Doxorubicin cardiotoxicity in children

Gender Differences in Oxidative Stress in Relation to Cancer Susceptibility and Survival

Genetic, developmental, biochemical, and environmental variables interact intricately to produce sex differences. The significance of sex differences in cancer susceptibility is being clarified by numerous studies. Epidemiological research and cancer registries have revealed over the past few years that there are definite sex variations in cancer incidence, progression, and survival. However, oxidative stress and mitochondrial dysfunction also have a significant impact on the response to treatment of neoplastic diseases. Young women may be more protected from cancer than men because most of the proteins implicated in the regulation of redox state and mitochondrial function are under the control of sexual hormones. In this review, we describe how sexual hormones control the activity of antioxidant enzymes and mitochondria, as well as how they affect several neoplastic diseases. The molecular pathways that underlie the gender-related discrepancies in cancer that have been identified may be better understood, which may lead to more effective precision medicine and vital information on treatment options for both males and females with neoplastic illnesses.

A Patent Review on Cardiotoxicity of Anticancerous Drugs

Chemotherapy-induced cardiotoxicity is an increasing concern and it is critical to avoid heart dysfunction induced by medications used in various cancers. Dysregulated cardiomyocyte homeostasis is a critical phenomenon of drug-induced cardiotoxicity, which hinders the cardiac tissue's natural physiological function. Drug-induced cardiotoxicity is responsible for various heart disorders such as myocardial infarction, myocardial hypertrophy, and arrhythmia, among others. Chronic cardiac stress due to drug toxicity restricts the usage of cancer medications. Anticancer medications can cause a variety of adverse effects, especially cardiovascular toxicity. This review is focused on anticancerous drugs anthracyclines, trastuzumab, nonsteroidal anti-inflammatory medications (NSAIDs), and immune checkpoint inhibitors (ICI) and associated pathways attributed to the drug-induced cardiotoxicity. Several factors responsible for enhanced cardiotoxicity are age, gender specificity, diseased conditions, and therapy are also discussed. The review also highlighted the patents assigned for different methodologies involved in the assessment and reducing cardiotoxicity. Recent advancements where the usage of trastuzumab and bevacizumab have caused cardiac dysfunction and their effects alone or in combination on cardiac cells are explained. Extensive research on patents associated with protection against cardiotoxicity has shown that chemicals like bis(dioxopiperazine)s and manganese compounds were cardioprotective when combined with other selected anticancerous drugs. Numerous patents are associated with druginduced toxicity, prevention, and diagnosis, that may aid in understanding the current issues and developing novel therapies with safer cardiovascular outcomes. Also, the advancements in technology and research going on are yet to be explored to overcome the present issue of cardiotoxicity with the development of new drug formulations.

MicroRNA composition of plasma extracellular vesicles: a harbinger of late cardiotoxicity of doxorubicin

BACKGROUND

The use of doxorubicin is associated with an increased risk of acute and long-term cardiomyopathy. Despite the constantly growing number of cancer survivors, little is known about the transcriptional mechanisms which progress in the time leading to a severe cardiac outcome. It is also unclear whether long-term transcriptomic alterations related to doxorubicin use are similar to transcriptomic patterns present in patients suffering from other cardiomyopathies.

METHODS

We have sequenced miRNA from total plasma and extracellular vesicles (EVs) from 66 acute lymphoblastic leukemia (ALL) survivors and 61 healthy controls (254 samples in total). We then analyzed processes regulated by differentially expressed circulating miRNAs and cross-validated results with the data of patients with clinically manifested cardiomyopathies.

RESULTS

We found that especially miRNAs contained within EVs may be informative in terms of cardiomyopathy development and may regulate pathways related to neurotrophin signaling, transforming growth factor beta (TGFβ) or epidermal growth factor receptors (ErbB). We identified vesicular miR-144-3p and miR-423-3p as the most variable between groups and significantly correlated with echocardiographic parameters and, respectively, for plasma: let-7g-5p and miR-16-2-3p. Moreover, vesicular miR-144-3p correlates with the highest number of echocardiographic parameters and is differentially expressed in the circulation of patients with dilated cardiomyopathy. We also found that distribution of particular miRNAs between of plasma and EVs (proportion between compartments) e.g., miR-184 in ALL, is altered, suggesting changes within secretory and miRNA sorting mechanisms.

CONCLUSIONS

Our results show that transcriptomic changes resulting from doxorubicin induced myocardial injury are reflected in circulating miRNA levels and precede development of the late onset cardiomyopathy phenotype. Among miRNAs related to cardiac function, we found vesicular miR-144-3p and miR-423-3p, as well as let-7g-5p and miR-16-2-3p contained in the total plasma. Selection of source for such studies (plasma or EVs) is of critical importance, as distribution of some miRNA between plasma and EVs is altered in ALL survivors, in comparison to healthy people, which suggests that doxorubicin-induced changes include miRNA sorting and export to extracellular space.

