But no increases in overall use of resources

The use of high-sensitivity cardiac troponin-T (hs-cTnT) assays significantly increased the number of diagnoses of myocardial injury and myocardial infarction (MI), especially in women and those with type 2 MI; however, apart from angiography, it did not increase the use of overall resources. In patients without increases in cTnT, researchers documented more ED discharges and less cardiac testing.

In the first study of its kind, Olatunde Ola, MD, MPH, of the Mayo Clinic Health System, La Crosse, Wisconsin, and colleagues assessed the transition from a contemporary cardiac troponin T (cTnT) assay that used an overall 99th percentile (4th generation) to a high-sensitivity (hs) cTnT assay with sex-specific 99thpercentiles (5th generation) for the diagnosis of myocardial injury and infarction (MI). Their results were published in the Journal of the American College of Cardiology.

“The Roche 5th Gen cTnT assay, referred to as hs-cTnT, received United States (US) Food and Drug Administration (FDA) clearance in January 2017. Several other hs-cTnI assays have since received 510k clearance. However, limited real-life U.S. data exists, especially in regard to the frequency of MI diagnoses and resource utilization following hs-cTn implementation. The latter information will have important clinical, logistic, and financial implications as wider implementation of these assays occurs. Further, U.S. practices tend to use cTn more broadly than those in Europe, which has led to concerns about these critical issues,” wrote Ola and fellow researchers.

In their observational cohort study of 3,536 patients in the U.S. admitted to the emergency department who underwent cTnT measurements during the transition from the 4th to 5th generation cTnT tests, Ola and colleagues sought to “assess the impact of transitioning from 4th to 5th Gen cTnT on the incidence of myocardial injury and MI diagnoses following the Fourth Universal Definition of MI (UDMI) and resource utilization in a US regional healthcare system.”

Using the 5th generation cTnT test, patients with ≥1 cTnT of <99th percentile increased compared with 4th generation cTnT (47% vs 15%; P˂0.0001), as did acute MI (8.1% vs 3.3%; P˂0.0001), and myocardial injury (38% vs 11%; P˂0.0001).

Ola and colleagues also found that although type 1 MIs were more frequently diagnosed using the 5th vs 4th generation testing (2.9% vs 1.7%, respectively; P=0.0097), the overall increase in MIs was—in large part—due to the diagnosis of more type 2 MIs (5.2% versus 1.6%; P˂0.0001). In men, acute MI increased from 4.4% to 8.5% (OR: 2.05; 95% CI: 1.42-2.94; P˂0.0001), and in women, from 2.3% to 7.7% (OR: 3.60; 95% CI: 2.29-5.67; P˂0.0001). Similarly, myocardial injury in men increased from 16% to 39% (OR: 3.50; 95% CI: 2.85-4.30 P˂0.0001), and in women, from 7.5% to 38% (OR: 7.50; 95% CI: 5.81-9.69; P˂0.0001).

They also observed that using the 4th generation cTnT, women were less likely than men to have MI (2.3% versus 4.4%; P=0.008), but not when using the 5th generation cTnT (7.7% versus 8.5%; P=0.46). Women were also less likely than men to have cTnT concentrations greater than 99th percentile (9.7% versus 20%; P˂0.0001) and myocardial injury (7.5 versus 16%; P˂0.0001). But, using 5th generation cTnT, they found no differences in men and women in the proportion of those with cTnT concentrations greater than 99th percentile or myocardial injury.

In addition, there were reductions in overall length of stay (LOS) and stress testing but increases in angiography (all P˂0.05). In patients with and without cTnT increases, stress testing was reduced (6.5% versus 4.9%, respectively; P=0.02), while invasive coronary angiography was increased postimplementation (2.3% versus 3.5%; P=0.02).

In patients without increases in cTnT, more ED discharges occurred, as well as reductions in LOS, and echocardiography and stress testing (all P˂0.05).

“Hs-cTnT/I assays were introduced in routine clinical practice in Europe and Australia/New Zealand/Canada in 2010 and in the United States in 2017. Clinical practice guidelines recommend that in patients with acute chest discomfort hs-cTnT/I should be clinically used embedded in well-validated rapid triage algorithms. The European Society of Cardiology (ESC) hs-cTnT/I 0/1h-algorithms with their second blood draw at 1h, and the ESC hs-cTnT/I 0/2h-algorithms with their second blood draw at 2h, are the preferred rapid algorithms and recommended with a class IA recommendation. They have data-driven assay-specific cut-offs, derived and validated to achieve predefined performance characteristics for both rapid rule-out and rule-in of AMI justifying immediate therapeutic consequences (Figure). They are available for numerous hs-cTnT/I assays and supported by real-life studies documenting safe and efficient implementation,” wrote Christian Mueller, MD, of the Cardiovascular Research Institute Basel, University of Basel, Switzerland, and co-authors in an accompanying editorial. The findings from Ola et al complement these observations, they noted, adding that they also offer insight into four common themes:

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  • If the full potential of these assays is not used, “the magnitude of the operational benefits observed with the implementation of hs-CtnT/I is reduced.”
  • The use of formal multivariate risk scores is no longer required for “rapid rule-out of AMI using the ESC hs-cTnT/I 0/1 h or 0.2h-algorithms, or the HIGHSTEACS-pathway.”
  • The use of uniform or sex-specific cut-offs in patients with acute chest discomfort is still controversial.
  • Acute chest discomfort was present in only 46% of patients in this study, and findings of the benefits of hs-CtNt versus cTnT may have “been diluted by adding 54% of patients with unknown indications of (hs)-cTnT testing.”

“Further research as well as continuous interdisciplinary medical education is required to maximize the medical and economic value of hs-cTnT/I-testing to patients and institutions. This will help reduce overcrowding in the ED, reduce patient’s anxiety and uncertainty, improve patients care, and significantly reduce health care costs. Given the very high number of patients presenting with acute chest discomfort to the ED in North America and Europe, widespread implementation of the ESC hs-cTnT/I 0/1h-algorithm may help save more than 12 billion US dollars in scarce health care spending per year,” concluded Mueller and colleagues.

  1. The implementation of Hs-cTnT brought about significant increases in the diagnosis of myocardial injury and MI, especially in women and patients with type 2 MI.

  2. Despite this, overall resource use did not increase except for angiography, and in patients without cTnT increases, more ED discharges and fewer cardiac tests occurred.

Liz Meszaros, Deputy Managing Editor, BreakingMED™

This publication was made possible in part by the Mayo Clinic CTSA through grant number UL1TR002377 from the National Center for Advancing Translational Sciences (NCATS), a component of the National Institutes of Health (NIH).

Ola reported no disclosures.

Mueller has received research support from the University Hospital Basel, the University of Basel, the Swiss National Science Foundation, the Swiss Heart Foundation, the KTI, the Stiftung für kardiovaskuläre Forschung Basel; Abbott, Beckman Coulter, Brahms, Novartis, Ortho Diagnostics, Quidel, Roche, Siemens, Singulex, Sphingotec, as well as speaker honoraria/consulting honoraria from Amgen, Astra Zeneca, Boehringer Ingelheim, BMS, Daiichi-Sankyo, Novartis, Osler, Roche, and Sanofi, outside the submitted work.

Cat ID: 358

Topic ID: 74,358,254,730,358,914,192,925