Thrombotic Complications Following Immune Checkpoint Inhibitor Monotherapy: Expanding the Spectrum of Immune-Related Cardiovascular Toxicity: A Narrative Mini-Review

Abstract

Context: Immune checkpoint inhibitors (ICIs) have transformed cancer treatment but are associated with cardiovascular toxicities, particularly myocarditis. Thrombotic adverse effects remain underrecognized despite increasing reports of venous and arterial complications. Evidence Acquisition: This narrative mini-review examined the current evidence on the risk of thrombotic events following ICI monotherapy, potential immunothrombosis-related mechanisms, and the clinical implications of these events. Results: Population-level studies have reported venous thromboembolic event rates of 2% to 4% at 6 months and 4% to 7% at 12 months, whereas chart-reviewed cohorts have reported higher rates of 5% to 15%. Arterial complications, including myocardial infarction and stroke, have also been reported. Thrombosis most commonly occurs within the first 6 months of treatment and may be associated with other immune-mediated adverse effects. Immunothrombosis involving T-cell activation, endothelial inflammation, and neutrophil extracellular traps may contribute to these events. Conclusions: ICI-associated thrombosis may represent part of a broader spectrum of immune-mediated cardiovascular toxicity that differs from conventional cancer-associated thrombosis. Clinicians should maintain a low threshold for diagnostic evaluation, particularly during the first few months of immunotherapy.