Longitudinal assessment of concurrent changes in left ventricular ejection fraction and left ventricular myocardial tissue characteristics after administration of cardiotoxic chemotherapies using T1-weighted and T2-weighted cardiovascular magnetic resonance

Anthracycline-induced cardiotoxicity: mechanisms, monitoring, and prevention

Anthracyclines are the most fundamental and important treatment of several cancers especially for lymphoma and breast cancer. However, their use is limited by a dose-dependent cardiotoxicity which may emerge early at the initiation of anthracycline administration or several years after termination of the therapy. A full comprehending of the mechanisms of anthracycline-induced cardiotoxicity, which has not been achieved and is currently under the efforts, is critical to the advance of developing effective methods to protect against the cardiotoxicity, as well as to early detect and treat it. Therefore, we review the recent progress of the mechanism underlying anthracycline-induced cardiotoxicity, as well as approaches to monitor and prevent this issue.

Serial Cardiac MRI for Quantification of the Dynamics of Anthracycline-Induced Subclinical Myocardial Injury

BACKGROUND

Anthracyclines are known to be associated with chemotherapy-induced cardiotoxicity. Limited data focus on dynamic myocardial injury during the course of chemotherapy in patients with breast cancer.

PURPOSE

To investigate the variation of tissue characterization and myocardial deformation derived by cardiac MRI during anthracycline chemotherapy.

STUDY TYPE

Prospective.

POPULATION

Fifty-eight female breast cancer patients (mean age: 52.82 ± 2.61 years) were enrolled.

FIELD STRENGTH/SEQUENCE

A 3.0-T, cardiac MRI including cine balanced steady-state free precession, a modified Looker-Locker inversion recovery (MOLLI), and a fast spin echo (FSE) T2-weighted sequences were performed.

ASSESSMENT

Cardiac MRI was performed baseline and after two, four, and six cycles of chemotherapy. Assessment of global longitudinal strain (GLS), global circumstance strain (GCS), global radial strain (GRS), and strain rate (GLS-s, GCS-s, GRS-s) and T1, T2 and T2* were accomplished by CVI42. The anthracycline dose and risk factors were also collected before each cardiac MRI.

STATISTICAL TESTS

Analysis of variance (ANOVA) for repeated measures was used to compare the changes in LVEF cardiac function, strain and T1/T2/T2* parameters over time. Pearson correlation analyses were performed to estimate the potential associations between differences in myocardial characteristics (∆) and the chemotherapy cycle. A P value <0.05 was considered statistically significant.

RESULTS

LVEF was not significantly different from pretreatment MRI regarding each cycle of chemotherapy (P = 0.54). Compared with baseline, patients had significantly lower GLS (-15.85% ± 0.83%, -14.50% ± 0.88%, -12.34% ± 1.01% vs. -18.82% ± 0.92%) and GLS-s (-0.71% ± 0.07%, -0.65% ± 0.05%, -0.64% ± 0.04% vs. -0.95 ± 0.06%) and increased T2 values (57.21 ± 4.27 msec, 58.60 ± 3.93 msec, 58.10 ± 3.17 msec vs. 43.88 ± 3.28 msec) at two, four and six cycles of chemotherapy treatment. ∆GLS and ∆GLS-s were significantly associated with the chemotherapy cycle (correlation coefficients for GLS = 0.75, GLS-s = 0.75).

DATA CONCLUSION

Cardiac MRI can precisely detect the dynamic changes of anthracycline-induced subclinical myocardial injury that is represented as a gradually decrease in GLS and GLS-s. These parameters may provide new insight for monitoring risk and therapy in patients with breast cancer.

EVIDENCE LEVEL

2.

TECHNICAL EFFICACY

Stage 1.

A case of Brugada phenocopy alteration induced by immune checkpoint inhibitors

Immunotherapy has shown remarkable efficacy in various cancer treatments. However, enhanced T-cell immune surveillance can lead to aberrant immune responses, resulting in severe immune checkpoint inhibitor-related adverse events. This is a case report of a patient previously treated with immune checkpoint inhibitors who presented with ST-segment elevation without abnormal troponin and cardiac enzyme spectrum test results. Cardiac toxicity of immune checkpoint inhibitors mainly manifests as acute immune-mediated myocarditis. While Brugada phenocopy is commonly caused by fever, electrolyte abnormalities, tricyclic/tetracyclic antidepressants, and marijuana use, we suspect that it was induced by immune checkpoint inhibitors in the current case.

Cardiovascular Imaging in Contemporary Cardio-Oncology: A Scientific Statement From the American Heart Association

Advances in cancer therapeutics have led to dramatic improvements in survival, now inclusive of nearly 20 million patients and rising. However, cardiovascular toxicities associated with specific cancer therapeutics adversely affect the outcomes of patients with cancer. Advances in cardiovascular imaging have solidified the critical role for robust methods for detecting, monitoring, and prognosticating cardiac risk among patients with cancer. However, decentralized evaluations have led to a lack of consensus on the optimal uses of imaging in contemporary cancer treatment (eg, immunotherapy, targeted, or biological therapy) settings. Similarly, available isolated preclinical and clinical studies have provided incomplete insights into the effectiveness of multiple modalities for cardiovascular imaging in cancer care. The aims of this scientific statement are to define the current state of evidence for cardiovascular imaging in the cancer treatment and survivorship settings and to propose novel methodological approaches to inform the optimal application of cardiovascular imaging in future clinical trials and registries. We also propose an evidence-based integrated approach to the use of cardiovascular imaging in routine clinical settings. This scientific statement summarizes and clarifies available evidence while providing guidance on the optimal uses of multimodality cardiovascular imaging in the era of emerging anticancer therapies.

Impaired Cardiac and Skeletal Muscle Energetics Following Anthracycline Therapy for Breast Cancer

BACKGROUND

Anthracycline-related cardiac toxicity is a recognized consequence of cancer therapies. We assess resting cardiac and skeletal muscle energetics and myocyte, sarcomere, and mitochondrial integrity in patients with breast cancer receiving epirubicin.

METHODS

In a prospective, mechanistic, observational, longitudinal study, we investigated chemotherapy-naive patients with breast cancer receiving epirubicin versus sex- and age-matched healthy controls. Resting energetic status of cardiac and skeletal muscle (phosphocreatine/gamma ATP and inorganic phosphate [Pi]/phosphocreatine, respectively) was assessed with 31P-magnetic resonance spectroscopy. Cardiac function and tissue characterization (magnetic resonance imaging and 2D-echocardiography), cardiac biomarkers (serum NT-pro-BNP and high-sensitivity troponin I), and structural assessments of skeletal muscle biopsies were obtained. All study assessments were performed before and after chemotherapy.

RESULTS

Twenty-five female patients with breast cancer (median age, 53 years) received a mean epirubicin dose of 304 mg/m2, and 25 age/sex-matched controls were recruited. Despite comparable baseline cardiac and skeletal muscle energetics with the healthy controls, after chemotherapy, patients with breast cancer showed a reduction in cardiac phosphocreatine/gamma ATP ratio (2.0±0.7 versus 1.1±0.5; P=0.001) and an increase in skeletal muscle Pi/phosphocreatine ratio (0.1±0.1 versus 0.2±0.1; P=0.022). This occurred in the context of increases in left ventricular end-systolic and end-diastolic volumes (P=0.009 and P=0.008, respectively), T1 and T2 mapping (P=0.001 and P=0.028, respectively) but with preserved left ventricular ejection fraction, mass and global longitudinal strain, and no change in cardiac biomarkers. There was preservation of the mitochondrial copy number in skeletal muscle biopsies but a significant increase in areas of skeletal muscle degradation (P=0.001) in patients with breast cancer following chemotherapy. Patients with breast cancer demonstrated a reduction in skeletal muscle sarcomere number from the prechemotherapy stage compared with healthy controls (P=0.013).

