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103 Is it Safe to Use a High Sensitivity Troponin T Assay for Early “Rule Out” in Patients with Suspected Acute Coronary Syndrome?
  1. Dennis Sandeman
  1. NHS Fife

Abstract

The European Cardiac Society have recommended high-sensitivity cardiac troponin testing can be used as part of a “rule-out” strategy for patients with suspected acute coronary syndrome. NICE have recommended the use of 2 assays in clinical practice – Abbott high-sensitivity cardiac troponin I assay and the Roche high-sensitivity cardiac troponin T assay. NHS Fife has introduced the Roche high-sensitivity cardiac troponin T assay.

We wanted to determine if introducing a “rule out” pathway for “low risk” patients with suspected acute coronary syndrome would be safe.

Study Is it safe to use a high sensitivity Troponin T assay for early “rule out” in patients with suspected Acute Coronary Syndrome?

Methods We carried out a retrospecteive study looking at all patients who had high-sensitivity cardiac troponin measured who were admitted to our Cardiac Care UNit, Emergency Department and Admissions Unit over a 10 month period. This was regardless of symptoms or time of onset.

Primary Endpoint: Those patients with initial high-sensitivity cardiac troponin levels under the diagnostic threshold of 14ng/L who went on to have a significant rise in their peak sample. An absolute delta rise >10 ng/L is used to determine if a rise is significant.1

Secondary Endpoint: 30 day mortality rates and rate of myocardial infarction in those patients with an initial high-sensitivity cardiac troponin of <5 ng/L.

Results

  • Total patients who had high sensitivity cardiac troponin tested 4521

  • Patients who had only one sample taken 2539 - excluded

  • Patients who had serial samples taken 1982 - included

  • Patients with initial sample >14 ng/L 1045

  • Patients with initial sample <14 ng/L 937 (M 476/F 461)

Primary Outcomes

  • 444 (48%) of 937 patients had an initial sample <5 ng/L

  • 5 patients (1.1%) went on to have a peak sample >10 ng/L

  • This gave a negative predictive value (NPV) of 98.7% of a significant rise if initial sample is <5 ng/L.

Secondary Outcomes 30 day mortality was zero and 30 day myocardial infarction rate was 2 patients.

Discussion Onlt 2 of the 5 patients who went on to have a rise in their peak sample >10 ng/L had a type 1 Myocardial Infarction. The other 3 had atrial fibrillation, chronic pulmonary hypertension with recent normal coronary angiography and another was a known arteriopath who had non obstructive coronary disease on angiography and did not have revasculrisation.

Conclusions We have shwon it is safe to use the Roch high-sensitivity cardiac tropoinin T assay in clinical practice as part of an early rule-out strategy for patients with suspected acute coronary syndrome.

Cardiac Troponin results should should be interpreted in the context of the clinical presentation.

Reference

  1. Reichlin T, Irfan A, Twerenbold R, Reiter M, Hochholzer W, Burkhalter H, Basetti S, Steur S, Winkler K, Peter F, Meissner J, Haaf P, Potocki M, Drexler B, Osswald S, Mueller C. Utility of Absolute and Relative Changes in Cardaic Troponin Concentration in the Early Diagnosis of Myocardial Infarction. Circulation. 2011;124:136-45

  • high-sensitity troponin
  • myocardial infarction
  • rule-out

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