Newest echocardiographic techniques for the detection of cardiotoxicity and heart failure during chemotherapy

Rationale and design of the Children's Oncology Group study AAML1831 integrated cardiac substudies in pediatric acute myeloid leukemia therapy

Background

Pediatric acute myeloid leukemia (AML) therapy is associated with substantial short- and long-term treatment-related cardiotoxicity mainly due to high-dose anthracycline exposure. Early left ventricular systolic dysfunction (LVSD) compromises anthracycline delivery and is associated with inferior event-free and overall survival in de novo pediatric AML. Thus, effective cardioprotective strategies and cardiotoxicity risk predictors are critical to optimize cancer therapy delivery and enable early interventions to prevent progressive LVSD. While dexrazoxane-based cardioprotection reduces short-term cardiotoxicity without compromising cancer survival, liposomal anthracycline formulations have the potential to mitigate cardiotoxicity while improving antitumor efficacy. This overview summarizes the rationale and methodology of cardiac substudies within AAML1831, a randomized Children's Oncology Group Phase 3 study of CPX-351, a liposomal formulation of daunorubicin and cytarabine, in comparison with standard daunorubicin/cytarabine with dexrazoxane in the treatment of de novo pediatric AML.

Methods/design

Children (age <22 years) with newly diagnosed AML were enrolled and randomized to CPX-351-containing induction 1 and 2 (Arm A) or standard daunorubicin and dexrazoxane-containing induction (Arm B). Embedded cardiac correlative studies aim to compare the efficacy of this liposomal anthracycline formulation to dexrazoxane for primary prevention of cardiotoxicity by detailed core lab analysis of standardized echocardiograms and serial cardiac biomarkers throughout AML therapy and in follow-up. In addition, AAML1831 will assess the ability of early changes in sensitive echo indices (e.g., global longitudinal strain) and cardiac biomarkers (e.g., troponin and natriuretic peptides) to predict subsequent LVSD. Finally, AAML1831 establishes expert consensus-based strategies in cardiac monitoring and anthracycline dose modification to balance the potentially competing priorities of cardiotoxicity reduction with optimal leukemia therapy.

Discussion

This study will inform diagnostic, prognostic, preventative, and treatment strategies regarding cardiotoxicity during pediatric AML therapy. Together, these measures have the potential to improve leukemia-free and overall survival and long-term cardiovascular health in children with AML. Clinical trial registration: https://clinicaltrials.gov/, identifier NCT04293562.

Subclinical reduction in left ventricular function using triplane and 2D speckle tracking echocardiography after anthracycline exposure in children

Objective:

Speckle tracking echocardiography (STE) enables global and regional evaluation of the left ventricle (LV); therefore, it is the most useful method for detecting subclinical dysfunction in patients exposed to cardiotoxic agents. A novel technique triplane (3P) echocardiography also allows single beat assessment of LV global longitudinal strain values. We firstly aimed to demonstrate both two-dimensional (2D)- and 3P-STE-derived LV global longitudinal strain measurements in children after anthracycline exposure.

Methods:

This study included 23 cross-sectionally enrolled asymptomatic pediatric cancer patients who received anthracycline chemotherapy and 17 healthy controls matched by age, gender, and body surface area. All subjects underwent detailed 2D, Doppler, 2D-STE, and 3P-STE for assessment of LV function. The patients had received a median cumulative dose of 150 mg/m².

Results:

1. From “Pulsed” Doppler-based measurements, only pulmonary vein flow ratio showed a significant difference between the groups. 2. When measurements were taken from the interventricular septum, the patients’ ejection time values decreased significantly and their myocardial performance index values increased significantly; when the measurements were taken from the LV free wall, the peak systolic velocities showed a statistically significant difference. 3. Both 2D- and 3P-STE-derived longitudinal myocardial deformation values of LV were lower in the patient group. 4. 2D-STE-derived LV circumferential strain values were decreased in the patient group, whereas radial strain values were not significantly different compared with matched controls.

Conclusion:

Using Doppler and 2D- and 3P-STE methods, this study confirmed the subclinical LV dysfunction in patients after anthracycline exposure.

Endothelial Function in Patients with Hematologic Malignancies Undergoing High-Dose Chemotherapy Followed by Hematopoietic Stem Cell Transplantation

The aim of the study was to examine endothelial function in patients with hematological malignancies treated with high-dose chemotherapy followed by hematopoietic stem cell transplantation. The studies were conducted on 43 consecutive patients qualified for HSCT following high-dose chemotherapy based on the current standards. Then, due to exclusion criteria, a group of 38 patients were chosen for further investigations. Evaluation of endothelial function by means of flow-mediated dilatation (FMD) was conducted in patients with hematological malignancies before HSCT (test A) and after HSCT (test B). Brachial artery diameter (BAD) after occlusion, change in BAD and FMD were significantly lower after HSCT as compared to the results obtained before the transplantation (p < 0.05). The regression analysis indicated that administration of fludarabine and cytarabine, and also higher blood concentrations of creatinine represented risk factors for the impairment of endothelial function expressed as decreased FMD value. In patients with hematopoietic malignancies treated with HSCT, endothelial function assessed by the flow-mediated dilatation was impaired after chemotherapy and stem cell administration.

