[Clinical characteristics analysis of patients with severe immune checkpoint inhibitors related myocarditis]

Objective: To analyze the clinical characteristics of patients with severe immune checkpoint inhibitors (ICIs) related myocarditis. Methods: A retrospective study was conducted on the 50 patients with ICIs-related myocarditis in the multidisciplinary cardio-oncology clinic of Zhongshan Hospital affiliated to Fudan University from April 2020 to April 2022. The age of patients was (63.7±10.8) years old, including 37 males and 13 females. The patients were divided into the mild group (n=37) and the severe group (n=13) according to severity. The differences of basic characteristics, clinical manifestations, laboratory tests, auxiliary examination, combined irAEs, treatment and outcomes between the two groups of patients were analyzed. Results: The immunotherapy time [M(Q₁,Q₃)] of patients in the mild group and severe group were 81 (49, 134) and 24 (20, 116) days, respectively (P<0.05). In the severe group, the levels of cTnT [0.605 (0.317, 1.072) μg/L], NT-proBNP [1 126 (386, 1 744) ng/L], CK-MB [78 (48, 238) U/L], and CK-MM [240 (45, 6 543) U/L] were higher than those in the mild group [0.104 (0.045, 0.189) μg/L, 237 (39, 785) ng/L, 24 (20, 33) U/L, 108 (72, 168) U/L, respectively] (all P<0.05). The left ventricular ejection fraction of the severe group [64% (57%, 65%)] was lower than that of the mild group [66% (63%, 69%)] (P<0.05), and the incidence of conduction block (n=4, 4/13) and abnormal ventricular wall motion (n=4, 4/13), the incidence of ICIs-related myositis (n=10, 10/13), ICIs-related hepatitis (n=4, 4/13) and ICIs-related neurotoxicity (n=4, 4/13) were higher than those in the mild group (n=1, 2.7%; n=2, 5.4%; n=16, 43.2%; n=2, 5.4%; n=1, 2.7%, respectively) (all P<0.05). The proportion of patients receiving intensified immunosuppressive therapy and mortality rate in the severe group were 12/13 (n=12) and 4/13 (n=4), which were both higher than those in the mild group [10.8% (n=4) and 0] (both P<0.05). Conclusions: The incidence of ICIs-related myocarditis is not high, but the severe rate and mortality are high. The differential diagnosis of severe ICIs related myocarditis should be combined with myocardial markers, electrocardiogram and echocardiogram, and early diagnosis and treatment can improve the prognosis of patients.