Prehospital Troponin Testing With EMS Input Could Save a Lot of Money

Allowing paramedics to measure cardiac troponin levels in patients with acute chest pain could save the healthcare system substantial sums of money, according to a modeling study. 

With appropriate risk stratification and prehospital point-of-care troponin testing by emergency medical services (EMS), the estimated annual cost savings could be as low as A$6 million to as high as A$70 million within the Australian state of Victoria, Luke P. Dawson, MBBS (The Alfred Hospital/Monash University, Melbourne), and colleagues report in a study published online last week in JAMA Internal Medicine.

“We know that all of our emergency departments are under enormous strain for multifaceted reasons,” senior investigator Dion Stub, MBBS, PhD (The Alfred Hospital/Monash University), told TCTMD. “Both Australian and international data suggest that more than 10% of EMS presentations are related to chest pain and a significant proportion of these presentations turn out to be nonspecific. Then equally, a small but significant percentage end up being a significant, life-threatening condition, such as acute coronary syndrome, pneumonia, pulmonary embolism, aortic dissection, and more. Being able to diagnose and treat in an efficient and expeditious manner is crucial.”

Prehospital point-of-care troponin testing has been evaluated in several studies, with data suggesting it can effectively triage patients to appropriate care pathways. Small studies have shown that prehospital troponin testing can reduce the time spent in the emergency department (ED) and expedite admission to PCI-capable centers, but use of point-of-care testing is not routine EMS practice.

Justin A. Ezekowitz, MBBCh, MSc (University of Alberta, Edmonton, Canada), the lead investigator of the PROACT-4 study evaluating point-of-care troponin testing in the ambulance, said that while the cost-modeling study shows that prehospital testing can save money, the main advantage of an early diagnosis is that it allows EMS to strategize what medications or treatments are needed and to route people to the most-appropriate hospitals.

In the patient with ACS, that would be sending the ambulance directly to a center with revascularization capabilities, Ezekowitz told TCTMD. The randomized, controlled trials to date have shown prehospital troponin testing is feasible, with data suggesting it can help diagnose ACS earlier than conventional pathways. There is a cautious optimism, he said, that its use is the appropriate next step in the evolution of prehospital care for patients with suspected ACS.

“Is there the ability to get more-effective triage?” asked Ezekowitz. “We think so, but that’s where larger randomized trials and larger deployments are really needed to test those strategies.”

Paul W. Armstrong, MD (University of Alberta), senior investigator of PROACT-4, said having cardiac troponin and the ECG, along with the patient’s history, to calculate the risk score provides a “triangulation” of clinical information to help healthcare providers make an accurate diagnosis at an early point in time, all of which affects the ambulance’s destination. “Do we go to the nearest community hospital with 50 beds, three of them monitored? Is that OK because the patient is low risk? Or are we talking about an hour’s drive or a helicopter to a tertiary care facility? I think that’s where the money is, both literally and figuratively, in terms of figuring this out,” he told TCTMD.    

Armstrong added that “anytime you can move proximal in a disease, such as acute coronary syndrome or acute heart failure, the better.” Engaging paramedics is the best way to go, he added, especially in areas where there is a wide distribution between the number of specialized facilities and community hospitals. 

Saving Millions of Dollars

Stub said there are well-validated risk models to aid decision-making for patients with suspected ACS, including the HEART risk score, which has been validated in the prehospital setting. The HEART score is focused exclusively on ACS, taking into account the patient’s history, ECG, age, risk factors, and troponin levels, but Stub noted there are other significant, noncardiac issues that may be causing acute chest pain. For this reason, they developed the broader Early Chest Pain Admission Mortality and Myocardial Infarction (ECAMM) score to pick up a variety of ACS and non-ACS diagnoses, such as pulmonary embolism, heart failure, aortic dissection, and pneumonia.

The purpose of the present study was to assess savings to the healthcare system with different triage strategies. The decision tree involved three potential care pathways: 1) existing care; 2) prehospital pathway with risk stratification and point-of-care troponin testing that involved transport to the nearest hospital or revascularization center; and 3) the same pathway as the latter except low-risk patients could be discharged prior to hospital admission after a virtual ED visit. The virtual ED assessment, said Stub, emerged during the COVID-19 pandemic and has also been adopted for stroke assessments by the neurology team.