Sex-Specific Cardiovascular Risks of Cancer and Its Therapies

In both cardiovascular disease and cancer, there are established sex-based differences in prevalence and outcomes. Males and females may also differ in terms of risk of cardiotoxicity following cancer therapy, including heart failure, cardiomyopathy, atherosclerosis, thromboembolism, arrhythmias, and myocarditis. Here, we describe sex-based differences in the epidemiology and pathophysiology of cardiotoxicity associated with anthracyclines, hematopoietic stem cell transplant (HCT), hormone therapy and immune therapy. Relative to males, the risk of anthracycline-induced cardiotoxicity is higher in prepubertal females, lower in premenopausal females, and similar in postmenopausal females. For autologous hematopoietic cell transplant, several studies suggest an increased risk of late heart failure in female lymphoma patients, but sex-based differences have not been shown for allogeneic hematopoietic cell transplant. Hormone therapies including GnRH (gonadotropin-releasing hormone) modulators, androgen receptor antagonists, selective estrogen receptor modulators, and aromatase inhibitors are associated with cardiotoxicity, including arrhythmia and venous thromboembolism. However, sex-based differences have not yet been elucidated. Evaluation of sex differences in cardiotoxicity related to immune therapy is limited, in part, due to low participation of females in relevant clinical trials. However, some studies suggest that females are at increased risk of immune checkpoint inhibitor myocarditis, although this has not been consistently demonstrated. For each of the aforementioned cancer therapies, we consider sex-based differences according to cardiotoxicity management. We identify knowledge gaps to guide future mechanistic and prospective clinical studies. Furthering our understanding of sex-based differences in cancer therapy cardiotoxicity can advance the development of targeted preventive and therapeutic cardioprotective strategies.

Lipid Emulsion Inhibits the Late Apoptosis/Cardiotoxicity Induced by Doxorubicin in Rat Cardiomyoblasts

This study aimed to examine the effect of lipid emulsion on the cardiotoxicity induced by doxorubicin in H9c2 rat cardiomyoblasts and elucidates the associated cellular mechanism. The effects of lipid emulsion on cell viability, Bax, cleaved caspase-8, cleaved capase-3, Bcl-XL, apoptosis, reactive oxygen species (ROS), malondialdehyde, superoxide dismutase (SOD), catalase and mitochondrial membrane potential induced by doxorubicin were examined. Treatment with doxorubicin decreased cell viability, whereas pretreatment with lipid emulsion reduced the effect of doxorubicin by increasing cell viability. Lipid emulsion also suppressed the increased expression of cleaved caspase-3, cleaved caspase-8, and Bax induced by doxorubicin. Moreover, pretreatment with lipid emulsion decreased the increased Bax/Bcl-XL ratio induced by doxorubicin. Doxorubicin-induced late apoptosis was reduced by treatment with lipid emulsion. In addition, pretreatment with lipid emulsion prior to doxorubicin enhanced glycogen synthase kinase-3β phosphorylation. The increased malondialdehyde and ROS levels by doxorubicin were reduced by lipid emulsion pretreatment. Furthermore, lipid emulsion attenuated the reduced SOD and catalase activity and the decreased mitochondrial membrane potential induced by doxorubicin. Taken together, these results suggest that lipid emulsion attenuates doxorubicin-induced late apoptosis, which appears to be associated with the inhibition of oxidative stress induced by doxorubicin.

Histamine 2 receptor antagonism elicits protection against doxorubicin-induced cardiotoxicity in rodent model

Doxorubicin (DOX), an anthracycline-based antibiotic, is regularly used in the management of carcinomas, and haematological malignancies have been downplayed in chemotherapy because of its ability to induce dilated cardiomyopathy (DCM). Dexrazoxane is approved to combat the cardiotoxicity, but limited by its adverse effects. Redox imbalance and reactive oxygen species generation plays major role in DOX-induced cardiotoxicity. Histamine, known to mediate various cardiovascular effects, but nevertheless the role of histamine or its receptors in DOX-induced DCM is remained obscure. Hence, this study is aimed to examine the effect of Famotidine (FAM), a H2 receptor antagonist on DOX-induced DCM in Wistar rats. Myocardial antioxidant status, stress and apoptosis markers, myocardial morphology and function were evaluated as the end points. Treatment with FAM has alleviated DOX doxorubicin-induced cardiotoxicity by reducing oxidative and nitrosative stress evident from lipid peroxidation and total nitrate-to-nitrite ratio, and enhanced the activity of super oxide dismutase. Cardiac stress markers like LDH and Na⁺-K⁺ATPase activities as well as CK-MB and Cardiac troponin levels were reduced by FAM treatment. It also normalised the myocardial function as assessed by 2D echocardiography and myocardial index. Treatment imparted anti-apoptotic effect as evident from decrease in myocardial caspase 3 and 9 activity and cleaved PARP expression. Effect of FAM is found to be comparable to the standard ACE inhibitor Captopril (CAP). The results from this study collectively suggest H2 receptor antagonism as a novel therapeutic strategy to impart biochemical, structural and functional improvement indicating its cardio-protective activity.