CONCLUSIONS

Contemporary doses of epirubicin for breast cancer treatment result in a significant reduction of cardiac and skeletal muscle high-energy 31P-metabolism alongside structural skeletal muscle changes.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04467411.

Multimodality imaging in cardio-oncology: the added value of CMR and CCTA

During the last 30 years, we have assisted to a great implementation in anticancer treatment with a subsequent increase of cancer survivors and decreased mortality. This has led to an ongoing interest about the possible therapy-related side-effects and their management to better guide patients therapy and surveillance in the chronic and long-term setting. As a consequence cardio-oncology was born, involving several different specialties, among which radiology plays a relevant role. Till the end of August 2022, when European Society of Cardiology (ESC) developed the first guidelines on cardio-oncology, no general indications existed to guide diagnosis and treatment of cancer therapy-related cardiovascular toxicity (CTR-CVT). They defined multimodality imaging role in primary and secondary prevention strategies, cancer treatment surveillance and early CTR-CVT identification and management. Cardiac computed tomography angiography (CCTA) has acquired a central role in coronary assessment, as far as coronary artery disease (CAD) exclusion is concerned; but on the side of this well-known application, it also started to be considered in left ventricular function evaluation, interstitial fibrosis quantification and cardiac perfusion studies. Cardiac magnetic resonance (CMR), instead, has been acknowledged as the gold standard alternative to trans-thoracic echocardiography (TTE) poor acoustic window in quantification of heart function and strain modifications, as well as pre- and post-contrast tissue characterization by means of T1-T2 mapping, early Gadolinium enhancement (EGE), late Gadolinium enhancement (LGE) and extracellular volume (ECV) evaluation. Our review is intended to provide a focus on the actual role of CMR and CCTA in the setting of a better understanding of cardiotoxicity and to draw some possible future directions of cardiac imaging in this field, starting from the recently published ESC guidelines.

New Insights in the Era of Clinical Biomarkers as Potential Predictors of Systemic Therapy-Induced Cardiotoxicity in Women with Breast Cancer: A Systematic Review

Cardiotoxicity induced by breast cancer therapies is a potentially serious complication associated with the use of various breast cancer therapies. Prediction and better management of cardiotoxicity in patients receiving chemotherapy is of critical importance. However, the management of cancer therapy-related cardiac dysfunction (CTRCD) lacks clinical evidence and is based on limited clinical studies.

AIM

To provide an overview of existing and potentially novel biomarkers that possess a promising predictive value for the early and late onset of CTRCD in the clinical setting.

METHODS

A systematic review of published studies searching for promising biomarkers for the prediction of CTRCD in patients with breast cancer was undertaken according to PRISMA guidelines. A search strategy was performed using PubMed, Google Scholar, and Scopus for the period 2013-2023. All subjects were >18 years old, diagnosed with breast cancer, and received breast cancer therapies.

RESULTS

The most promising biomarkers that can be used for the development of an alternative risk cardiac stratification plan for the prediction and/or early detection of CTRCD in patients with breast cancer were identified.

CONCLUSIONS

We highlighted the new insights associated with the use of currently available biomarkers as a standard of care for the management of CTRCD and identified potentially novel clinical biomarkers that could be further investigated as promising predictors of CTRCD.

Longitudinal assessment of cardiac parameters through MRI in breast cancer patients treated with anti-HER2 therapy

BACKGROUND

We evaluated the early changes in left ventricular (LV) volumetric, functional, and tissue characteristics in human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients treated with trastuzumab and/or pertuzumab at cardiac magnetic resonance imaging (MRI).

METHODS

HER2-positive breast cancer patients undergoing planned anti-HER2 therapy and nonanthracycline-based chemotherapy were enrolled and subdivided into dual anti-HER2 (trastuzumab plus pertuzumab) group and trastuzumab group. Cardiac MRI was performed before treatment and three months after starting, covering ventricular volumes, cardiac function, systolic myocardial strain, myocardial oedema, and T1 and T2 relaxation times. Cardiac dysfunction was primarily defined as a > 10% reduction in LV ejection fraction (LVEF) to < 55% and/or a > 15% global longitudinal strain (GLS) change at the follow-up MRI examination.

RESULTS

Twenty-four HER2-positive patients were evaluated (16 in the dual anti-HER2 group, 8 in the trastuzumab group). Six patients developed cardiac dysfunction at follow-up, five of them in the dual anti-HER2 group. One patient developed symptomatic heart failure, and five patients developed asymptomatic cardiac dysfunction. Patients displayed significantly decreased systolic function and increased T1 and T2 relaxation time at follow-up (p ≤ 0.031). Systolic dysfunction remained significant in the dual anti-HER2 group. The decrease in GLS in the trastuzumab group was not significant (p = 0.169). T1 and T2 relaxation times tended to increase, but this was not significant at subgroup analysis.

CONCLUSIONS

Cardiac MRI scans showed frequent signs of subclinical cardiotoxicity after short-term anti-HER2 therapy and nonanthracycline-based chemotherapy; the effect was slightly stronger in patients treated with dual therapy.

KEY POINTS

• A frequent subclinical cardiotoxicity was detected by cardiac magnetic resonance imaging after short-term anti-human epidermal growth factor receptor 2 (HER2) therapy. • The change in myocardial strain was more marked in patients treated with dual (trastuzumab plus pertuzumab) than with trastuzumab only anti-HER2 therapy. • Cardiotoxicity surveillance through MRI is an interesting option particularly in patients treated with dual anti-HER2 therapy.

Role of advanced cardiovascular imaging in chemotherapy-induced cardiotoxicity

The development of cardiotoxicity induced by cancer treatments has emerged as a significant clinical problem, both in the short run, as it may influence drug administration in chemotherapeutic protocols, and in the long run, because it may determine adverse cardiovascular outcomes in survivors of various malignant diseases. Therefore, early detection of anticancer drug-related cardiotoxicity is an important clinical target to improve prevention of adverse effects and patient care. Today, echocardiography is the first-line cardiac imaging techniques used for identifying cardiotoxicity. Cardiac dysfunction, clinical and subclinical, is generally diagnosed by the reduction of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS). However, myocardial injury detected by echocardiography is preceded by other alterations, such as myocardial perfusion and mitochondrial and metabolic dysfunction, that can only be recognized by second-level imaging techniques, like cardiac magnetic resonance (CMR) and nuclear imaging, which, using targeted radiotracers, may help to provide information on the specific mechanisms of cardiotoxicity. In this review, we focus on the current and emerging role of CMR, as a critical diagnostic tool of cardiotoxicity in the very early phase, due to its availability and because it allows the contemporary detection of functional alterations, tissue alterations (mainly performed using T1, T2 mapping with the evaluation of extracellular volume-ECV) and perfusional alteration (evaluated with rest-stress perfusion) and, in the next future, even metabolic changes. Moreover, in the subsequent future, the use of Artificial Intelligence and big data on imaging parameters (CT, CMR) and oncoming molecular imaging datasets, including differences for gender and countries, may help predict cardiovascular toxicity at its earliest stages, avoiding its progression, with precise tailoring of patients' diagnostic and therapeutic pathways.

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.

