Cardiac magnetic relaxometry versus ejection fraction in anthracycline-related cardiac changes: a systematic review and meta-analysis.

PURPOSE: The purpose of this meta-analysis is to compare the magnitude of the changes in left ventricular ejection fraction (LVEF) and cardiac magnetic resonance (CMR) relaxometry techniques soon after the completion of anthracycline therapy. Anthracyclines are associated with myocardial functional and morphological changes. LVEF is currently used to identify the functional changes. Anthracyclines can also cause myocardial inflammation and oedema. This can be assessed using CMR relaxometry techniques; T1 and T2 mapping and extracellular volume (ECV) fraction. METHODS: Three databases were systematically searched for studies evaluating CMR relaxometry parameter at baseline and 1±1 months after anthracycline completion (the last search date 17 March 2023). CMR parameters pre and post anthracycline-based chemotherapy were abstracted. A random effects model was used to pool mean difference (MD) in LVEF and ECV. Standardised mean difference (SMD) was also calculated for T1 and T2 mapping due to the variations in techniques, normal ranges and for the comparison among the parameters. RESULTS: A total of 296 patients were included from 10 studies. 84% were female with a mean age of 54.9 years. Statistically significant alterations were observed in LVEF (MD -3.38% (95% CI -5.13%, -1.62%)) and ECV (1.92% (1.30%, 2.53%)). The pooled SMDs were also significant in LVEF, T1, T2 and ECV with -0.61 (-0.91, -0.30), 0.53 (0.16, 0.90), 0.59 (0.22, 0.96) and 0.74 (0.41, 1.06), respectively. CONCLUSIONS: Our meta-analysis demonstrated small but significant alterations in CMR relaxometry parameters soon after anthracycline therapy, where ECV was superior to LVEF and T1 or T2 mapping. However, these short-term MDs were below the minimal detectable differences. PROSPERO REGISTRATION NUMBER: CRD42020196296.