Relation of left ventricular mass, preload, afterload and contractility in pediatric patients with essential hypertension

Prevalence of left ventricular hypertrophy in children and young people with primary hypertension: Meta-analysis and meta-regression

BACKGROUND

Left ventricular hypertrophy (LVH) is the main marker of HMOD in children and young people (CYP). We aimed to assess the prevalence of LVH and its determinants in CYP with primary hypertension (PH).

METHODS

A meta-analysis of prevalence was performed. A literature search of articles reporting LVH in CYP with PH was conducted in Medline, Embase, and Cochrane databases. Studies with a primary focus on CYP (up to 21 years) with PH were included. Meta-regression was used to analyze factors explaining observed heterogeneity.

RESULTS

The search yielded a total of 2,200 articles, 153 of those underwent full-text review, and 47 reports were included. The reports evaluated 51 study cohorts including 5,622 individuals, 73% male subjects, and a mean age of 13.6 years. LVH was defined as left ventricle mass index (LVMI) ≥ 95th percentile in 22 (47%), fixed cut-off ≥38.6 g/m2.7 in eight (17%), sex-specific fixed cut-off values in six (13%), and miscellaneously in others. The overall prevalence of LVH was 30.5% (95% CI 27.2-33.9), while heterogeneity was high (I 2 = 84%). Subgroup analysis including 1,393 individuals (76% male subjects, mean age 14.7 years) from pediatric hypertension specialty clinics and LVH defined as LVMI ≥95th percentile only (19 study cohorts from 18 studies), reported prevalence of LVH at 29.9% (95% CI 23.9 to 36.3), and high heterogeneity (I 2 = 84%). Two studies involving patients identified through community screening (n = 1,234) reported lower LVH prevalence (21.5%). In the meta-regression, only body mass index (BMI) z-score was significantly associated with LVH prevalence (estimate 0.23, 95% CI 0.08-0.39, p = 0.004) and accounted for 41% of observed heterogeneity, but not age, male percentage, BMI, or waist circumference z-score. The predominant LVH phenotype was eccentric LVH in patients from specialty clinics (prevalence of 22% in seven studies with 779 participants) and one community screening study reported the predominance of concentric LVH (12%).

CONCLUSION

Left ventricular hypertrophy is evident in at least one-fifth of children and young adults with PH and in nearly a third of those referred to specialty clinics with a predominant eccentric LVH pattern in the latter. Increased BMI is the most significant risk association for LVH in hypertensive youth.

Decreased Incidence of Intraventricular Hemorrhage in Extremely Low Birth Weight Infants Using Customized Circulatory Management to Evaluate the Hemodynamic Change of Patent Ductus Arteriosus

Background: In extremely low birth weight (ELBW) infants, the patent ductus arteriosus (PDA) with left-to-right shunt and an increase in systemic artery resistance may cause increasing preload and afterload of the left ventricle. The immature myocardium in ELBW infants has a limited ability to respond to the change, which leads to hemorrhagic complications. In this study, we detected the hemodynamic change of cardiac performance and applied a clinical strategy to prevent PDA-associated hemorrhagic complications in ELBW infants. Methods: We enrolled ELBW infants at a single medical center in Taiwan. The customized circulatory management was performed by echocardiography after birth until the PDA closed. Inotropic agents were administrated according to the requirements of hemodynamic parameters or clinical conditions. The primary outcomes were hemorrhagic complications including pulmonary hemorrhage and intraventricular hemorrhage (IVH) greater than grade II. The secondary outcomes were the rate of surgical ligation of PDA, mortality, necrotizing enterocolitis, and bronchopulmonary dysplasia. Results: A total of 20 ELBW infants were evaluated by customized circulatory management from 2019 to 2020. We reviewed 35 ELBW infants born between 2017 and 2018 in our hospital, who served as the non-management group. The management group had a significantly lower incidence rate of IVH greater than grade 2 (p = 0.02). Other outcomes showed no significant differences. Dobutamine was prescribed in 8 cases in the management group, and end-systolic wall stress (ESWS) was significantly decreased after Dobutamine administration (p = 0.017). Conclusion: The incidence rate of IVH greater than grade II in ELBW infants decreased after use of customized circulatory management in our study. The strategy of customized circulatory management might be an effective "early target therapy" for hemodynamically significant PDA in high-risk ELBW infants. Inotropic therapy with Dobutamine could be a useful medical choice for improving cardiac function to prevent hemorrhagic complications.