Prospective multiparametric CMR characterization and MicroRNA profiling of anthracycline cardiotoxicity: A pilot translational study

Background

Anthracycline cardiotoxicity is a significant clinical challenge. Biomarkers to improve risk stratification and identify early cardiac injury are required.

Objectives

The purpose of this pilot study was to prospectively characterize anthracycline cardiotoxicity using cardiovascular magnetic resonance (CMR), echocardiography and MicroRNAs (MiRNAs), and identify baseline predictors of LVEF recovery.

Methods

Twenty-four patients (age 56 range 18-75 years; 42 % female) with haematological malignancy scheduled to receive anthracycline chemotherapy (median dose 272 mg/m2 doxorubicin equivalent) were recruited and evaluated at three timepoints (baseline, completion of chemotherapy, and 6 months after completion of chemotherapy) with multiparametric 1.5 T CMR, echocardiography and circulating miRNAs sequencing.

Results

Seventeen complete datasets were obtained. CMR left ventricular ejection fraction (LVEF) fell significantly between baseline and completion of chemotherapy (61 ± 3 vs 53 ± 3 %, p < 0.001), before recovering significantly at 6-month follow-up (55 ± 3 %, p = 0.018). Similar results were observed for 3D echocardiography-derived LVEF and CMR-derived longitudinal, circumferential and radial feature-tracking strain. Patients were divided into tertiles according to LVEF recovery (poor recovery, partial recovery, good recovery). CMR-derived mitral annular plane systolic excursion (MAPSE) was significantly different at baseline in patients exhibiting poor LVEF recovery (11.7 ± 1.5 mm) in comparison to partial recovery (13.7 ± 2.7 mm), and good recovery (15.7 ± 3.1 mm; p = 0.028). Furthermore, baseline miRNA-181-5p and miRNA-221-3p expression were significantly higher in this group. T2 mapping increased significantly on completion of chemotherapy compared to baseline (54.0 ± 4.6 to 57.8 ± 4.9 ms, p = 0.001), but was not predictive of LVEF recovery. No changes to LV mass, extracellular volume fraction, T1 mapping or late gadolinium enhancement were observed.

Conclusions

Baseline CMR-derived MAPSE, circulating miRNA-181-5p, and miRNA-221-3p were associated with poor recovery of LVEF 6 months after completion of anthracycline chemotherapy, suggesting their potential predictive role in this context. T2 mapping increased significantly on completion of chemotherapy but was not predictive of LVEF recovery.

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.

Early Detection of Cardiotoxicity From Systemic and Radiation Therapy in Patients With Breast Cancer: Protocol for a Multi-Institutional Prospective Study

Background

The incidence of breast cancer is rising worldwide. Recent advances in systemic and local treatments have significantly improved survival rates of patients having early breast cancer. In the last decade, great attention has been paid to the prevention and early detection of cardiotoxicity induced by breast cancer treatments. Systemic therapy-related cardiac toxicities have been extensively studied. Radiotherapy, an essential component of breast cancer treatment, can also increase the risk of heart diseases. Consequently, it is important to balance the expected benefits of cancer treatment with cardiovascular risk and to identify strategies to prevent cardiotoxicity and improve long-term outcomes and quality of life for these patients.

Objective

This CardioTox Breast study aims to investigate the use of cardiac imaging, based on cardiac magnetic resonance and echocardiography, and to identify associated circulating biomarkers to assess early tissue changes in chemo-induced and radiation-induced cardiotoxicity in the time window of 12 months after the end of radiotherapy in patients with breast cancer.

Methods

The CardioTox Breast trial is a multicenter observational prospective longitudinal study. We aim to enroll 150 women with stage I-III unilateral breast cancer, treated with breast conserving surgery, who planned to receive radiotherapy with or without systemic therapy. Baseline and follow-up data include cardiac measurements based on cardiac magnetic resonance imaging, echocardiography, and circulating biomarkers of cardiac toxicity.

Results

This study details the protocol of the CardioTox Breast trial. Recruitment started in September 2020. The results of this study will not be published until data are mature for the final analysis of the primary study end point.

Conclusions

The CardioTox Breast study is designed to investigate the effects of systemic and radiation therapy on myocardial function and structure, thus providing additional evidence on whether cardiac magnetic resonance is the optimal screening imaging for cardiotoxicity.

Trial Registration

ClinicalTrials.gov NCT04790266; https://clinicaltrials.gov/ct2/show/NCT04790266

International Registered Report Identifier (IRRID)

DERR1-10.2196/31887

Left ventricular dyssynchrony in long-term childhood cancer survivors treated with anthracyclines: a retrospective cross-sectional study

The purpose of this study was to investigate left ventricular contraction patterns in asymptomatic Childhood cancer survivors (CCS) using two-dimensional speckle tracking echocardiography (2DSTE). Left ventricular longitudinal and circumferential myocardial parameters were assessed using 2DSTE, in asymptomatic CCS and age matched healthy controls. Time to peak (T2P) systolic strain was quantified. Dyssynchrony index (DI) was measured by calculating the standard deviation of T2P systolic strain of six segments in each view. Difference between T2P systolic longitudinal strain of septal and lateral wall was also assessed as a parameter for dyssynchrony. We included 115 CCS with a median age of 17.2 years (range 5.6–39.5) and a median follow up of 11.3 years (range 4.9–29.5) and 119 controls. Conventional echocardiographic parameters and global longitudinal strain were significantly decreased in CCS compared to controls (p < 0.01 and p = 0.02, respectively). Dyssynchrony index did not differ between CCS and controls. There was a clinically insignificant smaller absolute difference between T2P systolic longitudinal of septal and lateral wall in CCS compared to controls. We showed no difference in longitudinal or circumferential left ventricular dyssynchrony in CCS compared to controls using 2DSTE. Future research should focus on assessing dyssynchrony in more segments and a larger CCS population, using both 2D and 3DSTE.

Myocardial damage assessed by late gadolinium enhancement on cardiovascular magnetic resonance imaging in cancer patients treated with anthracyclines and/or trastuzumab

AIMS

In cancer patients with cardiomyopathy related to anthracyclines and/or trastuzumab, data regarding late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging are confusing. The prevalence ranges from 0% to 30% and the patterns are ill-defined. Whether treatment with anthracyclines and/or trastuzumab is associated with LGE is unclear. We aimed to investigate these topics in a large cohort of consecutive cancer patients with suspected cardiotoxicity from anthracyclines and/or trastuzumab.

METHODS AND RESULTS

We studied 298 patients, analysed the prevalence, patterns, and correlates of LGE, and determined their causes. We compared the findings with those from 100 age-matched cancer patients who received neither anthracyclines nor trastuzumab. Amongst those who received anthracyclines and/or trastuzumab, 31 (10.4%) had LGE. It had a wide range of extent (3.9-34.7%) and locations. An ischaemic pattern was present in 20/31 (64.5%) patients. There was an alternative explanation for the non-ischaemic LGE in 7/11 (63.6%) patients. In the age-matched patients who received neither anthracyclines nor trastuzumab, the prevalence of LGE was higher at 27.0%, while the extent of LGE and the proportion with ischaemic pattern were not different.