Speckle-Tracking Echocardiography to Detect Cardiac Toxicity in Children Who Received Anthracyclines During Pregnancy

Cardiac toxicities remain a possible risk to fetuses that received anthracyclines during pregnancy. The introduction of new echocardiographic techniques will improve the detection of early cardiac damage. Thus, we began a observational study using speckle-tracking echocardiography (STE) in children who had received anthracyclines during pregnancy, including the first trimester. From 2009 to 2013, we performed STE on patients > 5 years old, whose mothers had received anthracyclines during pregnancy. Siblings or cousins of equivalent age and gender were used as the control group. A total of 90 children fulfilled the entry criteria. Our results with STE were normal in all echocardiography parameters and did not show any differences when compared with the findings from the control group. We consider that the use of anthracyclines during pregnancy does not produce cardiac damage in newborns and can be safely administered, because no cardiac toxicity was evident in these children and it is of benefit to the mother.

Heart failure and chemotherapeutic agents

Advances in chemotherapeutic agents over the past two decades have resulted in significantly improved cancer survival rates. Cardiac toxicity, however, has emerged as a leading cause of morbidity, both during and years after treatment. One of the most common manifestations of cardiotoxicity is that of heart failure and left ventricular systolic dysfunction. Consequently, the field of cardio-oncology is a rapidly emerging field of sub-specialty, with growing research interests in all aspects of management. In this review, current opinions and guidelines in this field are discussed, with particular focus on the most common culprits, the anthracyclines and the monoclonal antibody, trastuzumab.

Evaluation and management of patients with heart disease and cancer: cardio-oncology

The care for patients with cancer has advanced greatly over the past decades. A combination of earlier cancer diagnosis and greater use of traditional and new systemic treatments has decreased cancer-related mortality. Effective cancer therapies, however, can result in short- and long-term comorbidities that can decrease the net clinical gain by affecting quality of life and survival. In particular, cardiovascular complications of cancer treatments can have a profound effect on the health of patients with cancer and are more common among those with recognized or unrecognized underlying cardiovascular diseases. A new discipline termed cardio-oncology has thus evolved to address the cardiovascular needs of patients with cancer and optimize their care in a multidisciplinary approach. This review provides a brief introduction and background on this emerging field and then focuses on its practical aspects including cardiovascular risk assessment and prevention before cancer treatment, cardiovascular surveillance and therapy during cancer treatment, and cardiovascular monitoring and management after cancer therapy. The content of this review is based on a literature search of PubMed between January 1, 1960, and February 1, 2014, using the search terms cancer, cardiomyopathy, cardiotoxicity, cardio-oncology, chemotherapy, heart failure, and radiation.

Recognizing and managing left ventricular dysfunction associated with therapeutic inhibition of the vascular endothelial growth factor signaling pathway

OPINION STATEMENT

Therapeutic inhibition of the vascular endothelial growth factor (VEGF) signaling pathway (VSP) is increasingly employed in the contemporary treatment of many cancer types. VSP inhibitors include the anti-VEGF monoclonal antibody (bevacizumab), soluble VEGF receptors (VEGF Trap), and small molecule tyrosine kinase inhibitors (TKIs) targeting the intracellular kinase domain of VEGF receptors. These agents are associated with cardiovascular toxicities such as hypertension, thrombosis, myocardial ischemia, and left ventricular (LV) dysfunction. Data on VSP inhibitor-associated LV dysfunction are largely limited to retrospective studies. Prospective studies are needed to establish the clinical significance of VSP inhibitor-associated LV dysfunction in the general population. Pre-clinical models of VSP inhibitor-associated LV dysfunction have identified mechanisms of cardiotoxicity and may improve our understanding of the pathophysiology underlying other cardiomyopathies. This review provides an overview of LV dysfunction that can occur in patients treated with VSP inhibitors. Potential strategies for clinical detection and management of this cardiotoxicity are explored, while acknowledging that currently available data specific to VSP-inhibitor LV dysfunction are limited. Avenues for future research are suggested.

Validation of noninvasive indices of global systolic function in patients with normal and abnormal loading conditions: a simultaneous echocardiography pressure-volume catheterization study

BACKGROUND

Noninvasive indices based on Doppler echocardiography are increasingly used in clinical cardiovascular research to evaluate left ventricular global systolic chamber function. Our objectives were to clinically validate ultrasound-based methods of global systolic chamber function to account for differences between patients in conditions of abnormal load, and to assess their sensitivity to load confounders.

