Adverse Myocardial and Vascular Side Effects of Immune Checkpoint Inhibitors: a Prospective Multimodal Cardiovascular Assessment

Background: Immune checkpoint inhibitors (ICIs) can induce cardiovascular toxicities.

Objectives: To prospectively assess the incidence of major cardiovascular events (MACE) on ICIs in solid cancer patients: myocarditis, pericarditis, acute coronary syndrome, heart failure, high-degree conduction abnormalities or sustained ventricular arrhythmias, or cardiovascular death at 6 weeks (early MACE), including asymptomatic clinical changes by an independent adjudication committee using current recommended diagnostic criteria. The secondary objective was the incidence of the above-mentioned events adding atrial fibrillation (AF) at 6 months (late MACE).

Results: Participants underwent pre-ICIs and repeated multimodality cardiac imaging (echocardiogram, cardiac magnetic resonance (CMR)), serum biomarkers (ultrasensitive troponin I), and rhythm surveillance (ambulatory ECG monitoring) at 6 weeks and 6 months. Forty-nine patients (38 (77.6%) male; mean age 64.3 (SD 11.0) years old) were included (June 2020-December 2021). Early MACE were observed in 9 (18.4%) patients at mean 40.1 (SD 5.9) days, with heart failure (HF) in 5 (10.2%), ventricular arrhythmias, or new conduction disorders in 4 (8.2%) patients. History of AF (HR 4.49 (CI 1.11-18.14), P = 0.035) predicted early MACE. At 6 months follow-up, 18 MACE were observed in 15/49 (31%) patients, with 6 (12.2%) HF events, 5 (10.2%) significant ventricular arrhythmias, or conduction disorders, and 4 (8.2%) AF. There was a significant decline in LVEF (P < 0.001) in patients with no MACE (P = 0.003) or HF (P = 0.0028). Higher creatinine at inclusion (HR 0.99 [0.98-1.00], P = 0.006) predicted HF on multivariate analysis. There were no significant T1 or T2 mapping changes in our study cohort on repeated CMR.

Conclusions: Cardiotoxicity on ICIs is more frequent than previously described when using a thorough detection strategy, consisting mainly in HF and asymptomatic rhythm disorders.