The purpose of this review article is to summarize the preclinical and clinical evidence supporting the notion of clonal hematopoiesis of indeterminate potential (CHIP), highlight current knowledge gap, and provide future directions.

Epidemiological studies show that advanced age is a major risk factor for the development of cardiovascular disease (CVD) and cancer, the two leading causes of morbidity and mortality worldwide. While the negative effect of aging on CVD is a reflection of cumulative exposure to various established traditional CVD risk factors, genetic sequencing of whole blood-derived DNA recently revealed that clonal mutations in myeloid stem cells are associated with higher risks of cardiovascular events and hematopoietic malignancies. The clinical repercussions of this biological state, termed CHIP, are increasingly appreciated. Historically, CHIP has been associated with an increased risk of hematological malignancies. However, new research is showing that CHIP is also associated with an increased risk of several cardiac-related conditions, including atherosclerosis, myocardial infarction, aortic valve stenosis, and congestive heart failure. CHIP is increasingly being appreciated worldwide as a CVD risk factor, and further studies are needed to better understand the complex relationship between these two disorders.

Whether cardiovascular (CV) disease is associated with clinical outcomes in cancer patients receiving immunotherapy is unknown. We reviewed the Mayo Clinic database for all cancer patients who received an immune checkpoint inhibitor (ICI). Multivariate logistic regression analysis, survival analyses, and Cox proportional-hazards models were formulated. Between March, 2010 and July, 2019, 3,326 patients received ICI. Mean patient age was 63.5 years (range: 16 to 96 years). In a Cox proportional-hazards model, obesity (hazard ratio [HR] 0.65, 95% confidence level [CI] 0.55 to 0.77, p < 0.001) and hypercholesterolemia (HR 0.80, 95% CI 0.72 to 0.89, p < 0.001) were associated with lower all-cause mortality while hypertension (HR 1.32, 95% CI 1.17 to 1.49, p < 0.001) and smoking (HR 1.17, 95% CI 1.06 to 1.29, p = 0.002) were associated with higher overall mortality. Among patients with lung cancer, multivariable-adjusted hazard ratios for death from any cause for beta blocker users, as compared with patients who had never used a beta blocker, were 1.39 (95% CI 1.10 to 1.76, p = 0.006). A total of 80 patients (2.4%) experienced CV immune-related adverse events. Event-related morality for ICI-induced myocarditis was 41.7% (5/12). Multivariable-adjusted hazard ratios for ICI-induced myocarditis were 5.2 (95% CI 1.4 to 18.7, p = 0.01) for history of heart failure, 4.06 (95% CI 1.15 to 14.3, p = 0.03) for history of acute coronary syndrome, and 1.07 (per each 1-year increase, 95% CI 1.01 to 1.14, p = 0.02) for age. In conclusion, our study shows that CV factors are associated with clinical outcomes in cancer patients receiving ICI and could be used to predict mortality. In patients with lung cancer, pretreatment beta blocker use is associated with higher all-cause mortality. Three clinical factors-history of heart failure, history of acute coronary syndrome, and age greater than 80 years-help identify patients at higher risk of ICI-induced myocarditis who might benefit from more intensive cardiac surveillance.