Occult cardiotoxicity in childhood cancer survivors exposed to anthracycline therapy

Anthracycline therapy induces an early decline of cardiac contractility in low-risk patients with breast cancer

AIMS

Cancer therapy-related cardiac dysfunction (CTRCD) is a dreaded complication of anthracycline therapy. CTRCD most frequently appears in patients with cardiovascular risk factors (CVR) or known cardiovascular disease. However, limited data exist on incidence and course of anthracycline-induced CTRCD in patients without preexisting risk factors. We therefore aimed to longitudinally investigate a cohort of young women on anthracycline treatment due to breast cancer without cardiovascular risk factors or known cardiovascular disease (NCT03940625).

METHODS AND RESULTS

We enrolled 59 women with primary breast cancer and scheduled anthracycline-based therapy, but without CVR or preexisting cardiovascular disease. We conducted a longitudinal assessment before, immediately and 12 months after cancer therapy with general laboratory, electrocardiograms, echocardiography and cardiovascular magnetic resonance (CMR), including myocardial relaxometry with T1, T2 and extracellular volume mapping. Every single patient experienced a drop in CMR-measured left ventricular ejection fraction (LVEF) of 6 ± 3% immediately after cancer therapy. According to the novel definition 32 patients (54.2%) developed CTRCD after 12 months defined by reduction in LVEF, global longitudinal strain (GLS) and/or biomarkers elevation, two of them were symptomatic. Global myocardial T2 relaxation times as well as myocardial mass increased coincidently with a decline in wall-thickening. While T2 values and myocardial mass normalized after 12 months, LVEF and GLS remained impaired.

CONCLUSION

In every single patient anthracyclines induce a decline of myocardial contractility, even among patients without pre-existing risk factors for CTRCD. Our data suggest to thoroughly evaluate whether this may lead to an increased risk of future cardiovascular events.

Imaging Assessment of Radiation Therapy-Related Normal Tissue Injury in Children: A PENTEC Visionary Statement

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) consortium has made significant contributions to understanding and mitigating the adverse effects of childhood cancer therapy. This review addresses the role of diagnostic imaging in detecting, screening, and comprehending radiation therapy-related late effects in children, drawing insights from individual organ-specific PENTEC reports. We further explore how the development of imaging biomarkers for key organ systems, alongside technical advancements and translational imaging approaches, may enhance the systematic application of imaging evaluations in childhood cancer survivors. Moreover, the review critically examines knowledge gaps and identifies technical and practical limitations of existing imaging modalities in the pediatric population. Addressing these challenges may expand access to, minimize the risk of, and optimize the real-world application of, new imaging techniques. The PENTEC team envisions this document as a roadmap for the future development of imaging strategies in childhood cancer survivors, with the overarching goal of improving long-term health outcomes and quality of life for this vulnerable population.

T1 Mapping in Cardiovascular Magnetic Resonance-A Marker of Diffuse Myocardial Fibrosis in Patients Undergoing Hematopoietic Stem Cell Transplantation

Introduction: Hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of cardiovascular diseases. In our study, we aimed to find subclinical changes in myocardial tissue after HSCT with the help of cardiovascular magnetic resonance (CMR) tissue imaging techniques. Methods: The data of 44 patients undergoing autologous and allogeneic HSCT in the Hospital of Lithuanian University of Health Sciences Kaunas Clinics from October 2021 to February 2023 were analyzed. Bioethics approval for the prospective study was obtained (No BE-2-96). CMR was performed two times: before enrolling for the HSCT procedure (before starting mobilization chemotherapy for autologous HSCT and before starting the conditioning regimen for allogeneic HSCT) and 12 ± 1 months after HSCT. LV end-diastolic volume, LV end-systolic volume, LV mass and values indexed to body surface area (BSA), and LV ejection fraction were calculated. T1 and T2 mapping values were measured. Results: There was a statistically significant change in T1 mapping values. Before HSCT, mean T1 mapping was 1226.13 ± 39.74 ms, and after HSCT, it was 1248.70 ± 41.07 ms (p = 0.01). The other parameters did not differ significantly. Conclusions: Increases in T1 mapping values following HSCT can show the progress of diffuse myocardial fibrosis and may reflect subclinical injury. T2 mapping values remain the same and do not show edema and active inflammation processes at 12 months after HSCT.

CMR reveals myocardial damage from cardiotoxic oncologic therapies in breast cancer patients

BACKGROUND

Breast cancer is a common and increasingly treatable disease. However, survivors have a significantly elevated risk of cardiac events afterwards. This study aimed to characterise cardiac changes during cardiotoxic cancer therapy using cardiovascular magnetic resonance (CMR) imaging.

METHODS

This study involved 34 patients with histologically proven breast cancer and planned cardiotoxic therapy. All patients underwent CMR before starting therapy, and 6 and 12 months thereafter. The CMR protocol included volumetric and functional analyses, parametric mapping, and deformation analysis using feature tracking. As the control group, 10 healthy female volunteers were scanned using the same protocol.

RESULTS

With therapy, there was a significant reduction of left ventricular and right ventricular ejection fractions (both p < 0.05) without reaching pathologic values. Left ventricular radial (p = 0.008), circumferential (p = 0.010), and longitudinal strain (p = 0.036) were also reduced at follow-up. In the parametric mapping, there was a significant increase in native T1 time (start: 1037 ± 41 ms vs. 6 months: 1068 ± 51 ms vs. 12 months: 1017 ± 57 ms, p < 0.001) and T2 time (start: 55 ± 4 ms vs. 6 months: 59 ± 3 ms vs. 12 months: 57 ± 3 ms, p = 0.001), with unchanged extracellular volume and relative late gadolinium enhancement. Twelve months after cancer diagnosis, the breast cancer patients exhibited significant impairments in left ventricular global radial (p = 0.001), circumferential (p = 0.001), and longitudinal strain (p = 0.002) and T2 time (p = 0.008) compared to the healthy controls.

DISCUSSION

Breast cancer patients receiving cardiotoxic chemotherapy show persistent deterioration in left ventricular strain values. This is accompanied by inflammatory changes in non-invasive tissue characterisation. Larger studies with longer follow-up periods are needed to identify patients at risk and establish preventive and therapeutic approaches.

The Role of Advanced Cardiovascular Imaging Modalities in Cardio-Oncology: From Early Detection to Unravelling Mechanisms of Cardiotoxicity

Advances in cancer therapies have led to a global improvement in patient survival rates. Nevertheless, the price to pay is a concomitant increase in cardiovascular (CV) morbidity and mortality in this population. Increased inflammation and disturbances of the immune system are shared by both cancer and CV diseases. Immunological effects of anti-cancer treatments occur with both conventional chemotherapy and, to a greater extent, with novel biological therapies such as immunotherapy. For these reasons, there is growing interest in the immune system and its potential role at the molecular level in determining cardiotoxicity. Early recognition of these detrimental effects could help in identifying patients at risk and improve their oncological management. Non-invasive imaging already plays a key role in evaluating baseline CV risk and in detecting even subclinical cardiac dysfunction during surveillance. The aim of this review is to highlight the role of advanced cardiovascular imaging techniques in the detection and management of cardiovascular complications related to cancer treatment.

