High-Sensitivity Cardiac Troponin for Diagnosis of Myocardial Infarction in Women
abstract
This abstract is available on the publisher's site.
Access this abstract nowOBJECTIVE
To evaluate the diagnosis of myocardial infarction using a high sensitivity troponin I assay and sex specific diagnostic thresholds in men and women with suspected acute coronary syndrome.
DESIGN
Prospective cohort study.
SETTING
Regional cardiac centre, United Kingdom.
PARTICIPANTS
Consecutive patients with suspected acute coronary syndrome (n=1126, 46% women). Two cardiologists independently adjudicated the diagnosis of myocardial infarction by using a high sensitivity troponin I assay with sex specific diagnostic thresholds (men 34 ng/L, women 16 ng/L) and compared with current practice where a contemporary assay (50 ng/L, single threshold) was used to guide care.
MAIN OUTCOME MEASURE
Diagnosis of myocardial infarction.
RESULTS
The high sensitivity troponin I assay noticeably increased the diagnosis of myocardial infarction in women (from 11% to 22%; P<0.001) but had a minimal effect in men (from 19% to 21%, P=0.002). Women were less likely than men to be referred to a cardiologist or undergo coronary revascularisation (P<0.05 for both). At 12 months, women with undisclosed increases in troponin concentration (17-49 ng/L) and those with myocardial infarction (≥50 ng/L) had the highest rate of death or reinfarction compared with women without (≤16 ng/L) myocardial infarction (25%, 24%, and 4%, respectively; P<0.001).
CONCLUSIONS
Although having little effect in men, a high sensitivity troponin assay with sex specific diagnostic thresholds may double the diagnosis of myocardial infarction in women and identify those at high risk of reinfarction and death. Whether use of sex specific diagnostic thresholds will improve outcomes and tackle inequalities in the treatment of women with suspected acute coronary syndrome requires urgent attention.
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Additional Info
Disclosure statements are available on the authors' profiles:
High Sensitivity Cardiac Troponin and the Under-Diagnosis of Myocardial Infarction in Women: Prospective Cohort Study
BMJ 2015 Jan 21;2015(350)g7873, AS Shah, M Griffiths, KK Lee, DA McAllister, AL Hunter, AV Ferry, A Cruikshank, A Reid, M Stoddart, F Strachan, S Walker, PO Collinson, FS Apple, AJ Gray, KA Fox, DE Newby, NL MillsFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
High-sensitivity troponin assays are revolutionizing the evaluation of patients presenting with chest pain. Nearly 100% of acute myocardial infarctions can now be ruled out in patients presenting within a few hours of chest pain, especially when deemed low risk by TIMI or GRACE scores. Rapid rule-in protocols will allow us to achieve more thorough evidenced-based therapies. As we move forward, we will need to pay specific attention to sex-specific diagnostic thresholds, so that more women will be accurately diagnosed and be able to receive the evidenced-based therapies they have been denied for so long.
High-sensitivity cardiac troponin is used for diagnosing myocardial infarction (MI) in women. Troponin tests have been used to determine cardiac damage, but the standard troponin test could only measure down to 10 ng/L, and the MI threshold was set at 50 ng/L. Interestingly, women tend to have lower troponin levels; with the threshold of 50 ng/L, many women would not be diagnosed with having an MI.
The authors of this study took this concept and compared the high-sensitivity cardiac troponin with the regular troponin in over 1100 patients with suspected acute coronary syndrome. The high-sensitivity test can measure down to 1.2 ng/L, which is almost 10 times lower than the standard test. This study used the 50 ng/L cut-off for the old assay and a 16 ng/L cut-off for the high-sensitivity assay. With the old assay, 11% of women were diagnosed with an MI, but, with the high-sensitivity assay, MI was detected in 22% of the women. The high-sensitivity assay did not impact the detection rate very much in men, who tend to have higher troponin levels; the MI detection rate improved from 19% to 21%.
The authors suggest that gender-specific cut-off points might improve MI detection in the female population.