“If we brought these three aspects together—the risk-decision tool, point-of-care troponin assessments, and use of a virtual ED—could we develop protocols for a rigorous prehospital assessment of chest pain that may include not transporting patients to hospital?” said Stub. “What would the cost implications of that be?”

For the study, they calculated costs based on 188,551 patients with acute chest pain with linked emergency and admission data transported by EMS to public hospitals during a 5-week period in 2022.

The capital outlay to equip more than 800 ambulances and their branches in Victoria with point-of-care high-sensitivity troponin capabilities was estimated to be nearly A$5 million. Despite the up-front costs, Stub said the savings were profound. The annual cost savings for the prehospital point-of-care troponin pathway (without prehospital discharge) was estimated to be A$6.45 million. If the HEART score was used with troponin testing to identify low-risk patients who could be discharged prior to hospital admission after a virtual ED consultation, the cost savings was estimated to be A$42.84 million. If the ECAMM score was used instead, the cost savings was A$71.84 million annually.

Cumulatively, the estimated savings over 5 years in Victoria was A$64.66 million for the usual-care pathway, A$258.93 million when incorporating prehospital troponin testing but admitting all patients, and A$462.87 million when using prehospital troponin testing along with early discharge for low-risk patients following a virtual ED consultation.

“The findings are quite provocative,” said Stub, “but the savings could be enormous. If you end up not transporting low-risk patients to hospital by using both the risk-decision [scores] and virtual ED, you can have roughly $50 million in savings a year. The reduction in pressure to our emergency departments would also be huge. The key piece is to do this in a safe fashion and to make sure you’re not misdiagnosing patients with chest pain and you’re not missing acute coronary syndromes. You have to do this in a safe, controlled manner. That still needs to be borne out with further study.”

Stub said they are planning to launch a pilot study to investigate the safety and feasibility of the different care pathways. Later studies, if the feasibility assessments pan out, will investigate patient outcomes, an important piece of the puzzle, particularly for those not admitted to the hospital. 

In an editorial, Isabel Ostrer, MD (University of California, San Francisco), and Tracy Wang, MD (Duke Clinical Research Institute, Durham, NC), note that point-of-care troponin testing devices were only recently approved by the US Food and Drug Administration, and while these devices continue to improve, they still need further serial testing for most patients with suspected ACS to ensure optimal diagnostic accuracy. They also point out that virtual ED consults are rare in the US, and that most patients will end up in the ED for triage. Nonetheless, the new modeling study provides a financial incentive for moving chest-pain risk stratification more upstream, write Ostrer and Wang.

Avoiding the Emergency Department

Prehospital care has evolved substantially since PROACT-4, said Ezekowitz, noting that patients were enrolled in the trial 8 to 10 years ago. In that study, for example, investigators used a conventional troponin assay, but emergency departments are routinely using high-sensitivity assays. In addition, hospitals have adopted far more integrated systems of care for patients with suspected ACS transported to the hospital via EMS. Within these large, integrated healthcare systems is a good opportunity to show that prehospital troponin testing can lead to better patient triage and better clinical outcomes, said Ezekowitz.

“This is where the randomized trials can help shed some light,” he said. “The cost model is really important for healthcare systems, but whether it results in better clinical outcomes for patients is still a little uncertain. From my perspective, you have an extremely well-trained workforce—the paramedics working in ambulances—and you have emergency departments which are overloaded and need to have care streamlined. It is a perfect setup for deploying these systems.” 

To TCTMD, Armstrong said that from the patient’s perspective, especially in the pandemic era, spending less time hanging around the emergency department is ideal. He said that a pathway that utilizes prehospital troponin testing and paramedic risk stratification to triage patients won’t always be perfect, so it will be necessary for community hospitals to have a fallback position in case a low-risk patient deteriorates in that setting.

While the present study focused on prehospital troponin testing, Armstrong noted that point-of-care testing that can also measure B-type brain natriuretic peptide (BNP) would be invaluable for the diagnosis of heart failure.

“Some patients never get chest pain, but have an acute coronary syndrome, and some people with discomfort may not have acute coronary syndrome but are feeling distressed because their lungs are filling because of heart failure,” he said. “In my definition of a perfect world, if you could cover both those bases with a simple low-cost device in an ambulance, then you’d really be informed in terms of triage and moving sensibly and proximally in terms of the disease.”