Grant: Operating Grant

Identifying patients with heart attacks (MI) in the emergency department is challenging. One of the most important diagnostic tests for an MI is a blood test for cardiac troponin, a protein released into the bloodstream during an MI. Higher levels of troponin in the bloodstream are associated with a higher risk of death in patients with MI. A new troponin test, known as high-sensitivity troponin T (hs-TnT), has recently replaced older troponin tests in many Canadian hospitals. hs-TnT is much more sensitive than previous tests: It can detect much smaller levels of troponin in the blood. This means that MIs may be diagnosed earlier, doctors will miss fewer MIs, and patients with chest pain or breathing problems can have the diagnosis of a MI excluded faster than before. The downside of this high sensitivity is that some patients with naturally high troponin levels may be misdiagnosed as having had an MI, and be subjected to risky additional tests without the prospect of benefit. There is no agreementin the expert medical community as to how the hs-TnT tests ought to be used. There is insufficient scientific data to clearly identify what cutoff level provides the best diagnostic accuracy, minimizing both missed MIs and misdiagnosed MIs. This research program has two objectives: First, we will identify what level of hs-TnT best identifies patients with chest pain who are at risk of short-term adverse outcomes (like death, MI or the need for emergency surgery or angioplasty) while minimizing misdiagnosis of patients with naturally high levels of troponin. This data will help doctors identify patients who need to be hospitalized for emergency cardiac testing. Second, we will identify what level of hs-TnT is associated with death among patients with chest pain. This information will help identify patients who require intensive monitoring during their hospital stay or additional testing to reduce their short- and long-term risk of death.