An observational study in Pulmonary Embolism, Venous Thromboembolism and Acute Pulmonary Embolism, sponsored by Marmara University Pendik Training and Research Hospital. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-04.
Sponsored by Marmara University Pendik Training and Research Hospital · Observational
Background: The 2026 American Heart Association/American College of Cardiology (AHA/ACC) Pulmonary Embolism Guideline (Creager et al., Circulation 2026) introduced a novel five-category (A-E) clinical classification system with subcategories and an R modifier, replacing prior risk stratification frameworks. Prospective validation of this classification system using composite clinical outcomes is lacking. Objective: To evaluate the prognostic value of the 2026 AHA/ACC clinical categorization (Categories A-E plus R modifier) for predicting 30-day Major Adverse Pulmonary Embolism Events (MAPEE) in emergency department (ED) patients with acute pulmonary embolism (PE). Methods: Prospective observational cohort study conducted at Marmara University Faculty of Medicine Emergency Department, enrolling 600 consecutive adult patients with confirmed acute PE by computed tomography (CT) pulmonary angiography between April 2026 and January 2027. Primary outcome: MAPEE composite (all-cause mortality OR hemodynamic deterioration OR treatment escalation OR cardiopulmonary resuscitation) within 30 days. Secondary outcomes include area under the receiver operating characteristic curve (AUC) comparison with the European Society of Cardiology (ESC) 2019 risk stratification (exploratory), negative predictive value (NPV) of low-risk categories (A+B) for safe discharge, MAPEE trend across C1/C2/C3, and R modifier odds ratio. Statistical analysis: Jamovi v2.x. Reporting follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) 2007 checklist.
STUDY DESIGN: Single-center prospective observational cohort. No intervention applied. Patients managed per standard of care. SETTING: Marmara University Pendik Training and Research Hospital Emergency Department, Istanbul, Turkey. Annual ED census approximately 200,000 visits. STUDY POPULATION: Adult patients (18 years or older) presenting to the ED with confirmed acute PE on computed tomography (CT) pulmonary angiography, enrolled consecutively from April 2026 to January 2027 (anticipated enrollment period 10 months). EXPOSURE: 2026 AHA/ACC PE clinical category assigned independently by two trained emergency physicians at presentation. Categories: A (subclinical/incidental), B (symptomatic, low severity; Pulmonary Embolism Severity Index (PESI) I-II / simplified PESI (sPESI)=0), C1/C2/C3 (elevated severity; stratified by right ventricular (RV) dysfunction and cardiac biomarkers), D1/D2 (incipient cardiopulmonary failure), E1/E2 (established cardiopulmonary failure). R modifier applied when hypoxemia/tachypnea/escalating oxygen requirement present without meeting higher category criteria. PRIMARY OUTCOME - MAPEE (Major Adverse Pulmonary Embolism Event): composite endpoint defined as occurrence of any of the following within 30 days: (1) All-cause mortality, (2) Hemodynamic deterioration (systolic blood pressure (SBP) less than 90 mmHg for at least 15 minutes or vasopressor requirement), (3) Treatment escalation (systemic thrombolysis, catheter-directed therapy, surgical embolectomy, or extracorporeal membrane oxygenation (ECMO)), (4) Cardiopulmonary resuscitation. Expected event rate: 12% (n approximately 59 events out of 492 analyzable patients after 18% attrition from 600 gross enrollment). SAMPLE SIZE RATIONALE: Based on the Hanley-McNeil variance formula (Hanley and McNeil, Radiology 1982;143:29-36). H0: AUC=0.65 (minimum clinically meaningful discrimination); H1: AUC=0.80 (supported by published composite-outcome AUC values for comparable systems: PESI 0.84, Bova score 0.82, Hestia criteria SROC 0.81); two-sided alpha=0.05. At the planned n_gross=600 enrollment (n_net=492 analyzable, 59 expected events, 433 non-events), the design provides approximately 97.6% power for H1=0.80 using the standard single-proportion Hanley-McNeil test (a conservative pooled-variance sensitivity approach yields approximately 79.2%; the sample size is considered adequate under either method). Minimum detectable AUC at 80% power is approximately 0.761. Events per variable (EPV) = 59/5 = 11.8, supporting multivariable models with up to 5 predictor variables (EPV of at least 10 recommended per Peduzzi et al. 1996). DeLong AUC comparison (AHA/ACC 2026 vs ESC 2019, secondary outcome S1) will require substantially larger samples for adequate power given the two correlated ROC curves; this comparison is designated exploratory/hypothesis-generating and will not be used for confirmatory inference. STROBE COMPLIANCE: This study follows the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) 2007 checklist for reporting of observational studies.