Cardiac Imaging in Childhood Cancer Survivors: A State-of-the-Art Review

Childhood cancer survival has improved significantly in the past few decades, reaching rates of 80% or more at 5 years. However, with improved survival, early- and late-occurring complications of chemotherapy and radiotherapy exposure are becoming progressively more evident. Cardiovascular diseases represent the leading cause of non-oncological morbidity and mortality in this highly vulnerable population. Therefore, the necessity of reliable, noninvasive screening tools able to early identify cardiac complications early is now pre-eminent in order to implement prevention strategies and mitigate disease progression. Echocardiography, may allow identification of myocardial dysfunction, pericardial complications, and valvular heart diseases. However, additional imaging modalities may be necessary in selected cases. This manuscript provides an in-depth review of noninvasive imaging parameters studied in childhood cancer survivors. Furthermore, we will illustrate brief surveillance recommendations according to available evidence and future perspectives in this expanding field.

Cardiopulmonary Exercise Testing Characterizes Silent Cardiovascular Abnormalities in Asymptomatic Pediatric Cancer Survivors

Late-onset cardiovascular complications are serious concerns for pediatric cancer survivors (PCS) including those who are asymptomatic. We investigated whether cardiopulmonary exercise testing (CPET) can delineate the underlying pathophysiology of preclinical cardiovascular abnormalities in PCS. We examined CPET data via cycle ergometer in asymptomatic PCS with normal echocardiogram and age-matched controls. Peak and submaximal parameters were analyzed. Fifty-three PCS and 60 controls were studied. Peak oxygen consumption (VO₂), peak work rate (WR), and ventilatory anaerobic threshold (VAT) were significantly lower in PCS than controls (1.86 ± 0.53 vs. 2.23 ± 0.61 L/min, 125 ± 45 vs. 154 ± 46 W, and 1.20 ± 0.35 vs. 1.42 ± 0.43 L/min, respectively; all p < 0.01), whereas peak heart rate (HR) and ventilatory efficiency (a slope of minute ventilation over CO₂ production or ∆VE/∆VCO₂) were comparable. Peak respiratory exchange ratio (RER) was significantly higher in PCS (p = 0.0006). Stroke volume (SV) reserve was decreased in PCS, indicated by simultaneous higher dependency on HR (higher ∆HR/∆WR) and lower peak oxygen pulse (OP). Twelve PCS with high peak RER (≥ 1.3) revealed lower pVO₂ and VAT than the rest of PCS despite higher ventilatory efficiency (lower ∆VE/∆VCO₂), suggesting fundamental deficiency in oxygen utilization in some PCS. Poor exercise performance in PCS may be mainly attributed to limited stroke volume reserve, but the underlying pathophysiology is multifactorial. Combined assessment of peak and submaximal CPET parameters provided critical information in delineating underlying exercise physiology of PCS.

The Use of Stress Cardiovascular Imaging in Pediatric Population

Although not frequent in the pediatric population, ischemia could occur in children due to several congenital and acquired disease. Stress imaging is key for the non-invasive evaluation of myocardial abnormalities and perfusion defect in this clinical setting. Moreover, beyond ischemia assessment, it can provide complementary diagnostic and prognostic information in valvular heart disease and cardiomyopathies. When performed using cardiovascular magnetic resonance, it could detect, in addition, myocardial fibrosis and infarction, increasing the diagnostic yield. Several imaging modalities are currently available for the evaluation of stress myocardial perfusion. Advances in technologies have also increased the feasibility, safety and availability of these modalities in the pediatric age group. However, despite the established role of stress imaging and its increasing use in daily clinical practice, there are currently no specific guidelines, and little data are available in the literature on this topic. The aim of this review is to summarize the most recent evidence on pediatric stress imaging and its clinical application with a focus on the advantages and limitations of each imaging modality currently available.

Myocardial Contractility Pattern Characterization in Radiation-Induced Cardiotoxicity Using Magnetic Resonance Imaging: A Pilot Study with ContractiX

Radiation therapy (RT) plays an integral role in treating thoracic cancers, despite the risk of radiation-induced cardiotoxicity. We hypothesize that our newly developed magnetic resonance imaging (MRI)-based contractility index (ContractiX) is a sensitive marker for early detection of RT-induced cardiotoxicity in a preclinical rat model of thoracic cancer RT. Adult salt-sensitive rats received image-guided heart RT and were imaged with MRI at 8 weeks and 10 weeks post-RT or sham. The MRI exam included cine and tagging sequences to measure left-ventricular ejection fraction (LVEF), mass, myocardial strain, and ContractiX. Furthermore, ventricular torsion, diastolic strain rate, and mechanical dyssynchrony were measured. Statistical analyses were performed between the sham, 8 weeks post-RT, and 10 weeks post-RT MRI parameters. The results showed that both LVEF and myocardial mass increased post-RT. Peak systolic strain and ContractiX significantly decreased post-RT, with a more relative reduction in ContractiX compared to strain. ContractiX showed an inverse nonlinear relationship with LVEF and continuously decreased with time post-RT. While early diastolic strain rate and mechanical dyssynchrony significantly changed post-RT, ventricular torsion changes were not significant post-RT. In conclusion, ContractiX measured via non-contrast MRI is a sensitive early marker for the detection of subclinical cardiac dysfunction post-RT, and it is superior to other MRI cardiac measures.

Cardio-Oncology in Childhood: State of the Art

PURPOSE OF REVIEW

Cardio-oncology is an increasingly important field of cardiology that focuses on the detection, monitoring, and treatment of cardiovascular disease (CVD) occurring during and after oncological treatments. The survival rate for childhood cancer patients has dramatically increased thanks to new treatment protocols and cardiovascular (CV) sequelae represent the third most frequent cause of mortality in surviving patients. This study aims to provide a complete and updated review of all the main aspects of cardio-oncology in childhood and to highlight the critical issues.

RECENT FINDINGS

The problem of CV complications in childhood cancer survivors raises the need to make an early diagnosis of cardiotoxicity by the new imaging and laboratory techniques in order to intervene promptly and to implement pharmacological strategies and lifestyle changes to reduce or even to prevent cardiac injury. Furthermore, a stratification of CV risk, also including new predisposing factors such as the presence of some genetic mutations, is of paramount importance before undertaking oncological treatments. Besides, a systematic and personalized planning of long-term follow-up is fundamental to ensure a transition from pediatric to adult hospital and to avoid missed or late diagnosis of cardiomyopathy. We reviewed the main risk factors for cardiotoxicity in children, both traditional and emerging ones: the mechanisms of toxicity of both old and new antineoplastic therapies, the techniques for detecting cardiac damage, and the current evidence regarding pharmacological cardioprotection. At the end, we focused our attention on the existing guidelines and strategies about the long-term follow-up of childhood cancer survivors.

