News Conference News ESC 2014

Algorithm Helps Identify MI Within 1 Hour in Patients with Acute Chest Pain

Author profile picture By Todd Neale

BARCELONA, Spain—A high-sensitivity cardiac troponin T assay allowed for the rule-in or rule-out of myocardial infarction (MI) within 1 hour in about three-quarters of patients who presented to the emergency department with acute chest pain, according to a study presented on August 30, 2014, at the European Society of Cardiology Congress. Earlier diagnoses could have a substantial impact on medical and economic outcomes, the author said.

“When used in conjunction with all other clinical information, including the ECG and clinical assessment, the high-sensitivity cardiac troponin T 1-hour algorithm will be a safe and effective approach to substantially reduce time to diagnosis,” said presenter Christian Mueller, MD, of University Hospital Basel (Basel, Switzerland).

Methods

In TRAPID-AMI—an observational study conducted at 12 centers in the United States, Europe, and Australia—Dr. Mueller and colleagues sought to validate the 1-hour algorithm examined in the APACE trial, which showed a high negative predictive value for ruling out MI (100%) and a relatively high positive predictive value for diagnosing MI (76%). The algorithm places patients into 3 groups depending on their baseline troponin levels and changes over the next hour, as measured using the high-sensitivity cardiac troponin T assay:

  • MI is ruled out if the level is less than 12 ng/L at baseline and increases by less than 3 ng/L
  •  MI is diagnosed if the level is ≥ 52 ng/L at baseline or increases by at least 5 ng/
  •  All other patients are placed in the observational zone
TRAPID-AMI included 1,282 consecutive patients (mean age 62 years; 63% men) with chest pain suggestive of acute MI who had symptom onset within the past 6 hours (average 3.4 hours) and had their first blood drawn within 45 minutes of presentation. Treating physicians were blinded to the results of the high-sensitivity troponin T tests.

MI Ruled In or Out Within an Hour in Most Patients

The algorithm ruled out MI in 63.4% of patients—with a negative predictive value (primary endpoint) of 99.1%—and diagnosed MI in 14.4%—with a positive predictive value of 77.2%—within the first hour. The remaining 22.2% of patients were placed in the observational zone. 

The findings were consistent across subgroups defined by sex, age, presence of CAD, and whether patients presented within 3 hours of chest pain onset.

Mortality at 30 days was very low (0.1%) in the rule-out group, compared with < 1% in the observational group and about 2.5% in the rule-in group (P < .001). 

High-Sensitivity Troponin T Assays Changing How MI is Diagnosed

Panel co-chair Marco Roffi, MD, of University Hospital of Geneva (Geneva, Switzerland), said the results are “really impressive” and potentially practice changing.

Dr. Mueller agreed, saying that the accumulated data on the approach are now “very strong.” He said the introduction of high-sensitivity troponin T assays has changed the role of cardiac CT in diagnosing MI. 

In rule-out and low-risk patients, “there’s no more room to justify radiation exposure and the cost of a CT if you can do the same thing with the same safety with biomarkers,” he said, adding that patients in the observational zone might be the target population for CT in the future.

In response to a question from panelist Marco Valgimigli, MD, PhD, of Erasmus Medical Center (Rotterdam, The Netherlands), about patients who present either very early (within 30 minutes of symptom onset) or very late (≥ 12 hours), Dr. Mueller said the algorithm works in late presenters but acknowledged that further study is needed to assess its utility in very early presenters. 

In the latter group of patients, he said, “I would still … advocate serial testing beyond 1 hour until we have more data.

Source:
 Mueller C. Multicenter evaluation of a 1h-algorithm in the diagnosis of myocardial infarction using high-sensitivity cardiac troponin T. Presented at: European Society of Cardiology Congress; August 30, 2014; Barcelona, Spain.

  • Dr. Mueller reports receiving research support through his institution from the Swiss National Science Foundation and Fondation Suisse de Cardiologie and having institutional relationships with several diagnostics companies.

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Todd Neale
by Todd Neale

Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …

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Disclosures
  • The study was sponsored by Roche Diagnostics.

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