Are There Any Differences in Major Adverse Cardiac Events Between Undetectable vs. 99th Percentile High-Sensitivity Troponin? Ryan Kenny, BS; Jennifer Johnson, BA; Cristina Pelin, BA; Deshaun Allen, BS; Ajay Puri, MD; Mark Richman, MD Department of Emergency Medicine, Northwell Health – Long Island Jewish Medical Center Donald and Barbara Zucker School of Medicine at Hofstra/Northwell
BACKGROUND • Acute coronary syndromes persist in the United States as a leading cause of mortality and morbidity. The expeditious and certain diagnosis of such pathological events is imperative toward minimizing these tragic numbers. Cardiac biomarkers are a reliable indicator in the diagnosis of ACS events; the “gold-standard” of which being cardiac-specific troponin. The evolution of such assays has resulted in an increased sensitivity for ACS detection, at the consequence of increased Type 1 error, financial cost, and burden of testing. • LIJ Emergency Department's ACS work-up algorithm states patients with undetectable high-sensitivity (HS) troponin (<6 ng/L) at least 3 hours after cardiac symptom onset do not need a repeat troponin, whereas patients with troponin 6-14 ng/L (detectable, but within the 99th percentile) require a repeat troponin 1 hour after the first troponin was drawn.
Table 1: Demographics of Sample Troponin <6 ng/L (N, %) (N = 858)
Troponin 6-14 ng/L (N, %) (N = 858)
P-value
Age: <40
264 (30.77%)
84 (9.79%)
p < 0.0001
40-64
497 (57.93%)
369 (43.00%)
p < 0.0001
65-84
94 (10.96%)
356 (41.49%)
p < 0.0001
85
3 (0.35%)
49 (5.71%)
p < 0.0001
Male
247 (28.79%)
429 (50.00%)
p < 0.0001
Female
611 (71.21%)
429 (50.00%)
p < 0.0001
AfricanAmerican
309 (36.01%)
316 (36.83%)
p = 0.7242
Non-AfricanAmerican
549 (63.99%)
542 (63.17%)
p = 0.7242
Gender:
OBJECTIVE + HYPOTHESIS • Investigate whether patients with initial troponin results of 6-14 ng/L (99th percentile) have significant difference in 30day major adverse cardiac event (MACE) outcomes than patients with initial troponin results <6 ng/L (undetectable). • No difference would support modifying LIJ ED's ACS algorithm to expand the troponin values not requiring 1-hour repeat troponin from undetectable range to 99th percentile benchmark, as well as extrapolating this protocol to universally utilize the 99th percentile as a potential negative benchmark.
CONCLUSIONS
RESULTS
Race:
• A greater proportion of patients less than 65 years old had troponin levels in the undetectable range as compared to the 99th percentile range, suggesting either an overall lower baseline troponin level or a lower overall risk for major adverse cardiac events (MACE), consistent with clinical understanding. • A greater proportion of patients greater than or equal to 65 years old had troponin levels in the 99th percentile range as compared to the undetectable range, suggesting either an overall higher baseline troponin level or a higher overall risk for MACE, consistent with clinical understanding. • Males exhibited higher incidences of troponin levels within the 6-14 ng/L cohort than in the undetectable range, suggesting a potentially higher baseline cardiac-specific troponin level or greater incidence of MACE. • Females exhibited the converse, with more patients exhibiting troponin levels in the <6 ng/L cohort, insinuating a potentially lower baseline troponin level or lower overall risk for MACE. • There was no statistical significance in the proportion of African Americans and non-African Americans who had troponin levels uniquely in either range. Therefore, baseline troponin levels are likely to be independent of race or there was no difference in race-associated ACS diagnoses or MACE outcomes.
METHODS
REFERENCES
FUTURE DIRECTION
• Setting: Single academic, urban, tertiary care adult Emergency Department (ED) with an annual volume of ~100,000 patients from racially and socioeconomically diverse populations • Participants: All adult ED patients with a troponin from July 1 to Dec. 31, 2018 • Inclusion: High-sensitivity troponin ordered in ED. • Exclusion : <18 years old or confounding variables that elevate troponin, such as CHF, PE, sepsis, CKD, pericarditis, and myocarditis. • Statistics: N-1 Chi square analysis was used to determine significance for cohort demographic proportions. Students Ttest will be used to evaluate continuous parametric variables and Mann-Whitney for non-parametric values. ANOVA will be used for analysis of multiple comparisons.
• Sethi A, Bajaj A, Malhotra G, Arora RR, Khosla S. Diagnostic accuracy of sensitive or high-sensitive troponin on presentation for myocardial infarction: a metaanalysis and systematic review. Vasc Health Risk Manag. 2014;10:435-450. Published 2014 Jul 21. doi:10.2147/VHRM.S63416 • Morrow DA, Cannon CP, Jesse RL, et al. National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines: clinical characteristics and utilization of biochemical markers in acute coronary syndromes. Clin Chem. 2007 Apr;53(4):552-74. PMID: 17384001. • Roongsritong C, Warraich I, Bradley C. Common causes of troponin elevations in the absence of acute myocardial infarction: incidence and clinical significance. Chest. 2004 May;125(5):1877-84. PMID: 15136402. • Anda Bularga, Kuan Ken Lee, Stacey Stewart, Amy V. Ferry, Andrew R. Chapman, Lucy Marshall, Fiona E. Strachan, Anne Cruickshank, Donogh Maguire, Colin Berry, Iain Findlay, Anoop S.V. Shah, David E. Newby, Nicholas L. Mills, Atul Anand, On behalf of the High-STEACS Investigators. High-Sensitivity Troponin and the Application of Risk Stratification Thresholds in Patients With Suspected Acute Coronary Syndrome. Circulation. 2019;140:1557–1568. doi.org/10.1161/CIRCULATIONAHA.119.042866
• Review the EHR charts of the sample populations to identify 30-day outcomes from ED discharge or admission. • Perform a literature review to assess the documented risk in the aforementioned demographic groups with respect to MACE, ACS events, and confounding troponin elevating variables. • Analyze the listed cohorts for potential differences in MACE outcomes to further characterize the significant differences in troponin proportions as related to risk versus baseline levels. • Identify a potential explanation for the lack of statistical significance based on race given previously-understood racial clinical variations such as eGFR utility.
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