High-Sensitivity Troponin Test Yields Only Modest Benefit in Assessing Chest Pain in ER

Larry Hand

August 12, 2016

BEDFORD PARK, AUSTRALIA — Use of high-sensitivity troponin T (hs-TnT) assays, compared with standard TnT assays, may result in only modest improvement in evaluating emergency-department patients with chest pain, according to a new study[1].

For the high-sensitivity assays to be clinically effective, it may require closely joining them with protocols that can help guide interpretation and care, researchers conclude.

"The adoption of new technologies such as high-sensitivity TnT assays requires commensurate adaptions in the health service. Just releasing the assays provides very modest improvements in care and outcome since practice, appropriately, needs to remain conservative," Dr Derek P Chew (Flinders Medical Center, South Australia), told heartwire from Medscape by email.

Chew and colleagues conducted a prospective trial involving 1937 emergency-department patients without ST-segment elevation presenting at five hospitals in Adelaide, Australia, between July 2011 and March 2013.

The results were published online August 9, 2016 in Circulation: Cardiovascular Quality and Outcomes.

The patients were randomized to troponin testing reported to standard TnT levels (>30 ng/L n=964) or high-sensitivity TnT levels (>3 ng/L, n=973) to assess for the cumulative composite end point of all-cause mortality and new or recurrent acute coronary syndrome (ACS) within 12 months. Median patient age was 61, and just over half were men.

The researchers found no significant between-group differences for the primary end point. At 12 months, deaths or new or recurrent ACS occurred in 57 (9.7%) of patients in the high-sensitivity group and in 69 (7.2%) of patients in the standard group (hazard ratio 0.83, P=0.362).

Although the researchers found no between-group differences overall in discharge to home directly from the emergency department, they did observe a higher rate of discharge from the emergency department among low- or no-risk patients in the high-sensitivity group compared with the standard group (168 vs 148, P=0.010).

Researchers observed a significant interaction between use of hs-TnT and the prescription of aspirin among patients with peak troponin of 14 to 29 mg/L within 24 hours (55.4% vs 34.0%, P=0.006).

During the index hospitalization, 1466 patients (75.7%) reached maximal troponin of <30 ng/L within 24 hours.

The researchers found no between-group difference in performance of angiography, and high-sensitivity reporting did not lead to a reduction in 12-month death or new or recurrent ACS overall. But they did observe a modest reduction in death or new or recurrent ACS among patients with troponin levels <30 ng/L (2.6% vs 4.4%, HR 0.58, P=0.050).

The authors say that this study is the first to evaluate unguided troponin T reporting at levels that are possible with a high-sensitivity troponin T assay "on clinical care and outcome within a randomized clinical trial embedded within routine emergency-department care.

"Reporting of the troponin T level without integration with clinical protocols had relatively little impact on admission and cardiac investigations, with modest differences in discharge rates among patients at low and intermediate risk based on other clinical criteria," they conclude.

"To that end, I am a little surprised that the difference is very small, given the numerous voices demanding access to new tests," Chew said. "Clearly, better access will require validated protocols. The further research that is needed is validation of some of the emerging protocols that have been promoted without randomized evidence of safety and efficacy. We have commenced a randomized study with a 1-hour protocol."

The National Health & Medical Research Council of Australia and the South Australian Department of Health supported this research. The authors reported no relevant financial relationships.

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