Pediatric Bone Marrow Transplantation: Intensive Care Management

Bone marrow transplantation (BMT) has assumed in creasing importance in the treatment of bone marrow failure, hematopoietic malignancies, congenital immuno deficiencies, and solid tumors. Children undergoing BMT are at high risk for infection and hemorrhage dur ing the period of aplasia. In addition, life-threatening complications of circulatory, pulmonary, gastrointesti nal, hepatic, and renal function are common and fre quently require intensive supportive care. This review provides an overview of pediatric BMT that focuses on management problems relevant to intensive care. Thor ough pretransplantation assessment of underlying organ dysfunction is mandatory before undertaking BMT. The complications associated with preconditioning regi mens that use total body irradiation and high doses of ablative chemotherapy are described. Finally, problems involving individual organs are discussed by systems. The challenge of improving the results of BMT in the treatment of childhood malignant and hematopoietic disorders depends, in large part, on successful preven tive measures and good management of complications that occur immediately before and within the first 100 days after transplantation. As BMT is indicated for treat ment of an increasing number of diseases, more patients will require the care of intensivists familiar with trans plantation-related complications.

Recent Advances on Pathophysiology, Diagnostic and Therapeutic Insights in Cardiac Dysfunction Induced by Antineoplastic Drugs

Along with the improvement of survival after cancer, cardiotoxicity due to antineoplastic treatments has emerged as a clinically relevant problem. Potential cardiovascular toxicities due to anticancer agents include QT prolongation and arrhythmias, myocardial ischemia and infarction, hypertension and/or thromboembolism, left ventricular (LV) dysfunction, and heart failure (HF). The latter is variable in severity, may be reversible or irreversible, and can occur soon after or as a delayed consequence of anticancer treatments. In the last decade recent advances have emerged in clinical and pathophysiological aspects of LV dysfunction induced by the most widely used anticancer drugs. In particular, early, sensitive markers of cardiac dysfunction that can predict this form of cardiomyopathy before ejection fraction (EF) is reduced are becoming increasingly important, along with novel therapeutic and cardioprotective strategies, in the attempt of protecting cardiooncologic patients from the development of congestive heart failure.

Reproductive hormone levels and differential mitochondria-related oxidative gene expression as potential mechanisms for gender differences in cardiosensitivity to Doxorubicin in tumor-bearing spontaneously hypertensive rats

PURPOSE

Chemotherapy with doxorubicin (Dox) causes dose-limiting cardiotoxicity. We investigated the role that gender has on cardiosensitivity to Dox treatment by evaluating reproductive hormone levels in male, castrated male (c-male), female and ovariectomized female (o-female) adult spontaneously hypertensive rats (SHRs) and expression of mitochondria-related genes in male and female adult SHRs.

METHODS

SST-2 breast tumor-bearing SHRs were treated with saline, Dox, dexrazoxane (Drz) or both Dox and Drz and monitored for 14 days. Tumor size was used to monitor anticancer activity. Heart weight, cardiac lesion score and serum levels of cardiac troponin T (cTnT) were used to determine cardiotoxicity. Serum estradiol (E2) and testosterone were evaluated using electrochemiluminescence immunoassays. Expression of mitochondria-related genes was profiled in heart by MitoChip array analyses.

RESULTS

Dox significantly reduced tumor volume (±Drz) and increased heart weight in all genders (13-30% vs. control). Higher heart lesion scores were observed in reproductively normal animals (male 2.9, female 2.2) than in hormone-deficient animals (c-male 1.7, o-female 1.9). Lesion score and cTnT inversely correlated with hormone levels. Reduced levels of both sex hormones were observed after Dox treatment. Gene expression analyses of Dox-treated hearts showed significant differential expression of oxidative stress genes in male hearts and apoptotic genes in both male and female hearts.

CONCLUSIONS

Our results demonstrate that adult tumor-bearing male SHRs are more cardiosensitive to Dox than female or hormone-deficient animals. We provide evidence to suggest that reproductive hormones negatively regulate or are inhibited by Dox-induced cardiotoxicity and the selective cytotoxic mechanism likely functions through the greater activation of oxidative stress and apoptosis in male SHRs.

Evaluation of left ventricular function in asymptomatic children about to undergo anthracycline-based chemotherapy for acute leukemia: an outcome study

BACKGROUND

Cardiac toxicity is a well-recognized potential complication of anthracycline use. Children treated with anthracyclines undergo several cardiac screening procedures before therapy, but the usefulness of these pretherapy cardiac studies has never been evaluated. The authors examined whether induction chemotherapy in patients with high-risk acute lymphoblastic leukemia (ALL) was altered based on a pretherapy left ventricular shortening fraction (SF).