832 studies on the registry are indexed under Pulmonary Embolism; 171 are open to participants now.
This study's planned enrollment of 600 is above the median of 361 across 366 observational studies indexed under Pulmonary Embolism.
Browse Pulmonary Embolism studies →Marmara University Pendik Training and Research Hospital is the lead sponsor of 34 studies on the registry; 15 are open to participants now.
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Adult patients (>=18 years) presenting to Marmara University Pendik Training and Research Hospital Emergency Department with confirmed acute pulmonary embolism on CTPA between April 2026 and January 2027.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
All consecutive adult patients presenting to the emergency department with confirmed acute pulmonary embolism, assigned to 2026 AHA/ACC clinical categories (A-E) plus right ventricular strain (R) modifier at presentation. No study intervention is assigned; all patients are treated per standard of care per treating clinician judgment.
Other: 2026 AHA/ACC Clinical Risk Categorization
Not a therapeutic intervention. Refers to the 2026 AHA/ACC clinical categorization framework (Categories A-E plus R modifier for right ventricular strain) applied at presentation to prognostically classify patients with confirmed acute pulmonary embolism. All patients are managed per standard institutional practice; no protocol-driven treatment or diagnostic assignment is made based on this categorization.
Major Adverse Pulmonary Embolism Event (MAPEE) - 30-day composite
Composite of: (1) all-cause mortality, OR (2) hemodynamic deterioration (SBP \<90 mmHg for \>=15 minutes or vasopressor requirement), OR (3) treatment escalation (systemic thrombolysis, catheter-directed therapy, surgical embolectomy, or ECMO), OR (4) cardiopulmonary resuscitation - within 30 days of ED presentation.
Time frame: 30 days
S1: AHA/ACC vs ESC 2019 ROC-AUC comparison (exploratory)
Comparison of ROC-AUC: 2026 AHA/ACC A-E system vs ESC 2019 risk stratification for MAPEE prediction (DeLong test - EXPLORATORY/hypothesis-generating; n=600 enrollment marginally below the 621 required for 80% power at H1=0.80; no superiority claim will be made).
Time frame: 30 days
S2: NPV of AHA/ACC Category A+B for MAPEE
Negative Predictive Value (NPV) of AHA/ACC Category A+B for MAPEE, evaluating potential for safe emergency department discharge without hospital admission.
Time frame: 30 days
S3: MAPEE trend across AHA/ACC subcategories C1, C2, C3
Linear MAPEE event rate trend across AHA/ACC subcategories C1, C2, and C3, assessed via Cochran-Armitage trend test.
Time frame: 30 days
S4: Odds ratio for MAPEE by R modifier status
Odds ratio (OR) and likelihood ratio (LR+/LR-) for MAPEE in patients with vs without the R modifier (right ventricular strain) at presentation.
Time frame: 30 days
S5: Intensive care unit (ICU) admission rate by AHA/ACC category
ICU admission rate within 30 days of ED presentation, stratified by 2026 AHA/ACC clinical category at presentation.
Time frame: Up to 30 days
S6: 30-day ED revisit rate for PE-related complaints
Rate of emergency department revisit for pulmonary embolism-related complaints within 30 days of index presentation.
Time frame: 30 days
Plan to share: No — No plan to share individual participant data at this time; data sharing decisions will be reconsidered upon study completion and publication.
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Marmara University Pendik Training and Research Hospital