Intensified Chemotherapy With Dexrazoxane Cardioprotection in Newly Diagnosed Nonmetastatic Osteosarcoma: A Report From the Children's Oncology Group

BACKGROUND

Although chemotherapy has improved outcome of osteosarcoma, 30-40% of patients succumb to this disease. Survivors experience substantial morbidity and mortality from anthracycline-induced cardiotoxicity. We hypothesized that the cardioprotectant dexrazoxane would (i) support escalation of the cumulative doxorubicin dose (600 mg/m(2)) and (ii) not interfere with the cytotoxicity of chemotherapy measured by necrosis grading in comparison to historical control data.

PROCEDURE

Children and adolescents with nonmetastatic osteosarcoma were treated with MAP (methotrexate, doxorubicin, cisplatin) or MAPI (MAP/ifosfamide). Dexrazoxane was administered with all doxorubicin doses. Cardioprotection was assessed by measuring left ventricular fractional shortening. Interference with chemotherapy-induced cytotoxicity was determined by measuring tumor necrosis after induction chemotherapy. Feasibility of intensifying therapy with either high cumulative-dose doxorubicin or high-dose ifosfamide/etoposide was evaluated for "standard responders" (SR, <98% tumor necrosis at definitive surgery).

RESULTS

Dexrazoxane did not compromise response to induction chemotherapy. With doxorubicin (450-600 mg/m(2)) and dexrazoxane, grade 1 or 2 left ventricular dysfunction occurred in five patients; 4/5 had transient effects. Left ventricular fractional shortening z-scores (FSZ) showed minimal reductions (0.0170  ±  0.009/week) over 78 weeks. Two patients (<1%) had secondary leukemia, one as a first event, a similar rate to what has been observed in prior trials. Intensification with high-dose ifosfamide/etoposide was also feasible.

CONCLUSIONS

Dexrazoxane cardioprotection was safely administered. It did not impair tumor response or increase the risk of secondary malignancy. Dexrazoxane allowed for therapeutic intensification increasing the cumulative doxorubicin dose in SR to induction chemotherapy. These findings support the use of dexrazoxane in children and adolescents with osteosarcoma.

The imperative to prevent and treat childhood obesity: why the world cannot afford to wait

In the past 20 years, the prevalence of obesity in the United States increased almost 50% among adults and by 300% in children. Today, 9.7% of all U.S. infants up to 2 years old have abnormally high weight-for-recumbent length; 25% of children under age 5 are either overweight or obese; and 17% of adolescents are obese. Ethnic disparities in the rates of obesity are also large and apparent in childhood. Further, 44% of obese adolescents have metabolic syndrome. Obese children tend to become obese adults; thus, in a decade, young adults will likely have much higher risks of chronic disease, which has tremendous implications for the healthcare system. However, early childhood may be the best time to prevent obesity. Teachers' healthy eating choices are positively associated with changes in body mass index percentiles for children, for example. In addition, 8 million children attend afterschool programs, which can successfully promote health and wellness and successfully treat obesity. This childhood epidemic of obesity and its health-related consequences in adolescents should be a clinical and public health priority. However, this major public health problem cannot be managed solely in clinical settings. Rather, public health strategies must be integrated into home and family, school and community-based settings.

Exercise capacity in long-term survivors of pediatric cancer

10026

Background: Childhood cancer survivors may have premature symptomatic cardiovascular and noncardiovascular diseases that contribute to reduced capacity for physical activity. Controlled assessments of exercise capacity and identification of risk factors for reduced capacity in survivors are lacking. Methods: We assessed maximal myocardial oxygen consumption (VO2max; measure of exercise capacity) in survivors at least 4 years after diagnosis and sibling controls. We evaluated associations between VO2max and age, sex, treatments, cardiac structure and function, biomarkers, endocrine function, and physical activity. Results: Of 72 survivors (mean age, 22 y; range, 8.0 to 40 y) and 32 siblings (mean age, 20.2 y; range, 8 to 46 y), about half were male. The mean time since cancer diagnosis was 13.4 y (range, 4.5 to 31.6 y). In age- and sibling-pair adjusted analyses, VO2max was lower in survivors than siblings (males, 28.53 vs. 30.90 mL/kg/min, P = 0.08; females, 19.81 vs. 23.40 mL/kg/min, P = 0.03). In male survivors, older age (P = 0.01), higher percent body fat (P < 0.001) and high or low left ventricular (LV) mass Z-scores (P = 0.03) predicted lower VO2max. In females, older age (P < 0.001), methotrexate exposure (P = 0.01), and higher, but normal, LV load-dependent contractility (P = 0.02) predicted lower VO2max. Conclusions: Physical fitness for most participants in each group was poor, and was generally lower in survivors, particularly females. Older age, higher body fat, methotrexate exposure, and extremes of LV mass/function were associated with lower VO2max in survivors. Because physical activity can improve nutritional and cardiac conditions, survivors should be encouraged to engage in regular exercise with close medical monitoring.

No significant financial relationships to disclose.

Gender differences in long-term dexrazoxane cardioprotection in doxorubicin-treated children with acute lymphoblastic leukemia

10005

Background: Doxorubicin (DOX) causes progressive cardiac dysfunction, particularly in females. Adding dexrazoxane (DZR) to DOX treatment resulted in reduced myocardial injury in children with acute lymphoblastic leukemia (ALL) during Dana-Farber Cancer Institute Protocol 95–01. Methods: We centrally remeasured echocardiograms from childhood high-risk ALL survivors in their first continuous remission who were randomly assigned to treatment with DOX only (n = 66; 30 mg/m2/dose for 10 doses) or DOX plus DZR 30 minutes prior (n = 68; 300 mg/m2/dose). Results: Demographics and median follow-up (DOX 5.3 vs. DZR/DOX 5.5 y) were similar in both arms. Mean left ventricle (LV) end systolic dimension (ESD) z-score was significantly larger than predicted for body-surface area for DOX (mean = 0.46, P-value [deviation of mean from normal] = 0.01) but not so for DZR/DOX (mean = 0.06, P = 0.74); DOX LV fractional shortening (FS; -0.78, P = .001; DZR/DOX = -0.38, P = 0.11) and thickness to dimension ratio (-0.96, P < .001; DZR/DOX = -0.32, P = 0.08) were also abnormal. LV end diastolic posterior wall thickness (EDPWT) was reduced in both groups, though more so for DOX (-1.19, P < .001) than DZR/DOX (-0.74, P < .001). By gender, 5 years post treatment LVESD z-score was significantly larger than normal for DOX males (mean = 0.48, P = 0.04) but not DZR/DOX males (0.19, P = 0.41) or females (DOX female = 0.38, P = 0.22; DZR/DOX female = -0.17, P = 0.56). LVFS z-score was significantly different from normal in DOX females (mean = -1.29, P < .001), but not DZR/DOX females (-0.22, P = 0.54) or males (DOX = -0.45, P = 0.15; DZR/DOX = -0.52, P = 0.09), as was LV thickness to dimension ratio (DOX female = -1.03, P < .001; DZR/DOX female = 0.02, P = 0.93). DZR/DOX females were the only group with normal LVEDPWT z-score (mean = -0.43, P = 0.07; DOX/female = -1.43, P < .001; DOX male = -1.05, P < .001; DZR/DOX male = -0.94, P < .001). Conclusions: While its impact is seen in all groups, primarily females drive the long-term DZR cardioprotective effect. DZR/DOX females exhibit more normal LV dimensions and more appropriate wall thickness for LV dimension, both of which are consistent with less LV remodeling. DZR/DOX females also have more normal LV function than females who received DOX only or males of either group.

