- This study examined the implementation of high-sensitivity cardiac troponin (hs-cTn) assays at a diverse sample of 550 U.S. hospitals, in 171,038 patients with non–ST-segment elevation acute coronary syndrome (NSTE-ACS) and 79,962 with low-risk chest pain
- 66% of the hospitals had not implemented hs-cTn testing by September 2021
- Use of echocardiography was greater among patients with NSTE-ACS, and the use of invasive coronary angiography was lower among those with low-risk chest pain when they were evaluated with hs-cTn assays compared with conventional cTn assays
- Patients evaluated with hs-cTn had a modestly shorter length of stay and no difference in in-hospital mortality compared with patients evaluated by conventional assays
- These results provide reassurance that transitioning to hs-cTn assays does not increase inappropriate resource use
High-sensitivity cardiac troponin (hs-cTn) assays weren't approved in the U.S. until 2017, compared with 2010 in many other countries. There's little "real-world" U.S. data about whether hs-cTn implementation increases subsequent cardiac testing and length of stay. Furthermore, the benefits of hs-cTn established in international trials may not translate to U.S. practice, which involves more testing of low-risk patients because of more prevalent cardiovascular comorbidities and fears of litigation related to missed myocardial infarction.
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By studying hs-cTn testing using a large, diverse sample of U.S. hospitals, researchers at Massachusetts General Hospital have provided reassurance about those concerns. James L. Januzzi, MD, director of the Dennis and Marilyn Barry Fellowship in Cardiology Research at the Mass General Corrigan Minehan Heart Center, Cian P. McCarthy, MD, a cardiology fellow there, and colleagues published their findings in the Journal of the American College of Cardiology.
The researchers identified 550 hospitals that regularly participated in the National Cardiovascular Data Registry Chest Pain–MI Registry, sponsored by the American College of Cardiology, between January 1, 2019, and September 30, 2021, and had data available on the use of cTn assays.
The study cohort comprised 251,000 adults, of whom 171,038 had a non–ST-segment elevation acute coronary syndrome (NSTE-ACS, including 155,049 with myocardial infarction (MI) and 15,989 with unstable angina) and 79,962 had low-risk chest pain.
A hospital was considered to have implemented hs-cTn if ≥25% of registry patients were evaluated with such assays during a quarter. This cutoff took into account that hospitals may not make an immediate uniform transition to hs-cTn, and patients transferred from outside institutions may have been evaluated with other assays.
Implementation of hs-cTn assays increased from 3.3% in quarter 1 of 2019 to 32.6% in quarter 3 of 2021 (P for trend <0.001). There were no significant differences in the geographic region, hospital bed size, nonprofit status, or annual MI volume between hospitals that did or did not implement hs-cTn assays by September 2021.
11.5% of study patients were evaluated with hs-cTn assays during the study period. Key findings were:
- Patients with NSTE-ACS—Use of echocardiography was greater among those evaluated with hs-cTn than those evaluated with conventional assays (82% vs. 75%; adjusted OR, 1.43; P<0.001); echocardiography is appropriate in this population
- Patients with low-risk chest pain—No significant difference in the use of echocardiography between patients evaluated with vs. without hs-cTn
Stress testing or CT coronary angiography
- Both patient groups—No significant difference in the use of these tests between patients evaluated with vs. without hs-cTn
Invasive coronary angiography
- Patients with NSTE-ACS—Most without contraindications underwent invasive coronary angiography, with no significant difference in the use of the test between patients evaluated with vs. without hs-cTn
- Patients with low-risk chest pain—Those evaluated with hs-cTn were less likely to undergo invasive coronary angiography than those evaluated with conventional assays (3.7% vs. 4.5%; adjusted OR, 0.73; P=0.01)
- Both patient groups—Mortality was similar in patients evaluated with hs-cTn and those evaluated with conventional assays
Length of stay
- Patients with NSTE-ACS—Length of stay (LOS) was slightly but significantly shorter among patients evaluated with hs-cTn compared with conventional cTn (median, 66.9 vs. 67.8 hours; P=0.01)
- Patients with low-risk chest pain—Same conclusion (median, 5.8 vs. 6.2 hours; P<0.001)
The Value of Diagnostic Pathways
In October 2021, the American Heart Association and American College of Cardiology published joint guidelines on managing chest pain in the Journal of the American College of Cardiology, making a class I recommendation that hs-cTn is the preferred biomarker for evaluating acute chest pain. That formal approval may prompt more hospitals to start using the assays.
The results of this study suggest the adoption of hs-cTn assays would reduce unnecessary testing in patients with low-risk chest pain. Widespread implementation of hs-cTn–based accelerated diagnostic pathways is also needed, as they are expected to substantially reduce LOS in patients at low risk.
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