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ORLANDO -- Testing patients with chest pain for troponin levels prior to hospital arrival had a modest effect on time to hospital admission or discharge, according to results of a small randomized trial reported here.
The usual standard of care calls for troponin tests to be administered in the emergency department (ED), but the PROACT-4 study hoped to find that pre-hospital testing meant the patient would be evaluated earlier.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
- Testing patients with chest pain for troponin levels prior to hospital arrival had only a very modest effect on time to hospital admission or discharge from the Emergency Department, according to results of a small randomized, nonblinded trial.
- There was no benefit in the secondary trial endpoint of reduction in 30-day clinical events.
The nonblinded randomized trial involved 601 patients, 296 of which received usual care and 305 receiving the pre-hospital testing. Patients were 57% male, with a mean age of 66 years (range 53-78). There were 30% with coronary artery disease and 25% with diabetes.
Among patients who were discharged from the ED, the pre-hospital testing significantly shortened the total evaluation time, by 28 minutes (8.85 hours, 95% CI 6.65-10.23, versus 9.32 hours for usual care, 95% CI 7.37-11.00, P=0.021), reported , of the University of Alberta in a presentation at the American Heart Association meeting.
But there was no shortening of ED time for those eventually admitted (8.62 hours, 95% CI 5.25-12.55 versus 8.73 hours for usual care, 95% CI 5.43-11.95, P=0.959), and only a nonsignificant trend toward shorter times for the entire sample who received the pre-hospital troponin tests (8.85 hours, 95% CI 6.22-10.76, versus 9.14 hours for usual care, 95% CI 6.68-11.17, P=0.069).
And there was no benefit in a secondary endpoint of reduction in 30-day clinical events, Ezekowitz said.
Despite the mixed results, of Cedars-Sinai Medical Center in Los Angeles, called this an "important, practical, real life study," citing the importance of being expeditious in treating patients with chest pain.
"The concept is outstanding -- to move an early diagnostic tool into the ambulance, where paramedics are very motivated and can do a good job, and they successfully did that," said Henry, who was not involved in the study, in an interview with 麻豆传媒. "So for me, this is an excellent trial and it's really an example of trials we should do which improve care of a large number of patients in a really practical and real life manner."
Study discussant , of Duke University, commented that simply adding troponin testing in the emergency medical service allowed it to leverage a system of care that was already in place and perhaps reduce the overcrowding in emergency rooms.
"This is an excellent example of an opportunity for process improvement to streamline care in the emergency department," she said at the press conference.
Not surprisingly, giving the troponin test in the ambulance dramatically reduced the time to receive such testing compared with usual in-hospital testing, by 100 minutes (38 minutes, 95% CI 28-55 versus 138 minutes, 95% CI 101-218, respectively, P<0.001).
In per protocol analyses, earlier troponin testing had a small, but statistically significant effect on time of first medical contact to final disposition (8.75 hours, 95% CI 6.20-10.77 versus 9.14 hours, 95% CI 6.69-11.17, P=0.050) and time until discharge from the ED with earlier troponin testing (8.87 hours, 95% CI 6.73-10.57 versus 9.32 hours, 95% CI 7.37-10.98, P=0.035).
Upon diagnosis, 112 patients were found to have acute coronary syndromes, 16 with acute heart failure and 14 with angina. However, the majority (~70%) were found to have a noncardiac diagnosis for acute presentation, and 68% of those were "chest pain, not otherwise specified."
Limitations to the study include that there was no additional intervention, such as triage, based on the troponin result and that the troponin assay was sensitive and contemporary, but at the lower limit of detection (>0.03 ng/ml for the pre-hospital test), but not highly sensitive.
Henry said that rapid troponin tests are being developed to give even faster results, and that reduction in time multiplied by all the people who come into the ED with chest pain could add up to a big difference in care.
"You can do it better than this because you have better technology coming -- so if someone's driving in the ambulance for 15 minutes and you know their EKG and you know their troponin -- it's a huge difference," he concluded.
Disclosures
Funding for this trial was provided by the Heart & Stroke Foundation, with additional support from Alere, Alberta Health Services. Additional funding for the PROACT program was provided by Mazankowski Alberta Heart Institute and University Hospital Foundation.
One study co-author was an employee of Alere.
Newby disclosed no conflicts of interest.
Primary Source
American Heart Association
Ezekowitz JA, et al "Providing rapid out of hospital acute cardiovascular treatment (PROACT-4)" AHA 2015; Abstract 478885.