[Table: see text]

Cardiac status predicts quality of life in Hodgkin’s disease survivors

9029

Background: Long-term survivors of Hodgkin’s disease (HD) treated with mediastinal radiotherapy suffer from a variety of subclinical cardiac abnormalities including valvar defects and findings suggestive of restrictive cardiomyopathy. Their clinical importance has not been definitively demonstrated in longitudinal studies, but they may be related to the reduced quality of life reported by many HD survivors. Methods: The overlapping participants in two independent studies of HD survivors were identified in order to form a longitudinally studied cohort. In the first study, 48 survivors of childhood and young adulthood HD were evaluated by multiple cardiac testing modalities and quality-of-life assessment including the SF-36, a mean of 16 years after diagnosis. In the second performed about 5 years later, 511 survivors took part in a survey study, which also included the SF-36 instrument. A total of 23 patients participated in both studies and formed the current study population. Correlations were performed between key cardiac abnormalities uncovered during the first study and the physical component score (PCS) of the SF-36 measured in the second study, and the changes in PCS during the time between the 2 studies. Results: Average PCS was 44.05 at time of the second study, about 6.0 points lower than at time of cardiac testing. Maximum oxygen consumption correlated with PCS at time 2 (r=0.50, p=0.029). Univariate regression suggested that for every unit decrease in maximum oxygen consumption, the PCS decreased by 0.45 units. The higher the baseline PCS, the greater the negative change in PCS. Left ventricular fractional shortening correlated with PCS at time 2 (r=−0.579, p=0.0094) but not change in PCS. Conclusions: The study suggests that objective measures of reduced cardiac function are predictive of future quality of life in HD survivors. These results however need to be verified in a larger longitudinal study that allows for multivariate analysis.

No significant financial relationships to disclose.

Cardiac, aortic, and pulmonary arteriopathy in HIV-infected children: the Prospective P2C2 HIV Multicenter Study

Arteriopathy in human immunodeficiency virus (HIV)-infected patients is being increasingly recognized, especially in children. However, few studies have histologically evaluated the coronary arteries in HIV-infected children, and none have systematically assessed the aorta and pulmonary arteries. The coronary arteries, thoracic aorta, and the main and branch pulmonary arteries from the postmortem hearts of 14 HIV-infected children were systematically reviewed for vasculopathic lesions and compared with 14 age-matched controls. Findings from the HIV-infected children were compared with clinical, laboratory, and other postmortem findings. Coronary arteriopathy, seen in seven (50%) of the HIV-infected children, was primarily calcific, and it was associated with decreased CD3 and CD4 peripheral blood counts. Large vessel arteriopathy, seen in 9 (64%) of the 14 HIV-infected children, was primarily centered on the vasa vasorum and consisted mainly of medial hypertrophy and chronic inflammation. Large vessel lesions were associated with increased left ventricular mass z-scores (P = 0.02), and 78% of patients with large vessel arteriopathy had postmortem cardiomegaly. Coronary and large vessel arteriopathies are common in pediatric HIV-infection and have different clinicopathologic features suggesting different pathogenesis.

Maternal and infant factors associated with failure to thrive in children with vertically transmitted human immunodeficiency virus-1 infection: the prospective, P2C2 human immunodeficiency virus multicenter study

OBJECTIVE

Many children with human immunodeficiency virus-1 (HIV-1) have chronic problems with growth and nutrition, yet limited information is available to identify infected children at high risk for growth abnormalities. Using data from the prospective, multicenter P2C2 HIV study, we evaluated the relationships between maternal and infant clinical and laboratory factors and impaired growth in this cohort.

METHODS

Children of HIV-1-infected women were enrolled prenatally or within the first 28 days of life. Failure to thrive (FTT) was defined as an age- and sex-adjusted weight z score < or =-2.0 SD. Maternal baseline covariates included age, race, illicit drug use, zidovudine use, CD4+ T-cell count, and smoking. Infant baseline predictors included sex, race, CD4+ T-cell count, Centers for Disease Control stage, HIV-1 RNA, antiretroviral therapy, pneumonia, heart rate, cytomegalovirus, and Epstein-Barr virus infection status.

RESULTS

The study cohort included 92 HIV-1-infected and 439 uninfected children. Infected children had a lower mean gestational age, but birth weights, lengths, and head circumferences in the 2 groups were similar. Mothers of growth-delayed infants were more likely to have smoked tobacco and used illicit drugs during pregnancy. In repeated-measures analyses of weight and length or height z scores, the means of the HIV-1-infected group were significantly lower at 6 months of age (P <.001) and remained lower throughout the first 5 years of life. In a multivariable Cox regression analysis, FTT was associated with a history of pneumonia (relative risk [RR] = 8.78; 95% confidence interval [CI]: 3.59-21.44), maternal use of cocaine, crack, or heroin during pregnancy (RR = 3.17; 95% CI: 1.51-6.66), infant CD4+ T-cell count z score (RR = 2.13 per 1 SD decrease; 95% CI: 1.25-3.57), and any antiretroviral therapy by 3 months of age (RR = 2.77; 95% CI: 1.16-6.65). After adjustment for pneumonia and antiretroviral therapy, HIV-1 RNA load remained associated with FTT in the subset of children whose serum was available for viral load analysis.

CONCLUSIONS

Clinical and laboratory factors associated with FTT among HIV-1-infected children include history of pneumonia, maternal illicit drug use during pregnancy, lower infant CD4+ T-cell count, exposure to antiretroviral therapy by 3 months of age (non-protease inhibitor), and HIV-1 RNA viral load.

Cardiovascular monitoring and therapy for HIV-infected patients

Cardiovascular complications are important contributors to morbidity and mortality in HIV-infected patients. These complications can usually be detected at subclinical levels with monitoring, which can help guide targeted interventions. This article reviews available data on types and frequency of cardiovascular manifestations in HIV+ patients and proposes monitoring strategies aimed at early subclinical detection. In particular, we recommend routine echocardiography for HIV+ patients, even those with no evidence of cardiovascular disease. We also review preventive and therapeutic cardiovascular interventions. For procedures that have not been studied in HIV+ patients, we extrapolate from evidence-based guidelines for the general population.

