Emerging role of immune checkpoint inhibitors and their relevance for the cardiovascular system

Immune checkpoint inhibitor (ICI) therapy induces an immune response against cancer cells. Immune checkpoint inhibitor therapy has tremendously improved the prognosis for a large number of cancers, but is associated with considerable immune-related adverse events (irAEs). Cardiovascular complications from ICI therapy occur in a modest proportion of patients, but show the highest lethality rates of all ICI-related complications. While ICI-related myocarditis is the most dangerous complication, its clinical manifestation varies, e.g., asymptomatic reduction of left ventricular function, isolated increase in cardiac troponins, and arrhythmias. This review delineates current data on cardiovascular complications of ICI therapy. The effects of ICI therapy on the cardiovascular system are classified in the context of preclinical data on the biochemical and immunological function of the immune checkpoint signaling pathways in the heart and the vascular system. Incidence, suspected pathomechanisms, typical symptoms, as well as recommended diagnostics are summarized. Current therapy recommendations for ICI-related cardiotoxicity are outlined and innovative new approaches with high potential for improving outcome in ICI-related myocarditis are delineated. A better understanding of cardiovascular complications is essential for the best possible oncocardiology care of the growing number of patients undergoing ICI therapy.