CONCLUSION

LGE was present in only a minority. Its patterns and locations did not fit into a single unique profile. It had alternative explanations in virtually all cases. Finally, LGE was also present in cancer patients who received neither anthracyclines nor trastuzumab. Therefore, treatment with anthracyclines and/or trastuzumab is unlikely to be associated with LGE. The absence of LGE can help distinguish anthracycline- and/or trastuzumab-related cardiomyopathy from unrelated cardiomyopathies.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Role of cardiovascular magnetic resonance in early detection and treatment of cardiac dysfunction in oncology patients

The purpose of this review is to provide an overview of the essential role that cardiovascular magnetic resonance (CMR) has in the field of cardio-oncology. Recent findings: CMR has been increasingly used for early identification of cancer therapy related cardiac dysfunction (CTRCD) due to its precision in detecting subtle changes in cardiac function and for myocardial tissue characterization. Summary: CMR is able to identify subclinical CTRCD in patients receiving potentially cardiotoxic chemotherapy and guide initiation of cardio protective therapy. Multiparametric analysis with myocardial strain, tissue characterization play a critical role in understanding important clinical questions in cardio-oncology.

Damage to cardiac vasculature may be associated with breast cancer treatment-induced cardiotoxicity

BACKGROUND

Breast cancer is the most common female cancer worldwide. Effective therapies including doxorubicin and trastuzumab have improved survival, but are associated with a substantial risk of cardiovascular disease. Mechanisms underlying cancer treatment-induced cardiotoxicity (CTC) are poorly understood and have largely focused on cardiomyocyte damage, although other cellular populations in the heart such as the cardiac endothelium, may play an important role in cardiac damage. We treated a breast tumor-bearing mouse model with doxorubicin and trastuzumab to investigate the role of the cardiac endothelium in the development of CTC.

METHODS

Immune compromised mice were inoculated in the 4th mammary fat pad with human breast cancer cells overexpressing HER2 (BT474). When tumors were palpable, mice were treated weekly with doxorubicin (5 mg/kg) and trastuzumab (4 mg/kg). The cardiac phenotype of mice was assessed by echocardiography and histological evaluation of the heart. Cardiac vascular damage was assayed by in vivo permeability assays and primary cultures of murine cardiac endothelial cells were used to assay doxorubicin toxicity in vitro.

RESULTS

The growth of BT474 breast tumors in Balb/c Nude mice was suppressed upon treatment with doxorubicin and trastuzumab. Mice treated for 4 months with doxorubicin and trastuzumab maintained body weights, but demonstrated an echocardiographic phenotype consistent with preserved left ventricular (LV) ejection fraction, decreased LV mass and increased filling pressures (E/e'). Histological staining with Masson's trichrome and Picrosirius red showed extensive fibrosis and increased collagen deposition in the ventricular myocardium surrounding blood vessels of treated mice compared to untreated mice. Evans blue permeability assays demonstrated increased cardiac vasculature permeability while primary cardiac endothelial cells exposed to doxorubicin in vitro showed increased cell death as compared to lung or liver endothelial cells.

CONCLUSIONS

An orthotopic mouse model of human breast cancer in Nude mice treated with doxorubicin and trastuzumab resulted in a cardiac vascular defect accompanied by preserved LV ejection fraction, decreased LV mass, suggesting mild diastolic dysfunction and cardiac remodeling consistent with subclinical cardiotoxicity. Our data suggest that cardiac endothelium is more sensitive to doxorubicin therapy as compared to other organ endothelium and cardiac endothelial damage may correlate with breast cancer treatment-induced cardiotoxicity.

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.

Computed Tomographic Angiography Assessment of Epicardial Coronary Vasoreactivity for Early Detection of Doxorubicin-Induced Cardiotoxicity

Background

The vascular endothelium is a novel target for the detection, management, and prevention of doxorubicin (DOX)-induced cardiotoxicity.

Objectives

The study aimed to: 1) develop a methodology by computed tomography angiography (CTA) to evaluate stress-induced changes in epicardial coronary diameter; and 2) apply this to a chronic canine model of DOX-induced cardiotoxicity to assess vascular toxicity.

Methods

To develop and validate quantitative methods, sequential retrospectively gated coronary CTAs were performed in 16 canines. Coronary diameters were measured at prespecified distances during rest, adenosine (ADE) (280 μg/kg/min), rest 30 min post-ADE, and dobutamine (DOB) (5 μg/kg/min). A subgroup of 8 canines received weekly intravenous DOX (1 mg/kg) for 12 to 15 weeks, followed by rest-stress CTA at cumulative doses of ∼4-mg/kg (3 to 5 mg/kg), ∼8-mg/kg (7 to 9 mg/kg), and ∼12-mg/kg (12 to 15 mg/kg) of DOX. Echocardiograms were performed at these timepoints to assess left ventricular ejection fraction and global longitudinal strain.

Results

Under normal conditions, epicardial coronary arteries reproducibly dilated in response to ADE (left anterior descending coronary artery [LAD]: 12 ± 2%, left circumflex coronary artery [LCx]: 13 ± 2%, right coronary artery [RCA]: 14 ± 2%) and DOB (LAD: 17 ± 3%, LCx: 18 ± 2%, RCA: 15 ± 3%). With DOX, ADE vasodilator responses were impaired after ∼4-mg/kg (LAD: –3 ± 1%, LCx: 0 ± 2%, RCA: –5 ± 2%) and ∼8-mg/kg (LAD: –3 ± 1%, LCx: 0 ± 1%, RCA: –2 ± 2%). The DOB dilation response was preserved at ∼4-mg/kg of DOX (LAD: 18 ± 4%, LCx: 11 ± 3%, RCA: 11 ± 2%) but tended to decrease at ∼8-mg/kg of DOX (LAD: 4 ± 2%, LCx: 8 ± 3%, RCA: 3 ± 2%). A significant left ventricular ejection fraction reduction was observed only at 12 to 15 mg/kg DOX (baseline: 63 ± 2%, 12-mg/kg: 45 ± 3%). Global longitudinal strain was abnormal at ∼4-mg/kg of DOX (p = 0.011).

Conclusions

CTA can reliably assess epicardial coronary diameter in response to pharmacological stressors, providing a noninvasive functional index of coronary vasoreactivity. Impaired epicardial vasodilation occurs early in DOX-induced cardiotoxicity.

Magnetic Resonance Imaging to Detect Cardiovascular Effects of Cancer Therapy: JACC CardioOncology State-of-the-Art Review

This paper aims to empower and inform cardio-oncologists by providing a practical guide to the clinical application of cardiac magnetic resonance (CMR) in the rapidly evolving field of cardio-oncology. Specifically, we describe how CMR can be used to assess the cardiovascular effects of cancer therapy. The CMR literature, relevant societal guidelines, indication-specific imaging protocols, and methods to overcome some of the challenges encountered in performing and accessing CMR are reviewed.

Cardio-oncology, the myth of Sisyphus, and cardiovascular disease in breast cancer survivors

The number of breast cancer (BC) survivors has been increasing lately, due to the improvement in early detection strategies and oncological treatments. However, BC survivors are 3 times as likely to develop heart failure (HF) within 5 years of cancer diagnosis, and 7/100 of them will develop HF in a median follow-up of 8.5 years. Furthermore, HF in BC survivors has a worse prognosis compared to other causes of HF. Anthracyclines and trastuzumab have been proven to improve survival. However, they are also considered as the main causative factors of HF in BC survivors. Old patients, those with a pre-existing cardiovascular (CV) risk factors/disease, prior exposure to chemotherapy and radiotherapy are at increased risk. Serial evaluation of troponins and cardiac imaging parameters using echocardiography and cardiovascular magnetic resonance can significantly contribute to the early diagnosis of cardiac involvement before overt HF will develop. Assessment and immediate treatment of traditional CV risk factors is the first step for cardiotoxicity prevention. In BC survivors with known heart disease, the clinical stabilization is strongly recommended for cardiotoxicity prevention. Finally, in high-risk CV patients, primary prevention including cardioprotectants and/or CV drugs should be applied. According to recent studies, the early start of ACE inhibitors and β-blockers and the modification of anti-cancer treatment can prevent the decline in left ventricular ejection fraction. However, further multicenter studies are needed to establish both prevention and treatment protocols to successfully overcome HF development in BC survivors.

