Multimodal assessment diagnosed 75% of ICI-associated myocarditis cases; mortality was lower than reported, with overall survival 7.4±6.7 months in 24 confirmed cases.
Diagnosis of ICI myocarditis frequently requires multimodal assessment, and contemporary cohorts may have lower cardiac mortality than previously reported due to early detection of less severe cases.
Absolute Event Rate: 0% vs 0%
Abstract Introduction Immune checkpoint inhibitors (ICIs) are effective treatments for various malignancies including previously incurable ones, leading to a growing patient population. Diagnosing ICI associated myocarditis (ICImyocarditis) is crucial for timely initiation of potentially life-saving immunosuppressive therapy. Although it has been reported in only 1 % of ICI patients, it has a high mortality rate of up to 50 %. The 2021 International Cardio-Oncology Society (IC-OS) consensus outlines diagnostic criteria. The diagnosis can be made either histologically by a compelling endomyocardial biopsy (EMB) or clinically based on a significant troponin (Tn) elevation and 1 major or at least 2 minor criteria, including findings of cardiac magnetic resonance imaging (cMRI), electrocardiography (ECG), an ambiguous EMB and others. This case series highlights the diagnostic complexity and expands our understanding of this adverse event. Methods We performed a retrospective analysis of 32 patients’ medical records referred to our cardiology department over the last 3 years with suspected ICImyocarditis. Diagnostic workup included Tn in 94 %, ECG in 91 %, cMRI in 88 % and EMB in 41 % of cases. 24 patients met the IC-OS criteria. Baseline characteristics and survival are shown in Table 1. Statistical analysis used Fisher’s exact or unpaired t-test with p – values 0.05 considered significant. Results Of 24 confirmed cases, 3 were diagnosed histologically via EMB and 3 by cMRI meeting the revised Lake Louise criteria. In most cases (n = 18), however, multimodal assessment was necessary to establish diagnosis. When comparing baseline characteristics and survival, those who met IC-OS criteria tended to be older, more often male, had fewer cardiovascular risk factors and cardiovascular comorbidities without reaching statistical significance, but they had a significantly higher rate of distant metastases. Overall survival was 7.4 ± 6.7 months with a tendency to better survival in the group not meeting IC-OS criteria. We recorded 9 deaths, of which 2 were tumour-related, 1 infectious, 1 stroke, 1 cardiac and 4 of unknown cause. According to the 2018 American Society of Clinical Oncology Clinical Practice Guideline, most ICImyocarditis patients had mild to moderate disease (18 of 24 cases), 4 were asymptomatic and only 2 presented with severe disease. Of these 2 severe cases, 1 represents the single recorded cardiac death. Conclusion ICImyocarditis remains a diagnostic challenge. In 75 % of confirmed cases, no single test provided diagnostic certainty, emphasizing the need for multimodal assessment and awareness of minor criteria. Notably, our case series does not support the high mortality previously reported in patients with confirmed ICImyocarditis. We hypothesize that close clinical monitoring has revealed previously underreported less severe cases and early therapeutic intervention might prevent progression to severe, high-mortality ICImyocarditis.
Jarabo et al. (Sat,) reported a other. Multimodal assessment diagnosed 75% of ICI-associated myocarditis cases; mortality was lower than reported, with overall survival 7.4±6.7 months in 24 confirmed cases.