Early hemodynamic changes after transcatheter aortic valve implantation in patients with severe aortic stenosis measured by invasive pressure volume loop analysis

Replacement of a stenotic aortic valve reduces immediately the ventricular to aortic gradient and is expected to improve diastolic and systolic left ventricular function over the long term. However, the hemodynamic changes immediately after valve implantation are so far poorly understood. Within this pilot study, we performed an invasive pressure volume loop analysis to describe the early hemodynamic changes after transcatheter aortic valve implantation (TAVI) with self-expandable prostheses. Invasive left ventricular pressure volume loop analysis was performed in 8 patients with aortic stenosis (mean 81.3 years) prior and immediately after transfemoral TAVI with a self-expandable valve system (St. Jude Medical Portico Valve). Parameters for global hemodynamics, afterload, contractility and the interaction of the cardiovascular system were analyzed. Left ventricular ejection fraction, (53.9% vs. 44.8%, p = 0.018), preload recruitable stroke work (68.5 vs. 44.8 mmHg, p = 0.012) and end-systolic elastance (3.55 vs. 2.17, p = 0.036) both marker for myocardial contractility declined significantly compared to baseline. As sign of impaired diastolic function, TAU, a preload-independent measure of isovolumic relaxation (37.3 vs. 41.8 ms, p = 0.018) and end-diastolic pressure (13.1 vs. 16.4 mmHg, p = 0.015) raised after valve implantation. Contrarily, a smaller ratio of end-systolic to arterial elastance (ventricular-arterial coupling) indicates an improvement of global cardiovascular energy efficiency (1.40 vs. 0.97 p = 0.036). Arterial elastance had a strong correlation with the number of conducted rapid ventricular pacings (Pearson correlation coefficient, r = 0.772, p = 0.025). Invasive left ventricular pressure volume loop analysis revealed impaired systolic and diastolic function in the early phase after TAVI with self-expandable valve for the treatment of severe aortic stenosis. Contrarily, we found indications for early improvement of global cardiovascular energy efficiency.

Comparison of echocardiographic changes in children with primary hypertension and hypertension due to mild to moderate chronic kidney disease

BACKGROUND

Chronic systemic hypertension has a well-known association with increased cardiovascular morbidity and mortality. One of the most important target organs affected in systemic hypertension is the heart. In addition, chronic kidney disease (CKD) further increases the mortality from cardiovascular disease. The aim of this study was to evaluate the differences in the cardiovascular changes in pediatric patients with primary hypertension (pHTN) vs. those with secondary hypertension from chronic kidney disease (CKD-HTN).

METHODS

This was a retrospective chart review of patients with CKD-HTN and pHTN. The medical records were reviewed for anthropometric data, biochemical assessment of renal function, and for cardiovascular changes on echocardiogram.

RESULTS

Twenty-three patients with pHTN and 29 patients with CKD-HTN were included in the study. There were no differences in age, gender, weight, height, body mass index, and blood pressure between the 2 groups. There was a high prevalence of left ventricular diastolic dysfunction among both the groups (CKD-HTN 25 vs. pHTN 26%). Reduced mitral valve inflow Doppler E/A ratio, a marker of left ventricular diastolic dysfunction in echocardiogram, was more pronounced in CKD-HTN patents, in comparison to those with pHTN (p = 0.042). Also, diastolic function worsened with declining glomerular filtration rate in patients with CKD-HTN. Similarly, patients with CKD-HTN had a larger aortic root dimension when compared to patients with pHTN (p = 0.049).

CONCLUSIONS

The prevalence of left ventricular diastolic dysfunction is similar in patients with pHTN and CKD-HTN. Patients with CKD-HTN appear to have more severe diastolic dysfunction and larger aortic root dimensions.

Plasma dipeptidyl-peptidase-4 activity is associated with left ventricular systolic function in patients with ST-segment elevation myocardial infarction

