Chest Pain Patient Outcomes After Using hsTnT Assay

Study Questions:

Is the use of a high-sensitivity troponin T (hsTnT) assay associated with reduced incidence of major adverse cardiac events (MACE) in chest pain patients?

Methods:

The authors conducted a registry-based cohort study including all patients ≥18 years old who were discharged from Swedish hospitals with the diagnosis of “unspecified chest pain” (as defined by International Classification of Diseases-10th edition) between July 2006 and November 2013. Using national registries, cardiac troponin T (cTnT) assay results and hsTnT assay results were related to the occurrence of 30-day MACE and cardiovascular risk profile. The primary outcome was any MACE (myocardial infarction [MI], unplanned revascularization, or all-cause mortality) within 30 days of discharge. Multivariate regression models adjusting for sex, diabetes, hyperlipidemia, hypertension, obesity, prior MI, and heart failure were used in data analysis.

Results:

The study included 65,696 patients who were ruled out for MI and discharged with unspecified chest pain from 16 Swedish hospitals. The majority of patients 57,701 (88%) were discharged directly from the emergency department (ED), and 7,995 (12%) were discharged after admission. In the period prior to hsTnT assay use, 270 patients (0.9%) were discharged from the ED, who experienced a MACE, compared with 185 patients (0.6%) who suffered a MACE after the introduction of hsTnT (p < 0.001). The use of hsTnT was associated with fewer MACE (odds ratio [OR], 0.7; 95% confidence interval [CI], 0.57-0.83). Admitted patients had more cardiovascular risk factors compared with patients who were discharged from the ED. A total of 199 patients (3.4%) experienced a MACE within 30 days of discharge prior to the use of hsTnT, compared with 157 patients (7.2%) after the introduction of hsTnT assay (OR, 2.18; CI, 1.76-2.72). When adjusted for age, sex, type of hospital, and medical history, the association between the implementation of hsTnT and MACE was not significant among patients discharged directly from the ED (OR, 0.72; 95% CI, 0.48-1.08) or those discharged after admission (OR, 1.28; 95% CI, 0.85-1.95).

Conclusions:

This registry-based study showed that in univariate analysis, the introduction of hsTnT was associated with fewer adverse events in patients directly discharged from the ED with unspecified chest pain. The opposite (i.e., an increased risk of adverse events) was observed in patients discharged after an admission for chest pain when using the hsTnT assay. Multivariable analysis, however, showed MACE rates were not different before and after the implementation of hsTnT assay for both patients discharged from the ED or after admission.

Perspective:

This study suggests the use of hsTnT assay is associated with a decreased incidence of MACE in chest pain patients discharged from the ED and an increased incidence of MACE in patients discharged after a hospital admission. These findings may support the hypothesis that hsTnT can more effectively identify true at-risk patients, who were subsequently admitted, as well as lower-risk patients who were subsequently discharged from the ED. With that being said, the multivariate analysis, which adjusted for age and cardiovascular risk factors (both which differed among the admitted and ED groups and between those who received the cTnT and hsTnT assays) did not demonstrate a significant association of the hsTnT assay and MACE in either study group. Prospective investigations are needed to identify patients in whom hsTnT assay may have a better accuracy for detection of high-risk features or be predictive of adverse cardiovascular events.

Clinical Topics: Acute Coronary Syndromes, Dyslipidemia, Heart Failure and Cardiomyopathies, Prevention, ACS and Cardiac Biomarkers, Acute Heart Failure, Heart Failure and Cardiac Biomarkers, Hypertension

Keywords: Acute Coronary Syndrome, Biological Markers, Chest Pain, Diabetes Mellitus, Emergency Service, Hospital, Heart Failure, Hyperlipidemias, Hypertension, Myocardial Infarction, Obesity, Primary Prevention, Risk Factors, Troponin T


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