I may be reviewing this article just because of its acronym – a recognition of the serious efforts expended to derive SWEDEHEART and its full name: “Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies”.
Briefly, this is a prospective registry of patients admitted to coronary care units in Sweden with symptoms suggestive of acute coronary syndrome. These authors’ goal was to describe the implications and prognostic value of the new, 5th-generation highly-sensitive troponins, specifically the Elecsys hsTnT. This particular assay has a limit of detection of 5 ng/L, a 99th percentile in healthy controls of 14 ng/L, and less than 10% coefficient of variation at 13 ng/L. This compares to the prior generation of assays in which positive results were roughly ~50 ng/L. Overall, the authors reviewed the inpatient stays for 48,594 patients.
There are probably two useful takeaways from this article:
- Only 18% of patients with “positive” hsTnT between 14-49 ng/L were ultimately diagnosed with MI. This compares with 81.2% of those with hsTnT >50 ng/L.
- The one-year mortality of patients with hsTnT between 14-49 ng/L on admission was 10.3%. This compares to 2.0% for those less than 14 ng/L and 17.1% for those >50 ng/L.
The acute implication for Emergency Medicine is mostly a recognition of the prevalence of elevations >99th percentile outside the context of an acute coronary syndrome. The less acute, but equally important implication, is recognizing the need for aggressive referral and follow-up for those with small elevations in the absence of ACS. While no “emergency” intervention is necessary, detection of even low levels of cardiac suffering is a strong predictor of future risk, and should be recognized accordingly.
“Implications of Introducing High-Sensitivity Cardiac Troponin T Into Clinical Practice”
http://www.ncbi.nlm.nih.gov/pubmed/25908071