Plasma dipeptidyl-peptidase-4 activity (DPP4a) is inversely associated with left ventricular function in patients with heart failure (HF) or diabetes. However, the association between DPP4a and left ventricular function in ST-segment elevation myocardial infarction (STEMI) patients has not been reported. We studied this association in 584 consecutive STEMI patients at a tertiary referral center from July 2014 to October 2015. DPP4a and plasma N-terminal prohormone of B-type natriuretic peptide (NT-proBNP) levels were quantified by enzymatic assays. The median serum NT-proBNP levels were highest in patients of the lowest tertile (T1) of DPP4a compared with that of the highest tertile (T3) (p = 0.028). The STEMI patients in T1 exhibited lower left ventricular systolic function (T1 vs. T3: left ventricular ejection fraction (LVEF): 50.13 ± 9.12 vs. 52.85 ± 6.82%, p = 0.001). Multivariate logistic-regression analyses (adjusted for confounding variables) showed that a 1 U/L increase in DPP4a was associated with a decreased incidence of left ventricular systolic dysfunction (LVSD) (adjusted odds ratio: 0.90; 95% CI: 0.87–0.94; p < 0.01). In conclusion, low DPP4a is independently associated with LVSD in STEMI patients, which suggests that DPP4 may be involved in the mechanisms of LVSD in STEMI patients.

Circulatory Management Focusing on Preventing Intraventricular Hemorrhage and Pulmonary Hemorrhage in Preterm Infants

The goal of modern neonatal care of extremely preterm infants is to reduce mortality and long-term neurological impairments. Preterm infants frequently experience cerebral intraventricular or pulmonary hemorrhage, which usually occurs within 72 hours after birth and can lead to long-term neurological sequelae and mortality. These serious hemorrhagic complications are closely related to perinatal hemodynamic changes, including an increase in the afterload on the left ventricle of the heart after the infant is separated from the placenta, and an increased preload from a left-to-right shunt caused by a hemodynamically significant patent ductus arteriosus (PDA). The left ventricle of a preterm myocardium has limited ability to respond to such an increase in afterload and preload, and this can result in cardiac dysfunction and hemodynamic deterioration. We suggest that delayed umbilical cord clamping or umbilical cord milking to maintain optimal blood pressure and systemic blood flow (SBF), careful assessment to keep the afterload at an acceptable level, and a strategy of early targeted treatment of significant PDA to improve perfusion during this critical time period may reduce or prevent these serious complications in preterm infants.

Left Ventricular Hypertrophy Phenotype in Childhood-Onset Essential Hypertension

The aim of this study was to determine the risk factors associated with left ventricular (LV) hypertrophy (LVH) among 89 untreated children with primary hypertension. Clinic hypertension was confirmed by 24-hour ambulatory blood pressure (BP) monitoring. LV mass (LVM) index was calculated as LVM (g)/height (m)(2.7) and LVH was defined as LVM index >95th percentile. Children with (n=32) and without (n=57) LVH were compared. Both obesity and systolic BP were independently associated with LVH, with a higher contribution by body mass index. Obesity contributed significantly, with a nearly nine-fold increased risk of LVH. There was evidence of effect modification by the presence or absence of obesity on the relationship between systolic BP and LVH, whereby the relationship existed mainly in nonobese rather than obese children. Hence, to achieve reversal of LVH, clinicians should take into account both BP control and weight management.

Detection of early diastolic alterations by tissue Doppler imaging in untreated childhood-onset essential hypertension

The aim of the study was to determine the presence of preclinical diastolic dysfunction in hypertensive children relative to normotensive children by Tissue Doppler Imaging (TDI). We prospectively enrolled children with untreated essential hypertension in absence of any other disease and a matched healthy control group with normal blood pressure (BP); both groups confirmed by clinic BP and a 24-hour ambulatory BP monitoring. Echocardiographic diastolic parameters were determined using spectral transmitral inflow Doppler, flow propagation velocity, TDI, and systolic parameters were determined via midwall shortening fraction and ejection fraction. A total of 80 multiethnic children were prospectively enrolled for the study: 46 hypertensive (median age, 13 years; 72% males) and 34 control (median age, 14 years; 65% males). The only echocardiography parameters that had a statistically significant change compared with the control children, were regional mitral Ea, Aa, and the E/Ea ratio by TDI. In comparison with controls, hypertensive children had lower Ea and Aa velocities of anterior and posterior walls and higher lateral wall E/Ea ratio. The decrease in posterior wall Ea and Aa remained significant after adjustment for gender, age, body mass index, ethnicity, and left ventricular hypertrophy on multivariate analysis. The lateral and septal wall E/Ea ratios correlated significantly with fasting serum insulin levels on similar multivariate analysis. Decreased regional TDI velocities were seen with preserved left ventricular systolic function even when other measures of diastolic dysfunction remained unchanged in untreated hypertensive children. Hypertension and serum insulin levels had strong associations with preclinical diastolic alterations in children.

