Physician Update: AHA Special Edition
Read more articles from our most relevant research presented at the 2021 AHA Scientific Sessions.
Clinical Heart and Vascular Center
UT Southwestern was among the first U.S. health care systems to implement high-sensitivity troponin assays for the evaluation of acute coronary syndrome. Our protocol, which was implemented in the Parkland Health & Hospital System in December of 2017, has been shown to be both safe and efficient. During the session on Troponin Testing in Acute Coronary Syndrome at #AHA21, I was asked to discuss our experience with adoption of both hs-cTnT and hs-cTnI algorithms, including lessons learned from implementation of these protocols.
Using the high-sensitivity protocol, more patients rule out with either a baseline or baseline and one-hour blood draw as compared to the conventional protocol. Although myocardial injury or type 2 MI is more frequently diagnosed with higher-sensitivity assays, we saw improvements in emergency department efficiency with implementation of our protocol with lower emergency department dwell times and an increase in emergency department discharges.
“Among patients with abnormal values in the lowest tertile of I/T ratio (i.e., the ratio of hs-cTnI to hs-cTnT), there were higher rates of comorbidities such as diabetes, coronary artery disease, heart failure, and renal disease.”
We recently studied a cohort of patients undergoing evaluation for suspected MI who had both hs-cTnT and hs-cTnI assays drawn. Consistent with prior studies, we found a modest correlation between the assays. The majority of abnormal values were secondary to myocardial injury. At higher ranges, the hs-cTnI levels were much higher than the hs-cTnT, and at lower ranges, the hs-cTnI levels were lower than hs-cTnT. Among patients with abnormal values in the lowest tertile of I/T ratio (i.e., the ratio of hs-cTnI to hs-cTnT), there were higher rates of comorbidities such as diabetes, coronary artery disease, heart failure, and renal disease. Additionally, the lowest I/T ratio tertile patients had higher proportions of patients with chronic myocardial injury as compared to the top tertile. These data highlight that important phenotypic differences exist among patients with abnormal troponin I and T levels. Clinicians who work in hospitals that use different assays or potentially switch assays will need to be aware of these assay differences as they interpret abnormal values.