1 / 25

Anything that you want to know about troponins but never ask

Anything that you want to know about troponins but never ask. Thao Huynh & Roland Sabbagh Division of Cardiology MUHC. WHO classification of MI. 2/3 these criteria: Ischemic symptoms EKG changes. Increased serum markers. CPK-MB. 15% of cardiac CPK, small amount in skeletal muscle

omer
Télécharger la présentation

Anything that you want to know about troponins but never ask

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. Anything that you want to know about troponins but never ask Thao Huynh & Roland Sabbagh Division of Cardiology MUHC

  2. WHO classification of MI 2/3 these criteria: • Ischemic symptoms • EKG changes. • Increased serum markers.

  3. CPK-MB • 15% of cardiac CPK, small amount in skeletal muscle • Validated as marker for MI. However: • Can increase after muscle injury, muscular diseases. • Can be found in tongue, intestine, diaphragm, uterus, prostate.

  4. Myoglobin • Rapid rise • Non-specific. • Cannot be used alone to confirm MI

  5. Tropomyosin: Troponin T, Troponin I, Troponin C. Actin and tropomyosin

  6. Cardiac troponins: • Troponin C: binds with calcium. • Troponin T: binds with tropomyosin. • Troponin I: inhibites contraction.

  7. Troponin C Same isoform for both skeletal and cardiac muscles.

  8. Troponin T & I • Require myocardial necrosis for release from sarcomere. • Early rise (4-12 hours after symptom). • Peak 12-24 hours. • Continuous release up to 10-14 days 2nd to constant release/necrotic sarcomeres. • Unclear excretion pathway.

  9. Troponin I • Only 1 isoform. • The cardiac isoform of troponin I is only found in cardiac muscles. • Highly bound to the tropomyosin complex in the sarcomere. • <5% in cytosol.

  10. Troponin I • N ,C terminus and central portion. • Myocardial necrosis: cleavage of the terminus (more unstable). • Different assays with antibodies measuring different terminus (6 assays). • Strong binding with troponin C (calcium dependent) may affect measurement. • Assays also affected by other protein kinases and fibrinogen levels.

  11. Troponin T • Cardiac troponin T: 4 isoforms. • Fetal skeletal muscle: + cardiac troponin isoform. • Muscle injury, myopathy, renal failure: reexpression of cardiac troponin T in muscles.

  12. Troponin T • Two monoclonal antibodies: • 1 for capture (M11.7) and 1 for detection (M7).

  13. Troponin T • Only 1 manufacturer: Roche Boeringer • Possible false + with first generation assay in renal failure. • M11.7 and M7 isoforms have to be both present for 2nd and 3rd generation assays to be detected.

  14. Troponins and ACS 7 clinical trials and 19 cohort studies: For death & MI: • 5,360 troponin T: OR 3-5. • 6,603 troponin I: OR 3-8. • Comparable accuracy of troponin T & I.

  15. How do troponin compare with EKG in ACS? • Negative troponin and normal EKG, mortality 1%. • Negative troponin and ischemic EKG: mortatity 4% at 1 month. • Troponin and EKG changes complementary.

  16. TIMI score • Age  65 years. •  3 risk factors for CAD. • Coronary stenosis  50%. • ASA use in past 7 days. • Severe angina  24 hours • + cardiac markers. • ST deviation  0.5 mm. Each point scores 1. Intermediate:3-4 (14-days events:13-20%). High: 6-7 (14-days events: 40%).

  17. Troponin and GPIIbIIIa inhibitors • Substudies of clinical trials: patients with troponin rises benefit more from GPIIbIIIa inhibitors. • ACC/AHA recommend these medications in + troponins. • No prospective study examining the role of initiating these medications as per troponin levels.

  18. ACC/AHA/ESC 1999 Myocardial infarction: elevation of serum troponin T/I >0.1.

  19. Bedside testing • Trop T and I. • 96% concordance with quantitative tests.

  20. Troponins in ESRD 733 patients Troponins T & I 2-year mortality: • T: <0.01=8.4% • T 0.01-<0.04= 26%. • T 0.04-0.1= 39%. • T 0.1= 47% • I<0.1= 30% and I 0.1=52%. • RR for TnT: 5.0 and TnI: 2.1.

  21. Troponins in renal failure and ACS • GUSTO IV: 581 patients: • Creat clearance >58 ml/min, + TnT odds ratio: 1.7. • Creat clearance <30 ml/min, + TnT odds ratio: 2.5. • TnT +: >0.1 ug/l.

  22. Troponin T and renal failure • Can have chronic elevation. • Not related with frequency and efficacy of dialysis or creatinine level. • Predict increased adverse outcomes in stable patients. • ACS: also increased adverse outcomes. Serial measurements important. (>50% increase=MI).

  23. Troponins and congestive heart failure • May have chronic elevation of both TnT and TnI. • As low as TnT<0.05 predicts increased risk. • Diagnosis of ACS require serial measurement.

  24. Conclusions • Troponins T and I important clinical tools. • Problems with TnI: variability of assays. • Complement clinical risk factors and EKG changes. • May help decision to initiate GPIIb/IIIa blockade.

More Related