Cardiac MRI assessment of anthracycline-induced cardiotoxicity

The objective of this review article is to discuss how cardiovascular magnetic resonance (CMR) imaging measures left ventricular (LV) function, characterizes tissue, and identifies myocardial fibrosis in patients receiving anthracycline-based chemotherapy (Anth-bC). Specifically, CMR can measure LV ejection fraction (EF), volumes at end-diastole (LVEDV), and end-systole (LVESV), LV strain, and LV mass. Tissue characterization is accomplished through T1/T2-mapping, late gadolinium enhancement (LGE), and CMR perfusion imaging. Despite CMR’s accuracy and efficiency in collecting data about the myocardium, there are challenges that persist while monitoring a cardio-oncology patient undergoing Anth-bC, such as the presence of other cardiovascular risk factors and utility controversies. Furthermore, CMR can be a useful adjunct during cardiopulmonary exercise testing to pinpoint cardiovascular mediated exercise limitations, as well as to assess myocardial microcirculatory damage in patients undergoing Anth-bC.

Cardiovascular Magnetic Resonance Imaging in the Early Detection of Cardiotoxicity Induced by Cancer Therapies

The significant progress in cancer treatment, including chemotherapy, immunotherapy, radiotherapy, and combination therapies, has led to higher long-term survival rates in cancer patients, while the cardiotoxicity caused by cancer treatment has become increasingly prominent. Cardiovascular magnetic resonance (CMR) is a non-invasive comprehensive imaging modality that provides not only anatomical information, but also tissue characteristics and cardiometabolic and energetic assessment, leading to its increased use in the early identification of cardiotoxicity, and is of major importance in improving the survival rate of cancer patients. This review focused on CMR techniques, including myocardial strain analysis, T1 mapping, T2 mapping, and extracellular volume fraction (ECV) calculation in the detection of early myocardial injury induced by cancer therapies. We summarized the existing studies and ongoing clinical trials using CMR for the assessment of subclinical ventricular dysfunction and myocardial changes at the tissue level. The main focus was to explore the potential of clinical and preclinical CMR techniques for continuous non-invasive monitoring of myocardial toxicity associated with cancer therapy.

SCMR expert consensus statement for cardiovascular magnetic resonance of acquired and non-structural pediatric heart disease

Cardiovascular magnetic resonance (CMR) is widely used for diagnostic imaging in the pediatric population. In addition to structural congenital heart disease (CHD), for which published guidelines are available, CMR is also performed for non-structural pediatric heart disease, for which guidelines are not available. This article provides guidelines for the performance and reporting of CMR in the pediatric population for non-structural ("non-congenital") heart disease, including cardiomyopathies, myocarditis, Kawasaki disease and systemic vasculitides, cardiac tumors, pericardial disease, pulmonary hypertension, heart transplant, and aortopathies. Given important differences in disease pathophysiology and clinical manifestations as well as unique technical challenges related to body size, heart rate, and sedation needs, these guidelines focus on optimization of the CMR examination in infants and children compared to adults. Disease states are discussed, including the goals of CMR examination, disease-specific protocols, and limitations and pitfalls, as well as newer techniques that remain under development.

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

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.

Herceptin-Mediated Cardiotoxicity: Assessment by Cardiovascular Magnetic Resonance

Herceptin (trastuzumab) is a recombinant, humanized, monoclonal antibody that targets the human epidermal growth factor receptor 2 (HER2) and is used in the treatment of HER2-positive breast and gastric cancers. However, it carries a risk of cardiotoxicity, manifesting as left ventricular (LV) systolic dysfunction, conventionally assessed for by transthoracic echocardiography. Clinical surveillance of cardiac function and discontinuation of trastuzumab at an early stage of LV systolic dysfunction allow for the timely initiation of heart failure drug therapies that can result in the rapid recovery of cardiac function in most patients. Often considered the reference standard for the noninvasive assessment of cardiac volume and function, cardiac magnetic resonance (CMR) imaging has superior reproducibility and accuracy compared to other noninvasive imaging modalities. However, due to limited availability, it is not routinely used in the serial assessment of cardiac function in patients receiving trastuzumab. In this article, we review the diagnostic and prognostic role of CMR in trastuzumab-mediated cardiotoxicity.

Cardiovascular magnetic resonance characterisation of anthracycline cardiotoxicity in adults with normal left ventricular ejection fraction

BACKGROUND

Anthracycline therapy may lead to changes in cardiac structure and function not detectable by solely evaluating left ventricular ejection fraction (LVEF).

OBJECTIVES

We hypothesized that cardiovascular magnetic resonance (CMR) would identify structural and functional myocardial abnormalities in anthracycline-treated cancer survivors with normal LVEF, compared to a matched control population.

METHODS

Forty-five cancer survivors (56 ± 16 yrs., 60% female) with normal LVEF (59.5 ± 4.1%) were studied a median of 11 months (range 3-36) following administration of 237 ± 83 mg/m² anthracycline, and compared with forty-five healthy control subjects of similar age and sex (53 ± 16 yrs., 60% female) with normal LVEF (60.8 ± 2.4%) using 1.5 T CMR.

RESULTS

Significantly smaller indexed left ventricular mass (45.6 ± 8.7 vs 50.3 ± 10.1 g/m², p = 0.02) and indexed myocardial cell volume (30.5 ± 5.7 vs 34.8 ± 7.2 ml/m², p = 0.002) were evident in cancer survivors and the latter was inversely associated with cumulative anthracycline dose (r = -0.31, p = 0.02). Surrogate CMR markers of myocardial fibrosis were significantly increased in cancer survivors (native myocardial T₁: 1021 ± 40 vs 996 ± 35 ms, p = 0.002; extracellular volume: 29.5 ± 4.5 vs 27.4 ± 2.3%, p = 0.006). CMR-derived feature-tracking global longitudinal strain (GLS) was significantly impaired in cancer survivors (2D GLS -18.3 ± 2.6 vs -20.0 ± 2.0%, p < 0.001; 3D GLS -14.5 ± 2.3 vs -16.4 ± 2.6%, p < 0.001). Parameters exhibited good to excellent (ICC = 0.86-0.98) inter- and intra-observer reproducibility.

CONCLUSIONS

Anthracycline-treated cancer survivors with normal LVEF have significant perturbations of LV mass, myocardial cell volume, native myocardial T1, ECV, CMR-derived 2D and 3D GLS, compared to controls, with good to excellent levels of inter- and intra-observer reproducibility.

The Utility of Advanced Cardiovascular Imaging in Cancer Patients-When, Why, How, and the Latest Developments

Cardio-oncology encompasses the risk stratification, prognostication, identification and management of cancer therapeutics related cardiac dysfunction (CTRCD). Cardiovascular imaging (CVI) plays a significant role in each of these scenarios and has broadened from predominantly quantifying left ventricular function (specifically ejection fraction) to the identification of earlier bio-signatures of CTRCD. Recent data also demonstrate the impact of chemotherapy on the right ventricle, left atrium and pericardium and highlight a possible role for CVI in the identification of CTRCD through tissue characterization and assessment of these cardiac chambers. This review aims to provide a contemporary perspective on the role of multi-modal advanced cardiac imaging in cardio-oncology.

