Left Ventricular Strain Analysis During Submaximal Semisupine Bicycle Exercise Stress Echocardiography in Childhood Cancer Survivors

Abstract

Background Childhood cancer survivors (CCSs) show relevant cardiac morbidity and mortality throughout life. Early detection is key for optimal support of patients at risk. The aim of this study was to evaluate 2-dimensional speckle-tracking echocardiography strain analysis during semisupine exercise stress in CCSs for detection of subclinical left ventricular dysfunction after cancer treatment. Methods and Results Seventy-seven CCSs ≥1-year postchemotherapy were prospectively examined at rest, low, and submaximal stress level and compared with a cohort of healthy adolescents and young adults (n=50). Global longitudinal strain (GLS), short axis circumferential strain, and corresponding strain rates were analyzed using vendor-independent software. CCSs at median 7.8 years postchemotherapy showed comparable left ventricular GLS, circumferential strain, and strain rate values at all stress stages to healthy controls. Yet, prevalence of abnormal GLS (defined as <2 SD of controls reference) in CCSs was 1.3% at rest, 2.7% at low, and 8.6% at submaximal stress. In CCSs, relative change of circumferential strain from rest to submaximal stress was lower than in healthy controls, median 16.9 (interquartile range [IQR], 3.4; 28.8) % versus 23.3 (IQR, 11.3; 33.3) %, P=0.03, most apparent in the subgroups of CCSs after high-dose anthracycline treatment and cancer diagnosis before the age of 5 years. Conclusions In this prospective 2-dimensional speckle tracking echocardiography strain study, prevalence of abnormal left ventricular GLS increased with stress level reflecting impaired cardiac adaptation to exercise stress in some CCSs. However, relatively early after last chemotherapy, this did not result in significant differences of mean GLS-, circumferential strain-, and strain rate values between CCSs and controls at any stress level.

Keywords: 2D‐speckle‐tracking strain echocardiography; cardio‐oncology; childhood cancer survivor; stress echocardiography.

Figure 1. Exercise stress 2‐dimensional‐speckle tracking echocardiography strain analysis in childhood cancer survivors.

Childhood cancer survivors (CCSs), median 7.8 years postchemotherapy, showed an increasing frequency of abnormal global longitudinal strain (GLS) with higher exercise level, reflecting an impaired cardiac adaption in up to 8.6% of CCSs at submaximal stress (top). Yet, there was no relevant difference in mean GLS between CCSs and healthy controls at any stress level neither considering all CCSs (n=77) nor when stratifying for CCSs with high cardiomyopathy risk (n=20), defined as cumulative equivalent anthracycline dose ≥250 mg/m² or chest radiation dose ≥35 Gy or anthracycline dose ≥100 mg/m² and chest radiation ≥15 Gy (middle). Individuals GLS course at different stress levels is shown at the bottom. CCSs indicates childhood cancer survivors; GLS, global longitudinal strain; and n.s., not significant.

Figure 2. Strain curves of a CCS.

Apical 4‐chamber view strain curves from a CCS at rest (top), low (middle), and submaximal stress level (bottom). White curve indicates mean longitudinal strain. CCS indicates childhood cancer survivor.