Factors affecting graft function in pediatric and adult recipients of adult live donor kidney transplants

The aims of this investigation were to compare changes of function of adult living kidney grafts transplanted into adult and child recipients and to analyze factors associated with graft function during the first post-transplant year. The study involved 53 adult and 23 pediatric recipients with immediate graft function and without complications that could influence graft function. In comparison to children, adult recipients and their donors were older, and having been longer on hemodialysis they had received more transfusions. Although similar baseline graft function--GFR(0) was transplanted in both groups, absolute and relative GFR in adults rose and maintained stable, while in children absolute GFR decreased and remained similar to the GFR(0) until the end of the study. Significant predictors of kidney function in both adult and child recipients were donor age, ratio between GFR(0) and recipient BSA, induction immunosuppression, and systolic hypertension. In conclusion, the function of adult live kidney grafts changed differently in children and adults because of different functional requirements of recipients but donor age, induction immunosuppression and hypertension are significant predictor of graft function in both adults and children.

Diastolic filling abnormalities in children with essential hypertension

OBJECTIVE

To evaluate whether essential hypertension impacts diastolic function in children.

STUDY DESIGN

In this cross-sectional study, patients with essential hypertension (n = 50) were compared with a normotensive group (n = 53). Echocardiographic assessment of diastolic function included measures derived from transmitral, color M-mode, and tissue Doppler interrogation. Cardiac dimensions, wall thickness, geometry, and systolic function were also assessed. Multiple linear regression analysis was performed to identify predictors of altered diastolic function.

RESULTS

Diastolic filling abnormalities were found in 36% of the children with blood pressure elevation. Those subjects with concentric hypertrophy were more significantly affected. Abnormalities in indices reflective of left ventricular (LV) relaxation occurred more commonly (39%) than those of LV compliance (33%). Elevated indexed LV mass was found to be the most significant independent predictor of diastolic filling abnormalities.

CONCLUSIONS

LV diastolic filling abnormalities were found in one-third of the pediatric subjects with essential hypertension. Whether these changes represent an adaptive or maladaptive response requires further study.

Evaluation of Concentric Left Ventricular Geometry in Humans

There might be limitations in identifying concentric left ventricular (LV) geometry by ratio of diastolic posterior wall thickness (WT p ) to cavity radius, defined as relative wall thickness (RWT p ). This study has been designed to evaluate age effects on RWT p . WT p , mean of septal thickness and WT p (WT m ), and cavity radius were cross-sectionally evaluated in 766 1- to 85-year-old, normotensive, nonobese subjects and 331 hypertensive Italians (used as a test series). RWT p ≥0.43 defined “traditional” concentric LV geometry. The ratios WT m /radius (RWT m ) and RWT p increased by 0.005 and 0.006 per year of age in the age stratum up to 17 years and by 0.002 in the older age stratum (18 years or older; all P <0.0001). Thus, RWT m and RWT p were normalized to average age in both age strata (10 and 46 years) by age-specific regression coefficients. The 90th and 95th percentiles of age-normalized RWT p or RWT m were 0.40 and 0.42 or 0.41 and 0.43, respectively, in adults and 0.36 and 0.39 or 0.36 and 0.38, respectively in young subjects. In hypertensive subjects, traditional RWT p cutoff identified 74 subjects (22%) with concentric LV geometry; by 95th or 90th normal percentiles, normalized RWT m identified 112 (34%), or 149 (45%) subjects with concentric LV geometry, and normalized RWT p 29% and 39%, respectively (all P <0.0001 versus unadjusted RWT p ). Thus, prevalence of concentric LV geometry increases with age-normalized RWT. Accordingly, we suggest that concentric LV hypertrophy be defined by coexistence of high LV mass with age-normalized RWT m >0.41 or RWT p >0.40. Further studies are required to establish prognostic implications of our findings.

Early posttransplantation hypertension and poor long-term renal allograft survival in pediatric patients

OBJECTIVE

To evaluate the effect of early hypertension on long-term allograft survival in children with kidney transplantation.

STUDY DESIGN

Data from a total of 159 patients (mean age, 12.8+/-4.8 years) who underwent kidney transplantation between 1978 and 1998 and whose allograft was functioning for at least 1 year were analyzed retrospectively. Patients were divided according to the presence of hypertension within the first year after transplantation. Primary outcome was time of allograft failure (death, return to dialysis, or retransplantation).