Early detection of myocardial changes with and without dexrazoxane using serial magnetic resonance imaging in a pre-clinical mouse model

Background

Cancer therapy-related cardiac dysfunction may occur in pediatric cancer survivors. Identification of early markers of myocardial damage secondary to anthracycline exposure is crucial to develop strategies that may ameliorate this complication.

Objectives

The purpose of this study was to identify early myocardial changes induced by doxorubicin with and without cardioprotection using dexrazoxane detected by serial cardiac magnetic resonance imaging (CMR) in a pre-clinical mouse model.

Methods

Serial CMR examinations were performed in 90 mice distributed in 3 groups: 45 received doxorubicin (DOX group), 30 mice received doxorubicin with dexrazoxane (DOX/DEX group) and 15 mice received saline injections (control group). We obtained the following CMR parameters in all mice: T2, extracellular volume quantification (ECV), myocardial deformation, and functional quantification.

Results

Myocardial edema assessed by T2 time was the earliest parameter demonstrating evidence of myocardial injury, most notable in the DOX group at week 4 and 8 compared with DOX/DEX group. Similarly, global longitudinal strain was abnormal in both the DOX and DOX/DEX groups. However, this change persisted only in the DOX group. The ECV was significantly elevated in the DOX group at the final CMR, while only minimally elevated in the DOX/DEX group. The right and left ejection fraction was decreased, along with the mass to volume ratio in the DOX group. The T2 time, ECV, and deformation correlated with ejection fraction and left ventricular volume.

Conclusions

T2 time and deformation by CMR identifies early myocardial injury from anthracyclines. Dexrazoxne did not prevent the initial edema, but the inflammatory changes were not sustained. CMR may be useful for early detection of cardiac dysfunction. Serial CMR demonstrates dexrazoxane minimizes cardiac dysfunction and aids recovery in a mouse model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40959-021-00109-8.

Effect of anthracycline therapy on myocardial function and markers of fibrotic remodelling in childhood cancer survivors

AIMS

Anthracyclines are a cornerstone of paediatric cancer treatment. We aimed to quantify myocardial cardiac magnetic resonance (CMR) native T1 (NT1) and extracellular volume fraction (ECV) as markers of fibrosis in a cohort of childhood cancer survivors (CCS).

METHODS AND RESULTS

A cohort of CCS in remission underwent CMR T1 mapping. Diastolic function was assessed by echocardiography. Results were compared to a cohort of normal controls of similar age and gender. Fifty-five CCS and 46 controls were included. Both groups had similar mean left ventricular (LV) NT1 values (999 ± 36 vs. 1007 ± 32 ms, P = 0.27); ECV was higher (25.6 ± 6.9 vs. 20.7 ± 2.4%, P = 0.003) and intracellular mass was lower (37.5 ± 8.4 vs. 43.3 ± 9.9g/m2, P = 0.02) in CCS. The CCS group had lower LV ejection fraction (EF) and LV mass index with otherwise normal diastolic function in all but one patient. The proportion of subjects with elevated ECV compared to controls did not differ between subgroups with normal or reduced LV EF (22% vs. 28%; P = 0.13) and no correlations were found between LVEF and ECV. While average values remained within normal range, mitral E/E' (6.6 ± 1.6 vs. 5.9 ± 0.9, P = 0.02) was higher in CCS. Neither NT1 nor ECV correlated with diastolic function indices or cumulative anthracycline dose.

CONCLUSIONS

There is evidence for mild diffuse extracellular volume expansion in some asymptomatic CCS; myocyte loss could be part of the mechanism, accompanied by subtle changes in systolic and diastolic function. These findings suggest mild myocardial damage and remodelling after anthracycline treatment in some CCS which requires continued monitoring.

Diagnosis, Prevention, Treatment and Surveillance of Anthracycline-Induced Cardiovascular Toxicity in Pediatric Cancer Survivors

Advances in pediatric cancer therapies have dramatically improved the likelihood of survival. As survivors are aging, however, we are now understanding that treatment carries a significant risk of cardiovascular toxicity, which can develop immediately, or even many years after completing therapy. Anthracycline derivates are some of the most commonly used agents in pediatric oncology treatment protocols, which have a dose-dependent correlation with the development of cardiac toxicity. As we learn more about the mechanisms of toxicity, we are developing prevention strategies, including improvements in surveillance, to improve early diagnosis of heart disease. Current survivorship surveillance protocols often include screening echocardiograms to evaluate systolic function by measuring the ejection fraction or fractional shortening. However, these measurements alone are not enough to capture early myocardial changes. The use of additional imaging biomarkers, serum biomarkers, electrocardiograms, as well as cholesterol and blood pressure screening, are key to the early detection of cardiomyopathy and cardiovascular disease. Medical treatment strategies are the same as those used for heart failure from other causes, but earlier recognition and implementation can lead to improved long term outcomes.

Cardiotoxicity in HER2-positive breast cancer patients

Due to the recent advances in diagnosis and management of patients with HER2-positive breast cancer, especially through novel HER2-targeted agents, cardiotoxicity becomes an emerging problem. Although chemotherapy significantly increases survival, the risk of cardiovascular disease development is high and still underestimated and could imply treatment discontinuation. Frequently, due to lack of rigorous diagnosis strategies, cardiotoxicity assessment is delayed, and, moreover, the efficacy of current therapy options in restoring heart function is questionable. For a comprehensive risk assessment, it is vital to characterize the clinical spectrum of HER2-targeted agents and anthracyclines, as well as their pathogenic pathways involved in cardiotoxicity. Advanced cardiovascular multimodal imaging and circulating biomarkers plays primary roles in early assessing cardiotoxicity and also in guiding specific preventive measures. Even though the knowledge in this field is rapidly expanding, there are still questions that arise regarding the optimal approach in terms of timing and methods. The aim of the current review aims to providean overview of currently available data.

Cardiac functional magnetic resonance imaging at 7T: Image quality optimization and ultra-high field capabilities

BACKGROUND

7T cardiac magnetic resonance imaging (MRI) introduces several advantages, as well as some limitations, compared to lower-field imaging. The capabilities of ultra-high field (UHF) MRI have not been fully exploited in cardiac functional imaging.

AIM

To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning, which improves scan efficiency. In this study, we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.

METHODS

We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus. We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality, B1 field homogeneity, signal-to-noise ratio (SNR), blood-myocardium contrast-to-noise ratio (CNR), and tagging persistence throughout the cardiac cycle.

RESULTS

The results showed the capability of achieving improved image quality with high spatial resolution (0.75 mm × 0.75 mm × 2 mm), high temporal resolution (20 ms), and increased tagging persistence (for up to 1200 ms cardiac cycle duration) at 7T cardiac MRI after adjusting scan set-up and imaging parameters. Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-to-blood CNR. Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions, especially in subjects with small chest size.

CONCLUSION

Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization, which would allow for more streamlined and efficient UHF cardiac MRI.

