Predictors and Risk Score for Immune Checkpoint-Inhibitor-Associated Myocarditis Severity
Authors: Power John R , Dolladille Charles , Procureur Adriel , Ederhy Stephane R , Palaskas Nicolas L , Lehmann Lorenz H , Cautela Jennifer , Courand Pierre-Yves , Hayek Salim S , Zhu Han , Zaha Vlad G , Cheng Richard K , Alexandre Joachim , Roubille Francois , Baldassarre Lauren A , Baik Alan H , Laufer-Perl Michal , Tamura Yuichi , Asnani Aarti , Francis Sanjeev , Gaughan Elizabeth M , Rainer Peter P , Bailly Guillaume , Flint Danette , Arangalage Dimitri , Cariou Eve , Florido Roberta , Narezkina Anna , Liu Yan , Sandhu Shahneen , Leong Darryl , Issa Nahema , Piriou Nicolas , Heinzerling Lucie , Peretto Giovanni , Crusz Shanthini M , Akhter Nausheen , Levenson Joshua E , Turker Isik , Eslami Assie , Fenioux Charlotte , Moliner Pedro , Obeid Michel , Chang Wei-Ting , Ewer Stephen M , Kassaian Seyed Ebrahim ,   International ICI-Myocarditis Registry, Johnson Douglas B , Nohria Anju , Ben Zadok Osnat Itzhaki , Moslehi Javid J , Salem Joe-Elie 
Published: June 2024

Background: Immune-checkpoint inhibitors (ICI) are associated with life-threatening myocarditis but milder presentations are increasingly recognized. The same autoimmune process that causes ICI-myocarditis can manifest concurrent generalized myositis, myasthenia-like syndrome, and respiratory muscle failure. Prognostic factors for this 'cardiomyotoxicity' are lacking. Methods: A multicenter registry collected data retrospectively from 17 countries between 2014-2023. A multivariable cox regression model (hazard-ratio(HR), [95%confidence-interval]) was used to determine risk factors for the primary composite outcome: severe arrhythmia, heart failure, respiratory muscle failure, and/or cardiomyotoxicity-related death. Covariates included demographics, comorbidities, cardio-muscular symptoms, diagnostics, and treatments. Time-dependent covariates were used and missing data were imputed. A point-based prognostic risk score was derived and externally validated. Results: In 748 patients (67% male, age 23-94), 30-days incidence of the primary composite outcome, cardiomyotoxic death, and overall death were 33%, 13%, and 17% respectively. By multivariable analysis, the primary composite outcome was associated with active thymoma (HR=3.60[1.93-6.72]), presence of cardio-muscular symptoms (HR=2.60 [1.58-4.28]), low QRS-voltage on presenting electrocardiogram (HR for ≤0.5mV versus >1mV=2.08[1.31-3.30]), left ventricular ejection fraction (LVEF) <50% (HR=1.78[1.22-2.60]), and incremental troponin elevation (HR=1.86 [1.44-2.39], 2.99[1.91-4.65], 4.80[2.54-9.08], for 20, 200 and 2000-fold above upper reference limit, respectively). A prognostic risk score developed using these parameters showed good performance; 30-days primary outcome incidence increased gradually from 3.9%(risk-score=0) to 81.3%(risk-score=4). This risk-score was externally validated in two independent French and US cohorts. This risk score was used prospectively in the external French cohort to identify low risk patients who were managed with no immunosuppression resulting in no cardio-myotoxic events. Conclusions: ICI-myocarditis can manifest with high morbidity and mortality. Myocarditis severity is associated with magnitude of troponin, thymoma, low-QRS voltage, depressed LVEF, and cardio-muscular symptoms. A risk-score incorporating these features performed well.