RESULTS

Kaplan-Meier analysis showed that systolic (P<.0001) and diastolic (P=.016) hypertension was associated with overall worse allograft survival. Children with systolic hypertension had a significantly higher graft failure rate regardless of the type of donor, cause of kidney failure, presence or absence of acute rejection, and allograft function at 1 year after transplantation. The multivariate Cox regression model proved that systolic hypertension was a significant and independent risk factor for poor graft survival (hazard ratio [HR], 1.79; P<.0001). Other predictors included allograft function at 1 year after transplantation (HR, 0.97; P<.0001), acquired cause of end-stage kidney disease (HR, 1.96; P=.01) and age <6 years (HR, 2.61; P=.045).

CONCLUSIONS

Early posttransplantation systolic hypertension strongly and independently predicts poor long-term graft survival in pediatric patients.

Left atrial size in children with hypertension: the influence of obesity, blood pressure, and left ventricular mass

OBJECTIVE

To evaluate the prevalence of left atrial enlargement and the correlates of left atrial size in children and adolescents with essential hypertension.

BACKGROUND

Left atrial enlargement has been associated with increased risk of cardiovascular disease, including stroke in adults. Risk factors for left atrial size in adults with hypertension include age, race, and obesity.

METHODS AND RESULTS

Patients (n =112; average age, 14.2 years) with essential hypertension were studied with echocardiography. The average left atrial dimension was 2.8 (+/- 0.5) cm; 51% patients had left atrial dimension >95% upper confidence limit. The patients with left atrial enlargement had greater body mass index (P <.05) than those without left atrial enlargement. In multiple regression analysis, height, body mass index, systolic blood pressure, and left ventricular geometry were significant independent correlates of left atrial size. Children with eccentric left ventricular hypertrophy were more likely to have a larger left atrial dimension.

CONCLUSIONS

Left atrial enlargement is prevalent in children and adolescents with essential hypertension. This may indicate an increased risk of cardiovascular disease morbidity and mortality. Control of obesity and blood pressure elevation offer two approaches for treatment that may prevent left atrial enlargement.

Changes in left ventricular mass index in children and adolescents after renal transplantation

Recent reports indicate a high prevalence of left ventricular hypertrophy (LVH) in children on dialysis and after renal transplantation (Tx), as identified by cross-sectional analysis. However, the evolution of LVH in pediatric patients with end-stage renal disease after renal Tx is not well established. To assess changes of left ventricular mass (LVM), we prospectively performed echocardiography in 23 children and adolescents between November 1998 and July 2000. Each patient had an echocardiographic evaluation while on dialysis (for at least 6 weeks) and a follow-up evaluation at least 6 months after successful renal Tx (i.e. with a measured glomerular filtration rate [GFR] of at least 40 mL/min/1.73 m2). The LVM index was estimated by indexing LVM to height(2.7). Sixteen patients had a cadaveric transplant and seven had a live donor transplant; the mean duration between the two studies was 1.9 +/- 1.6 yr; and the mean GFR was 55.0 +/- 21.4 mL/min/1.73 m2. There was no significant difference in the mean values of the LVM index while on dialysis and after renal Tx (43.9 +/- 17.8 g/m2.7 and 39.3 +/- 12.0 g/m2.7, respectively, p = 0.19), or in the prevalence of LVH (52% and 56%, respectively). Interval changes in the LVM index in individual subjects between the two studies were significantly associated with interval changes in indexed systolic (r = 0.42, p = 0.04) and diastolic (r = 0.42, p = 0.05) blood pressures. Interval changes in hemoglobin, blood urea nitrogen (BUN), creatinine, and duration after Tx did not correlate with changes in the LVM index. There was no significant difference in LVM index change according to the type of dialysis, donor source, and the cause of renal failure. In multivariate analysis, the baseline LVM index and changes in indexed SBP were independent predictors for LVM index change after renal Tx. We conclude that LVH persists in children and adolescents after renal Tx. Control of blood pressure might be an important factor in regression or prevention of progression of LVH in these patients.

Short-term pediatric renal transplant survival: blood pressure and allograft function