HIV-associated cardiovascular complications: a new challenge for emergency physicians

Cardiac complications associated with the AIDS may present to emergency physicians and are often secondary to opportunistic infections or malignancy, but may also be associated with other aspects of the human immunodeficiency virus (HIV) or its treatment. In this review article, we will discuss HIV-associated cardiac disease which may be encountered in the ED, emphasizing the prevalence, pathogenesis, and treatment of related disorders.

Epidemiology of cardiovascular involvement in HIV disease and AIDS

The epidemiology of cardiac complications related to HIV including cardiomyopathy, increased left ventricular mass, myocarditis, pericardial effusion, endocarditis, and malignancy are discussed. A large number of HIV-infected individuals will present with cardiac complications in the next decade as chronic viral infection, co-infections, drug therapy, and immunosuppression affect the heart. Understanding the nature and course of cardiac illness related to HIV infection will allow appropriate monitoring, early intervention and therapy, and will provide a baseline to evaluate the effects of new therapeutic regimens such as highly active antiretroviral therapy on the cardiovascular system.

Cardiac manifestations of HIV infection in infants and children

Cardiac manifestations of HIV infection in children are common, but etiologies, contributing factors, and the natural history are largely unexplored. The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted Human Immunodeficiency Virus Infection Study (P2C2 HIV Study) was initiated in 1989 by the National Heart, Lung and Blood Institute, USA. A primary objective of this study is to examine the epidemiology of cardiovascular problems associated with HIV infection in a cohort of children vertically infected. Findings of the study thus far show that cardiovascular problems associated with HIV infection including left ventricular dysfunction and increased left ventricular mass are common and clinically important indicators of survival for children infected with HIV.

Pathogenesis of HIV-associated cardiomyopathy

Reviews and studies published before the introduction of highly active antiretroviral therapy (HAART) regimens have tracked the incidence and course of human immunodeficiency virus (HIV) infection in relation to cardiac illness in both children and adults. HAART regimens have significantly modified the course of HIV disease, with longer survival rates and improvement of life quality in HIV+ subjects expected. However, early data raised concerns about HAART's being associated with an increase in both peripheral and coronary arterial diseases. A variety of potential etiologies have been postulated in HIV-related heart disease, including myocardial infection with HIV itself, opportunistic infections, viral infections, autoimmune response to viral infection, drug-related cardiotoxicity, nutritional deficiencies, and prolonged immunosuppression. In this review article we discuss HIV-associated cardiovascular complications, focusing on pathogenetic mechanisms that may play a role in diagnosis, management, and therapy of these complications.

The use of serum levels of cardiac troponin T to compare the protective activity of dexrazoxane against doxorubicin- and mitoxantrone-induced cardiotoxicity

PURPOSE

To compare the protective effect of dexrazoxane (DRZ) against cardiotoxicity induced by doxorubicin (DXR) and mitoxantrone (MTX).

METHODS

Adult male spontaneously hypertensive rats (SHR) were treated with 1 mg/kg DXR (i.v.) or 0.5 mg/kg MTX (i.v.), either alone or 30 min after 25 mg/kg DRZ (i.p.) weekly for up to 12 weeks. Animals treated with DXR alone either died (n = 2) or were killed (n = 3) at a cumulative dose of 10 mg/kg. The severity of cardiac lesions (cytoplasmic vacuolization and myofibrillar loss) were graded semiquantitatively by light microscopy on a scale of 0 to 3.

RESULTS

Cardiac lesions were observed in all SHR given DXR or MTX alone, and were attenuated in those given DRZ prior to either DXR (mean lesion scores 2.7 vs 1.5; P < 0.05) or MTX (mean lesion scores 2.0 vs 1.25; P < 0.05). Cardioprotection was also demonstrated by monitoring serum levels of cardiac troponin T (cTnT), which were elevated in all animals receiving DXR or MTX alone. These elevations were attenuated in SHR given the combination of DXR and DRZ (mean values 0.79 ng/ml vs 0.24 ng/ml; P < 0.05) and MTX and DRZ (mean values 0.19 ng/ml vs 0.04 ng/ ml; P < 0.05). Biochemical studies have shown that both DXR and MTX form potentially cardiotoxic complexes with iron. ADR-925 (the hydrolysis product of DRZ) and other chelators (EDTA, diethylenetriaminepentaacetic acid and desferrioxamine) removed Fe(III) from its complex with MTX or DXR.

CONCLUSIONS

The present study showed that DRZ significantly attenuates the cardiotoxicity induced by DXR and MTX, and that this protective activity can be assessed by morphological evaluation of cardiac tissues and by monitoring the concentrations of cTnT in serum.

Pathogenesis of HIV-associated cardiovascular complications

Reviews and studies published before the introduction of highly active antiretroviral therapy (HAART) have tracked the incidence and course of HIV infection in relation to cardiac illness in both children and adults. The introduction of HAART regimens has significantly modified the course of HIV disease, with longer survival rates and improvement of life quality in HIV-infected people expected. However, early data raised concerns about HAART being associated with an increase in both peripheral and coronary arterial diseases. In this review we discuss HIV-associated cardiovascular complications focusing on pathogenetic mechanisms that could have a role in diagnosis, management, and therapy of these complications in the HAART era.

Reliability of multicenter pediatric echocardiographic measurements of left ventricular structure and function: the prospective P(2)C(2) HIV study

BACKGROUND

To assess the reliability of pediatric echocardiographic measurements, we compared local measurements with those made at a central facility.

METHODS AND RESULTS

The comparison was based on the first echocardiographic recording obtained on 735 children of HIV-infected mothers at 10 clinical sites focusing on measurements of left ventricular (LV) dimension, wall thicknesses, and fractional shortening. The recordings were measured locally and then remeasured at a central facility. The highest agreement expressed as an intraclass correlation coefficient (ICC=0.97) was noted for LV dimension, with much lower agreement for posterior wall thickness (ICC=0.65), fractional shortening (ICC=0.64), and septal wall thickness (ICC=0.50). The mean dimension was 0.03 cm smaller in central measurements (95% prediction interval [PI], -0.32 to 0.25 cm) for which 95% PI reflects the magnitude of differences between local and central measurements. Mean posterior wall thickness was 0.02 cm larger in central measurements (95% PI, -0.18 to 0.22 cm). Mean fractional shortening was 1% smaller in central measurements. However, the 95% PI was -10% to 8%, indicating that a fractional shortening of 32% measured centrally could be anywhere between 22% and 40% when measured locally. Central measurements of mean septal thickness were approximately 0.1 cm thicker than local ones (95% PI, -0.18 to 0.34 cm). Centrally measured wall thickness was more closely related to mortality and possibly was more valid than local measurements.

