A New Scoring System for the Evaluation of Ibrutinib-Associated Arrhythmias in Chronic Lymphocytic Leukemia: The ACEF Score

Objective: Bruton tyrosine kinase inhibition in cardiac tissue causes inhibition of the PI3K-AKT signaling pathway, which is responsible for protecting cardiac tissue during stress. Therefore, there is an increase in the risk of arrhythmia. This study explores the prediction of that risk with the Age-Creatinine-Ejection Fraction (ACEF) score as a simple scoring system based on the components of age, creatinine, and ejection fraction.

Materials and methods: Patients diagnosed with chronic lymphocytic leukemia (CLL) and receiving ibrutinib treatment for at least 1 year were evaluated with echocardiography and Holter electrocardiography and the results were compared with a control group of CLL patients who had not received treatment. ACEF score was calculated with the formula age/left ventricular ejection fraction+1 (if creatinine >2.0 mg/dL).

Results: When the arrhythmia development of the patients was evaluated, no statistically significant difference was found between the control and ibrutinib groups in terms of types of arrhythmias other than paroxysmal atrial fibrillation (PAF). PAF was found to occur at rates of 8% versus 22% (p=0.042) among ibrutinib non-users versus users. For patients using ibrutinib, an ACEF score of >1.21 predicted the development of PAF with 77% sensitivity and 75% specificity (area under the curve: 0.830, 95% confidence interval: 0.698-0.962, p<0.001).

Conclusion: The ACEF score can be used as a risk score that predicts the development of PAF in patients diagnosed with CLL who are scheduled to start ibrutinib.