A high-sensitivity blood test can improve diagnosis for 1 in 5 patients who have a heart muscle injury, according to a U.K. hospital study.
University of Edinburgh scientists analyzed the impact of implementing a high-sensitivity assay capable of measuring cardiac troponin at low levels on long-term outcomes for patients with suspected acute coronary syndrome.
The research team said it could reduce future heart attacks in at-risk patients by 10% after five years. Furthermore, those who benefited the most were patients with a heart muscle injury caused by other heart conditions, such as heart failure, heart valve conditions, and heart arrhythmias. These patients saw an almost 10% drop in future hospital admissions and deaths in the five years following getting the new test compared to those who had received the older, less-sensitive test.
The study was carried out in 10 hospital emergency departments in Scotland, with findings reported in the BMJ.
“It is very encouraging to see that the new test trialed here is better at predicting long-term outcomes for these patients, whether they had a heart attack or a different kind of heart injury. This can lead to improved care for such patients,” said Professor Sir Nilesh Samani, medical director at the British Heart Foundation, which funded the research.
“In the past, clinicians could have been falsely reassured by the results of the less sensitive troponin test, discharging patients that appeared to not have heart disease,” Dr. Kuan Ken Lee, clinical lecturer in cardiology at Edinburgh University and the study's co-author, said.
“In our trial, introducing this test led to an impressive reduction in the number of future heart attacks and deaths seen in this at-risk group,” Ken Lee said.
More than 10,000 patients were found to have high troponin levels, indicating a heart injury. Around 1 in 5 of these patients were only spotted by the new high-sensitivity test, which was able to detect more subtle warning signs. Improvements in outcome were greatest in patients with a diagnosis of nonischemic myocardial injury.
By identifying heart injury patients who may otherwise have gone unnoticed and untreated, the researchers hope that more people could receive the specialist heart care they need to avoid more serious events in the future. There have been concerns that lower diagnostic thresholds could reduce the specificity of cardiac troponin for type 1 myocardial infarction, which could result in misdiagnosis and unnecessary investigation or treatment.
“We found no evidence of unnecessary treatment for acute coronary syndrome or harm in patients identified as having non-ischemic myocardial injury. On the contrary, we observed that improvements in outcomes at five years were greatest in those patients with an index diagnosis of non-ischemic myocardial injury,” the authors wrote.