Author + information
- Louise Cullen, MB, BS∗ (, )
- Martin Than, MB, BS and
- W. Frank Peacock, MD
- ↵∗Emergency Medicine, Royal Brisbane and Women's Hospital, Herston, Brisbane, Queensland 4029, Australia
We read with great interest the recent publication by Bandstein et al. (1), and congratulate the authors on their thought-provoking results. If the findings are substantiated, then such an approach could have a major impact on the resources and time required to investigate patients with possible cardiac chest pain. The conclusion is emphatically worded: “All patients with chest pain who have an initial hs-cTnT level of <5 ng/l and no signs of ischemia on ECG [electrocardiogram] have a minimal risk of MI [myocardial infarction] or death within 30 days and can be safely discharged directly from the ED [emergency department].” We therefore ask the authors whether they believe that such an investigative approach is ready for widespread international uptake without further external validation using robust recruitment and follow-up processes? The impressive size of the study was achievable only by making a number of methodological compromises that we shall discuss in the following text.
First, this was an observational trial, and no patients were actually discharged by virtue of their findings. In fact, at least 21% were hospitalized using unknown criteria, many for as long as 4 to 5 days (mean length of stay was 1.5 days), where it’s likely that they underwent further investigation and risk modification despite an initial single negative troponin test. One must assume hospitalization resulted in at least some element of risk mitigation.
Furthermore, Bandstein et al. (1) report that 89% (n = 1,704) of those with an initial troponin <5 ng/l had a second test. The total “low-risk population” who had serial troponin tests was 1,917 patients. Thus, of the 8,907 with an initial troponin <5 ng/l, only 19% (n = 1,704) had serial troponin testing? If correct, this practice is inconsistent with either the European Society of Cardiology or American Heart Association/American College of Cardiology guidelines. Were many of the initial troponins ordered inappropriately for clinical scenarios later not considered to be consistent with acute coronary syndrome?
Of patients with a second troponin test performed, 3% (44 of 1,704) of levels were elevated. If not an acute MI (AMI), what were their diagnoses? And, if the 3% elevated second troponin rate was applied to the single troponin low-risk cohort, an additional 210 patients may have had an elevated second troponin. Without a second troponin level, how can it be claimed that an elevation wasn’t present? By not using a standard AMI evaluation, is it possible that missed AMI occurred and were not found upon follow-up simply because the patient didn’t die? Further, 39 patients were diagnosed with MI by 30 days, implying a 2% (39 of 1,917) event rate. If this event rate is also applied to the low-risk population with a single troponin level, it is possible that as many as 140 MIs were missed simply because the patients weren’t tested nor dead in 1 year.
Ultimately, the suggested approach needs the further support of an interventional trial with accurate follow-up and in which data are collected to measure the effect of the investigators’ recommendation. Until this consideration is validated, the “one and done” troponin strategy should only be considered as hypothesis generating.
Please note: Dr. Cullen has received grant funding from Rochehttp://dx.doi.org/10.13039/100004337, Abbott Diagnostics, and Alere; and has received speaker’s fees or honoraria from Abbott Diagnostics, Beckman Coulter, and Alere. Dr. Than has received grant funding, consulting fees, or honoraria from Rochehttp://dx.doi.org/10.13039/100004337, Beckman Coulter, Abbott Diagnostics, and Alere. Dr. Peacock has received research grants from Abbott, Alere, Banyan, Cardiorentis, Portola, Rochehttp://dx.doi.org/10.13039/100004337, and The Medicines Company; has received consultancy fees from BG Medicine, Beckman, Boehringer-Ingelheim Instrument Labs, The Medicines Company, Alere, Cardiorentis, and Jannsen; and he has ownership interests in Comprehensive Research Associates LLC and Emergencies in Medicine LLC.
- American College of Cardiology Foundation