Hypertension is prevalent after renal transplantation (Tx) and associated with graft failure in children and adults. However, the effect of blood pressure (BP) on short-term renal allograft function is uncertain. We assessed the associations among BP pretransplant, and 3 months and 1 yr post-transplant, and 1-yr post-transplant measured glomerular filtration rate (mGFR) in 61 children with a functioning graft. The GFR was determined using a single intravenous (i.v.) injection of Optiray 350(R). Data were collected between January 1994 and January 2000. The mean mGFR 1 yr after renal transplant was 63.6 +/- 19.9 mL/min/1.73 m2 in 26 live donor recipients and 50.8 +/- 23.3 mL/min/1.73 m2 in 35 cadaveric donors (p = 0.029). Correlation analysis showed significant negative associations of 1-yr mGFR with systolic blood pressure (SBP) and diastolic blood pressure (DBP) 3 months after renal Tx (r = - 0.58, p < 0.0001 and r = - 0.50, p < 0.0001, respectively), and with SBP (r = - 0.37, p = 0.003) and DBP (r = - 0.32, p = 0.01) 1 yr after renal Tx. Multi-variate regression analysis showed that the SBP 3 months after Tx (p < 0.001), number of acute rejections (p = 0.002), donor age (p = 0.02), and cold ischemia time (p = 0.03) were independent predictors for the 1-yr mGFR. These results indicate that a higher SBP in the first few months post-renal Tx is associated with decreased renal allograft function in children 1 yr post-Tx.

Interaction between body size and cardiac workload: influence on left ventricular mass during body growth and adulthood

The development of the left ventricle parallels body growth. During infancy, the relation between body size and left ventricular (LV) mass is very close. With advancing age, variability of LV mass in relation to body size markedly increases. To test the hypothesis that the age-related increase in variability of LV mass is due to the progressive impact of hemodynamic stimuli on LV growth, quantitative M-mode echocardiograms were obtained in 766 normal-weight, normotensive individuals over a range of ages from 1 day to 85 years (330 female subjects, 373 subjects younger than 18 years). LV mass was linearly related to height2.7 (r2=.69). Prediction of values of LV mass by body size was more accurate at birth and progressively less precise with increasing age. Stroke work (stroke volume times systolic pressure) was closely related to LV mass (r2=.74). The explained variance of LV mass increased from 69% in the univariate regression with height2.7 to 82% in a multivariate model including height2.7, stroke work, and gender. In children and adolescents (younger than 18 years), height2.7 was the main determinant of LV mass, whereas during adulthood stroke work and gender were more important predictors of LV mass than height2.7. Thus (1) the influence of body growth on development of LV mass decreases after early infancy because of both the variability of hemodynamic load and the increasing effect of gender; (2) after adolescence, during adulthood, in normotensive, normal-weight individuals, the impact of hemodynamic load and male gender on LV mass is greater than the one of body size; and (3) an appreciable proportion of variability of LV mass remains unexplained with the studied models. This might be due to genotypic variations and/or measurement error.

Computer modeling of the effects of aortic valve stenosis and arterial system afterload on left ventricular hypertrophy

The degree of left ventricular hypertrophy is generally thought to reflect the severity of aortic stenosis. However, the compounded influence of arterial system load is poorly understood. We developed a computer model to investigate the effects of aortic valve stenosis in combination with various systemic arterial parameters in the development of left ventricular hypertrophy. Data show that an increased peripheral resistance and/or aortic valve resistance, results in an increase in left ventricular wall thickness and mass, while peak systolic wall stress remains constant. Changing arterial compliance to above normal level would not induce significant changes in wall thickness, while reduction in arterial compliance below normal would cause an increase in ventricular wall thickness. When a double load is imposed on the left ventricle by way of a stenotic valve and an increased arterial afterload, a greater and an aggregated increase in wall thickness results, hastening the hypertrophic process.

Relations of left ventricular geometry and function to body composition in children with high casual blood pressure

To determine whether abnormal casual blood pressure (BP) is associated with left ventricular (LV) abnormalities in children, 190 6- to 11-year-old children (77 girls, 113 boys) were studied at a school site in Naples, Italy, by limited echocardiography and bioelectric impedance to calculate fat-free body mass (FFM). Single-visit BP measurements (defined as casual BP) were high (based on the Italian tables of BP) in 34 children (18%; 9 girls, 25 boys; 133+/-8/81+/-10 mm Hg) and obesity was present in 44 (23%; 15 girls, 29 boys). Sex- and age-independent risk of high casual BP value was 2.9-fold (odds ratio) greater in obese than in normal-weight children (95% confidence interval, 1.3 to 6.5; P<.01). LV mass (as both absolute value and normalized for height or FFM) was higher and relative wall thickness increased in children with high casual BP (all P<.01). Prevalence of LV hypertrophy was 21% among children with high casual BP (P<.004 versus 4.3% in normal group). Risk of LV hypertrophy was 5.5-fold higher in the presence of high casual BP (P<.004), whereas obesity, age, and sex did not have independent effects. Endocardial shortening was slightly higher in children with high casual BP (36.8+/-8.2%) than in children with normal BP (34.3+/-4.8%, P<.02), whereas midwall shortening was identical in the two groups (20%). Both endocardial shortening and midwall shortening were negatively related to end-systolic stress (r=-.62, SEE=3.8% and r=-.32, SEE=2.4% in normal children). Shortening as a percentage of predicted from wall stress was increased in children with high casual BP at the endocardial level (P<.001), whereas it was normal at the midwall. Therefore, (1) casual detection of high BP in school children is associated with LV geometric abnormalities similar to those found in adults with sustained hypertension (LV hypertrophy, concentric pattern); (2) similar to in adult hypertension, endocardial chamber function in children is supranormal; and (3) in contrast to findings in adults, midwall shortening is normal in children with high casual BP.