The Role of Cardiovascular MRI in Cardio-Oncology

"Cardiac imaging is an essential tool in the field of cardio-oncology. Cardiovascular magnetic resonance (CMR) stands out for its accuracy, reproducibility, and ability to provide tissue characterization. These attributes are particularly helpful in screening and diagnosing cardiotoxicity, infiltrative disease, and inflammatory cardiac disease. The ability of CMR to detect subtle changes in cardiac function and tissue composition has made it a useful tool for understanding the pathophysiology of cardiotoxicity. Because of these unique features, CMR is gaining prominence in both the clinical and research aspects of cardio-oncology."

Cardiac changes in pediatric cancer survivors

Cardiac damage from chemotherapy is a known phenomenon leading to significant morbidity and mortality in the cancer surviving population, and identifying high-risk pediatric patients early is challenging. The purpose of this pilot study was to evaluate whether echo strain, cardiac MRI (CMR), and serum biomarkers are more sensitive methods for detecting cardiac toxicity than standard echo and to examine the relationship between biomarkers in patients without decreased systolic function as determined by standard echo. In this pilot study, we prospectively enrolled pediatric subjects after completion of anthracycline inclusive chemotherapy. Each subject underwent a post-treatment echocardiogram (standard with strain), serum biomarkers (N-terminal brain natriuretic peptide (NT-pro-BNP) and interleukin 1 receptor-like 1 protein (ST2)), and CMR (standard and extracellular volumes (ECVs)). We correlated the markers using Pearson correlation. We enrolled 30 subjects, 11F/19M, aged 8-21 years. Cumulative anthracycline dose (CAD) correlated with BNP (p=0.06), CMR ECV 4-chamber (p=0.05) and sagittal (p=0.01), and mitral valve E/A (p=0.02). BNP correlated with CMR ECV 4-chamber (p=0.001) and sagittal (p=0.001) and with echo average longitudinal strain (ALS) (p=0.05). This study demonstrated a significant correlation of CAD with BNP and CMR ECV. There was also a significant correlation of NT-pro-BNP with CMR ECV and ALS. Combining these parameters with standard echo has the potential to identify high-risk patients early. Further studies are needed for long-term follow-up and management in this vulnerable population.

Cardiac Disease in Childhood Cancer Survivors: Risk Prediction, Prevention, and Surveillance: JACC CardioOncology State-of-the-Art Review

Cardiac diseases in the growing population of childhood cancer survivors are of major concern. Cardiotoxicity as a consequence of anthracyclines and chest radiotherapy continues to be relevant in the modern treatment era. Mitoxantrone has emerged as an important treatment-related risk factor and evidence on traditional cardiovascular risk factors in childhood cancer survivors is accumulating. International surveillance guidelines have been developed with the aim to detect and manage cardiac diseases early and prevent symptomatic disease. There is growing interest in risk prediction models to individualize prevention and surveillance. This State-of-the-Art Review summarizes literature from a systematic PubMed search focused on cardiac diseases after treatment for childhood cancer. Here, we discuss the prevalence, risk factors, prevention, risk prediction, and surveillance of cardiac diseases in survivors of childhood cancer.

Optimized cardiac functional MRI of small-animal models of cancer radiation therapy

Cardiac MRI of small animal models of cancer radiation therapy (RT) is a valuable tool for studying the effect of RT on the heart. However, standard cardiac MRI exams require long scanning times, which is challenging for sick animals that may not survive extended periods of imaging under anesthesia. The purpose of this study is to develop an optimized, fast MRI exam for comprehensive cardiac functional imaging of small-animal models of cancer RT. Ten adult female rats (2 non-irradiated and 8 irradiated) were scanned using the developed exam. Optimal imaging parameters were determined, which minimized scanning time while ensuring measurement accuracy and avoiding imaging artifacts. This optimized, fast MRI exam lasted for 30 min, which was tolerated by all animals. EF was normal in all imaged rats, although it was significantly increased in the irradiated rats, which also showed ventricular hypertrophy. However, myocardial strain was significantly reduced in the irradiated rats. In conclusion, a fast MRI exam has been developed for comprehensive cardiac functional imaging of rats in 30 min, with optimized imaging parameters to ensure accurate measurements and tolerance by irradiated rats. The generated strain measurements provide an early marker of regional cardiac dysfunction before global function is affected.

Childhood cancer survivors: The integral role of the cardiologist and cardiovascular imaging

IMPORTANCE

With 80% of childhood cancer survivors (CCS) alive 30 years after diagnosis, preventable causes of death, such as cardiovascular disease resulting from initial cancer therapy, becomes an important metric. This leads to a more pronounced role for cardiologists in the care of CCS.

OBSERVATIONS

While routine cardiovascular screening has been traditionally performed by the hematologist/oncologist or primary care provider, our understanding of cardiovascular disease in CCS has advanced. The measurement of left ventricular ejection fraction (LVEF) can now be complemented with additional assessments of strain, LV mass, right ventricular function, diastolic function, valve function, the pericardium, coronary perfusion, and biomarkers. Risk factor modification, prophylaxis, and timing of treatment are also critical.

CONCLUSIONS AND RELEVANCE

Early cardiovascular screening and treatment in asymptomatic CCS can be nuanced and complex. As a result, there is a renewed opportunity for the cardiologist to play an integral role in the care of CCS.

KEY POINTS

Question/Purpose: Review cardiovascular disease and the role of the cardiologist in the care of asymptomatic childhood cancer survivors (CCS).

FINDINGS

Cardiovascular care in CCS benefits from a multi-faceted approach that does not overly rely on LVEF. Meaning: Adequate screening and treatment of cardiovascular disease in asymptomatic CCS may often be optimized by the involvement of a cardiologist.

Cardiovascular Magnetic Resonance Imaging: Identifying the Effects of Cancer Therapy

The era of modern oncology incorporates an ever-evolving personalized approach to hematological malignancies and solid tumors. As a result, patient survival rates have, in part, substantially improved, depending on the specific type of underlying malignancy. However, systemic therapies may come along with potential cardiotoxic effects resulting in heart failure with increased morbidity and mortality. Ultimately, patients may survive their malignancy but die as a result of cancer treatment. Cardiovascular magnetic resonance imaging has long been in use for the assessment of function and tissue characteristics in patients with various nonischemic cardiac diseases. Besides an introductory overview on the general definition of cardiotoxicity including potential underlying mechanisms, this review provides insight into the application of various cardiovascular magnetic resonance imaging techniques in the setting of cancer therapy-related cardiac and vascular toxicity. Early identification of cardiotoxic effects may allow for on-time therapy adjustment and/or cardioprotective measures to avoid subsequent long-term heart failure with increased mortality.