METHODS AND RESULTS

Twenty-seven patients (8 dilated cardiomyopathy, 10 normal ejection fraction, and 9 end-stage liver disease) underwent simultaneous echocardiography and left heart catheterization with pressure-conductance instrumentation. The reference index, maximal elastance (Emax), was calculated from pressure-volume loop data obtained during acute inferior vena cava occlusion. A wide range of values were observed for left ventricular systolic chamber function (Emax: 2.8±1.0 mm Hg/mL), preload, and afterload. Among the noninvasive indices tested, the peak ejection intraventricular pressure difference showed the best correlation with Emax (R=0.75). A significant but weaker correlation with Emax was observed for ejection fraction (R=0.41), midwall fractional shortening (R=0.51), global circumferential strain (R=-0.53), and strain rate (R=-0.46). Longitudinal strain and strain rate failed to correlate with Emax, as did noninvasive single-beat estimations of this index. Principal component and multiple regression analyses demonstrated that peak ejection intraventricular pressure difference was less sensitive to load, whereas ejection fraction and longitudinal strain and strain rate were heavily influenced by afterload.

CONCLUSIONS

Current ultrasound methods have limited accuracy to characterize global left ventricular systolic chamber function in a given patient. The Doppler-derived peak ejection intraventricular pressure difference should be preferred for this purpose because it best correlates with the reference index and is more robust in conditions of abnormal load.

Managing cardiotoxicity of chemotherapy

OPINION STATEMENT

The increase in survivorship of cancer patients makes the understanding of the available options for prevention and treatment of cardiotoxicity induced by antineoplastic agents a crucial topic both for cardiologists and oncologists. The most frequent and typical clinical manifestation of cardiotoxicity is asymptomatic or symptomatic left ventricular dysfunction, which may progress to overt heart failure. It may be induced not only by conventional cancer therapy, like anthracyclines, but also by new antitumoral targeted therapy such as trastuzumab. The current standard for monitoring cardiac damage during antineoplastic treatment, mainly based on the quantification of left ventricular ejection fraction, detects cardiac toxicity only when a functional impairment has already occurred. Evaluation of cardiac biomarkers such as troponin, however, has shown excellent sensitivity in the early detection of cardiotoxicity by the identification of patients with subclinical cardiac injury that precedes the development of cardiac dysfunction. The use of angiotensin-converting enzyme inhibitors in patients with troponin elevation during chemotherapy may be an effective tool to prevent left ventricular ejection fraction reduction and late cardiac events. There are no well established recommendations for treatment of cancer patients who develop cardiac dysfunction. Angiotensin-converting enzyme inhibitors and beta-blockers have proven to be effective in this setting. However, there are concerns in using these medications in cancer patients, and therefore the tendency is to treat patients only if symptomatic. However, the clinical benefit of these medications may be more evident in asymptomatic patients, and the recovery of cardiac function strongly depends on the amount of time elapsed from the end of chemotherapy to the start of heart failure therapy. This observation suggests that the early detection of cardiac damage is crucial and early use of angiotensin-converting enzyme inhibitors and beta-blockers should be considered in patients with left ventricular dysfunction induced by antineoplastic agents.

Myocardial function in children after fetal chemotherapy exposure. A tissue Doppler and myocardial deformation imaging study

Chemotherapy and particularly anthracycline exposure are associated with acute and chronic cardiotoxicity. Few data exist on the effect of cardiac function after in utero exposure to maternal chemotherapy. Our recently published multicenter prospective study showed no significant changes in systolic function using conventional echocardiographic parameters. The purpose of this study was to further investigate whether early functional changes can be detected using tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking echocardiography (STE). Sixty-two children (median/range age 1.7 (1-9.8) years) exposed to chemotherapy during fetal life were enrolled and compared to 62 age- and gender-matched controls. TDI velocities were measured at the basal interventricular septum (IVS) and right and left ventricular (LV) free walls. LV global longitudinal and circumferential systolic strains were derived using 2D STE. We found small but significant differences between the groups (patients versus controls) in LV fractional shortening [35 (29-46)% versus 39 (28-53)%, p < 0.001], LV ejection fraction [66 (57-79)% versus 70 (57-83)%, p < 0.001], LV posterior wall thickness z score [-0.15 (-2.32-1.81) versus -0.10 (-1.9-2.0), p < 0.001], and IVS thickness z score [-1.06 (-2.6-1.3) versus -0.5 (-2.1-1.7), p < 0.001]. No significant differences in TDI velocities or LV global strains were observed. Within the patient group, the cardiac functional parameters did not correlate to the number of cycles of anthracycline or the cumulative anthracycline dose. Children exposed to fetal chemotherapy have a lower normal fractional shortening and mildly lower left ventricular wall thickness. Tissue Doppler and strain measurements are within normal range and not statistically different from normal controls. The long-term implications of these findings will be further studied in this prospective cohort study.

Late cardiac effects of cancer treatment

Cardiac toxicities from cancer therapy can become evident many years after treatment, and these late cardiac effects can have a profound impact on cancer survivors. There are a myriad of potential cardiovascular complications from cancer therapy, but these can be grouped into three main categories. First, vascular conditions including atherosclerosis, thrombosis, and hypertension predominate. Second, cardiac structural problems, especially valvular degeneration, can have a dramatic impact long term. Lastly, and most importantly, cardiac dysfunction and heart failure are potentially common late cardiac effects and can certainly be prevented or detected early during active cancer therapy to result in optimal outcomes. Future research on late cardiac effects in cancer survivors needs to include advanced cardiac imaging techniques, novel cardiac biomarkers, and genetic determinants of response to cancer treatment.