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.

Angiotensin-(1–7) reduces doxorubicin-induced cardiac dysfunction in male and female Sprague-Dawley rats through antioxidant mechanisms

Doxorubicin (Dox) is an effective chemotherapeutic for a variety of pediatric malignancies. Unfortunately, Dox administration often results in a cumulative dose-dependent cardiotoxicity that manifests with marked oxidative stress, leading to heart failure. Adjunct therapies are needed to mitigate Dox cardiotoxicity and enhance quality of life in pediatric patients with cancer. Angiotensin-(1–7) [Ang-(1–7)] is an endogenous hormone with cardioprotective properties. This study investigated whether adjunct Ang-(1–7) attenuates cardiotoxicity resulting from exposure to Dox in male and female juvenile rats. Dox significantly reduced body mass, and the addition of Ang-(1–7) had no effect. However, adjunct Ang-(1–7) prevented Dox-mediated diastolic dysfunction, including markers of decreased passive filling as measured by reduced early diastole mitral valve flow velocity peak ( E) ( P < 0.05) and early diastole mitral valve annulus peak velocity ( e′; P < 0.001) and increased E/e′ ( P < 0.001), an echocardiographic measure of diastolic dysfunction. Since Dox treatment increases reactive oxygen species (ROS), the effect of Ang-(1–7) on oxidative by-products and enzymes that generate or reduce ROS was investigated. In hearts of male and female juvenile rats, Dox increased NADPH oxidase 4 ( P < 0.05), a major cardiovascular NADPH oxidase isozyme that generates ROS, as well as 4-hydroxynonenal ( P < 0.001) and malondialdehyde ( P < 0.001), markers of lipid peroxidation; Ang-(1–7) prevented these effects of Dox. Cotreatment with Dox and Ang-(1–7) increased the antioxidant enzymes SOD1 (male: P < 0.05; female: P < 0.01) and catalase ( P < 0.05), which likely contributed to reduced ROS. These results demonstrate that Ang-(1–7) prevents diastolic dysfunction in association with a reduction in ROS, suggesting that the heptapeptide hormone may serve as an effective adjuvant to improve Dox-induced cardiotoxicity.

NEW & NOTEWORTHY Ang-(1–7) is a clinically safe peptide hormone with cardioprotective and antineoplastic properties that could be used as an adjuvant therapy to improve cancer treatment and mitigate the long-term cardiotoxicity associated with doxorubicin in pediatric patients with cancer.

Changes in Cardiovascular Biomarkers With Breast Cancer Therapy and Associations With Cardiac Dysfunction

Background

We examined the longitudinal associations between changes in cardiovascular biomarkers and cancer therapy–related cardiac dysfunction (CTRCD) in patients with breast cancer treated with cardotoxic cancer therapy.

Methods and Results

Repeated measures of high‐sensitivity cardiac troponin T (hs‐cTnT), NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide), myeloperoxidase, placental growth factor, and growth differentiation factor 15 were assessed longitudinally in a prospective cohort of 323 patients treated with anthracyclines and/or trastuzumab followed over a maximum of 3.7 years with serial echocardiograms. CTRCD was defined as a ≥10% decline in left ventricular ejection fraction to a value <50%. Associations between changes in biomarkers and left ventricular ejection fraction were evaluated in repeated‐measures linear regression models. Cox regression models assessed the associations between biomarkers and CTRCD. Early increases in all biomarkers occurred with anthracycline‐based regimens. hs‐cTnT levels >14 ng/L at anthracycline completion were associated with a 2‐fold increased CTRCD risk (hazard ratio, 2.01; 95% CI, 1.00–4.06). There was a modest association between changes in NT‐proBNP and left ventricular ejection fraction in the overall cohort; this was most pronounced with sequential anthracycline and trastuzumab (1.1% left ventricular ejection fraction decline [95% CI, −1.8 to –0.4] with each NT‐proBNP doubling). Increases in NT‐proBNP were also associated with CTRCD (hazard ratio per doubling, 1.56; 95% CI, 1.32–1.84). Increases in myeloperoxidase were associated with CTRCD in patients who received sequential anthracycline and trastuzumab (hazard ratio per doubling, 1.28; 95% CI, 1.04–1.58).

Conclusions

Cardiovascular biomarkers may play an important role in CTRCD risk prediction in patients with breast cancer who receive cardiotoxic cancer therapy, particularly in those treated with sequential anthracycline and trastuzumab therapy.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01173341.

MRI of Cardiotoxicity

Cardiovascular magnetic resonance (CMR) imaging is useful to identify systolic dysfunction, particularly when echocardiographic imaging is not acceptable because of poor acoustic windows or when left ventricular ejection fraction (LVEF) is inconclusive by other modalities and an accurate LVEF measurement is needed. Of particular advantage in cardio-oncology is CMR's capability to perform tissue characterization to noninvasively identify changes in pathologic conditions related to cancer therapy or to discriminate causes of disease that may confound presentation in cardio-oncology patients. For these reasons, there is an increasing use of CMR in the screening and surveillance of cardio-oncology patients.

Effect of Intensive Blood Pressure Reduction on Left Ventricular Mass, Structure, Function, and Fibrosis in the SPRINT-HEART

In observational studies, left ventricular mass (LVM) and structure are strong predictors of mortality and cardiovascular events. However, the effect of hypertension treatment on LVM reduction and its relation to subsequent outcomes is unclear, particularly at lower blood pressure (BP) targets. In an ancillary study of SPRINT (Systolic Blood Pressure Intervention Trial), where participants were randomly assigned to intensive BP control (target systolic BP target <120 mm Hg) versus standard BP control (<140 mm Hg), cardiac magnetic resonance imaging was performed at baseline and 18-month follow-up to measure: LVM, volumes, ejection fraction, and native T1 mapping for myocardial fibrosis. At baseline, 337 participants were examined (age: 64±9 years, 45% women); 300 completed the 18-month exam (153 intensive control and 147 standard control). In the intensive versus standard BP control group at 18 months, there was no difference in change in LVM (mean±SE =-2.7±0.5 g versus -2.3±0.7 g; P=0.368), ejection fraction, or native T1 (P=0.79), but there was a larger decrease in LVM/end-diastolic volume ratio (-0.04±0.01 versus -0.01±0.01; P=0.002) a measure of concentric LV remodeling. There were fewer cardiovascular events in the intensive control group, but no significant association between the reduced events and change in LVM or any other cardiac magnetic resonance imaging measure. In SPRINT-HEART, contrary to our hypothesis, there were no significant between-group differences in LVM, function, or myocardial T1 at 18-month follow-up. These results suggests that mediators other than these LV measures contribute to the improved cardiovascular outcomes with intensive BP control.

Left Ventricular Mass Change After Anthracycline Chemotherapy

BACKGROUND

Myocardial atrophy and left ventricular (LV) mass reductions are associated with fatigue and exercise intolerance. The relationships between the receipt of anthracycline-based chemotherapy (Anth-bC) and changes in LV mass and heart failure (HF) symptomatology are unknown, as is their relationship to LV ejection fraction (LVEF), a widely used measurement performed in surveillance strategies designed to avert symptomatic HF associated with cancer treatment.