Effect of ligation of patent ductus arteriosus on left ventricular performance and its determinants in premature neonates

OBJECTIVES

The purpose of this study was to determine in preterm newborn infants the effects of ductal ligation on ventricular performance and its determinants: preload, afterload and contractility.

BACKGROUND

Neonatal ventricular performance is highly sensitive to afterload. Therefore, the increase in systemic vascular resistance associated with ligation of a patent ductus arteriosus might worsen ventricular performance in the preterm infant.

METHODS

All 14 premature infants undergoing patent ductus arteriosus ligation in a 1-year period at our institution underwent echocardiography at three times: before, immediately after and 24 h after ligation. Indexes studied included ventricular performance (fractional area change), preload (left ventricular end-diastolic dimension), afterload (end-systolic wall stress) and contractility (the difference between the measured and predicted velocity of circumferential fiber shortening). Blood pressure was measured; systemic resistance was calculated. These data were compared with those of 14 preterm infants without patent ductus arteriosus.

RESULTS

The infants with patent ductus arteriosus had higher values for ventricular performance (mean +/- SD fractional area change 60 +/- 9% vs. 52 +/- 11%, p < 0.05) and lower values for wall stress (22 +/- 6 vs. 44 +/- 17 g/cm2, p < 0.05) before ligation than did the control group. At 24 h after ligation, ventricular performance was not significantly changed (fractional area change 60 +/- 9% to 57 +/- 12%). There were significant increases in blood pressure and systemic vascular resistance but no changes in wall stress or contractility.

CONCLUSIONS

Ventricular performance is higher in premature infants with than in those without patent ductus arteriosus because afterload is lower in the former group. Although ductal ligation increases blood pressure and systemic resistance, wall stress and ventricular performance are maintained. Our results suggest that the premature newborn maintains ventricular performance during stress, at least in part, by manipulating afterload.

Effect of lean body mass, fat mass, blood pressure, and sexual maturation on left ventricular mass in children and adolescents. Statistical, biological, and clinical significance

BACKGROUND

Left ventricular hypertrophy has been established as an independent risk factor for the development of cardiovascular morbidity and mortality. It is clear that left ventricular mass increases during childhood and adolescence with body growth. The extent to which other factors, such as obesity, stage of sexual maturation, and level of blood pressure, determine left ventricular mass has been controversial.

METHODS AND RESULTS

The study was a cross-sectional evaluation of the relationship of left ventricular mass determined by echocardiography with lean body mass and fat mass determined by dual-energy x-ray absorptiometry, which is the most valid and reliable method for determination of body composition in children and adolescents. The relationship of left ventricular mass with the stage of sexual maturation and with systolic and diastolic blood pressure was also evaluated. Two hundred one subjects (105 boys, 96 girls; 103 white and 98 black) 6 to 17 years old were studied. Age (r = .72), height (r = .81), weight (r = .84), body surface area (r = .87), sexual maturation (r = .75), lean body mass (r = .86), fat mass (r = .54), systolic BP (r = .58), and diastolic BP (r = .48) were all univariate correlates of left ventricular mass. In a multiple regression analysis, only lean body mass, fat mass, and systolic blood pressure were statistically significant independent correlates of left ventricular mass. Lean body mass alone explained 75% of the variance of left ventricular mass, whereas fat mass and systolic blood pressure explained only 1.5% and 0.5% of the variance, respectively. Lean body mass was the strongest determinant of left ventricular mass in all four race-sex groups.

CONCLUSIONS

This study provides an opportunity to separate the effects on left ventricular mass of lean body mass resulting from linear growth from those of fat mass resulting from obesity. Lean body mass, fat mass, and systolic blood pressure all have a statistically significant independent association with left ventricular mass, suggesting that all three play an important biological role in determining left ventricular mass. However, fat mass and systolic blood pressure have only a small impact on left ventricular mass. This indicates that fat mass and blood pressure would be expected to be of only minor clinical importance in determining left ventricular mass in normal children and adolescents.

