From the Journals

hs-cTnT test tied to fewer reinfarctions but no survival benefit

 

Key clinical point: The introduction of the new high-sensitivity cardiac troponin T test was associated with an 11% decrease in reinfarctions but showed no evidence of improving survival.

Major finding: Over an average of 3.9 years of follow-up, the adjusted risk of all-cause mortality was identical whether patients’ initial MI was diagnosed with the new troponin test or with the conventional one.

Study details: National cohort study of 87,879 patients with first myocardial infarction, 2009-2013.

Disclosures: Dr. Odqvist and one coinvestigator had no relevant disclosures. Senior author Martin J. Holzmann, MD, PhD, disclosed ties to Actelion and Pfizer. Two other coinvestigators disclosed ties to Roche, Gilead, Janssen, AbbVie, CTI Biopharma, GlaxoSmithKline, Abbott Laboratories, and AstraZeneca, and Fiomi Diagnostics.

Source: Odqvist M et al. J Am Coll Cardiol. 2018 Jun 12;71(23):2616-24.

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Results reassure, raise questions

It’s unclear why reinfarctions were 11% lower after MI was diagnosed with high-sensitivity cardiac troponin (hs-cTn) assays instead of conventional troponin tests in this study.

Use of evidence-based medicines changed only slightly after hospitals implemented the switch. It is tempting to associate the reduction in reinfarction with increased use of angiography and revascularization, but this may be too simplistic. Intervention might have most benefited patients whom conventional troponin assay would have missed. Shifts in medication compliance or rehabilitation might also have been factors.

Used appropriately, hs-cTnT assays can more rapidly rule MI in or out, shorten emergency department stays, and cut costs. Based on the Swedish experience, the increase in MI diagnoses will be modest and manageable. Nonetheless, we will need to develop strategies to manage patients with myonecrosis from etiologies other than MI that will be detected using hs-cTn assays.

L. Kristin Newby, MD, MHS , and Angela Lowenstern, MD , of Duke University in Durham, N.C., made these comments in an accompanying editorial (J Am Coll Cardiol. 2018;71:625-7). Dr. Newby has received consulting honoraria from Roche Diagnostics, Ortho-Clinical Diagnostics, and Philips Healthcare. Dr. Lowenstern is supported by a National Institutes of Health training grant to Duke University .


 

FROM JACC

The introduction of the new high-sensitivity cardiac troponin T (hs-cTnT) test was linked with an 11% decrease in reinfarctions but showed no evidence of improving survival in a large longitudinal cohort study.

Over an average of 3.9 years of follow-up, the adjusted risk of all-cause mortality was identical whether patients’ initial MI was diagnosed with the new troponin test or the conventional one, reported Maria Odqvist, MD, of South Alvsborg Hospital, Boras, Sweden, and her associates. “As hs-cTn assays become widely available and clinicians gain experience interpreting the results, more work is needed to enhance clinical reasoning and implementation to improve patient outcomes,” the researchers wrote in the Journal of the American College of Cardiology.

High-sensitivity cardiac troponin T assays detect acute coronary syndrome more rapidly than their conventional predecessors. However, hs-cTnT’s higher sensitivity comes with lost specificity and hence has raised concerns about potentially wasting health care resources. Some clinicians have asked whether the new test is worthwhile and how to maximize its benefits.

The study, which included nearly 88,000 patients with initial MI from the Swedish National Patient Registry, spanned 2009-2013, when 73% of Swedish acute care hospitals transitioned from conventional troponin tests (cTn) to hs-cTnT. After adjustment for factors such as age, sex, location, chronic kidney disease, cardiovascular history, and prescriptions, Dr. Odqvist and her associates compared each test types’ risks of death, reinfarction, coronary angiography, and revascularization among patients diagnosed.

In all, 47,133 (54%) patients’ initial MI was diagnosed with cTn while 46% were diagnosed with hs-cTnT. Overall, the rate of MI rose by 5% during the 90 days after hospitals implemented hs-cTnT, compared with the 90 days before. But hospitals used varying hs-cTnT thresholds for MI, which might explain why some hospitals initially observed a marked initial decrease in MI while others saw a relatively large increase, the investigators wrote.

There were 15,766 reinfarctions over an average of 3.1 years of follow-up. Although there was no difference in all-cause mortality, risk of reinfarction was 11% lower among patients diagnosed using hs-cTnT, compared with those diagnosed by cTn.

At the hospital level, coronary angiography and revascularization became only slightly more common during the 3 months after hospitals switched to hs-cTnT, the researchers wrote. However, patients whose MIs were diagnosed with hs-cTnT were 16% more likely to undergo coronary angiography and 13% more likely to undergo revascularization within the next 30 days, compared with patients diagnosed with cTn. Patients diagnosed with hs-cTnT also were more likely to receive statins, but trends in other prescriptions did not change.

The Swedish Heart-Lung Foundation funded one investigator. Dr. Odqvist and one coinvestigator reported having no relevant conflicts of interest. Senior author Martin J. Holzmann, MD, PhD, disclosed ties to Actelion and Pfizer. Two other coinvestigators disclosed ties to Roche, Gilead, Janssen, Abbvie, CTI Bipharma, GlaxoSmithKline, Abbott Laboratories, and AstraZeneca, and Fiomi Diagnostics.

SOURCE: Odqvist M et al. J Am Coll Cardiol. 2018 Jun 12;71(23):2616-24

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