic thrombolysis.

1. Ultrasound-assisted catheter-directed thrombolysis (USAT): The EKOS system combines low-dose CDT with high-frequency, low-power ultrasound to enhance thrombolytic penetration. Whether the ultrasound component adds clinical benefit beyond the low-dose lytic delivery remains debated.

1. Aspiration thrombectomy: Large-bore catheters (FlowTriever, Indigo) that mechanically extract thrombus without thrombolytics. Advantages include applicability in patients with thrombolytic contraindications. The FLARE trial demonstrated significant RV/LV ratio reduction with FlowTriever.

1. Rheolytic thrombectomy: AngioVac and similar devices for surgical-grade thrombus extraction with extracorporeal bypass.

Decision Point: When to choose which modality:

Surgical Embolectomy

Reserved for massive PE when thrombolysis has failed or is contraindicated AND catheter-based therapies are unavailable or have failed. Requires cardiopulmonary bypass. Mortality has decreased significantly at experienced centers but remains substantial (15-30%).

Audience Poll: Do you have experience with catheter-directed therapies for PE?

• A) Yes, my institution has an active CDT program
• B) We have the capability but rarely use it
• C) No, we rely on systemic thrombolysis
• D) No, we transfer patients who need advanced interventions

Section 6: The Pulmonary Embolism Response Team (PERT)

Duration: 10 min | Content Tier: Teaching Point

%%FIG5%% Teaching Point: The Pulmonary Embolism Response Team (PERT) is a multidisciplinary rapid-response model designed to optimize PE management, particularly for intermediate-high risk and massive PE cases. Modeled after STEMI activation systems, PERT brings together emergency medicine, critical care, interventional radiology/cardiology, hematology, cardiac surgery, and pharmacy to provide rapid, coordinated decision-making.

Why PERT Exists

The rationale for PERT stems from several clinical realities:

1. Treatment decisions are complex: The choice between anticoagulation alone, systemic thrombolysis, CDT, aspiration thrombectomy, and surgical embolectomy requires expertise that no single clinician possesses
2. Time pressure is real: Massive PE patients can decompensate within minutes
3. Individual physician bias: Without a team approach, treatment selection may be driven by which specialist is consulted first (the "hammer looking for a nail" problem)
4. Data collection: PERT registries provide invaluable outcomes data for quality improvement

PERT Activation Criteria

MUST ACT: Consider PERT activation for:

• Any massive PE (Category D or E)
• Intermediate-high risk PE (Category C) with clinical concern for deterioration
• PE in pregnancy
• PE with absolute or relative contraindications to standard therapy
• PE with concurrent conditions requiring multidisciplinary input (e.g., active malignancy, recent surgery, intracranial pathology)

Chen et al. demonstrated that RV dysfunction alone, assessed by imaging, was superior and sufficient for risk stratification by a PERT — more complicated risk stratification tools using multiple clinical variables may actually underestimate short-term mortality in these patients (PMID: 31375993).

Nuance: Not every institution has a formal PERT. If your institution lacks one, the principles still apply: when managing a complex PE, involve multiple specialists early, make decisions collaboratively, and document the rationale.

Say Out Loud: "For any PE that makes me nervous — I activate the team. I want the interventionalist, the intensivist, and the hematologist all looking at this with me before I commit to a treatment pathway."

Audience Poll: Does your institution have a PERT?

• A) Yes, and it's well-established and regularly activated
• B) Yes, but it's inconsistently used
• C) No, but we have informal multidisciplinary consultation
• D) No, and PE management is largely managed by individual physicians

Section 7: Fluid Management in Acute PE — A Nuanced Approach

Duration: 8 min | Content Tier: Nuance

Nuance: The traditional teaching of aggressive volume resuscitation in PE-related shock is being challenged by emerging evidence. The physiology of RV failure in PE is fundamentally different from hypovolemic or distributive shock, and the volume management strategy must reflect this.

The RV Dilemma

In acute PE, the RV faces sudden pressure overload from pulmonary vascular obstruction. The RV dilates acutely, which shifts the interventricular septum leftward, impairing LV filling (ventricular interdependence). Excessive volume loading can worsen RV dilation, exacerbate septal shift, and further reduce cardiac output — a vicious cycle.

Decision Point: Ferrari et al. conducted a randomized trial comparing diuretics versus volume expansion in 60 patients with intermediate-high risk PE. While troponin kinetics and echocardiographic RV parameters did not differ between groups, BNP normalization was achieved significantly faster in the diuretic group (56 vs 108 hours, p=0.05), with a shorter time to 50% decrease from peak (36 vs 54 hours, p=0.003). A single dose of furosemide 40 mg was well-tolerated and associated with no serious adverse events (PMID: 35381867).