Myocardial 2D Strain During Long-Term (>5 Years) Follow-Up of Childhood Survivors of Acute Lymphoblastic Leukemia Treated With Anthracyclines

Anthracycline-induced cardiotoxicity can lead to clinical and subclinical heart failure. Decrease of global longitudinal strain is a predictor for heart failure. Early detection of subclinical cardiotoxicity is crucial for timely intervention and prevention of further progression. Cardiac function of 41 survivors of childhood acute lymphoblastic leukemia (ALL) was assessed. Values of cardiac troponin T, N-terminal-pro-brain natriuretic peptide, conventional and myocardial 2D strain echocardiography were measured before (T = 0), during (T = 1, cumulative dose of 120 mg/m²), shortly after (T = 2) and long after anthracycline treatment (T = 3, ≥5 years after anthracycline exposure). Cardiac function of survivors at the latest follow up was compared with 70 healthy age-matched controls. None of the survivors showed clinical signs of cardiac failure at T = 3. Strain values decreased during anthracycline treatment and an ongoing reduction was seen at the latest follow-up (T = 3) with preserved cardiac function (normal ejection fraction and shortening fraction). At T = 1, a relative reduction in longitudinal strain (≥10% compared with baseline) was observed in 38% of the survivors, which increased to 54% at T=3. ALL survivors showed significantly lower conventional and myocardial 2D strain values, especially strain rate, compared with healthy age-matched controls. At T = 3, we did not find any abnormal cardiac troponin T levels. Six percent of the survivors showed abnormal N-terminal-pro-brain natriuretic peptide levels. This prospective study showed an ongoing reduction of 2D myocardial strain and strain rate, with preserved left ventricular ejection fraction (≤10% decrease compared with baseline) in asymptomatic ALL survivors at late follow-up.

Sex differences in anthracycline-induced cardiotoxicity: the benefits of estrogens

Anthracyclines are the cornerstone for many oncologic treatments, but their cardiotoxicity has been recognized for several decades. Female subjects, especially before puberty and adolescence, or after menopause, seem to be more at increased risk, with the prognostic impact of this sex issue being less consistent compared to other cardiovascular risk factors. Several studies imply that sex differences could depend on the lack of the protective effect of sex hormones against the anthracycline-initiated damage in cardiac cells, or on differential mitochondria-related oxidative gene expression. This is also reflected by the results obtained with different diagnostic methods, such as cardiovascular biomarkers and imaging techniques (echocardiography, magnetic resonance, and nuclear medicine) in the diagnosis and monitoring of cardiotoxicity, confirming that sex differences exist. The same is true about protective strategies from anthracycline cardiotoxicity. Indeed, first studied to withstand oxidative damage in response to ischemia/reperfusion (I/R) injury, cardioprotection has different outcomes in men and women. A number of studies assessed the differences in I/R response between male and female hearts, with oxidative stress and apoptosis being shared mechanisms between the I/R and anthracyclines heart damage. Sex hormones can modulate these mechanisms, thus confirming their importance in the pathophysiology in cardioprotection not only from the ischemia/reperfusion damage, but also from anthracyclines, fueling further cardio-oncologic research on the topic.

Relationship between regional left ventricular dysfunction and cancer-therapy-related cardiac dysfunction

OBJECTIVE

The aim of our study was to assess the association between risk of cancer-therapy-related cardiac dysfunction (CTRCD) after first follow-up and the difference in echocardiographic measures from baseline to follow-up.

METHODS

We retrospectively enrolled 87 consecutive patients (58±14 years, 55 women) who received anthracycline and underwent echocardiographic examinations both before (baseline) and after initial anthracycline administration (first follow-up). We measured absolute values of global longitudinal strain (GLS), apical longitudinal strain (LS), mid-LS and basal-LS at baseline and first follow-up, and per cent changes (Δ) of these parameters were calculated. Among 61 patients who underwent further echocardiographic examinations (second follow-up, third follow-up, etc), we assessed the association between regional left ventricular (LV) systolic dysfunction from baseline to follow-up and development of CTRCD, defined as LV ejection fraction (LVEF) under 53% and more absolute decrease of 10% from baseline, after first follow-up.

RESULTS

LVEF (65%±4% vs 63±4%, p=0.004), GLS (23.2%±2.6% vs 22.2±2.4%, p=0.005) and basal-LS (21.9%±2.5% vs 19.9±2.4%, p<0.001) at first follow-up significantly decreased compared with baseline. Among the 61 patients who had further follow-up echocardiographic examinations, 13% developed CTRCD. In the Cox-hazard model, worse Δbasal-LS was significantly associated with CTRCD. By Kaplan-Meier analysis, patients with Δbasal-LS decrease of more than the median value (-9.7%) had significantly worse event-free survival than those with a smaller decrease (p=0.015).

CONCLUSIONS

Basal-LS significantly decreased prior to development of CTRCD, and worse basal-LS was associated with development of CTRCD in patients receiving anthracycline chemotherapy.

Left ventricle segmental function in childhood cancer survivors using speckle-tracking echocardiography

AIM

Anthracycline-associated cardiotoxicity in childhood cancer survivors may relate to global or segmental left ventricular abnormalities from associated thromboembolic events and myocardial microinfarcts. We characterized left ventricular segmental changes by two-dimensional speckle-tracking echocardiography in anthracycline-treated asymptomatic childhood cancer survivors.

METHODS AND RESULTS

Childhood cancer survivors' echocardiograms with normal left ventricular fractional shortening >1 year after anthracycline chemotherapy were studied. Cancer-free control children had normal echocardiograms. Apical two-, three-, and four-chamber peak systolic left ventricular longitudinal and global longitudinal strain, and peak systolic left ventricular radial and circumferential strain at papillary muscle levels were analyzed. The mean (standard deviation) age was 12.7 (3.8) years in 41 childhood cancer survivors. The median (interquartile range) follow-up after anthracycline chemotherapy was 4.73 (2.15-8) years. The median (range) cumulative anthracycline dose was 160.2 (60-396.9) mg/m2. In childhood cancer survivors, the mean (standard deviation) left ventricular longitudinal strain was lower in two- (-18.6 [3.2] versus -21.3 [2.5], p < 0.001), three- (-16.3 [6.0] versus -21.7 [3.0], p < 0.001), and four- (-17.6 [2.7] versus -20.8 [2.0], p < 0.001) chamber views compared to controls. The left ventricular global longitudinal strain (-17.6 [2.7] versus -21.3 [2.0]) and circumferential strain (-20.8 [4.3] versus -23.5 [2.6], p < 0.001) were lower in childhood cancer survivors. Among childhood cancer survivors, 12 out of 16 left ventricular segments had significantly lower longitudinal strain than controls.

CONCLUSIONS

Asymptomatic anthracycline-treated childhood cancer survivors with normal left ventricular fractional shortening had lower global longitudinal and circumferential strain. The left ventricular longitudinal strain was lower in majority of the segments, suggesting that anthracycline cardiotoxicity is more global than regional.

Anthracycline Therapy Is Associated With Cardiomyocyte Atrophy and Preclinical Manifestations of Heart Disease

OBJECTIVES

The goal of this study was to demonstrate that cardiac magnetic resonance could reveal anthracycline-induced early tissue remodeling and its relation to cardiac dysfunction and left ventricular (LV) atrophy.

BACKGROUND

Serum biomarkers of cardiac dysfunction, although elevated after chemotherapy, lack specificity for the mechanism of myocardial tissue alterations.