Serial changes in left and right ventricular systolic and diastolic dynamics during the first year after an index left ventricular Q wave myocardial infarction

OBJECTIVES

This study quantified serially biventricular emptying and filling after infarction and related these to changes in volume, muscle mass, wall stress and contractility.

BACKGROUND

There are limited data on serial changes in ventricular dynamics after infarction.

METHODS

Forty patients had serial electron beam computed tomographic examinations during the first year after index Q wave infarction (21 anterior, 19 inferior), and global biventricular volumes, peak rates of emptying and filling and left ventricular muscle masses were quantified. Mean mid-left ventricular end-systolic wall stresses, rate-corrected velocities of circumferential shortening and two indexes of left ventricular contractility--the end-systolic wall stress/volume ratio and the end-systolic wall stress/rate-corrected velocity of circumferential shortening relation--were estimated in each instance.

RESULTS

Patients with anterior infarction had an increase in biventricular chamber volume of 15% to 35% by 1 year. Global biventricular peak rates of emptying and filling were decreased by 20% to 30% from hospital discharge to 6 weeks but thereafter remained unchanged. Despite a significant increase in mean wall stresses, the end-systolic wall stress/volume ratio remained unchanged during the year. The rate-corrected velocities of circumferential shortening declined serially after anterior infarction but did so in proportion to the increase in mean wall stresses, consistent with no net change in left ventricular contractility. Patients with inferior infarction showed a trend toward similar changes, but the magnitudes did not reach significance.

CONCLUSIONS

Left (and right) ventricular global peak rates of emptying and filling during the first year after infarction can be altered in the absence of additional ischemic injury but are more consistent with responses to changes in left ventricular afterload than changes in intrinsic ventricular performance or contractility. Serial changes in left ventricular afterload after infarction are largely due to progressive chamber enlargement and limited development of compensatory hypertrophy during the first year. Intrinsic global left ventricular contractile performance was not altered by postinfarction cardiac remodeling in the patients examined.

Cardiovascular status in young patients with insulin-dependent diabetes mellitus

BACKGROUND

Although the existence of diabetic cardiomyopathy in adults is firmly established, the presence of cardiac abnormalities in young diabetic patients is not universally accepted. We sought to determine the early stages of cardiac derangement and whether they are associated with renal dysfunction.

METHODS AND RESULTS

Thirty-nine patients (29 boys; mean age, 17.6 +/- 3.4 years) with insulin-dependent diabetes mellitus underwent echocardiography and timed overnight urine collection. Echocardiographic evaluation consisted of left ventricular mass, performance (shortening fraction, velocity of circumferential fiber shortening, stroke volume, and cardiac index), preload (end-diastolic dimension and volume), after-load (end-systolic wall stress and systemic vascular resistance), and contractility (velocity of fiber shortening relative to wall stress). Creatinine clearance and albumin excretion were measured from the urine sample. Glycosylated hemoglobin levels were measured; height and weight were measured; and Quetelet index (weight/height2) was calculated. These data were compared with control data. Left ventricular mass (26 +/- 6 versus 22 +/- 6 g/ht2.7, P < .01), the indexes of performance, blood pressure, and contractility (0.14 +/- 0.14 versus 0.003 +/- 0.03 circumference/s, P < .0003) were significantly higher in the diabetic patients than in control subjects. To evaluate the correlates of left ventricular mass and contractility in the diabetic patients, univariate and multiple regression analyses were performed. Significant univariate correlations of mass included albumin excretion (r = .36, P < .02), glycosylated hemoglobin (r = .35, P < .04), and stroke volume (r = .34, P < .03). A multivariate model included Quetelet index, albumin excretion, and duration of diabetes. Significant univariate correlations of contractility included insulin dosage (r = -.36, P < .02), creatinine clearance (r = .40, P < .02), and Quetelet index (r = .34, P < .03). A multivariate model included insulin dosage and creatinine clearance.

CONCLUSIONS

Early onset of diabetes mellitus is associated with increased left ventricular mass, performance, contractility, and blood pressure. These cardiovascular findings are correlated with increased creatinine clearance and microalbuminuria. These relations suggest that alterations in cardiovascular and renal function may occur in parallel in adolescents with insulin-dependent diabetes mellitus.