7 Oct 2021
High-sensitivity cardiac troponin assays are used in the evaluation of patients with suspected acute coronary syndromes in the emergency department (ED), however, these tests are typically laboratory based. In this interview, Dr. Martin Than, Director of Emergency Medicine Research, Christchurch Hospital, New Zealand, discusses the impact that a point-of-care high-sensitivity cardiac troponin assay would have on the ED, the key factors that would need to be considered when introducing this test, as well as its potential impact beyond the ED.
Hello, from New Zealand. My name is Martin Than and I am an emergency medicine specialist here in Christchurch, and director of emergency medicine and research, and a lab and cardiac biomarker enthusiast. So I do think that high-sensitivity point-of-care troponin is going to be extremely useful to emergency physicians for two reasons. So first of all, there is diagnosing myocardial infarction allowing us to institute important treatments earlier, although that is a relatively small number of patients.
But I do believe that emergency physicians will find it particularly useful in identifying which patients do not have myocardial infarction, and that allows us to make really crucial disposition decisions around which patient needs to stay in hospital and go home. And so the turnaround time is very important, at eight minutes. And that's obviously a lot shorter than the turnaround time of almost any central lab assay.
But what's also important is not simply the turnaround time but the fact that the result is available to the clinician when they leave the cubicle and they're making their decision, because that's virtually never the case in my experience with a central lab assay. And the results of that is the physician goes off and does other things.
So even when the result is available, it's not actioned or seen. So I think this is crucial for emergency medicine. It'll make a really fundamental difference to our ability to assess our patients and make decisions about them. So determining whether point-of-care high-sensitivity troponin at the bedside makes an impact is a tricky question. And it's tempting to use surrogates like does it have a better turnaround time?
Which it obviously does. Or whether decisions are made quicker? Which is also likely. But they don't really touch on what the real impact would be, to me, and what you'd really want to measure which is the length of stay of the patient in the emergency department partly because you want to get patients out to treatment in the cath lab and also partly because you want to be able to get them home because overcrowding the emergency department is a worldwide issue that causes patient harm.
So the key factors in implementing point-of-care high-sensitivity troponin in the ED start with having extant diagnostic accuracy. No clinician is going to use a test which they believe is going to have false results in relation to myocardial infarction. So that's very important. And the clinicians also have to believe that there is a high level of lab reliability and reproducibility of the test.
If you get over those barriers, which I think are very much possible, then there's still issues around making sure that the test is introduced within a structured pathway. And that's often one of the problems about test introduction. I think it's very important that there's clear guidance about how different test levels are integrated with a patient context and decision-making that flows on from that.
Finally, I think it's very important this is a broad team project, so nursing staff are crucial to this as are a number of other team members who are liaising with other specialties. And it's not just an ED test. We've got to liaise with general medicine, cardiology, and the lab. And everybody's got to work together to understand that although there is some barriers to get over, both in terms of staff training and maybe a little bit of extra time taking doing the test, that the trade-off in terms of patient length of stay and actually the time a patient is under one's care is well worth the work that has to be done through to set something up.
So how do I think that high-sensitivity point-of-care troponin is going to influence care in the future? Well, it is clearly, I believe, going to make a difference in the emergency department whether improved turnaround time, having results available for the clinician when they have to make a decision will transform our ability to make admission-discharge decisions on our patients.
But it's not just the emergency department where there's a potential impact. I think there's a huge role for this in primary care, particularly rural primary care where patients might have to be transferred long distances in order to get a lab test done or be assessed in the hospital. And it also brings along the possibility that for certain patient groups with low-risk features, this might be something that's possible for us to use in ambulance services as well.
And that would be a fundamental game-changer, in my opinion.
Christchurch Hospital, New Zealand
Dr. Martin Than is Director of Emergency Medicine Research and an emergency medicine specialist at Christchurch Hospital in New Zealand. His research is centred on quality improvement initiatives for the emergency department, focusing on cardiac biomarkers.