METHODS

A total of 27 women with breast cancer (mean age 51.8 ± 8.9 years, mean body mass index 26.9 ± 3.6 kg/m²), underwent cardiac magnetic resonance before and up to 3 times after anthracycline therapy. Cardiac magnetic resonance variables were LV ejection fraction, normalized T2-weighted signal intensity for myocardial edema, extracellular volume (ECV), LV cardiomyocyte mass, intracellular water lifetime (τ_ic; a marker of cardiomyocyte size), and late gadolinium enhancement.

RESULTS

At baseline, patients had a relatively low (10-year) Framingham cardiovascular event risk (median 5%), normal LV ejection fractions (mean 69.4 ± 3.6%), and normal LV mass index (51.4 ± 8.0 g/m²), a mean ECV of 0.32 ± 0.038, mean τ_ic of 169 ± 69 ms, and no late gadolinium enhancement. At 351 to 700 days after anthracycline therapy (240 mg/m²), mean LV ejection fraction had declined by 12% to 58 ± 6% (p < 0.001) and mean LV mass index by 19 g/m² to 36 ± 6 g/m² (p < 0.001), and mean ECV had increased by 0.037 to 0.36 ± 0.04 (p = 0.004), while mean τ_ic had decreased by 62 ms to 119 ± 54 ms (p = 0.004). Myocardial edema peaked at about 146 to 231 days (p < 0.001). LV mass index was associated with τ_ic (β = 4.1 ± 1.5 g/m² per 100-ms increase in τ_ic, p = 0.007) but not with ECV. Cardiac troponin T (mean 4.6 ± 1.4 pg/ml at baseline) increased significantly after anthracycline treatment (p < 0.001). Total LV cardiomyocyte mass, estimated as: (1 - ECV) × LV mass, declined more rapidly after anthracycline therapy, with peak cardiac troponin T >10 pg/ml. There was no evidence for any significant interaction between 10-year cardiovascular event risk and the effect of anthracycline therapy.

CONCLUSIONS

A decrease in LV mass after anthracycline therapy may result from cardiomyocyte atrophy, demonstrating that mechanisms other than interstitial fibrosis and edema can raise ECV. The loss of LV cardiomyocyte mass increased with the degree of cardiomyocyte injury, assessed by peak cardiac troponin T after anthracycline treatment. (Doxorubicin-Associated Cardiac Remodeling Followed by CMR in Breast Cancer Patients; NCT03000036).

MRI in cardio-oncology: A review of cardiac complications in oncologic care

From detailed characterization of cardiac abnormalities to the assessment of cancer treatment-related cardiac dysfunction, cardiac MRI is playing a growing role in the evaluation of cardiac pathology in oncology patients. Current guidelines are now incorporating the use of MRI for the comprehensive multidisciplinary approach to cancer management, and innovative applications of MRI in research are expanding its potential to provide a powerful noninvasive tool in the arsenal against cancer. This review focuses on the application of cardiac MRI to diagnose and manage cardiovascular complications related to cancer and its treatment. Following an introduction to current cardiac MRI methods and principles, this review is divided into two sections: functional cardiovascular analysis and anatomical or tissue characterization related to cancer and cancer therapeutics. Level of Evidence: 5 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1349-1366.

Is health status impaired in childhood cancer survivors? A systematic review and meta-analysis

BACKGROUND

An increase in survival rates of childhood cancer is associated with long-term health issues in survivors.

METHODS

We conducted a systematic review and meta-analysis comparing health status-related endpoints in childhood cancer survivors (CCS) versus controls.

RESULTS

Eighty-six studies (n = 98,480 participants, 62% CCS) were included in the review. Of these, 73 studies (n = 96,550, 63% CCS) could be meta-analyzed. CCS showed a lower left ventricular ejection and fractional shortening (SMD=-0.59 and -0.55, respectively, both p < 0.01 [n=1,824 and 1,880]), a lower HDL-cholesterol concentration (SMD=-0.48, p<0.001, n=1,378) and a higher waist-to-hip ratio (SMD=0.61, p < 0.01, n=229) than their healthy peers. No significant differences were found for the remaining endpoints.

CONCLUSIONS

CCS is associated with a lower left ventricular function and HDL-cholesterol level, and a higher waist-to-hip ratio than healthy controls. These findings support the need to closely monitor the cardiometabolic health status of CCS and to implement preventive lifestyle interventions for this population.

Doxorubicin-Induced Cardiotoxicity in Collaborative Cross (CC) Mice Recapitulates Individual Cardiotoxicity in Humans

Anthracyclines cause progressive cardiotoxicity whose ultimate severity is individual to the patient. Genetic determinants contributing to this variation are difficult to study using current mouse models. Our objective was to determine whether a spectrum of anthracycline induced cardiac disease can be elicited across 10 Collaborative Cross mouse strains given the same dose of doxorubicin. Mice from ten distinct strains were given 5 mg/kg of doxorubicin intravenously once weekly for 5 weeks (total 25 mg/kg). Mice were killed at acute or chronic timepoints. Body weight was assessed weekly, followed by terminal complete blood count, pathology and a panel of biomarkers. Linear models were fit to assess effects of treatment, sex, and sex-by-treatment interactions for each timepoint. Impaired growth and cardiac pathology occurred across all strains. Severity of these varied by strain and sex, with greater severity in males. Cardiac troponin I and myosin light chain 3 demonstrated strain- and sex-specific elevations in the acute phase with subsequent decline despite ongoing progression of cardiac disease. Acute phase cardiac troponin I levels predicted the ultimate severity of cardiac pathology poorly, whereas myosin light chain 3 levels predicted the extent of chronic cardiac injury in males. Strain- and sex-dependent renal toxicity was evident. Regenerative anemia manifested during the acute period. We confirm that variable susceptibility to doxorubicin-induced cardiotoxicity observed in humans can be modeled in a panel of CC strains. In addition, we identified a potential predictive biomarker in males. CC strains provide reproducible models to explore mechanisms contributing to individual susceptibility in humans.

Paediatric cardio-oncology: epidemiology, screening, prevention, and treatment

With 5-year survival of children with cancer exceeding 80% in developed countries, premature cardiovascular disease is now a major cause of early morbidity and mortality. In addition to the acute and chronic cardiotoxic effects of anthracyclines, related chemotherapeutics, and radiation, a growing number of new molecular targeted agents may also have detrimental effects on the cardiovascular system. Survivors of childhood cancer also may have earlier development of conventional cardiovascular risk factors such as hypertension, dyslipidaemia, and diabetes, which further increase their risk of serious cardiovascular disease. This review will examine the epidemiology of acute and chronic cardiotoxicity relevant to paediatric cancer patients, including genetic risk factors. We will also provide an overview of current screening recommendations, including the evidence regarding both imaging (e.g. echocardiography and magnetic resonance imaging) and blood-based biomarkers. Various primary and secondary prevention strategies will also be discussed, primarily in relation to anthracycline-related cardiomyopathy. Finally, we review the available evidence related to the management of systolic and diastolic dysfunction in paediatric cancer patients and childhood cancer survivors.