METHODS AND RESULTS

We performed blinded, serial assessments of body weight, LVEF and mass, LV-arterial coupling, aortic stiffness, and Minnesota Living with Heart Failure Questionnaire measures before and 6 months after initiating Anth-bC (n=61) and non-Anth-bC (n=15), and in 24 cancer-free controls using paired t and χ² tests and multivariable linear models. Participants averaged 51±12 years, and 70% were women. Cancer diagnoses included breast cancer (53%), hematologic malignancy (42%), and soft tissue sarcoma (5%). We observed a 5% decline in both LVEF (P<0.0001) and LV mass (P=0.03) in the setting of increased aortic stiffness and disrupted ventricular-arterial coupling in those receiving Anth-bC but not other groups (P=0.11-0.92). A worsening of the Minnesota Living with Heart Failure Questionnaire score in Anth-bC recipients was associated with myocardial mass declines (r=-0.27; P<0.01) but not with LVEF declines (r=0.11; P=0.45). Moreover, this finding was independent of LVEF changes and body weight.

CONCLUSIONS

Early after Anth-bC, LV mass reductions associate with worsening HF symptomatology independent of LVEF. These data suggest an alternative mechanism whereby anthracyclines may contribute to HF symptomatology and raise the possibility that surveillance strategies during Anth-bC should also assess LV mass.

Effect of candesartan and metoprolol on myocardial tissue composition during anthracycline treatment: the PRADA trial

Aims

Anthracycline treatment may cause myocyte loss and expansion of the myocardial extracellular volume (ECV) fraction by oedema and fibrosis. We tested the hypotheses that adjuvant treatment for early breast cancer with the anthracycline epirubicin is dose dependently associated with increased ECV fraction and total ECV, as well as reduced total myocardial cellular volume, and that these changes could be prevented by concomitant angiotensin or beta-adrenergic blockade.

Methods and results

PRevention of cArdiac Dysfunction during Adjuvant breast cancer therapy (PRADA) was a 2 × 2 factorial, placebo-controlled, double-blinded trial of candesartan and metoprolol. Sixty-nine women had valid ECV measurements. ECV fraction, total ECV, and total cellular volume were measured by cardiovascular magnetic resonance before and at the completion of anthracycline therapy. ECV fraction increased from 27.5 ± 2.7% to 28.6 ± 2.9% (P = 0.002). A cumulative doxorubicin equivalent dose of 268 mg/m2 was associated with greater increase in ECV fraction than doses <268 mg/m2 (mean change 3.4% [95% confidence interval (CI) 1.2, 5.5] vs. 0.7% [95% CI 0.0, 1.5], P = 0.006), as well as greater increase in total ECV (1.9 mL [95% CI 0.4, 3.5] vs. 0.1 mL [95% CI -0.6, 0.8], P = 0.04). In patients receiving candesartan, total cellular volume decreased (-3.5 mL [95% CI - 4.7, -2.2], P < 0.001) while in patients not receiving candesartan, it remained unchanged (P = 0.45; between group difference P = 0.003).

Conclusions

Anthracycline therapy is associated with dose-dependent increase in ECV fraction and total ECV. Concomitant treatment with candesartan reduces left ventricular total cellular volume.

Precision Cardio-Oncology

Modern oncologic therapies and care have resulted in a growing population of cancer survivors with comorbid, chronic health conditions. As an example, many survivors have an increased risk of cardiovascular complications secondary to cardiotoxic systemic and radiation therapies. In response, the field of cardio-oncology has emerged as an integral component of oncologic patient care, committed to the early diagnosis and treatment of adverse cardiac events. However, as current clinical management of cancer therapy-related cardiovascular disease remains limited by a lack of phenotypic data, implementation of precision medicine approaches has become a focal point for deep phenotyping strategies. In particular, -omics approaches (a field of study in biology ending in -omic, such as genomics, proteomics, or metabolomics) have shown enormous potential in identifying sensitive biomarkers of cardiovascular disease, applying sophisticated, pattern-revealing technologies to growing databases of biologic molecules. Moreover, the use of -omics to inform radiologic strategies may add a dimension to future clinical practices. In this review, we present a paradigm for a precision medicine approach to the care of cardiotoxin-exposed cancer patients. We discuss the role of current imaging techniques; demonstrate how -omics can advance our understanding of disease phenotypes; and describe how molecular imaging can be integrated to personalize surveillance and therapeutics, ultimately reducing cardiovascular morbidity and mortality in cancer patients and survivors.

Protecting the heart in cancer therapy

Recent advances in cancer prevention and management have led to an exponential increase of cancer survivors worldwide. Regrettably, cardiovascular disease has risen in the aftermath as one of the most devastating consequences of cancer therapies. In this work, we define cancer therapeutics-induced cardiotoxicity as the direct or indirect cardiovascular injury or injurious effect caused by cancer therapies. We describe four progressive stages of this condition and four corresponding levels of prevention, each having a specific goal, focus, and means of action. We subsequently unfold this didactic framework, surveying mechanisms of cardiotoxicity, risk factors, cardioprotectants, biomarkers, and diagnostic imaging modalities. Finally, we outline the most current evidence-based recommendations in this area according to multidisciplinary expert consensus guidelines.

Cardiovascular Magnetic Resonance in the Oncology Patient

Patients with or receiving potentially cardiotoxic treatment for cancer are susceptible to developing decrements in left ventricular mass, diastolic function, or systolic function. They may also experience valvular heart disease, pericardial disease, or intracardiac masses. Cardiovascular magnetic resonance may be used to assess cardiac anatomy, structure, and function and to characterize myocardial tissue. This combination of features facilitates the diagnosis and management of disease processes in patients with or those who have survived cancer. This report outlines and describes prior research involving cardiovascular magnetic resonance for assessing cardiovascular disease in patients with or previously having received treatment for cancer.

In Vivo Reactive Oxygen Species Detection With a Novel Positron Emission Tomography Tracer, 18F-DHMT, Allows for Early Detection of Anthracycline-Induced Cardiotoxicity in Rodents

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LVEF is used to detect doxorubicin-induced cardiotoxicity in patients, but this index is variable and has limited ability to detect early cardiotoxicity.

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Doxorubicin induces cardiotoxicity largely through the excessive production of ROS.

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We hypothesized that ¹⁸F-DHMT, a PET tracer that detects superoxide production, would provide an early index of cardiotoxicity in rodents.

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¹⁸F-DHMT PET imaging was able to detect an elevation in cardiac superoxide production before a fall in LVEF.

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The early elevation in myocardial superoxide production was associated with only mild myocardial toxicity and occurred before cellular apoptosis or significant activation of MMPs; enzymes associated with myocardial remodeling.

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A drop in LVEF was associated with a significant increase in MMP activation, cellular apoptosis, and significant myocardial toxicity.

Reactive oxygen species (ROS) are involved in doxorubicin-induced cardiotoxicity. The authors investigated the efficacy of ¹⁸F-DHMT, a marker of ROS, for early detection of doxorubicin-induced cardiotoxicity in rats. Echocardiography was performed at baseline and 4, 6, and 8 weeks post-doxorubicin initiation, whereas in vivo superoxide production was measured at 4 and 6 weeks with ¹⁸F-DHMT positron emission tomography. Left ventricular ejection fraction (LVEF) was not significantly decreased until 6 weeks post-doxorubicin treatment, whereas myocardial superoxide production was significantly elevated at 4 weeks. ¹⁸F-DHMT imaging detected an elevation in cardiac superoxide production before a fall in LVEF in rodents and may allow for early cardiotoxicity detection in cancer patients.

