MI diagnoses rise with fifth-generation troponin assay; no resource utilization increase
Fifth-generation troponin testing improved diagnosis of MI and myocardial injury, but it did not significantly affect overall resource utilization, according to data presented at the American College of Cardiology Scientific Session.
“Our findings are among the first in the U.S. to provide insights into the real-life implementation of high-sensitivity cardiac troponin into clinical practice. While some previous studies offered some data, ours provides data on the implementation of high-sensitivity cardiac troponin T using sex-specific 99th percentile upper-reference limits and diagnoses adjudicated using the Fourth Universal Definition of MI,” Yader Sandoval, MD, interventional cardiologist and consultant in the department of cardiovascular medicine at Mayo Clinic, told Healio. “Our findings, consistent with previous studies done outside the U.S., inform that the transition to these assays, particularly if shifting from an insensitive assay, are associated with more injury and MIs, particularly in women and in patients with type 2 MIs.”
For this retrospective, observational, multicenter study, researchers assessed adult ED visits that included at least one cardiac troponin T test on clinical indication during the transition from fourth-generation to fifth-generation troponin T testing. The researchers aimed to determine whether the transition to high-sensitivity cardiac troponin testing affected the diagnoses of MI and acute MI as well as resource utilization.
For fourth-generation troponin testing, the 99th percentile is defined as troponin concentration of less than 0.01 ng/mL. Fifth-generation troponin testing used sex-specific 99th percentiles defined as 10 ng/L for women and 15 ng/L for men.
According to the study, ED presentations with more than one high-sensitivity troponin test greater than the 99th percentile increased using the fifth-generation troponin test compared with the fourth-generation test (15% vs. 47%; P < .0001).
Diagnoses of acute MI (3.3% vs. 8.1%; P < .0001) and myocardial injury (12% vs. 39%; P < .0001) increased after the transition to fifth-generation troponin testing.
Researchers reported that, although diagnoses of type 1 MI increased (1.7% vs. 2.8%; P = .0095) after the implementation of fifth-generation troponin testing, the overall increase in MI was driven by elevated frequency of type 2 MI (1.6% vs. 5.2%; P < .0001).
“Critically, while type 1 MI increased, most MIs were type 2 MIs. This is important as data continues to emerge showing that type 2 MI is increasingly encountered, particularly using more sensitive tests. Likewise, while events increased in both men and women, the increase in diagnoses was particularly notable in women,” Sandoval told Healio. “These latter findings are of importance, as women are a population were concern for under-diagnosis has often existed and the use of high-sensitivity cardiac troponin with sex-specific thresholds appears to help with diagnosis.”
According to the study, overall resource utilization did not increase significantly after the transition to fifth-generation troponin T testing:
- median length of stay fell from 4.3 hours to 4.2 hours (P = .01);
- use of stress testing declined from 6.5% to 4.9% (P = .02);
- direct discharges from the emergency department did not change (P = .17); and
- echocardiography use changed from 16% vs. 17% (P = .24).
However, use of angiography increased after implementing fifth-generation troponin testing vs. fourth-generation testing (2.3% vs. 3.5%; P = .02).
Among patients without elevated troponin, length of hospital stay (3.6 vs. 3.2 hours; P < .0001), echocardiography (12% vs. 6.5%; P < .0001) and stress tests (6.5% vs. 4.8%; P = .05) were reduced after implementation of fifth-generation troponin testing. Direct ED discharges increased markedly after fifth-generation cardiac troponin T implementation (60% vs. 74%; P < .0001) compared with fourth-generation testing.
“There is an ongoing controversy whether uniform cutoffs or sex-specific cutoffs should be used in the evaluation of patients with acute chest discomfort,” Christian Mueller, MD, of the Cardiovascular Research Institute Basel and the department of cardiology at University Hospital Basel, Switzerland, and colleagues wrote in a related editorial in JACC. “Given the broad differential diagnosis in women presenting with acute chest discomfort and borderline high-sensitivity cardiac troponin T/I concentrations, the use of sex-specific cutoffs as in Wisconsin and Boston resulted in a disproportional increase in the rule-in of conditions, for which currently no evidenced-based therapy is available such as type 2 MI and myocardial injury. It will also invariably lead to an underdiagnosis of type 1 MI in men, a condition for which evidence-based therapy is available.
“Further research as well as continuous interdisciplinary medical education is required to maximize the medical and economic value of high-sensitivity cardiac troponin T/I testing to patients and institutions. This will help reduce overcrowding in the ED, reduce patients’ anxiety and uncertainty, improve patients’ care and significantly reduce health care costs,” Mueller and colleagues wrote. “Given the very high number of patients presenting with acute chest discomfort to the ED in North America and Europe, widespread implementation of the European Society of Cardiology high-sensitivity cardiac troponin T/I 0-/1-hour-algorithm may help [save] more than $12 billion in scarce health care spending per year.”
References:
- Mueller C, et al. J Am Coll Cardiol. 2021;doi:10.1016/j.jacc.2021.04.063.
- Ola O, et al. J AM Coll Cardiol. 2021;doi:10.1016/j.jacc.2021.04.050.
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Ola O, et al. Ischemic heart disease: Clinical science 3. Presented at: American College of Cardiology Scientific Session; May 15-17, 2021 (virtual meeting).