New troponin test linked to improved outcome after heart attack
A newer high-sensitivity troponin test is capable of discovering smaller amounts of troponins (heart-specific proteins) as compared to the older troponin test and thus, can identify more myocardial infarction (MI) patients than before.
According to a new study published in the Journal of the American College of Cardiology, the risk of a future heart attack will be lower in patients diagnosed with this new test.
Martin Holzmann, associate professor of epidemiology at Karolinska Institutet's Department of Medicine in Solna, and colleagues conducted the study to investigate how the incidence of MI and prognosis after a first MI was affected by the introduction of high-sensitivity cardiac troponin T (hs-cTnT).
A blood test that measures the presence of troponins is used by emergency clinics to diagnose MI in patients with chest pain. For the past few years, a newer laboratory method has been used at most hospitals in Sweden that is ten times more sensitive than the conventional troponin test. The high-sensitivity troponin test can discover heart attacks earlier so that treatment can commence, which is thought to improve the patients' prognosis.
"But there is a lack of larger studies examining whether the high-sensitivity troponin test is of any significance for patients with newly diagnosed myocardial infarction in terms of survival or the risk of another heart attack," says Dr. Holzmann.
The study included all patients in Sweden who had had their first heart attack between 2009 and 2013. This gave a study population of almost 88,000 patients, 40,000 of whom had been diagnosed using the high-sensitivity troponin test and just over 47,000 using the conventional troponin test.
- Five percent more myocardial infarctions were being diagnosed in hospitals that used the high-sensitivity troponin test.
- A year after the heart attack was registered there was no difference in mortality between the two groups, although the number of new heart attacks was lower in the group that had been diagnosed using the high-sensitivity troponin test.
- The use of coronary angiographies and revascularizations increased in the hs-cTnT group.
"The increase we observed in our study was less than expected, which means that the high-sensitivity troponin test has enabled doctors to single out the patients who benefit from such intervention. We found no differences in medication between the two groups, so the differences in prognosis with fewer new heart attacks could be attributed to the fact that more coronary angiography and balloon dilation procedures have been performed on the right patients," says Dr Holzmann, who also believes that the study supports the idea that the handful of hospitals in Sweden that still do not use the high-sensitivity troponin test should start to do so.
Based on the cohort study of 87,879 patients with a first MI, the authors concluded that the introduction of hs-cTnT was associated with an increased incidence of MI, although with no impact on survival. The authors also found a reduced risk of reinfarction alongside increased use of coronary angiographies and revascularizations.
For further information click on the link: https://doi.org/10.1016/j.jacc.2018.03.515