CONCLUSIONS

Although LV dimension was reliably measured, local measurements of LV wall thickness and fractional shortening differed from central measurements.

Dilation of the aortic root in children infected with human immunodeficiency virus type 1: The Prospective P2C2 HIV Multicenter Study

BACKGROUND

Vascular lesions have become more evident in human immunodeficiency virus type 1 (HIV)-infected patients as the result of earlier diagnosis, improved treatment, and longer survival. Aortic root dilation in HIV-infected children has not previously been described. This study was undertaken to determine the prevalence of aortic root dilation in HIV-infected children and to evaluate some of the potential pathogenic mechanisms.

METHODS

Aortic root measurements were incorporated into the routine echocardiographic surveillance of 280 children of HIV-infected women: an older cohort of 86 HIV-infected children and a neonatal cohort of 50 HIV-infected and 144 HIV-uninfected children.

RESULTS

By repeated-measures analyses, mean aortic root measurements were significantly increased in HIV-infected children versus HIV-uninfected children (P values of < or =.04 and < or =.005 at 2 and 5 years of age, respectively, for aortic annulus diameter, sinuses of Valsalva, and sinotubular junction). Heart rate, systolic blood pressure, stroke volume, hemoglobin, and hematocrit were not significantly associated with aortic root size. Left ventricular dilation, increased serum HIV RNA levels, and lower CD4 cell count measurements were associated with aortic root dilation at baseline.

CONCLUSIONS

Mild and nonprogressive aortic root dilation was seen in children with vertically transmitted HIV infection from 2 to 9 years of age. Aortic root size was not significantly associated with markers for stress-modulated growth; however, aortic root dilation was associated with left ventricular dilation, increased viral load, and lower CD4 cell count in HIV-infected children. As prolonged survival of HIV-infected patients becomes more prevalent, some patients may require long-term follow-up of aortic root size.

Cardiac structure and function in fetuses of mothers infected with HIV: the prospective PCHIV multicenter study

BACKGROUND

This study was designed to determine if vertically transmitted HIV infection and maternal infection with HIV are associated with altered cardiovascular structure and function in utero.

METHODS

Fetal echocardiography was performed in 173 fetuses of 169 HIV-infected mothers (mean gestational age, 33.0 weeks; SD = 3.7 weeks) at 5 centers. Biparietal diameter, femur length, cardiovascular dimensions, and Doppler velocities through atrioventricular and semilunar valves and the umbilical artery were measured. Measurements were converted to z scores based on published normal data.

RESULTS

Fetuses determined after birth to be HIV-infected had similar echocardiographic findings as fetuses later determined to be HIV-uninfected except for slightly smaller left ventricular diastolic dimensions (P =.01). The femur length (P =.03) was also smaller in the fetuses postnatally identified as HIV-infected. Differences in cardiovascular dimensions and Doppler velocities were identified between fetuses of HIV-infected women and previously published normal fetal data. The reason for the differences may be a result of maternal HIV infection, maternal risk factors, or selection bias in the external control data.

CONCLUSIONS

Vertically transmitted HIV infection may be associated with reduced left ventricular size but not with altered cardiac function in utero. Fetuses of HIV-infected mothers may have abnormal cardiovascular structure and function and increased placental vascular resistance, regardless of whether the fetuses are subsequently found to be infected with HIV.

Cardiac dysfunction and mortality in HIV-infected children: The Prospective P2C2 HIV Multicenter Study. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection (P2C2 HIV) Study Group

BACKGROUND

Left ventricular (LV) dysfunction is common in children infected with the human immunodeficiency virus (HIV), but its clinical importance is unclear. Our objective was to determine whether abnormalities of LV structure and function independently predict all-cause mortality in HIV-infected children.

METHODS AND RESULTS

Baseline echocardiograms were obtained on 193 children with vertically transmitted HIV infection (median age, 2.1 years). Children were followed up for a median of 5 years. Cox regression was used to identify measures of LV structure and function predictive of mortality after adjustment for other important demographic and baseline clinical risk factors. The time course of cardiac variables before mortality was also examined. The 5-year cumulative survival was 64%. Mortality was higher in children who, at baseline, had depressed LV fractional shortening (FS) or contractility; increased LV dimension, thickness, mass, or wall stress; or increased heart rate or blood pressure (P0.02 for each). Decreased LV FS (P<0.001) and increased wall thickness (P=0.004) were also predictive of increased mortality after adjustment for CD4 count (P<0.001), clinical center (P<0.001), and encephalopathy (P<0.001). FS showed abnormalities for up to 3 years before death, whereas wall thickness identified a population at risk only 18 to 24 months before death.

CONCLUSIONS

Depressed LV FS and increased wall thickness are risk factors for mortality in HIV-infected children independent of depressed CD4 cell count and neurological disease. FS may be useful as a long-term predictor and wall thickness as a short-term predictor of mortality.

Absence of cardiac toxicity of zidovudine in infants. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection Study Group

BACKGROUND

Perinatal exposure to zidovudine may cause cardiac abnormalities in infants. We prospectively studied left ventricular structure and function in infants born to mothers infected with the human immunodeficiency virus (HIV) in order to determine whether there was evidence of zidovudine cardiac toxicity after perinatal exposure.

METHODS

We followed a group of infants born to HIV-infected women from birth to five years of age with echocardiographic studies every four to six months. Serial echocardiograms were obtained for 382 infants without HIV infection (36 with zidovudine exposure) and HIV-58 infected infants (12 with zidovudine exposure). Repeated-measures analysis was used to examine four measures of left ventricular structure and function during the first 14 months of life in relation to zidovudine exposure.

RESULTS

Zidovudine exposure was not associated with significant abnormalities in mean left ventricular fractional shortening, end-diastolic dimension, contractility, or mass in either non-HIV-infected or HIV-infected infants. Among infants without HIV infection, the mean fractional shortening at 10 to 14 months was 38.1 percent for those never exposed to zidovudine and 39.0 percent for those exposed to zidovudine (mean difference, -0.9 percent; 95 percent confidence interval, -3.1 percent to 1.3 percent; P=0.43). Among HIV-infected infants, the mean fractional shortening at 10 to 14 months was similar in those never exposed to zidovudine (35.4 percent) and those exposed to the drug (35.3 percent) (mean difference, 0.1 percent; 95 percent confidence interval, -3.7 percent to 3.9 percent; P=0.95). Zidovudine exposure was not significantly related to depressed fractional shortening (shortening of 25 percent or loss) during the first 14 months of life. No child over the age of 10 months had depressed fractional shortening.

CONCLUSIONS

Zidovudine was not associated with acute or chronic abnormalities in left ventricular structure or function in infants exposed to the drug in the perinatal period.

