Abstract 4143359: Troponin as a Predictor for Diagnosis and as a Prognostic Marker for Cardiovascular Outcomes in Immune Checkpoint Inhibitor (ICI) related Myocarditis.

Background: ICI-related myocarditis is challenging to diagnose and associated with adverse cardiovascular events and mortality. ICI therapy has also been associated with acute coronary events. There is limited data regarding cardiac troponin T (cTnT) and its association with these cardiovascular outcomes. Methods: All patients treated with ICI at a tertiary institution from 2011 to 2022 were identified, and the charts of those with cTnT measurements were reviewed. In patients with cTnT elevation (cutoff of >14 ng/L), if the Bonaca criteria for myocarditis were met, these patients were labeled as cTnT+/myocarditis+, otherwise as cTnT+/myocarditis-. Patients with non-elevated cTnT values were labeled cTnT-. Medical records were reviewed for baseline characteristics and long-term outcomes, including cardiac death, new heart failure (HF) diagnosis, and MACE (myocardial infarction, TIA/stroke, new HF diagnosis). Kaplan-Meier curves were created to plot the comparison between the three groups. Results: A total of 1669 cancer patients who received ICI therapy had post-ICI cTnT measurements. Mean age was 68.7±11.3, 58.3% were male, with follow-up at 1 year post ICI administration. Of these, 59 patients were cTnT+/myocarditis+, 1077 patients were cTnT+/myocarditis-, and 533 were cTnT-. Survival free of cardiac death, MACE and new HF diagnosis showed a graded response from worst in cTnT+/myocarditis+ patients and best in cTnT- patients; cTnT+/myocarditis- patients had a more favorable but still worse prognosis than cTnT- patients (Figure 1). A cTnT value of 95 ng/L was identified as the best cutoff for the diagnosis of ICI-related myocarditis (AUC 0.82, sensitivity 81.36%, specificity 81.62%). The optimal cTnT cutoff for cardiac death was 576 ng/L (0.70, sensitivity 72%, specificity of 61%) and for MACE 319 ng/L (AUC 0.61, sensitivity 70%, specificity of 52%). Conclusion: In cancer patients receiving ICI therapy cTnT elevations indicate a higher risk of MACE, HF, and cardiac mortality even in patients without myocarditis. Although worst outcomes are seen in those meeting diagnostic criteria for myocarditis.