Although more U.S. hospitals are using high-sensitivity cardiac troponin (hs-cTn) assays to evaluate and manage patients with suspected acute coronary syndromes, a majority still do not use them, despite hs-cTn assays being the preferred biomarker to diagnose myocardial infarction (MI).

Cian McCarthy, MB, BCh, BAO, of Massachusetts General Hospital, and colleagues reported these findings in a manuscript published Monday online and in the Jan. 24 issue of the Journal of the American College of Cardiology.

Because of its superiority to less sensitive conventional cTn assays, hs-cTn was recommended as the preferred biomarker to diagnose MI by the Universal Definition of MI Task Force.

McCarthy and colleagues evaluated the prevalence of hs-cTn assay use among hospitals that participate in the National Cardiovascular Data Registry (NCDR) Chest Pain-MI Registry and the association of hs-cTn assay use with cardiovascular testing and outcomes among patients included in the registry.

The registry includes adult patients with type 1 MI (both ST-segment elevation myocardial infarction [STEMI] and non-ST-segment elevation myocardial infarction), unstable angina or low-risk chest pain. It does not include patients transferred from an outside facility more than 24 hours previously, patients with type 2 MI or patients arriving for scheduled procedures unless they suffer an in-hospital STEMI.

The study evaluated 251,000 patients from Jan. 1, 2019, through Sept. 30, 2021, in 550 hospitals that participate in the registry. The rate of hs-cTn assay use increased from 3.3% in the first quarter of 2019 to 32.6% in the third quarter of 2021 (p-trend < 0.001).

Patients who were evaluated with hs-cTn were older (median age: 65.0 years [interquartile ratio (IQR): 54.0-74.0 years]) than patients who were not evaluated with hs-cTn (median age: 64.0 years [IQR: 53.0-74.0 years]; p<0.001). Patients evaluated with hs-cTn were less likely to be female (41.1% vs. 41.6%; p<0.001), more likely to be white (83.1% vs. 79.9%; p<0.001), and more likely to have private insurance (59.1% vs. 58.4%, p<0.001).

Patients evaluated with hs-cTn also generally had similar or heavier comorbidity burden than those not evaluated with hs-cTn, with the exception of non-smokers (hs-cTn 43.6% vs. no hs-cTn 45.8%; p<0.001), patients needing dialysis (2.3% vs. 3.0%; p<0.001), with diabetes (35.1% vs. 35.85, p=0.02) or with prior coronary artery bypass grafting (11.0% vs. 12.2%; p<0.001).

The use of hs-cTn was associated with more use of echocardiography among patients with non-ST-segment acute coronary syndrome (NSTE-ACS; 82.4% of patients with hs-cTn underwent echocardiography vs. 75.0% who did not have hs-cTn; adjusted odds ratio: 1.43; 95% confidence interval [CI]: 1.19-1.73), but not among patients with low-risk chest pain.

The use of hs-cTn was also associated with less invasive coronary angiography among low-risk patients (3.7% with hs-cTn underwent invasive coronary angiography vs. 4.5% without hs-cTn; adjusted odds radio: 0.73; 95% CI: 0.58-0.92).

The study also found no association between the use of hs-cTn and noninvasive stress testing or between the use of hs-cTn and coronary computed tomography angiography. Finally, hs-cTn use was not associated with revascularization or mortality in low-risk patients.

The study’s limitations included the possibility of selection bias because participating sites are not required to add patients with low-risk chest pain or unstable angina to the registry, which also does not allow the authors to compare the magnitude of the influence of hs-cTn use on patients with NSTEMI compared to those with unstable angina. The authors noted that the possible overrepresentation of NSTEMI patients in the study “is the exact scenario where higher sensitivity may be associated with a favorable impact on use.” They added the exclusion of type 2 MI patients as an limitation because “it is unknown whether their inclusion would have altered our observations.”

“Further efforts are needed to identify and overcome barriers to wider availability and implementation of hs-cTn assays,” the authors wrote. They also pointed out that the use of hs-cTn “does not appear to increase resource use,” which they said is contrary to concerns that hs-cTn “could be associated with excess admissions and increased use of costly testing.”

In an accompanying editorial, Martha Gulati, MD, MS, of Cedars Sinai Medical Center, Los Angeles, and David D. Berg, MD, MPH, of Brigham and Women’s Hospital, Harvard Medical School, Boston, wrote that the study by McCarthy and colleagues “offers the largest and clearest picture yet of where we stand with hs-cTn assays in U.S. hospitals.”

The expert commenters said the study “underscores the persistent implementation gap that is unfortunately all too common with novel cardiovascular technologies.”

“It is our hope that reports like this shine a spotlight on this issue and motivate quality improvement efforts to more effectively implement hs-cTn in U.S. hospitals,” Gulati and Berg concluded. “As report cards go, there is definite room for growth and improvement in implementation, but also the need for continued evaluation.”

Sources:

McCarthy C, Li S, Wang TY, et al. Implementation of High-Sensitivity Cardiac Troponin Assays in the United States. J Am Coll Cardiol 2023;81:207–219.

Gulati M, Berg DD. High-Sensitivity Cardiac Troponin Assays in U.S. Hospitals: A Report Card. J Am Coll Cardiol 2023;81:220–223.

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