Impact of High-Sensitivity cTn in Suspected Acute MI
What is the effect of the clinical introduction of high-sensitivity cardiac troponin (hs-cTn) assays on the use of coronary angiography, cardiac stress testing, and time to discharge from the emergency department (ED) in suspected acute myocardial infarction (AMI)?
The investigators evaluated the impact of the clinical introduction of hs-cTnT on the use of coronary angiography, stress testing, and time to discharge in 2,544 patients presenting with symptoms suggestive of AMI to the ED within a multicenter study either before (1,455 patients) or after (1,089 patients) hs-cTnT introduction. In order to adjust for possible confounders between the two time periods, multivariable regression models were used. History of coronary artery disease, known arterial hypertension, and age were used as co-variables in a multivariable model. Interrupted time series analyses were used to test for change in trends over time for duration of stay on the ED and total costs.
AMI was more often the clinical discharge diagnosis after hs-cTnT introduction (10 vs. 14%, p < 0.001), while unstable angina was less often the clinical discharge diagnosis (14 vs. 9%, p = 0.007). The rate of coronary angiography was similar before and after the introduction of hs-cTnT (23 vs. 23%, p = 0.092), as was the percentage of coronary angiographies showing no stenosis (11 vs. 7%, p = 0.361). In contrast, the use of stress testing was substantially reduced from 29 to 19% (p < 0.001). In outpatients, median time to discharge from the ED decreased by 79 minutes (p < 0.001). Mean total costs decreased by 20% in outpatients after the introduction of hs-cTnT (p = 0.002).
The authors concluded that clinical introduction of hs-cTn does not lead to an increased or inappropriate use of coronary angiography.
This study reports that the clinical introduction of hs-cTnT was not associated with an increase in the rate of coronary angiography, or the rate of potentially unnecessary coronary angiography and the rate of coronary revascularization procedures. Furthermore, hs-cTnT testing was associated with a reduction in the need for cardiac stress testing by >30%, and with a significant reduction in time to discharge by nearly 80 minutes, related to more rapid rule-out of AMI. The availability of more precise biomarker information in the lower range as offered by hs-cTnT was associated with improved allocation of patients to further diagnostic cardiac testing with low-risk patients to no further cardiac testing and high-risk patients to coronary angiography. These findings corroborate and extend prior studies highlighting the increased diagnostic accuracy achieved with hs-cTnT, and are consistent with the European Society of Cardiology guidelines.
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