New Insights into Mechanisms of Immune Checkpoint Inhibitor-Induced Cardiovascular Toxicity

Purpose of Review The review aims to summarize the present knowledge about cardiovascular toxicities associated with immune checkpoint inhibitors (ICI) and dissect underlying mechanism associated with individual cardiovascular toxicity. Recent Findings Widespread use of ICI therapy has allowed for increasing recognition of a wide spectrum of immune-related adverse events that leave all organ systems vulnerable. Immune-mediated cardiovascular toxicities, initially thought to be rare, are more often being reported and present considerable challenges due to their non-specific clinical presentation, potential to have a fulminant progression, and overlap with other cardiovascular and general medical illnesses. Myocarditis is the most common manifestation of ICI-associated cardiovascular toxicity. Pericardial diseases, vasculitis, Takotsubo syndrome, conduction abnormalities, and destabilization of atherosclerotic lesions constitute other significant adverse events. At this stage, mechanisms underlying fundamental biology of cardiac toxicity have not been studied comprehensively and there remain gaps of knowledge in the current literature concerning the underlying pathomechanisms. It is hypothesized that immune-mediated myocarditis is a result of an exaggerated adaptive immune response against shared epitopes in the myocardium and tumor cells. Further, underlying mechanism of other cardiovascular toxicities is still unclear, further compounded by sparsity of epidemiological data. Summary It is paramount to understand the mechanisms behind ICI-induced cardiovascular toxicities to develop appropriate treatment and prevention strategies and minimize the morbidity and mortality of cancer patients undergoing ICI therapy.