The Role of Cardiovascular Magnetic Resonance in the Management of Patients with Cancer

PURPOSE OF REVIEW

This article reviews the utility of cardiovascular magnetic resonance imaging (CMR) to detect abnormalities of the cardiovascular system that may result from cancer or its treatment.

RECENT FINDINGS

With CMR, one may assess cardiac anatomy, function, myocardial perfusion, tissue composition, and blood flow. For those with cancer, these capabilities allow one to differentiate myocardial masses that may relate to the presence of cancer and evaluate diseases of the pericardium. These features facilitate measurement of left ventricular (LV) volumes, ejection fraction, mass, strain, T1 and T2 relaxation properties, and the extracellular volume fraction all of which may be useful for detecting subclinical cardiovascular injury that results from the receipt of potentially cardiotoxic cancer treatment. CMR can provide an effective and efficient means to identify clinical abnormalities resulting from the diagnosis of cancer or subclinical cardiac injury that may be related to receipt of the therapy for cancer.

Diagnosis, Treatment, and Prevention of Cardiovascular Toxicity Related to Anti-Cancer Treatment in Clinical Practice: An Opinion Paper from the Working Group on Cardio-Oncology of the Korean Society of Echocardiography

Cardiovascular (CV) toxicity associated with anti-cancer treatment is commonly encountered and raises critical problems that often result in serious morbidity or mortality. Most cardiac toxicities are related to the cumulative dose of chemotherapy; however, the type of chemotherapy, concomitant agents, and/or conventional CV risk factors have been frequently implicated in CV toxicity. Approximately half of the patients exhibiting CV toxicity receive an anthracycline-based regimen. Therefore, serologic biomarkers or cardiac imagings are important during anti-cancer treatment for early detection and the decision of appropriate management of cardiotoxicity. However, given the difficulty in determining a causal relationship, a multidisciplinary collaborative approach between cardiologists and oncologists is required. In this review, we summarize the CV toxicity and focus on the role of cardiac imaging in management strategies for cardiotoxicity associated with anti-cancer treatment.

A recommended practical approach to the management of anthracycline-based chemotherapy cardiotoxicity: an opinion paper of the working group on drug cardiotoxicity and cardioprotection, Italian Society of Cardiology

Anthracyclines are the mainstay of treatment of a variety of haematological malignancies and solid tumours. Unfortunately, the clinical use of these drugs is limited by cumulative, dose-related cardiotoxicity which may ultimately lead to a severe and irreversible form of cardiomyopathy. Thus, there is an increasing need for close cooperation among cardiologists, oncologists and haemato-oncologists. As anthracyclines save lives, the logical goal of this cooperation, besides preventing or mitigating cardiotoxicity, is to promote an acceptable balance between the potential cardiac side effects and the vital benefit of anticancer treatment. This manuscript, which is specifically addressed to the cardiologist who has not accumulated much experience in the field of cancer therapy, focuses on several topics, that is old and new mechanisms of cardiac toxicity, late cardiac toxicity, the importance of overall risk assessment, the key role of a cardiology consult before starting cancer therapy, and the pros and cons of primary and secondary prevention programmes.

Cardiac Magnetic Resonance Imaging in Oncology

BACKGROUND

Cardiac magnetic resonance imaging (MRI) is emerging as an important diagnostic modality in the management of cardiovascular-related dysfunction in oncological diseases. Advances in imaging techniques have enhanced the detection and evaluation of cardiac masses; meanwhile, innovative applications have created a growing role for cardiac MRI for the management of cardiotoxicity caused by cancer therapies.

METHODS

An overview is provided of the clinical indications and technical considerations of cardiac MRI. Its role in the evaluation of cardiac masses and cardiac function is reviewed, and novel sequences are discussed that are giving rise to future directions in cardio-oncology research. A review of the literature was also performed, focusing on cardiac MRI findings associated with cardiac dysfunction related to cancer treatment.

RESULTS

Cardiac MRI can be used to differentiate benign and malignant primary cardiac tumors, metastatic disease, and pseudotumors with high spatial and temporal resolution. Cardiac MRI can also be used to detect the early and long-term effects of cardiotoxicity related to cancer therapy. This is accomplished through a multiparametric approach that uses conventional bright blood, dark blood, and postcontrast sequences while also considering the applicability of newer T1 and T2 mapping sequences and other emerging techniques.

CONCLUSIONS

Cardio-oncology programs have an expanding presence in the multidisciplinary approach of cancer care. Consequently, knowledge of cardiac MRI and its potential applications is critical to the success of contemporary cancer diagnostics and cancer management.

Left Ventricular Strain in Chemotherapy-Naive and Radiotherapy-Naive Patients With Cancer

BACKGROUND

We sought to investigate left ventricular (LV) function and mechanics in patients with cancer before they received chemotherapy or radiotherapy, as well as the relationship between cancer and reduced LV multidirectional strain in the whole study population.

METHODS

The retrospective study involved 122 chemotherapy- and radiotherapy-naive patients with cancer and 45 age- and sex-matched controls with a cardiovascular risk profile similar to that of the patients with cancer. All the patients underwent echocardiographic examination before introduction of chemotherapy or radiotherapy.

RESULTS

LV longitudinal (-19.1% ± 2.1% vs -17.8% ± 3.5%; P = 0.022), circumferential (-22.9% ± 3.5% vs -20.1% ± 4.1%; P < 0.001), and radial (40.5% ± 8.8% vs 35.2% ± 10.7%; P = 0.004) strain was significantly lower in the patients with cancer than in the control group. Endocardial and midmyocardial longitudinal LV strain was significantly reduced in the patients with cancer compared with the controls, whereas epicardial longitudinal strain was similar between these groups. Endocardial, midmyocardial, and epicardial circumferential strain was significantly lower in the chemotherapy- or radiotherapy-naive patients with cancer than in the controls. Cancer was associated with reduced longitudinal (odds ratio [OR], 9.0; 95% confidence interval [CI], 2.20-23.50; P < 0.001), reduced circumferential (OR, 7.1; 95% CI, 3.80-20.40; P < 0.001), and reduced radial strain (OR, 7.2; 95% CI, 3.41-25.10; P < 0.001) independent of age, sex, body mass index, diabetes, and hypertension.

CONCLUSIONS

LV mechanics was impaired in the patients with cancer compared with the controls even before initiation of chemotherapy and radiotherapy. Cancer and hypertension were associated with reduced LV multidirectional strain independent of other clinical parameters. The present results indicate that cancer itself potentially induces cardiac remodelling independent of chemotherapy and radiotherapy.

Cardiac MRI: a Translational Imaging Tool for Characterizing Anthracycline-Induced Myocardial Remodeling

Cardiovascular side effects of cancer therapeutics are the leading causes of morbidity and mortality in cancer survivors. Anthracyclines (AC) serve as the backbone of many anti-cancer treatment strategies, but dose-dependent myocardial injury limits their use. Cumulative AC exposure can disrupt the dynamic equilibrium of the myocardial microarchitecture while repeated injury and repair leads to myocyte loss, interstitial myocardial fibrosis, and impaired contractility. Although children are assumed to have greater myocardial plasticity, AC exposure at a younger age portends worse prognosis. In older patients, there is lower overall survival once they develop cardiovascular disease. Because aberrations in the myocardial architecture predispose the heart to a decline in function, early detection with sensitive imaging tools is crucial and the implications for resource utilization are substantial. As a comprehensive imaging modality, cardiac magnetic resonance (CMR) imaging is able to go beyond quantification of ejection fraction and myocardial deformation to characterize adaptive microstructural and microvascular changes that are important to myocardial tissue health. Herein, we describe CMR as an established translational imaging tool that can be used clinically to characterize AC-associated myocardial remodeling.