PATIENTS AND METHODS

Medical records of 134 children registered on treatment protocols of the Pediatric Oncology Group for high-risk B-precursor and T-cell ALL between 1987 and 1998 were reviewed. Demographic information consisting of age at diagnosis, sex, and past cardiac history was collected, as were the results of all echocardiographic evaluations for SF and actions taken based on these evaluations. The outcome measured was whether any changes were made in induction therapy based on initial SF. In addition, secondary SF results obtained at the cumulative anthracycline dose range of 90 to 150 mg/m2 were studied to determine whether modifications of future chemotherapy were made after this limited exposure.

RESULTS

Three of 128 children (2.3%) without a previous cardiac history had an initial SF on their pretherapy echocardiogram that prompted additional evaluation but no change in therapy. A secondary analysis of SF in 85 children who completed anthracycline doses of 90 to 150 mg/m2 was performed. There were three (3.5%) with abnormal study results who were evaluated further. Again, no changes were made in the anthracycline doses based on these findings. No cardiac dysfunction occurred among these six patients during later follow-up.

CONCLUSIONS

In the absence of a previous cardiac history or signs and symptoms or cardiac disease, pretherapy evaluation of left ventricular function may not be indicated in children about to undergo anthracycline-based treatment of acute leukemia. The timing of initiation of cardiac evaluation remains unclear, but these results suggest that even at a cumulative dose of 90 to 150 mg/m2, studies to determine left ventricular function do not yield data sufficient to warrant a change in the clinical management of these patients.

Changes in circulating atrial natriuretic peptide in relation to the cardiac status of Rhesus monkeys after total-body irradiation

PURPOSE

In order to determine the presence of cardiac damage associated with total-body irradiation (TBI), both echocardiographic parameters and circulating levels of atrial natriuretic peptide (ANP) were measured in three different age-cohorts of Rhesus monkeys (Macaca mulatta) previously treated with TBI without additional chemotherapy, at post irradiation intervals up to 30 years, at the former TNO/Radiobiological Institute at Rijswijk.

MATERIALS AND METHODS

Standard echocardiographic techniques were used to measure cardiac dimensions and left ventricular function in situ. Plasma-ANP concentration was measured by radioimmunoassay (RIA). After necropsy, tissue samples from the heart were taken for histological analysis.

RESULTS

Plasma-ANP levels of animals which received TBI were significantly (P = 0.0005) elevated when compared to age-matched controls (66.4 +/- 8.4 vs. 33.1 +/- 5.7 ng/l). Moreover, a positive correlation (P = 0.032) between plasma-ANP values and time post treatment was found in the TBI group. TBI affected cardiac dimensions; however, no significant differences in cardiac functional parameters were observed between the different treatment groups. Necropsy reports demonstrated slight but consistent cardiovascular damage in several animals treated with TBI, in terms of increased incidence of mild epicardial and coronary arterial wall fibrosis, compared to age-matched controls.

CONCLUSIONS

The concentration of plasma-ANP proved to be an important parameter for subclinical cardiac damage. In humans, serial determinations of plasma ANP in individual patients might provide relevant information about the cardiac status after TBI.

Differences in dose scheduling as a factor in the etiology of anthracycline-induced cardiotoxicity in Ewing sarcoma patients

Clinical observation suggested a high prevalence of cardiac morbidity and mortality in children with Ewing sarcoma (ES) treated at B.C.'s Children's Hospital. We therefore compared 30 patients treated for Ewing sarcoma between 1978 and 1991 with 26 soft tissue sarcoma (STS) patients treated with similar chemotherapy over the same period of time. All patients were evaluated for cardiac function using echocardiography. Shortening fraction (SF) and left ventricular mass index (Massl) were compared before and after treatment. The role of chest irradiation, dose concentration (DC) of adriamycin (AD), total mean doses of AD, cyclophosphamide (CY) and actinomycin (AC) were analysed. SF for patients with ES and STS postchemotherapy was significantly lower (P < .001 and P = 0.0004, respectively) than pretreatment values. Postchemotherapy SF for ES was lower than STS (P = 0.0097). Massl for each group did not change significantly. Six of the ES patients had postchemotherapy SF of < 0.20, with three in congestive failure, two cardiac deaths and one heart transplant. One additional ES patient had sick sinus syndrome and needed a pacemaker. Among the STS patients only one had SF < .20 and none were symptomatic. There were no significant differences in the mean AD, CY and AC doses for ES versus STS. The difference in the DC of AD for ES (mean 744) compared to STS (mean = 362) was significant (P = < 0.001). Regression analysis indicated a trend for decreasing SF with increasing DC (P = 0.017). Chest irradiation did not appear to increase the likelihood of cardiotoxicity. ES patients had a higher prevalence of cardiac dysfunction compared to STS. Studies are required to evaluate the importance of the components of DC, i.e., size of the individual dose and frequency of administration of AD, and to look at other possible factors in the causation of cardiomyopathy in ES.