Teaching Point: This does not mean we should routinely give diuretics in acute PE. Rather, it challenges the reflexive administration of large-volume crystalloid. The evidence supports a conservative, goal-directed approach:

• Small fluid challenges (250 mL) with reassessment
• Avoid large-volume resuscitation (>30 mL/kg) unless clear evidence of hypovolemia
• Monitor IVC size and collapsibility
• If RV is dilated and failing, volume may do more harm than good
• Vasopressors (norepinephrine first-line) may be needed to maintain coronary perfusion pressure to the failing RV

Emerging Adjunctive Therapies

Nuance: Nurkaev and Soldatov published a randomized study of inhaled nitric oxide (iNO) in 65 patients with moderate-low risk PE. The experimental group receiving iNO with standard anticoagulant therapy showed significantly greater decreases in systolic pulmonary artery pressure (sPAP) and right heart sizes by day 10, along with improvements in respiratory rate, heart rate, dyspnea scores, arterial oxygen partial pressure, and NT-proBNP compared to controls. While preliminary, this suggests that targeted pulmonary vasodilation may have a role in PE management (PMID: 41859793).

In contrast, Andersen et al. found that a single oral dose of sildenafil 50 mg did not improve cardiac index in acute intermediate-high risk PE but did lower systemic blood pressure significantly (mean arterial pressure decreased by 19 mmHg, p<0.001). This argues against oral pulmonary vasodilators in acute PE, where systemic hypotension is the primary concern (PMID: 33639897).

Section 8: Extended Management — Anticoagulation Duration and CTEPH Surveillance

Duration: 10 min | Content Tier: Nuance

%%FIG6%% Nuance: The acute management of PE is only the beginning. Long-term anticoagulation decisions and surveillance for chronic complications — particularly CTEPH — are equally critical for patient outcomes.

Duration of Anticoagulation

The CHEST 2021 guidelines provide the framework for anticoagulation duration decisions (PMID: 34352278):

Provoked PE (strong transient risk factor):

• Surgery, trauma, immobilization >3 days, hospitalization
• 3 months of anticoagulation, then stop
• Low recurrence risk (~3% per year after stopping)

Provoked PE (minor transient risk factor):

• Estrogen therapy, pregnancy, minor surgery, air travel >8 hours
• 3 months minimum; consider extension based on individual risk
• Intermediate recurrence risk

Unprovoked PE:

• No identifiable provoking factor
• Minimum 3 months, then reassess for extended therapy
• High recurrence risk (~10% in year 1, ~5% per year thereafter)
• Most guidelines recommend extended anticoagulation unless bleeding risk is high

Cancer-associated PE:

• Extended anticoagulation for the duration of active cancer
• DOACs (edoxaban, rivaroxaban) are now preferred over LMWH in most cancer-associated VTE, except in GI/GU malignancies where bleeding risk is higher

Teaching Point: After a decision to continue anticoagulation beyond 3 months, the dose can be reduced for secondary prevention:

• Apixaban: 2.5 mg BID (AMPLIFY-EXT trial)
• Rivaroxaban: 10 mg daily (EINSTEIN-CHOICE trial)
• These reduced doses maintain >80% risk reduction for recurrence with minimal excess bleeding

CTEPH — The Silent Complication

MUST ACT: Chronic thromboembolic pulmonary hypertension develops in approximately 3% of patients after acute PE and is one of the few curable forms of pulmonary hypertension. Missing the diagnosis condemns patients to progressive right heart failure (Yang et al., PMID: 36990148).

Teaching Point: Yang et al. published a comprehensive review of CTEPH evaluation and management in Chest (2023). Key points:

• CTEPH may present without a history of prior VTE, contributing to underrecognition
• V/Q scintigraphy is the best screening test (sensitivity >96% for CTEPH)
• CT imaging and advanced techniques play an expanding role in detection
• Pulmonary thromboendarterectomy (PTE) is potentially curative, with mortality ~2% at expert centers
• More than one-third of patients may be considered inoperable but now have effective alternatives: pharmacotherapy (riociguat) and balloon pulmonary angioplasty (BPA)

Decision Point: Who should be screened for CTEPH?

• All PE patients with persistent dyspnea or functional limitation at 3-6 months post-PE
• Patients with known risk factors: large clot burden at diagnosis, previous VTE, elevated sPAP at diagnosis, young age, idiopathic PE
• The PEITHO-2 data showed that nearly 25% of intermediate-risk PE patients had persistent RV dysfunction at 6 months — these patients warrant CTEPH screening (PMID: 36539534)

Johnson et al. reviewed the contemporary landscape of pulmonary hypertension, emphasizing that advances in CTEPH management have expanded the therapeutic armamentarium significantly. PTE surgery can now address more distal disease, and BPA provides an interventional option for surgically inaccessible lesions (PMID: 37450768).