T1 and T2 Mapping in Cardiology: “Mapping the Obscure Object of Desire”

The increasing use of cardiovascular magnetic resonance (CMR) is based on its capability to perform biventricular function assessment and tissue characterization without radiation and with high reproducibility. The use of late gadolinium enhancement (LGE) gave the potential of non-invasive biopsy for fibrosis quantification. However, LGE is unable to detect diffuse myocardial disease. Native T1 mapping and extracellular volume fraction (ECV) provide knowledge about pathologies affecting both the myocardium and interstitium that is otherwise difficult to identify. Changes of myocardial native T1 reflect cardiac diseases (acute coronary syndromes, infarction, myocarditis, and diffuse fibrosis, all with high T1) and systemic diseases such as cardiac amyloid (high T1), Anderson-Fabry disease (low T1), and siderosis (low T1). The ECV, an index generated by native and post-contrast T1 mapping, measures the cellular and extracellular interstitial matrix (ECM) compartments. This myocyte-ECM dichotomy has important implications for identifying specific therapeutic targets of great value for heart failure treatment. On the other hand, T2 mapping is superior compared with myocardial T1 and ECM for assessing the activity of myocarditis in recent-onset heart failure. Although these indices can significantly affect the clinical decision making, multicentre studies and a community-wide approach (including MRI vendors, funding, software, contrast agent manufacturers, and clinicians) are still missing.

Cardiac Imaging: Multimodality Advances and Surveillance Strategies in Detection of Cardiotoxicity

Contemporary cancer management has increased the overall number of cancer survivors, but cardiotoxicity remains a subject of concern, which is a major cause of noncancer mortality among survivors. Among the potential cardiovascular complications, left ventricular (LV) systolic dysfunction is a poor prognostic factor. The importance of its early detection is based on the principle that the likelihood of response to heart failure (HF) treatment is temporally related to the initiation of HF treatment. For these reasons, cardiac monitoring is commonly applied in general practice, based on serial measurements of LV ejection fraction (LVEF); transthoracic echocardiography (TTE) is generally used. However, the LVEF, as a diagnostic and predictive parameter, has significant limitations, which calls for more effective multimodality imaging strategies. This approach requires further study, but there is increasing available data in the literature, encouraging the combination of multimodality imaging parameters and techniques for early cancer therapeutic-related cardiac dysfunction (CTRCD) detection.

Frequency of Left Ventricular End-Diastolic Volume-Mediated Declines in Ejection Fraction in Patients Receiving Potentially Cardiotoxic Cancer Treatment

We sought to determine the frequency by which decreases in left ventricular (LV) end-diastolic volume (LVEDV) with and without increases in end-systolic volume (LVESV) influenced early cancer treatment-associated declines in LV ejection fraction (LVEF) or LV mass. One hundred twelve consecutively recruited subjects (aged 52 ± 14 years) with cancer underwent blinded cardiovascular magnetic resonance measurements of LV volumes, mass, and LVEF before and 3 months after initiating potentially cardiotoxic chemotherapy (72% of participants received anthracyclines). Twenty-six participants developed important declines in LVEF of >10% or to values <50% at 3 months, in whom 19% versus 60%, respectively, experienced their decline in LVEF due to isolated declines in LVEDV versus an increase in LVESV; participants who dropped their LVEF due to decreases in LVEDV lost more LV mass than those who dropped their LVEF due to an increase in LVESV (p = 0.03). Nearly one fifth of subjects experience marked LVEF declines due to an isolated decline in LVEDV after initiating potentially cardiotoxic chemotherapy. Because reductions in intravascular volume (which could be treated by volume repletion) may account for LVEDV-related declines in LVEF, these data indicate that LV volumes should be reviewed along with LVEF when acquiring imaging studies for cardiotoxicity during the treatment for cancer.

Anthracycline-Associated T1 Mapping Characteristics Are Elevated Independent of the Presence of Cardiovascular Comorbidities in Cancer Survivors

BACKGROUND

Cardiovascular magnetic resonance T1 mapping characteristics are elevated in adult cancer survivors; however, it remains unknown whether these elevations are related to age or presence of coincident cardiovascular comorbidities.

METHODS AND RESULTS

We performed blinded cardiovascular magnetic resonance analyses of left ventricular T1 and extracellular volume (ECV) fraction in 327 individuals (65% women, aged 64±12 years). Thirty-seven individuals had breast cancer or a hematologic malignancy but had not yet initiated their treatment, and 54 cancer survivors who received either anthracycline-based (n=37) or nonanthracycline-based (n=17) chemotherapy 2.8±1.3 years earlier were compared with 236 cancer-free participants. Multivariable analyses were performed to determine the association between T1/ECV measures and variables associated with myocardial fibrosis. Age-adjusted native T1 was elevated pre- (1058±7 ms) and post- (1040±7 ms) receipt of anthracycline chemotherapy versus comparators (965±3 ms; P<0.0001 for both). Age-adjusted ECV, a marker of myocardial fibrosis, was elevated in anthracycline-treated cancer participants (30.4±0.7%) compared with either pretreatment cancer (27.8±0.7%; P<0.01) or cancer-free comparators (26.9±0.2%; P<0.0001). T1 and ECV of nonanthracycline survivors were no different than pretreatment survivors (P=0.17 and P=0.16, respectively). Native T1 and ECV remained elevated in cancer survivors after accounting for demographics (including age), myocardial fibrosis risk factors, and left ventricular ejection fraction or myocardial mass index (P<0.0001 for all).

CONCLUSIONS

Three years after anthracycline-based chemotherapy, elevations in myocardial T1 and ECV occur independent of underlying cancer or cardiovascular comorbidities, suggesting that imaging biomarkers of interstitial fibrosis in cancer survivors are related to prior receipt of a potentially cardiotoxic cancer treatment regimen.

Role of Imaging in Cardio-Oncology

OPINION STATEMENT

Recent advances in cancer treatment and research have greatly improved survival rates for patients with cancer. However, many of these cancer survivors are developing cardiac disease-most commonly heart failure as a result of this treatment. Certain chemotherapeutic agents, including anthracyclines and trastuzumab, have been linked to cardiotoxicity-induced cardiomyopathy in cancer patients. It has been reported as early as during infusion and as late as several years following treatment. Radiation therapy, particularly to the left breast, has also been linked to cardiac disease. The responsibility of cardiac monitoring has traditionally fallen on oncologists using assessment of LVEF through multigated acquisition (MUGA) scans or echocardiograms. The "formal" definition of cardiotoxicity, as a 5 to 10% decrease in LVEF from its baseline, even though not validated, is currently used by clinicians to alter treatment, but it has been recently challenged, as a possible irreversible late stage of a myocardial insult. Furthermore, it falls into the interobserver variability range of echocardiography. The growing field of medicine called cardio-oncology is based on emerging research that has shown that more advanced imaging modalities can help detect cardiotoxicity early, allowing the patient to receive treatment and avoid developing heart failure from cancer treatment. While traditional imaging still has its place in cardiac monitoring, cardiac magnetic resonance imaging is the most accurate and detailed imaging modality available to assess cardiotoxicity. Our own pilot cardiac MRI study suggests that a normal left ventricular remodeling to chemotherapy, when patients have not developed heart failure symptoms, could occur over time. Perhaps, knowing a baseline normal response could help us to define a more accurate definition of cardiotoxicity by CMR. Here, we discuss various imaging modalities and emerging techniques that can assist in detecting early signs of cardiotoxicity and thus reduce the incidence of cardiac disease in cancer survivors.