Non-invasive assessment of rejection in pediatric transplant patients: serologic and echocardiographic prediction of biopsy-proven myocardial rejection

BACKGROUND

Cardiac allograft rejection is a multifocal immune process that is currently assessed using biopsy-guided histologic classification systems (International Society for Heart and Lung Transplantation). Cardiac troponin T and I are established serologic markers of global myocyte damage. The use of load-independent measures of contractility have also been shown to accurately assess the presence of ventricular dysfunction. Little is known about their utility in accurately predicting rejection in the pediatric age group. We undertook the present study to compare rejection grade with echocardiographic and serologic estimates of transplant rejection-related myocardial damage.

METHODS

We compared histologic rejection grades (0 to 4) with patient characteristics, echocardiographic measurements, catheterization measurements, and biochemical markers for 86 evaluations in 37 transplant recipients at Children's Hospital.

RESULTS

In univariate analyses, biopsy scores correlated (p < 0.05) inversely with left ventricular systolic function (shortening fraction) and contractility (stress velocity index, SVI), and directly with mitral E-wave amplitude. In multivariate analyses, lower contractility and higher mitral E-wave amplitude remained significantly (p < or = 0.01) associated with rejection (SVI, p = 0.002, odds ratio = 0.393; E wave, p = 0.0002, odds ratio = 228). Most rejection episodes were associated with elevation of biochemical markers of myocardial injury. Although troponin I was weakly associated with differences between rejection grades (p = 0.034), troponin T, creatine kinase-MB fraction, and C-reactive protein did not differ with biopsy-rejection scores. Serum markers had a poor predictive capacity for biopsy-detected rejection. Troponin T and I did correlate with increased left ventricular wall thickness and mass.

CONCLUSION

Progressively depressed left ventricular contractility and diastolic function are found with worsening pediatric heart transplant rejection-biopsy score; however, sensitive and specific serum markers do not correspond to the degree of active myocardial injury. The use of echocardiographic measures of contractility is associated with a specificity of 91.8% but low sensitivity of 66.7%. Overall we found poor concordance between serum markers and grade of rejection. It is unclear whether myocardial injury as assessed by serum markers, echocardiography, or histologic scoring is more important for assessment of acute rejection or long-term outcome, but it does not appear that serum and tissue markers of rejection can be used interchangeably.

Cardiac toxicity of intravenous terbutaline for the treatment of severe asthma in children: a prospective assessment

OBJECTIVE

To examine the cardiac toxicity as measured by elevations in serum cardiac troponin T (cTnT) and to compare creatine kinase (CK) and creatine kinase MB (CK-MB) and findings on electrocardiography (ECG) as markers of cardiac toxicity with cTnT during the infusion of intravenous terbutaline for the treatment of severe asthma in children.

STUDY DESIGN

Prospective cohort study of patients receiving intravenous terbutaline for severe asthma.

RESULTS

Only 3 (10%) of the 29 patients had elevations in cTnT. Each underwent mechanical ventilation for >72 hours, which was the earliest point at which cTnT elevations were identified. Eighteen (62%) patients had an elevation in CK, and 3 had an elevation in CK-MB fraction without an elevated cTnT. Twenty (69%) patients had ECG findings consistent with ischemia, and 19 of these patients had the ischemic findings on their preterbutaline ECG. Elevations in CK and CK-MB and ischemic changes on ECG did not correlate with elevations in cTnT. Both mechanical ventilation (P =.02) and prolonged administration (>72 hours) of intravenous terbutaline (P =. 02) were significantly associated with elevations in cTnT.

CONCLUSIONS

We found no clinically significant cardiac toxicity from the use of intravenous terbutaline for severe asthma as measured by serum cTnT elevations.

Electrocardiography and 24-hour electrocardiographic ambulatory recording (Holter monitor) studies in children infected with human immunodeficiency virus type 1. The Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV-1 Infection Study Group

Limited data are available on the electrocardiogram and ambulatory electrocardiogram recording (Holter) in children infected with the human immunodeficiency virus type 1 (HIV-1). The purpose of this study was to estimate the prevalence and cumulative incidence of rhythm and conduction abnormalities in HIV-1-infected children. Electrocardiograms and Holter monitoring studies were performed annually on 205 HIV-1-infected children enrolled after 28 days of life (group I), 93 HIV-1-infected infants enrolled during pregnancy or during the first 28 days of life (group IIa), and 463 HIV-1-uninfected infants enrolled during pregnancy or during the first 28 days of life (group IIb). The 5-year cumulative incidence in the group I children of second-degree atrioventricular block or supraventricular or ventricular tachycardia was 13.4%, and the 5-year incidence was higher for the older infected group I children (16.8% for children > or =4 years old at first study and 11.4% for children <4 years, p = 0.04). The mean corrected QT interval was also longer for the older infected group I children (p = 0.002) and prolonged in the HIV-1-infected compared to the HIV-1-uninfected group II children (p = 0.02). None of the children had atrial fibrillation or flutter. Arrhythmias are uncommon in children infected with HIV-1 and in children of HIV-1-infected mothers and the arrhythmias identified tend to be benign. Therefore, routine Holter monitoring does not appear to be indicated in asymptomatic children.

Design and implementation of the North American Pediatric Cardiomyopathy Registry

The Pediatric Cardiomyopathy Registry (PCMR) was established to describe the epidemiologic features and clinical course of selected cardiomyopathies in patients aged 18 years or younger and to promote the development of etiology-specific treatments. Sixty-one private and institutional pediatric cardiomyopathy practices in the United States and Canada were recruited to participate in the PCMR. The registry consists of a prospective, population-based cohort of patients in 2 regions (New England and the Central Southwestern United States) and a retrospective cohort of patients diagnosed between 1991 and 1996. Annual follow-up data are collected on all patients. As of June 1999, the PCMR consisted of 337 prospectively identified and 990 retrospectively identified patients. The PCMR has demonstrated the feasibility of establishing a large database of sociodemographic and clinical information on children with pediatric cardiomyopathy. Through this cooperative effort, the PCMR will obtain precise estimates of the incidence of pediatric cardiomyopathy and a better understanding of the natural history of this disease.

Alterations in cardiac and pulmonary function in pediatric rapid human immunodeficiency virus type 1 disease progressors. Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted Human Immunodeficiency Virus Study Group

OBJECTIVE

Infants with human immunodeficiency virus type 1 (HIV-1) can be divided into rapid progressors (RPs) and non-rapid progressors (non-RPs) based on symptoms and immunologic status, but detailed information about cardiac and pulmonary function in RP and non-RP children needs to be adequately described.

METHODOLOGY

Cardiac, pulmonary, and immunologic data and HIV-1 RNA burden were periodically measured in 3 groups: group I, 205 vertically infected children enrolled from 1990 to 1994 and followed through 1996; group II, a prospectively studied cohort enrolled at birth that included 93 infected (group IIa); and 463 noninfected infants (group IIb).