Cardiorespiratory status after treatment for acute lymphoblastic leukemia

The use of certain chemotherapeutic agents is associated with dose-related cardiotoxicity and, potentially, with restrictive lung disease. Therefore, we assessed the cardiopulmonary status and exercise capacity of 19 patients (pts; 9M:10F) 1.1 to 7.1 years (mean 4.6 +/- 1.5 years) after successful treatment of acute lymphoblastic leukemia (ALL) with Dana Farber Cancer Institute protocols. As body mass and nutritional status may influence exercise capacity, we also evaluated their anthropometric status and the plasma levels of rapid turnover proteins. Seven pts designated as "standard risk for relapse" (SR) had received low cumulative doses of doxorubicin (50 +/- 21 mg/m2), while twelve pts at "high or very high risk for relapse" (HR/VHR) had received higher doses (349 +/- 16 mg/m2). The evaluations included a questionnaire, anthropometric assessments, echocardiography, pulmonary function studies, exercise testing, and nutritional assays. Patients' data were compared with published normative data or with control values from our laboratories. In addition, we compared SR pt data with HR/VHR pt data. No pt had overt symptoms or signs of cardiorespiratory compromise. The pts had a higher percent of body fat than age-matched healthy controls (29.7 +/- 7.9% vs. 20 +/- 6%; P < 0.001). On echocardiography, cardiac systolic function was within normal limits in all. However, HR/VHR pts had lower left ventricular (LV) shortening fractions than SR pts (P < 0.05). LV filling velocity, indicative of diastolic function (the E/A ratio), was normal in most pts. Pulmonary function studies were normal. Exercise capacity was below predicted in most cases but heart rates at peak exercise and leg muscle function were within normal limits, suggesting a deconditioned state. Plasma levels of rapid turnover proteins were also normal. Despite lack of overt morbidity in our pt population, subtle abnormalities persist in cardiac function while pulmonary function is normal. Longitudinal studies will identify if further abnormalities or overt morbidity develop. In later years, continuing obesity and a sedentary state may contribute to clinically relevant heart disease.

Late echocardiographic findings following childhood chemotherapy with normal serial cardiac monitoring

PURPOSE

Late development of myocardial dysfunction years following successful treatment of childhood malignancy with anthracyclines is well documented. There have been few studies of late cardiac performance in children in whom serial monitoring during treatment suggested normal cardiac performance, and those studies that do exist rely on the results of extensive evaluation. It was our purpose to determine whether findings consistent with known late cardiac changes could be discovered in these patients by echocardiographic monitoring similar to that routinely performed during treatment.

PATIENTS AND METHODS

A total 28 consecutive asymptomatic patients who had completed anthracycline therapy at least 3 years previously, had been free of malignant disease since the completion of therapy, and who had had normal serial echocardiographic studies during and at completion of treatment were restudied by echocardiography. Of these 28, 12 had undergone mediastinal radiation as part of their acute treatment.

RESULTS

Four patients (14%) of the study group were found to have abnormally low values for left ventricular shortening and ejection fractions. All four had also received mediastinal radiation. The remaining 24 patients, while having values for shortening fraction within the normal range, had, as a group, experienced a significant decrease in echocardiographic left ventricular shortening since completion of treatment. In these patients, left ventricular wall thickness had not increased commensurate with growth in body size and left ventricular cavity dimension.

CONCLUSIONS

The known incidence of late asymptomatic cardiac dysfunction is confirmed despite the presence of persistently normal echocardiographic monitoring studies during and at completion of anthracycline treatment. Additionally, as a population, these patients show impaired myocardial growth over time, placing them at risk for future myocardial failure. Normal echocardiographic monitoring studies during antineoplastic treatment in children may not necessarily predict that patients will be free of the development of late cardiac dysfunction. Routine serial echocardiographic monitoring can, however, be helpful in the long-term management of these patients.

Gender difference in aerobic capacity in adolescents after cure from malignant disease in childhood

The aim of this study was to document gender difference in aerobic capacity after cure from malignant disease in childhood. We studied 18 males and 17 females aged 11-19 years and 10-18 years, respectively. They had all completed their treatment at least two years previously. Twelve males and 11 females received anthracyclines in comparable doses (range 150-500 mg/m2). Maximal exercise tests were performed on a cycle ergometer. Maximal oxygen consumption (ml/min/kg) was significantly (p < 0.001) lower only in females when compared to their controls. We postulate two causes: girls are smaller than their controls, possibly related to their higher vulnerability to cranial irradiation than boys; and girls were less involved than boys in sports. The influence of anthracycline treatment on aerobic capacity was only observed in males and not in females. This could be related to the higher exercise level in boys than in girls.