Audience Poll: How do you monitor your patients post-PE?

• A) Follow-up echo and clinical assessment at 3-6 months
• B) Follow-up clinic visit only — echo if symptomatic
• C) D-dimer at 1 month to guide anticoagulation duration
• D) No structured follow-up — they return to their PCP

Clinical Cases

Case 1: The Intermediate-High Risk Dilemma

Presentation: A 65-year-old woman with a history of hypertension and obesity presents with acute-onset dyspnea over 2 hours and pleuritic chest pain. She was recently discharged after knee replacement surgery 10 days ago. Vitals: HR 115, BP 105/65, SpO2 91% on room air, RR 28. She appears anxious and diaphoretic.

Workup:

• CTPA: bilateral segmental and subsegmental PE with saddle component
• Troponin I: 0.45 ng/mL (elevated)
• NT-proBNP: 2,800 pg/mL (markedly elevated)
• Lactate: 2.8 mmol/L
• Bedside echo: RV/LV ratio 1.3, RV free wall hypokinesis with apical sparing (McConnell's sign), TAPSE 12 mm, moderate TR, estimated RVSP 55 mmHg

Audience Poll: How would you classify this patient?

• A) Category B — Intermediate-low risk
• B) Category C — Intermediate-high risk
• C) Category D — Massive PE
• D) I'm not sure

Teaching Point: This is a Category C (intermediate-high risk) PE. She is hemodynamically stable (SBP >90) but has significant RV dysfunction on echo AND elevated biomarkers. She has multiple ominous features: RV/LV ratio >1.0, McConnell's sign, very low TAPSE, and elevated lactate.

Management: UFH drip initiated (anticipating possible need for escalation). Admitted to ICU. PERT activation considered. Serial troponin and lactate monitoring every 6 hours. Clear escalation pathway: if SBP drops below 90 for >15 minutes or lactate continues to rise, proceed to CDT or systemic thrombolysis.

Outcome: Over 12 hours, troponin trended downward, lactate normalized, and hemodynamics remained stable. She was transitioned to apixaban at 48 hours and discharged on day 5. At 3-month follow-up, echo showed improved RV function with RV/LV ratio 0.9 and TAPSE 19 mm. Extended anticoagulation recommended given provoked PE with persistent risk factors.

Key Teaching Point: This case illustrates the Category C management algorithm — admit to ICU, start UFH, monitor closely, have an escalation plan, and transition to DOAC when stable. Not every intermediate-high risk PE needs thrombolysis, but every one needs to be watched (PMID: 36539534).

Case 2: Massive PE and the Thrombolysis Decision

Presentation: A 58-year-old man collapses at home. EMS finds him obtunded with HR 130, BP 65/40, SpO2 78%. Paramedics intubate in the field. In the ED, he remains profoundly hypotensive despite 2L crystalloid and norepinephrine at 20 mcg/min.

Workup:

• Bedside echo: massively dilated RV with no visible RV contraction, bowed septum, "D-sign" in short axis, large thrombus visible in the right atrium
• CTPA (if obtainable): saddle PE with bilateral main pulmonary artery occlusion
• Lactate: 9.4 mmol/L

MUST ACT: This is Category D massive PE — he needs immediate reperfusion therapy.

Decision Point: Systemic thrombolysis vs. catheter-directed therapy vs. surgical embolectomy?

• Given his hemodynamic instability and need for immediate reperfusion, systemic thrombolysis is the fastest option
• Catheter-directed therapy requires mobilizing the interventional team — time is critical
• Surgical embolectomy requires bypass — likely too slow unless already in the OR

Management: Alteplase 100 mg IV over 2 hours administered. UFH drip continued simultaneously (debated but supported by most protocols). Within 90 minutes: SBP rises to 85, then 95 by end of infusion. Lactate begins to trend downward. Repeat echo at 6 hours shows improved RV function.

Outcome: Hemodynamics stabilize over 24 hours. Norepinephrine weaned off by 36 hours. Transitioned to LMWH bridged to warfarin (pre-existing renal impairment limiting DOAC use). IVC filter placed given recent fall with head contusion (relative contraindication to anticoagulation initially). Extensive hypercoagulability workup initiated.

Key Teaching Point: In massive PE with hemodynamic collapse, systemic thrombolysis is the fastest and most widely available reperfusion strategy. Time to treatment is the critical determinant of outcome.