Late effects of pediatric hematopoietic stem cell transplantation on left ventricular function, aortic stiffness and myocardial tissue characteristics

BACKGROUND

Pediatric hematopoietic stem cell transplantation (HSCT) recipients are at increased risk of cardiovascular disease later in life. As HSCT survival has significantly improved, with a growing number of HSCT indications, tailored screening strategies for HSCT-related late effects are warranted. Little is known regarding the value of cardiovascular magnetic resonance (CMR) for early identification of high-risk patients after HSCT, before symptomatic cardiovascular disease manifests. This study aimed to assess CMR-derived left ventricular (LV) systolic and diastolic function, aortic stiffness and myocardial tissue characteristics in young adults who received HSCT during childhood.

METHODS

Sixteen patients (22.1 ± 1.5 years) treated with HSCT during childhood and 16 healthy controls (22.1 ± 1.8 years) underwent 3 T CMR. LV systolic and diastolic function were measured as LV ejection fraction (LVEF), the ratio of transmitral early and late peak filling rate (E/A), the estimated LV filling pressure (E/Ea) and global longitudinal and circumferential systolic strain and diastolic strain rates, using balanced steady-state free precession cine CMR and 2D velocity-encoded CMR over the mitral valve. Aortic stiffness, myocardial fibrosis and steatosis were assessed with 2D velocity-encoded CMR, native T1 mapping and proton CMR spectroscopy (1H-CMRS), respectively.

RESULTS

In the patient compared to the control group, E/Ea (9.92 ± 3.42 vs. 7.24 ± 2.29, P = 0.004) was higher, LVEF (54 ± 6% vs. 58 ± 5%, P = 0.055) and global longitudinal strain (GLS) ( -20.7 ± 3.5% vs. -22.9 ± 3.0%, P = 0.063) tended to be lower, while aortic pulse wave velocity (4.40 ± 0.26 vs. 4.29 ± 0.29 m/s, P = 0.29), native T1 (1211 ± 36 vs. 1227 ± 28 ms, P = 0.16) and myocardial triglyceride content (0.47 ± 0.18 vs. 0.50 ± 0.13%, P = 0.202) were comparable. There were no differences between patients and controls in E/A (2.76 ± 0.92 vs. 2.97 ± 0.91, P = 0.60) and diastolic strain rates.

CONCLUSION

In young adults who received HSCT during childhood, LV diastolic function was decreased (higher estimated LV filling pressure) and LV systolic function (LVEF and GLS) tended to be reduced as compared to healthy controls, whereas no concomitant differences were found in aortic stiffness and myocardial tissue characteristics. When using CMR, assessment of LV diastolic function in particular is important for early detection of patients at risk of HSCT-related cardiovascular disease, which may warrant closer surveillance.

Identification of a novel microRNA profile in pediatric patients with cancer treated with anthracycline chemotherapy

Anthracycline chemotherapy (AC) is associated with decline in left ventricular ejection fraction (LVEF), yet the mechanisms remain unclear. Although changes in microRNAs (miRs) have been identified in adult cardiovascular disease, miR profiles in pediatric patients with AC have not been well studied. The goal of this study was to examine miR profiles (unbiased array) in pediatric patients with AC compared with age-matched referent normal patients. We hypothesize that pediatric patients with AC will express a unique miR profile at the initiation and completion of therapy and will be related to LVEF. Serum was collected in pediatric patients (10–22 yr, n = 12) with newly diagnosed malignancy requiring AC within 24–48 h after the initiation of therapy (30–60 mg/m2) and ~1 yr after completing therapy. A custom microarray of 84 miRs associated with cardiovascular disease was used (quantitative RT-PCR) and indexed to referent normal profiles (13–17 yr, n = 17). LVEF was computed by cardiac MRI. LVEF fell from AC initiation at ~1 yr after AC completion (64.28 ± 1.78% vs. 57.53 ± 0.95%, respectively, P = 0.004). Of the 84 miRs profiled, significant shifts in 17 miRs occurred relative to referent normal ( P ≤ 0.05). Moreover, the functional domain of miRs associated with myocardial differentiation and development fell over threefold at the completion of AC ( P ≤ 0.05). Moreover, eight miRs were significantly downregulated after AC completion in those patients with the greatest decline in LVEF (≥10%, P < 0.05). This study demonstrates, for the first time, that changes in miR expression occur in pediatric patients with AC. These findings suggest that miRs are a potential strategy for the early identification of patients with AC susceptible to left ventricular dysfunction.

NEW & NOTEWORTHY Although anthracycline chemotherapy (AC) is effective for a number of pediatric cancers, an all too often consequence of AC is the development of left ventricular failure. The present study identified that specific shifts in the pattern of microRNAs, which regulate myocardial growth, function, and viability, occurred during and after AC in pediatric patients, whereby the magnitude of this shift was associated with the degree of left ventricular failure.

Cardiac magnetic resonance T1 mapping. Part 2: Diagnostic potential and applications

Non-invasive identification and differentiation of myocardial diseases represents the primary objectives of cardiac magnetic resonance (CMR) longitudinal relaxation time (T1) and extracellular volume (ECV) mapping. Given the fact that myocardial T1 and ECV values overlap throughout and within left ventricular phenotypes, a central issue to be addressed is whether and to what extent myocardial T1 and ECV mapping provides additional or superior diagnostic information to standard CMR imaging, and whether native T1 mapping could be employed as a non-contrast alternative to late gadolinium enhancement (LE) imaging. The present review aims to summarize physiological and pathophysiological alterations in native T1 and ECV values and summarized myocardial T1 and ECV alterations associated with cardiac diseases to support the translation of research findings into routine CMR imaging.

Clinical and preclinical evidence of sex-related differences in anthracycline-induced cardiotoxicity

Anthracyclines are very effective chemotherapeutic agents that are widely used to treat pediatric and adult cancer patients. Unfortunately, the clinical utility of anthracyclines is limited by cardiotoxicity. There are several established risk factors for anthracycline-induced cardiotoxicity (AIC), including total cumulative dose, very young and very old age, concomitant use of other cardiotoxic agents, and concurrent mediastinal radiation. However, the role of sex as a risk factor for AIC is not well defined. In pediatric cancer patients, most studies support the notion that female sex is a significant risk factor for AIC. Conversely, there is anecdotal evidence that female sex protects against AIC in adult cancer patients. The lack of consistency in study designs and the different definitions of cardiotoxicity preclude reaching consensus regarding the role of sex as a risk factor for AIC in both pediatric and adult cancer patients. Therefore, more clinical research using reliable techniques such as cardiac magnetic resonance imaging is needed to determine if there truly are sex differences in AIC. In adult preclinical rodent studies, however, there is unequivocal evidence that female sex confers significant protection against AIC, with a possible protective effect of female sex hormones and/or a detrimental role of the male sex hormones. Although findings of these rodent studies may not perfectly mirror the clinical scenario in adult anthracycline-treated cancer patients, understanding the mechanisms of this significant sexual dimorphism may reveal important cardioprotective mechanisms that can be therapeutically targeted.