Atrial natriuretic peptide as a marker for doxorubicin-induced cardiotoxic effects

Doxorubicin is an effective antineoplastic agent, but it frequently causes dose-related cardiotoxic effects. Because the atrial natriuretic peptide (ANP) level is elevated in children with heart defects, the authors measured the ANP levels in children to determine whether ANP might serve as a simple diagnostic indicator of cardiotoxic effects. Sixteen patients, 5 to 19 years of age, who were being treated with doxorubicin (45 mg/m2 body surface area) for various malignancies had ANP levels measured in plasma. There was a group of six children, with a significant peak of plasma ANP (pANP) levels 3 weeks after the administration of the drug. Of these six patients, five had received high cumulative doses of doxorubicin (160 to 370 mg/m2), and two of them went into congestive heart failure without a previous decline in left ventricular ejection fraction, a standard technique for monitoring cardiac function during treatment with doxorubicin. The other ten patients had normal ANP levels throughout the study, and signs of cardiac dysfunction did not develop. None of the patients in the control group who had cancer and were not treated with doxorubicin and none of the healthy volunteers had elevated ANP levels. These preliminary results suggest that pANP may be useful as an early and sensitive indicator for doxorubicin-related myocardial damage.

Dobutamine stress echocardiography: a sensitive indicator of diminished myocardial function in asymptomatic doxorubicin-treated long-term survivors of childhood cancer

Doxorubicin is an effective anticancer chemotherapeutic agent known to cause acute and chronic cardiomyopathy. To develop a more sensitive echocardiographic screening test for cardiac damage due to doxorubicin, a cohort study was performed using dobutamine infusion to differentiate asymptomatic long-term survivors of childhood cancer treated with doxorubicin from healthy control subjects. Echocardiographic data from the experimental group of 21 patients (mean age 16 +/- 5 years) treated from 1.6 to 14.3 years (median 5.3) before this study with 27 to 532 mg/m2 of doxorubicin (mean 196) were compared with echocardiographic data from 12 normal age-matched control subjects. Graded dobutamine infusions of 0.5, 2.5, 5 and 10 micrograms/kg per min were administered. Echocardiographic Doppler studies were performed before infusion and after 15 min of infusion at each rate. Dobutamine infusion at 10 micrograms/kg per min was discontinued after six studies secondary to a 50% incidence rate of adverse symptoms. The most important findings were that compared with values in control subjects, end-systolic left ventricular posterior wall dimension and percent of left ventricular posterior wall thickening in doxorubicin-treated patients were decreased at baseline study and these findings were more clearly delineated with dobutamine stimulation. End-systolic left ventricular posterior wall dimension at baseline for the doxorubicin-treated group was 11 +/- 1.9 mm versus 13.1 +/- 1.5 mm for control subjects (p less than 0.01). End-systolic left ventricular posterior wall dimension at the 5-micrograms/kg per min dobutamine infusion for the doxorubicin-treated group was 14.1 +/- 2.4 mm versus 19.3 +/- 2.6 mm for control subjects (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Scintigraphic evaluation of myocardial uptake of thallium 201 and technetium 99m pyrophosphate utilizing a rat model of chronic doxorubicin cardiotoxicity

To evaluate the usefulness of myocardial scintigraphy as a monitoring tool for chronic doxorubicin (DXR) cardiotoxicity, a rat model was used to investigate the relationship between the myocardial uptake of thallium 201 (Tl) or rechnetium 99m pyrophosphate (99mTc-PPi) and histological changes of the heart. Although there was no significant difference in myocardial Tl uptake between control and DXR-treated rats at an early phase after Tl injection, late-phase Tl uptake was significantly higher in the DXR-treated rats than in the control rats, indicating a slow wash-out of Tl from the myocardium. The wash-out rate calculated from scintigraphic examination of DXR-treated rats was significantly decreased with increasing degree of cardiomyopathy. Since the Tl wash-out rate was sharply decreased even in animals with minimal histological changes, it may be a possible monitoring tool for the early detection of chronic DXR cardiotoxicity. On the other hand, myocardial 99mTc-PPi images could be obtained only in rats with severe myocardial changes and hence would not useful for early detection.

The survivors of childhood solid tumors

With the improvement in cancer therapy in recent years, the number of cancer survivors is rapidly increasing. Potential late medical and psychosocial sequelae of cancer therapy are reviewed. A practical guide for the primary health care giver is provided.

