High sensitivity cardiac troponin (hs-cTn) is an effective test for heart attacks; also known as acute myocardial infarctions (AMI). This test offers the potential to speed up the treatment process, avoiding unnecessary observations and additional tests.
The accuracy of hs-cTn is dependent on a number of conditions and currently different implementation strategies have not been evaluated for either clinical or cost effectiveness. In addition to this, the current absence of NICE guidance means that the use of this test varies significantly between hospitals.
This project has brought together the available evidence with analysis of service activity locally, to explore the potential impact on heart attack care pathways in the South West, if high sensitivity troponin is implemented consistently. This was achieved through the use of simulation modelling by the PenCHORD team to assess the possible impact of reconfiguring services on both patients and the NHS.
This study addressed the following questions to support the development of a clear strategy for using high sensitivity troponin:
1. How does the use of high sensitivity troponin vary across the South West?
2. How many patients are currently being admitted for observation of acute chest pain suspected of being a heart attack and how does this vary across the South West?
3. How might the use of high sensitivity troponin affect current patterns of health service use?
4. What are the barriers and facilitators to consistent and efficient use of high sensitivity troponin across hospitals in the South West?
Chest pain suggestive of Acute Coronary Syndrome (ACS) is the most common cause of emergency hospital admissions in the UK, accounting for 6% of all emergency attendances. In some patients, the underlying cause is an evolving acute myocardial infarction (AMI) which, if missed, may have fatal consequences, making accurate diagnosis critical. However, less than 35% of all patients with chest pain are diagnosed with ACS. This means that a significant number of patients are admitted and undergo unnecessary diagnostic procedures that could be avoided if AMI could be excluded at an earlier stage. This has substantial cost implications for the NHS.
As part of the Cardiac Reviews of Tests and Training (CaRoTT) project, we conducted a systematic review of the diagnostic accuracy of high sensitivity cardiac troponin T (Roche® Diagnostics). This is the locally used hs-cTn assay and our review has confirmed the very high predictive value of the test, demonstrating that a single test at presentation might be sufficient to rule out acute myocardial infarction, leading to earlier discharge of patients without AMI.
A computer model was built and data from four NHS trusts in the South West was used to test the model.
The project found variation in practice in the use of troponin across the South West and has identified the complexity of the diagnostic pathway for heart attacks and many barriers to the effective implementation of troponin.
There is a great deal of interest in this area and potential for follow on work, looking particularly at how changes to the diagnostic pathway could be implemented and in particular how the simulation pathway models might be adapted to look at ‘single-test’ rule out of patients with suspected myocardial infarction.
View the full report for the AHSN.