RESULTS

Mean respiratory rates were generally higher in group IIa RP than non-RP children throughout the period of follow-up, achieving statistical signifance at 1 month, 12 months, 24 months, 30 months, and 48 months of follow-up. Non-RP and group IIb (HIV-uninfected children) had similar mean respiratory rates from birth to 5 years of age. Significant differences in mean respiratory rates were found between group I RP and non-RP at 7 age intervals over the first 6 years of life. Mean respiratory rates were higher in RP than in non-RP at <1 year, 2.0 years, 2.5 years, 3.0 years, 3. 5 years, 4.0 years, and 6.0 years of age. Mean heart rates in group IIa RP, non-RP, and group IIb differed at every age. Rapid progressors had higher mean heart rates than non-RP at all ages through 24 months. Mean heart rates at 30 months through 60 months of age were similar for RP and non-RP children. Non-RP children had higher mean heart rates than did group IIb at 8 months, 24 months, 36 months, 42 months, 48 months, 54 months, and 60 months of age. In group I, RP had higher mean heart rates than non-RP at 2.0 years, 2.5 years, 3.0 years, and 4.0 years of age. After 4 years of age, the non-RP and RP had similar mean heart rates. Mean fractional shortening differed between the 3 group II subsets (RP, non-RP, and IIb) at 4, 8, 12, 16, and 20 months of age. Although mean fractional shortening was lower in RP than in non-RP in group II at all time points between 1 and 20 months, the mean fractional shortening was significantly lower in RP only at 8 months when restricting the statistical comparisons to the 2 HIV-infected groups (RP and non-RP). Mean fractional shortening increased in the first 8 months of life followed by a gradual decline through 5 years of age among group IIb children. No significant differences among the 3 groups in mean fractional shortening were detected after 20 months of age. In group I, differences between RP and non-RP in mean fractional shortening were detected at 1.5, 2.0, 2.5, and 3.0 years of age. After 3 years of age, group means for fractional shortening in RP and non-RP did not differ. Because of the limited data from the first months of the group I patients, it could not be determined whether this group experienced the gradual early rise in mean fractional shortening seen in the group II infants. In group IIa, RP had more clinical (eg, oxygen saturation <96%) and chest radiographic abnormalities (eg, cardiomegaly) at 18 months of life. RP also had significantly higher 5-year cumulative mortality than non-RP, higher HIV-1 viral burdens than non-RP, and lower CD8(+) T-cell counts.

CONCLUSIONS

Rapid disease progression in HIV-1- infected infants is associated with significant alterations in heart and lung function: increased respiratory rate, increased heart rate, and decreased fractional shortening. The same children exhibited the anticipated significantly increased 5-year cumulative mortality, increased serum HIV-1 RNA load, and decreased CD8(+) (cytotoxic) T-cell counts. Measurements of cardiopulmonary function in HIV-1-infected children seem to be useful in the total assessment of HIV-1 disease progression.

Changes in clinical measures of autonomic nervous system function related to cancer chemotherapy-induced nausea

Individual cancer patients differ in their nausea/vomiting response to chemotherapy. It is not known why patients receiving the same chemotherapy have different severity of side effects. Several lines of research implicate the autonomic nervous system (ANS) in the development of chemotherapy-induced nausea. We examined the association between autonomic reactivity and the level of nausea experienced following chemotherapy in 20 patients with ovarian cancer treated with cisplatin or carboplatin who received the same antiemetic. We applied eight common non-invasive clinical tests of autonomic function prior to inpatient chemotherapy treatment, 2 h after treatment and again 24 h following treatment. Two hours after chemotherapy and before any nausea was reported by the patients, the nine patients who subsequently experienced high levels of nausea had a greater overall percentage of abnormal clinical ANS tests than the 11 patients who subsequently developed low levels of nausea (P < 0.01). Twenty-four hours after treatment, the overall number of abnormal autonomic tests remained non-significantly higher than at the pretreatment baseline for the high nausea group. Demographic and clinical characteristics were not related to chemotherapy-induced nausea in this sample. Autonomic reactivity appears to be related to the development of nausea following chemotherapy. Further investigation of ANS involvement in chemotherapy-induced nausea could increase understanding of nausea etiology and potentially lead to the prediction of susceptible patients.

The detection of viral genomes by polymerase chain reaction in the myocardium of pediatric patients with advanced HIV disease

OBJECTIVES

The aim of this study was to investigate the frequency of viral nucleic acid detection in the myocardium of human immunodeficiency virus (HIV)-infected children to determine whether an association exists with the development of heart disease.

BACKGROUND

As improved medical interventions increase the life expectancy of HIV-infected patients, increased incidences of myocarditis and dilated cardiomyopathy (DCM) are becoming more apparent, even in patients without clinical symptoms.

METHODS

Myocardial samples were obtained from the postmortem hearts of 32 HIV-infected children and from 32 age-matched controls consisting of patients with structural congenital heart disease and no myocardial inflammation and no cardiac or systemic viral infection. The hearts were examined histologically and analyzed for the presence of viral sequences by polymerase chain reaction (PCR) or reverse transcription-PCR.

RESULTS

Myocarditis was detected histologically in 11 of the 32 HIV-infected patients, and borderline myocarditis was diagnosed in another 13 cases. Infiltrates were confined to the epicardium in two additional hearts. Virus sequences were detected by PCR in 11 of these 26 cases (42.3%); adenovirus in 6, CMV in 3 and both adenovirus and CMV in 2. Two cases without infiltrates were also positive for adenovirus: one had congestive heart failure (CHF) and the other adenoviral pneumonia. No other viruses were detected by PCR, including HIV proviral DNA. All control samples were negative for all viruses tested.

CONCLUSIONS

These data suggest that the presence of viral nucleic acid in the myocardium is common in HIV-infected children, and may relate to the development of myocarditis, DCM or CHF and may contribute to the rapid progression of HIV disease.

Cardiac complications in children with human immunodeficiency virus infection. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection (P2C2 HIV) Study Group, National Heart, Lung, and Blood Institute

OBJECTIVE

Although numerous cardiac abnormalities have been reported in HIV-infected children, precise estimates of the incidence of cardiac disease in these children are not well-known. The objective of this report is to describe the 2-year cumulative incidence of cardiac abnormalities in HIV-infected children.

DESIGN

Prospective cohort (Group I) and inception cohort (Group II) study design.

SETTING

A volunteer sample from 10 university and public hospitals.

PARTICIPANTS

Group I consisted of 205 HIV vertically infected children enrolled at a median age of 22 months. This group was comprised of infants and children already known to be HIV-infected at the time of enrollment in the study. Most of the children were African-American or Hispanic and 89% had symptomatic HIV infection at enrollment. The second group included 611 neonates born to HIV-infected mothers, enrolled during fetal life or before 28 days of age (Group II). In contrast to the older Group I children, all the Group II children were enrolled before their HIV status was ascertained.