Pediatric Hodgkin's disease: pulmonary, cardiac, and thyroid function following combined modality therapy

Since pediatric Hodgkin's disease is a curable malignancy, it is essential to limit treatment sequelae. This study examines post-treatment pulmonary, cardiac, and thyroid function in 34 children, ages 5 to 17 (23 male and 11 female) with Hodgkin's disease. All received combined modality therapy of 6 cycles of alternating ABVD/MOPP chemotherapy and low dose (1500-2500 cGy) involved field radiotherapy. Mean follow-up period is 27.5 months with actuarial freedom from relapse of 94% and survival of 92%. Twenty asymptomatic patients underwent pulmonary function testing following chemotherapy and supradiaphragmatic radiotherapy. Eleven patients had post-treatment carbon monoxide diffusing capacity (DLCO) performed. Six of 11 children (55%) had abnormal values (mean 66%, range 58-80) showing either a reduced DLCO compared to pretreatment or an low absolute value. Eight of the twenty patients (40%) tested post-treatment for FEV1, FVC, TLC and flow volume loop had abnormal results. Six showed restrictive abnormalities and two had obstructive dysfunction. Fourteen patients underwent cardiac nuclear gated angiogram after completion of chemotherapy. Two asymptomatic patients (14%) had abnormal scans showing either a low resting ejection fraction or a decreased response to exercise. Thyroid function was evaluated post-treatment in twenty-one patients by TSH, T4, free T4 or sensitive TSH analysis. Four (21%) had an elevated TSH with a normal T4 after treatment. Although post-treatment thyroid and cardiac effects were minimal, post-treatment pulmonary dysfunction in asymptomatic patients was substantial with more than 50% of tested children demonstrating an abnormal DLCO and 40% showing restrictive or obstructive pulmonary parameters. These abnormalities were observed following a maximum bleomycin dose of 60 units/m2. Bleomycin and pulmonary radiotherapy have adverse effects on diffusing capacity and the long-term pulmonary sequlae of combined ABVD chemotherapy and radiotherapy are unknown. Our analysis suggests that even in asymptomatic children, pulmonary abnormalities are frequent.

Anthracycline-induced congestive heart failure in two pediatric leukemia cases and long term follow-up

Endomyocardial biopsy was performed on two leukemia patients who had recovered from severe congestive heart failure (CHF) due to anthracycline cardiomyopathy at 41 months and 47 months after CHF. Microscopic myocardial findings in both patients revealed that myocytes were hypertrophic, but interstitial fibrosis was not observed, suggesting a compensatory mechanism for the damaged heart muscle during the acute episode of CHF. The improvement of clinical symptoms and the normalization of cardiac function, including fractional shortening and ECG changes, is thought to have been associated with this myocardial repairing process.

Cardiomyopathy in the young

The application of echocardiography is most helpful in recognizing hypertrophic or congestive cardiomyopathy. It cannot determine the cause of such findings but rather provides the clinician with useful information that may over time allow the correct diagnosis to become clearer. The alterations in hemodynamics after surgical or pharmacologic intervention can easily be evaluated with echo Doppler applications. Herein lies one of the major strengths of echocardiography: frequent sequential evaluation. The role of Doppler color flow imaging is just emerging. As time goes on, it may add useful information not otherwise obtained by the existing technology.

Anesthesia for intraoperative radiation therapy in children

Intraoperative radiation therapy (IORT) is a relatively new mode of cancer treatment which is being used with increasing frequency. IORT presents several challenges to the anesthesiologist, including patients who are debilitated from their disease or chemotherapy, operations involving major tumor resections, intraoperative interdepartmental transport of patients, and remote monitoring of patients during electron beam therapy. This report discusses the anesthetic management of ten children undergoing IORT. With adequate preparation and interdepartmental communication, complications can be avoided during these challenging cases.

Psychosocial consequences of cure

Survivors of childhood cancer, having overcome the biggest hurdle to a normal life span, must continue to be vigilant toward health care issues as well as toward certain psychological and social problems for which they are at a greater than normal risk. The long-term survivor's knowledge about his/her illness, its treatment, and the consequent need for health surveillance and maintenance practices must be continually updated. Equally important is the survivor's preparation for coping with any long-term consequences of disruption in family, academic, and social activities engendered by cancer treatment. Existing research has frequently focused on patients diagnosed in early childhood. Recent studies, however, suggest that the developmental disruptions may have special significance for the adolescent, who is already struggling with unique issues of separation, changes in peer relationships, emergent sexuality, and future academic and occupational goals. Previous investigations addressing the medical and psychiatric problems encountered by the long-term survivor of adolescent cancer are presented with a focus on current psychological adjustment and degree of emancipation achieved. A recent pilot study, from three major medical centers, collected extensive interview data on a group of long-term survivors and sibling controls. Preliminary analyses of these data are described, and areas for future research are suggested.