Case 3: Cancer-Associated PE and the DOAC Debate

Presentation: A 72-year-old woman undergoing chemotherapy for stage IIIB non-small cell lung cancer presents with progressive dyspnea over 3 days. CTPA shows bilateral lower lobe segmental PE. Echo shows mild RV dilation with preserved function. Troponin is mildly elevated. NT-proBNP is 650 pg/mL.

Nuance: Cancer-associated VTE presents unique management challenges. The traditional approach was LMWH monotherapy (based on the CLOT trial), but recent trials (Hokusai VTE-Cancer, SELECT-D) have shown DOACs are non-inferior with improved patient convenience.

Decision Point: DOAC vs. LMWH for cancer-associated PE?

• DOACs (edoxaban, rivaroxaban) are now preferred for most cancer-associated VTE
• Exception: GI and GU cancers have higher GI bleeding rates on DOACs — LMWH may be preferred
• Consider drug interactions with chemotherapy regimens
• Patient preference matters — many patients strongly prefer oral over daily injections

Management: She has lung cancer (not GI/GU), so a DOAC is appropriate. Started on rivaroxaban 15 mg BID for 21 days, then 20 mg daily. Anticoagulation planned for the duration of active cancer treatment and reassessed periodically.

Key Teaching Point: Cancer-associated PE requires extended anticoagulation. DOACs have largely replaced LMWH as the preferred option, except in GI/GU cancers or when drug interactions are prohibitive (PMID: 34352278).

Case 4: PE in Pregnancy — Every Decision is Two Patients

Presentation: A 32-year-old woman at 28 weeks gestation presents with sudden-onset pleuritic chest pain and dyspnea. D-dimer is expectedly elevated in pregnancy (non-diagnostic). CTPA shows right lower lobe segmental PE. Echo shows mild RV dilation. She is hemodynamically stable.

Decision Point: Anticoagulation in pregnancy requires careful consideration:

• DOACs are contraindicated in pregnancy (cross the placenta)
• Warfarin is teratogenic and crosses the placenta
• LMWH is the standard of care — does not cross the placenta
• UFH is an alternative but less convenient

Management: Started on enoxaparin 1 mg/kg BID with anti-Xa monitoring. Plan for delivery:

• Switch to UFH at 36 weeks for easier peripartum management
• Hold anticoagulation for delivery, restart 6-12 hours post-delivery
• Continue anticoagulation for minimum 6 weeks postpartum (total minimum 3 months)
• If breastfeeding: LMWH, warfarin, or apixaban/rivaroxaban are compatible

Key Teaching Point: Pregnancy-associated PE requires LMWH, careful peripartum planning, and extended postpartum anticoagulation. A multidisciplinary approach (hematology, obstetrics, critical care) is essential.

Case 5: CTEPH — The Late Complication

Presentation: A 55-year-old man presents to clinic 8 months after an unprovoked PE with persistent exertional dyspnea (NYHA Class II-III) despite 6 months of anticoagulation. His echo shows elevated RVSP (55 mmHg) and mild RV dilation. He was told his PE had "resolved."

Teaching Point: This presentation should raise immediate concern for CTEPH. The estimated incidence of CTEPH after acute PE is approximately 3%, but this is likely an underestimate due to underscreening (PMID: 36990148).

Workup:

• V/Q scan: multiple mismatched perfusion defects — highly suspicious for CTEPH
• Right heart catheterization: mean PAP 38 mmHg, PVR 6.2 Wood units, PAWP 12 mmHg — confirms precapillary PH
• Pulmonary angiography: organized thrombus in right main PA and left lower lobe segmental arteries

Management: Referred to a CTEPH center. Deemed operable by the multidisciplinary team. Underwent pulmonary thromboendarterectomy with excellent result — mean PAP decreased to 22 mmHg postoperatively. At 6 months post-PTE: asymptomatic, NYHA Class I, normalized RV function.

Key Teaching Point: CTEPH is treatable and potentially curable with PTE surgery. The key is early screening of PE patients with persistent symptoms. V/Q scan is the screening test of choice. Every PE patient should have structured follow-up at 3-6 months to assess for persistent symptoms and echocardiographic abnormalities (PMID: 36990148, PMID: 37450768).

Tonight on Shift

When you walk into the department tonight, remember these eight things:

1. Apply the severity classification immediately — Every PE gets categorized: Low (A), Intermediate-Low (B), Intermediate-High (C), Massive (D), or Arrest (E). The category determines everything.

1. Biomarkers are your risk stratification partners — Troponin AND NT-proBNP together identify the intermediate-high risk group. Both elevated = Category C. Monitor serially.