INTERVENTIONS

According to the study protocol, children underwent a series of cardiac evaluations including two-dimensional echocardiogram and Doppler studies of cardiac function every 4 to 6 months. They also had a 12- or 15-lead surface electrocardiogram (ECG), 24-hour ambulatory ECG monitoring, and a chest radiograph every 12 months.

OUTCOME MEASURES

Main outcome measures were the cumulative incidence of an initial episode of left ventricular (LV) dysfunction, cardiac enlargement, and congestive heart failure (CHF). Because cardiac abnormalities tended to cluster in the same patients, we also determined the number of children who had cardiac impairment which we defined as having either left ventricular fractional shortening (LV FS) </=25% after 6 months of age, CHF, or treatment with cardiac medications.

RESULTS

CARDIAC ABNORMALITIES: In Group I children (older cohort), the prevalence of decreased LV function (FS </=25%) was 5.7% and the 2-year cumulative incidence (excluding prevalent cases) was 15.3%. The prevalence of echocardiographic LV enlargement (LV end-diastolic dimension z score >2) at the time of the first echocardiogram was 8. 3%. The cumulative incidence of LV end-diastolic enlargement was 11. 7% after 2 years. The cumulative incidence of CHF and/or the use of cardiac medications was 10.0% in Group I children. There were 14 prevalent cases of cardiac impairment (LV FS </=25% after 6 months of age, CHF, or treatment with cardiac medications) in Group I. After excluding these prevalent cases, the 2-year cumulative incidence of cardiac impairment was 19.1% among Group I children and 80.9% remained free of cardiac impairment after 2 years of follow-up. Within Group II (neonatal cohort), the 2-year cumulative incidence of decreased LV FS was 10.7% in the HIV-infected children compared with 3.1% in the HIV-uninfected children. LV dilatation was also more common in Group II infected versus uninfected children (8.7% vs 2.1%). The cumulative incidence of CHF and/or the use of cardiac medications was 8.8% in Group II infected versus 0.5% in uninfected subjects. The 1- and 2-year cumulative incidence rates of cardiac impairment for Group II infected children were 10.1% and 12.8%, respectively, with 87.2% free of cardiac impairment after the first 2 years of life.

MORTALITY

In the Group I cohort, the 2-year cumulative death rate from all causes was 16.9% [95% CI: 11.7%-22. 1%]. The 1- and 2-year mortality rates after the diagnosis of CHF (Kaplan-Meier estimates) were 69% and 100%, respectively. In the Group II cohort, the 2-year cumulative death rate from all causes was 16.3% [95% CI: 8.8%-23.9%] in the HIV-infected children compared with no deaths among the 463 uninfected Group II children. Two of the 4 Group II children with CHF died during the 2-year observation period and 1 more died within 2 years of the diagnosis of CHF. The 2-year mortality rate after the

Correlation between serum levels of cardiac troponin-T and the severity of the chronic cardiomyopathy induced by doxorubicin

PURPOSE

To investigate, over a wide range of cumulative doxorubicin doses, the feasibility of using serum concentrations of cardiac troponin-T (cTnT) as a biomarker for doxorubicin-induced myocardial damage.

MATERIALS AND METHODS

Groups of spontaneously hypertensive rats (SHR) were given 1 mg/kg doxorubicin weekly for 2 to 12 weeks. Cardiomyopathy scores were assessed according to the method of Billingham and serum levels of cTnT were quantified by a noncompetitive immunoassay. Myocardial localization of cTnT was studied by immunohistochemical staining and confocal microscopy.

RESULTS

Increases in serum levels of cTnT (0.03 to 0.05 ng/mL) and myocardial lesions (cardiomyopathy scores of 1 or 1.5) were found in one out of five and two out of five SHR given 2 and 4 mg/kg doxorubicin, respectively. All animals given 6 mg/kg or more of doxorubicin had increases in serum cTnT and myocardial lesions. The average cTnT levels and the cardiomyopathy scores correlated with the cumulative dose of doxorubicin (0.13 v 0.4 ng/mL cTnT and scores of 1.4 v 3.0 in SHR given 6 and 12 mg/kg doxorubicin, respectively). Decreased staining for cTnT was observed in cardiac tissue from SHR receiving cumulative doses that caused only minimal histologic alterations (scores of 1 to 1.5). Staining for cTnT decreased simultaneously with increases in the severity of the cardiomyopathy scores.

CONCLUSION

cTnT is released from doxorubicin-damaged myocytes. Measurements of serum levels of this protein seem to provide a sensitive means for assessing the early cardiotoxicity of doxorubicin.

Genetics of neonatal cardiomyopathy

Cardiomyopathies, primary disorders of the myocardium, are a leading cause of morbidity and mortality in children and adults, and these disorders are responsible for a significant percentage of sudden cardiac deaths and cardiac transplants. Neonatal cardiomyopathies commonly are associated with poor prognosis, and the underlying etiology of this disorder differs considerably from cardiomyopathies in older children, adolescents, and adults with similar phenotypes. In this review, the major causes of neonatal cardiomyopathy are described.

Prevalence of congenital cardiovascular malformations in children of human immunodeficiency virus-infected women: the prospective P2C2 HIV Multicenter Study. P2C2 HIV Study Group, National Heart, Lung, and Blood Institute, Bethesda, Maryland

OBJECTIVES

The purpose of the study was to assess the effects of maternal HIV-1 (human immunodeficiency virus) infection and vertically transmitted HIV-1 infection on the prevalence of congenital cardiovascular malformations in children.

BACKGROUND

In the United States, an estimated 7000 children are born to HIV-infected women annually. Previous limited reports have suggested an increase in the prevalence of congenital cardiovascular malformations in vertically transmitted HIV-infected children.

METHODS

In a prospective longitudinal multicenter study, diagnostic echocardiograms were performed at 4-6-month intervals on two cohorts of children exposed to maternal HIV-1 infection: 1) a Neonatal Cohort of 90 HIV-infected, 449 HIV-uninfected and 19 HIV-indeterminate children; and 2) an Older HIV-Infected Cohort of 201 children with vertically transmitted HIV-1 infection recruited after 28 days of age.

RESULTS

In the Neonatal Cohort, 36 lesions were seen in 36 patients, yielding an overall congenital cardiovascular malformation prevalence of 6.5% (36/558), with a 8.9% (8/90) prevalence in HIV-infected children and a 5.6% (25/449) prevalence in HIV-uninfected children. Two children (2/558, 0.4%) had cyanotic lesions. In the Older HIV-Infected Cohort, there was a congenital cardiovascular malformation prevalence of 7.5% (15/201). The distribution of lesions did not differ significantly between the groups.