Computer assisted echocardiographic assessment of left ventricular function before and after anatomical correction of transposition of the great arteries

Left ventricular function before and after anatomical correction of transposition of the great arteries was assessed by computer assisted analysis of 78 echocardiographs from 27 patients obtained one year before to five years after operation. Sixteen patients had simple transposition, and 11 had complex transposition with additional large ventricular septal defect. Immediately after correction mean shortening fraction fell from 46(9)% to 33(8)%. There was a corresponding drop in normalised peak shortening rate from 5.4(3.7) to 3.3(1.1) s-1 and normal septal motion was usually absent. Systolic shortening fraction increased with time after correction and left ventricular end diastolic diameter increased appropriately for age. The preoperative rate of free wall thickening was significantly higher in simple (5.6(2.8) s-1) and complex transposition (4.5(1.8) s-1) than in controls (2.9(0.8) s-1). After operation these values remained high in both the short and long term. Thus, computer assisted analysis of left ventricular dimensions and their rates of change before and after anatomical correction showed only slight postoperative changes which tended to become normal with time. Septal motion was commonly absent after operation. This was associated with an increase in the rate of posterior wall thickening that suggested normal ventricular function associated with an altered contraction pattern. Computer assisted echocardiographic analysis may be helpful in the long term assessment of ventricular function after operation for various heart abnormalities.

Two sensitive echocardiographic techniques for detecting doxorubicin toxicity

This investigation was designed to evaluate echoes of patients who received a course of doxorubicin (225-550 mg/m2) by two sensitive indicators of myocardial fibrosis: (1) M-mode scans of thickening-thinning curves of the left ventricular posterior wall (LVPW), and (2) two-dimensional qualitative evaluation of LVPW contraction at three levels of the LV short axis (leaflet, chordal, and papillary). These were compared to standard M-mode shortening fraction (delta S). Eighteen children with cancer were evaluated; 11 had received doxorubicin and 7 were treated with other agents. Echocardiographers were unaware of the treatment category. All controls and 10 of 11 doxorubicin patients had normal delta S. An M-mode echocardiogram of the expanded LVPW was digitized and wall thickness was evaluated by determining if diastolic relaxation had the normal two phases or only one; six of ten doxorubicin patients and no controls had abnormal relaxation. Qualitative evaluation of LVPW and septal contraction toward the center of the ventricle showed that seven of eleven patients who received doxorubicin and one control (a postthoracotomy patient) had contraction deficits. Six of seven with contraction deficit were the same patients with slowed relaxation. The greatest contraction deficit occurred in the LVPW behind the posterior mitral leaflet. Patients with more extensive involvement had an additional contraction deficit extending to the apex. These tests are more sensitive for detection of doxorubicin toxicity than delta S.

Effect of age on cardiac index, stroke index and left ventricular ejection fraction at rest and during exercise as studied by radiocardiography

Radiocardiography was used to measure cardiac output, stroke volume and left ventricular ejection fraction at rest and during muscular exercise in relation with age in 148 healthy subjects (age range: 6-78 years). A clear dependence of these parameters on age was found. The mean annual decrease at rest was 22 +/- 9 ml/min/m2 for cardiac index, 0.22 +/- 0.04 ml/m2 for stroke index and 0.0017 +/- 0.0003 for left ventricular ejection fraction. Male subjects had significantly (p less than 0.001) greater cardiac (9 +/- 4%) and stroke indices (11 +/- 3%) than females. During submaximal exercise cardiac index increased from 3.5 +/- 0.7 l/min/m2 to 8.1 +/- 1.6 l/min/m2 in male subjects (mean age: 32 years) and from 3.1 +/- 0.4 l/min/m2 to 7.2 +/- 1.2 l/min/m2 in female subjects (mean age: 29 years). The corresponding increases in stroke index and left ventricular ejection fraction were: from 52 +/- 7 ml/m2 to 62 +/- 9 ml/m2, from 46 +/- 7 ml/m2 to 51 +/- 9 ml/m2 and from 0.66 +/- 0.08 to 0.79 +/- 0.05 and from 0.64 +/- 0.10 to 0.72 +/- 0.10. In subjects who were 60 years and older the increases of these parameters during exercise were considerably smaller.

Anthracycline cardiomyopathy

Life-threatening irreversible cardiomyopathy is a major complication of anthracycline therapy, particularly in the pediatric population. The pediatric cardiologist, in concert with the primary oncologist, should therefore play a major role in the care of patients receiving these agents and in clinical trials involving their use. Many risk factors and their relationships to drug pharmacokinetics, mechanisms of action, and toxicity have been identified. These data provide a rational basis for present-day recommendations regarding anthracycline administration and dosage scheduling. They furthermore provide potential avenues for clinical investigation aimed at improving the therapeutic index of these agents: alpha-tocopherol, cytochrome Q10, and other free radical scavengers may decrease the deleterious effects of free radical generation on the myocardium without apparent interference with tumoricidal effect. The cardiac glycosides may decrease cardiac toxicity by specific myocardial exclusion. Anthracycline analogs have been designed to specifically inhibit myocardial binding and/or free radical generation. Clinical trials involving these agents are difficult to interpret because of variability in front end risk factors and dosage schedules in the study population. Furthermore, the relatively low (5 to 10%) incidence of affected patients implies the need for large numbers to demonstrate a statistically significant benefit. Pediatric protocols addressing these issues are urgently needed. Guidelines for present-day management and future studies are outlined.