Written by Clay Smith
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Accelerated diagnostic protocols using delta high-sensitivity cardiac troponin (hs-cTn) assays had high diagnostic accuracy.
Why does this matter?
There have been several studies that led to the European Cardiology Society guidelines for ultra-rapid rule out of acute MI using hs-cTn T or I. How accurate are these 0/1, 0/2, or 0/3 hour accelerated diagnostic protocols?
Rapid rule-outs
This is a brief “Brass Tacks” from Annals of EM and TheNNT.com covering this big systematic review. In total, they found 32 studies with 30,066 patients. There was no major difference in accuracy among the different assays by Roche, Abbott, and Siemens. Diagnostic accuracy was as follows.
0/1-hour algorithm
- sensitivity 99% (95%CI 98.5% to 99.5%); negative likelihood ratio (LR-): 0.01 (95% CI 0.01 to 0.02)
- specificity 94.0% (95%CI 90.7 to 96.2%); positive likelihood ratio (LR+) 14 (95%CI 9 to 20)
- 17% ruled in; 54% ruled out; 29% undifferentiated
0/2-hour algorithm
- sensitivity 98.6% (95%CI 97.2 to 99.3%); LR- 0.02 (95%CI 0.01 to 0.04)
- specificity 96% (95%CI 92.9 to 97.9%); LR+ 21 (95%CI 13 to 35)
- 15% ruled in; 61% ruled out; 24% undifferentiated
0/3-hour algorithm
- sensitivity 93.7% (95%CI 87.4 to 97.0%); LR- 0.09 (95%CI 0.05 to 0.15)
- specificity 93% (95%CI 86.9 to 96.6%); LR+ 13 (95%CI 6.7 to 24)
- 19% ruled in; 66% ruled out; 15% undifferentiated
Limitations: There was heterogeneity among the studies. Some used clinical criteria plus hs-cTn; some did not. Prevalence of MI varied widely, from 4% to 37%. Authors noted that studies with very high MI prevalence also likely included a larger proportion of patients with conditions that elevated hs-cTn unrelated to AMI. Sometimes the timing of lab draws were way off the 1, 2, or 3-hour mark.
Source
Accuracy of the European Society of Cardiology 0/1-, 0/2-, and 0/3-hour algorithms for diagnosing acute myocardial infarction. Acad Emerg Med. 2022 Jan 22. doi: 10.1111/acem.14444. Online ahead of print.
