Left ventricular strain and strain rates are decreased in children with normal fractional shortening after exposure to anthracycline chemotherapy

Abstract

Anthracycline chemotherapeutic agents carry the well-recognised risk of cardiotoxicity. Previous methods to evaluate cardiac function are useful, but have significant limitations. We sought to determine the left ventricular strain and strain rate of paediatric cancer patients with normal fractional shortening treated with anthracyclines using the latest ultrasound feature-tracking technology. Echocardiograms on cancer patients before anthracycline exposure and following completion of treatment were retrospectively analysed using Velocity Vector Imaging software in the circumferential and longitudinal planes. The same analysis was performed on matched controls. Only patients with a fractional shortening ≥28% were included. In all, 71 patients were identified with an age at diagnosis of 10.5 ± 4.7 years. The time from diagnosis to follow-up was 3.9 ± 4.0 years and the cumulative anthracycline dose was 356 ± 106 mg/m². Following anthracycline exposure, paediatric cancer patients had a higher heart rate and a lower longitudinal strain, longitudinal diastolic strain rate, circumferential strain, and circumferential systolic and diastolic strain rate when compared with controls. Diastolic strain rate showed the greatest percent difference following anthracycline exposure versus controls. Despite having a normal fractional shortening, children exposed to anthracyclines have subclinical derangement of their left ventricular deformation as measured by decreases in strain and strain rate in both the circumferential and longitudinal axis. In particular, there was a profound decrease in diastolic strain rate following anthracycline exposure compared with controls. Whether the decline of strain or strain rate can predict future risk of developing cardiomyopathy requires further investigation.