1 / 23

D-dimer in the Diagnosis of Pulmonary Embolism

D-dimer in the Diagnosis of Pulmonary Embolism. Cheryl Pollock PGY-3. Clinical Case. 27 y.o. male Right anterior chest pain x 48h Pleuritic; constant ache Mild non-productive cough, no hemoptysis Dyspnea on exertion No h/o trauma. Physical Exam. Vitals: HR 76reg RR 18 T 37 BP 130/76

diem
Download Presentation

D-dimer in the Diagnosis of Pulmonary Embolism

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. D-dimer in the Diagnosis of Pulmonary Embolism Cheryl Pollock PGY-3

  2. Clinical Case • 27 y.o. male • Right anterior chest pain x 48h • Pleuritic; constant ache • Mild non-productive cough, no hemoptysis • Dyspnea on exertion • No h/o trauma

  3. Physical Exam • Vitals: • HR 76reg RR 18 T 37 BP 130/76 • CVS: • HS normal S1S2, no S3S4. No murmur. • No leg swelling. • Resp: • Normal breath sound intensity. • Fine crackles R base.

  4. Diagnostic Testing • Goal is to allow the clinician to revise the patient’s probability of having disease to a level greater than a treatment threshold or less than a test threshold

  5. Diagnostic Testing • The cost of missing pulmonary embolism (PE) is high • ED evaluation of patients with suspected PE is often complex, time-consuming • D-dimer is increasingly used in the evaluation of suspected PE

  6. Do you want a D-dimer? • Definition • Conditions that cause a positive D-dimer • Assays • Its role in the work-up of pulmonary embolus • Wells criteria • Diagnostic algorithm

  7. D-dimer Defined • Fibrin degradation product (FDP) • Plasmin splits fibrin into fibrinogen and FDPs • Fibrinolysis starts within 1h of thrombus formation • T1/2 D-dimers = 4-6 h • Continued PE fibrinolysis = elevated D-dimer levels for at least one week

  8. Positive D-dimer • Venous thromboembolism • DIC • Acute coronary syndromes • Vasculitis • Malignancies: lung, prostate, cervix, colon • Vaso-occlusive sickle cell crisis • Acute cerebrovascular accident • Critically ill with severe infection, trauma, inflammatory disorders

  9. Positive D-dimer • Many of these conditions are themselves risk factors for venous thromboembolism • This complicates the interpretation of an abnormal value

  10. D-dimer Assays • Five major types available: • Enzyme-linked immunosorbent assay (ELISA) • Rapid ELISA • Latex agglutination assay • Whole blood assay • Turbidimetric assay • Immunofiltration assay

  11. ELISA Assay • Positive if > 500ng/ml • In the diagnosis of PE: • Sensitivity= 94-97% • Specificity= 44% • Negative LR = 0.07 • Drawback: 2-4h to perform • Rapid ELISA • < 2h • Similar sensitivity and negative LR

  12. Interpretation of Results • Estimation of the pretest probability is imperative for proper application of results • Various methods: • Wells et al (Canada) • Wicki et al (Switzerland) • Kline et al (USA) • The Wells criteria is used in this facility

  13. Wells Criteria

  14. Wells Criteria: Risk Interpretation

  15. Low Probability

  16. Moderate Probability

  17. High Probability

  18. Summary • A normal D-dimer by an ELISA assay can safely exclude PE in patients with LOW to MODERATE pretest probability • HIGH pretest probability V/Q scan • D-dimer can’t “rule in” PE • In elderly or inpatients D-dimer usually abnormal- not useful

  19. Clinical Case • Wells score • No leg swelling, no pain • HR <100 • No immobilization • No prior DVT or PE • No hemoptysis • No malignancy • CXR: RLL infiltrate • Low pretest probability • D-dimer = negative

  20. The Simplest Algorithm • You can safely rule out PE in pretest LOW-probablilty patients with a negative D-dimer

  21. Hampton’s Hump

  22. High Probability VQ Scan

  23. EKG Findings

More Related