CONCLUSIONS

There was no statistically significant difference in congenital cardiovascular malformation prevalence in HIV-infected versus HIV-uninfected children born to HIV-infected women. With the use of early screening echocardiography, rates of congenital cardiovascular malformations in both the HIV-infected and HIV-uninfected children were five- to ten-fold higher than rates reported in population-based epidemiologic studies but not higher than in normal populations similarly screened. Potentially important subclinical congenital cardiovascular malformations were detected.

Epidemiology of anthracycline cardiotoxicity in children and adults

Anthracyclines, potent cytotoxic agents used to treat a broad spectrum of malignancies, are limited in their use by an attendant risk of cardiotoxicity. Malignancies affect all age ranges, and anthracyclines are used in all age ranges, thereby exposing a broad population of patients to the development of heart disease. For some treated patients, anthracyclines affect cardiac muscle, resulting in cardiomyopathy. The type and degree of cardiomyopathy, as well as when during or after treatment the condition occurs, are dependent on what risk factors are present. Age is a major risk factor. Children and adults may develop restrictive and dilated cardiomyopathy. The length of subsequent survival and amount of subsequent somatic growth may influence late anthracycline-associated cardiac outcome. Early cardiotoxicity, occurring during or within 1 year of completion of treatment, is the largest risk factor for the development of late cardiotoxicity, which occurs beyond a year of completion of treatment. Risk factors, which appear to be specific for early cardiotoxicity in children, include black race, trisomy 21, and the use of amsacrine therapy after anthracycline therapy. More cardiotoxic effects are seen in survivors of childhood cancer, the longer from completion of treatment a patient is followed. Cumulative as well as peak anthracycline doses affect adults and children alike, and cardiotoxicity occurs early and late. In adults, left ventricular contractility is affected by anthracyclines. Children may manifest impairment of left ventricular contractility and increased afterload due to thinning of left ventricular walls. Patients with an early presentation of depressed left ventricular contractility are likely to show progression of cardiac disease with time. In addition, female gender appears to affect early and late cardiotoxicity in both adults and children, although this risk factor has been described predominantly in the survivors of childhood cancer. Thus, although anthracycline chemotherapy has improved overall survivorship of patients with cancer, there is a significant risk of cardiotoxicity associated with this class of drugs.

Left ventricular structure and function in children infected with human immunodeficiency virus: the prospective P2C2 HIV Multicenter Study. Pediatric Pulmonary and Cardiac Complications of Vertically Transmitted HIV Infection (P2C2 HIV) Study Group

BACKGROUND

The frequency of, course of, and factors associated with cardiovascular abnormalities in pediatric HIV are incompletely understood.

METHODS AND RESULTS

A baseline echocardiogram (median age, 2.1 years) and 2 years of follow-up every 4 months were obtained as part of a prospective study on 196 vertically HIV-infected children. Age- or body surface area-adjusted z scores were calculated by use of data from normal control subjects. Although 88% had symptomatic HIV infection, only 2 had CHF at enrollment, with a 2-year cumulative incidence of 4.7% (95% CI, 1.5% to 7.9%). All mean cardiac measurements were abnormal at baseline (decreased left ventricular fractional shortening [LV FS] and contractility and increased heart rate and LV dimension, mass, and wall stresses). Most of the abnormal baseline cardiac measurements correlated with depressed CD4 cell count z scores and the presence of HIV encephalopathy. Heart rate and LV mass showed significantly progressive abnormalities, whereas FS and contractility tended to decline. No association was seen between longitudinal changes in FS and CD4 cell count z score. Children who developed encephalopathy during follow-up had depressed initial FS, and FS continued to decline during follow-up.

CONCLUSIONS

Subclinical cardiac abnormalities in HIV-infected children are common, persistent, and often progressive. Dilated cardiomyopathy (depressed contractility and dilatation) and inappropriate LV hypertrophy (elevated LV mass in the setting of decreased height and weight) were noted. Depressed LV function correlated with immune dysfunction at baseline but not longitudinally, suggesting that the CD4 cell count may not be a useful surrogate marker of HIV-associated LV dysfunction. However, the development of encephalopathy may signal a decline in FS.

Relationship between cumulative anthracycline dose and late cardiotoxicity in childhood acute lymphoblastic leukemia

PURPOSE

Late anthrocycline cardiotoxicity after treatment for childhood cancer is common and often progressive. A safe anthracycline dose that will not result in late cardiac abnormalities has not been established due to the limited dose ranges used in existing studies.

PATIENTS AND METHODS

To determine the relationship between cumulative anthracycline dose and late cardiotoxicity, we performed echocardiograms on 189 survivors of childhood acute lymphoblastic leukemia a median of 8.1 years (range, 2.0 to 23.4) after completion of anthracycline therapy. Patients were treated according to protocols that used widely varying cumulative anthracycline doses, but comparable nonanthracycline chemotherapy. Patients were divided into four groups based on the city of treatment and cumulative anthracycline dose: Copenhagen, 0 to 23 mg/m2 (n = 32); Boston, 45 mg/m2 (n = 17); Copenhagen, 73 to 301 mg/m2 (n = 53); and Boston, 244 to 550 mg/m2 (n = 87). Left ventricular dimension and fractional shortening were adjusted for sex and age or body-surface area through use of a control population (n = 296), and then compared among the four groups.

RESULTS

Mean left ventricular dimension was significantly increased in the high-dose Boston group (observed:predicted value, 4.57 cm:4.45 cm; P = .002) and significantly higher than in the two Copenhagen groups. In the three lower-dose groups, there was no significant increase in mean left ventricular dimension, and the groups were not significantly different from each other. Similarly, the mean left ventricular fractional shortening was significantly depressed in the high-dose Boston group (observed:predicted value, 29.0%:33.8%; P = .0001) and significantly lower than in the three lower-dose groups.

CONCLUSION

Depressed left ventricular fractional shortening and left ventricular dilatation were uncommon years after treatment of childhood leukemia when cumulative anthracycline doses were < or = 300 mg/m2.

Use of cardiac troponin T levels as an indicator of doxorubicin-induced cardiotoxicity

The release of cardiac troponin T (cTnT) as a biomarker of doxorubicin-induced chronic cardiac injury was evaluated in the spontaneously hypertensive rat (SHR) model. Elevations in serum levels of cTnT and decreased immunohistochemical staining of heart sections for this protein were noted in SHRs treated with cumulative doses of doxorubicin (7 mg/kg) that induced only minimal histological alterations in myocytes. Concentrations of cTnT were further elevated, coincident with reduced immunohistochemical staining, in SHRs given 10-12 mg/kg doxorubicin. Thus, monitoring serum levels of cTnT can detect doxorubicin-induced myocyte damage in SHR and may prove useful for the noninvasive evaluation of this toxicity in humans.