1. Echo the right ventricle — RV/LV ratio >1.0, McConnell's sign, TAPSE <16 mm, septal bowing. RV dysfunction independently predicts mortality and trumps composite scoring systems.

1. DOACs are first-line for most PE — Apixaban or rivaroxaban, single-drug approach, no heparin lead-in needed. Reserve UFH for patients who might need escalation to thrombolysis or CDT.

1. Category C is your danger zone — These patients look stable but can crash. ICU admission, UFH, serial biomarkers, and a clear escalation pathway. Have the conversation with your interventionalist early.

1. Systemic thrombolysis saves lives in massive PE — Don't hesitate when the patient is in Category D. Alteplase 100 mg over 2 hours, or accelerated 0.6 mg/kg over 15 minutes in peri-arrest. Time is clot.

1. Activate the team for complex cases — PERT or informal multidisciplinary consultation. No single physician can optimally manage a complex PE case alone.

1. Follow up for CTEPH — Screen all PE patients with persistent symptoms at 3-6 months. V/Q scan is the screening test. CTEPH is curable with surgery at expert centers.

References

1. Zuin M, Bikdeli B, Ballard-Hernandez J, et al. International Clinical Practice Guideline Recommendations for Acute Pulmonary Embolism: Harmony, Dissonance, and Silence. J Am Coll Cardiol. 2024;84(16):1554-1570. PMID: 39384264.
2. Lutsey PL, Zakai NA. Epidemiology and prevention of venous thromboembolism. Nat Rev Cardiol. 2023;20(4):248-262. PMID: 36258120.
3. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020;41(4):543-603. PMID: 31504429.
4. Stevens SM, Woller SC, Kreuziger LB, et al. Antithrombotic Therapy for VTE Disease: Second Update of the CHEST Guideline and Expert Panel Report. Chest. 2021;160(6):e545-e608. PMID: 34352278.
5. Mavromanoli AC, Barco S, Ageno W, et al. Recovery of right ventricular function after intermediate-risk pulmonary embolism: results from PEITHO-2. Clin Res Cardiol. 2023;112(10):1407-1419. PMID: 36539534.
6. Zuin M, Bilato C, Bongarzoni A, et al. Impact of clinical profile at admission on outcomes in acute PE: data from the IPER Registry. J Thromb Thrombolysis. 2023;55(1):89-97. PMID: 36350468.
7. Chen YL, Wright C, Pietropaoli AP, et al. Right ventricular dysfunction is superior and sufficient for risk stratification by a PERT. J Thromb Thrombolysis. 2020;49(1):121-128. PMID: 31375993.
8. Gao Y, Chen L, Jia D. A predictive tool for RV dysfunction in non-high-risk patients with acute PE. BMC Pulm Med. 2021;21(1):28. PMID: 33509132.
9. Ferrari E, Sartre B, Labbaoui M, et al. Diuretics Versus Volume Expansion in Acute Intermediate High-Risk PE. Lung. 2022;200(2):235-243. PMID: 35381867.
10. Andersen A, Waziri F, Schultz JG, et al. Sildenafil in acute intermediate-high risk PE: a randomized explorative trial. BMC Pulm Med. 2021;21(1):57. PMID: 33639897.
11. Nurkaev IR, Soldatov DG. Treatment with inhaled nitric oxide in patients with pulmonary embolism. Ter Arkh. 2026;98(3):247-253. PMID: 41859793.
12. Yang J, Madani MM, Mahmud E, et al. Evaluation and Management of Chronic Thromboembolic Pulmonary Hypertension. Chest. 2023;164(2):513-527. PMID: 36990148.
13. Johnson S, Sommer N, Cox-Flaherty K, et al. Pulmonary Hypertension: A Contemporary Review. Am J Respir Crit Care Med. 2023;208(5):527-548. PMID: 37450768.
14. Khandait H, Harkut P, Khandait V, et al. Acute pulmonary embolism: Diagnosis and management. Indian Heart J. 2023;75(3):175-183. PMID: 37207830.
15. Machanahalli Balakrishna A, Reddi V, Belford PM, et al. Intermediate-Risk Pulmonary Embolism: A Review of Contemporary Diagnosis, Risk Stratification and Management. Medicina. 2022;58(9):1186. PMID: 36143863.
16. Duffett L, Castellucci LA, Forgie MA. Pulmonary embolism: update on management and controversies. BMJ. 2020;370:m2177. PMID: 32759284.
17. Trott T, Bowman J. Diagnosis and Management of Pulmonary Embolism. Emerg Med Clin North Am. 2022;40(3):507-533. PMID: 35953217.

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