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Biomedical subjects

P Khoury

Publications and source records attributed to P Khoury.

At least 19 recordsLinked to original sources
PubMed2001

Changes in left ventricular mass in children and adolescents during chronic dialysis.

Left ventricular hypertrophy (LVH) is an independent risk factor for cardiac mortality in adults with end-stage renal disease (ESRD). It is prevalent in pediatric patients on chronic dialysis. The objectives of this study were to evaluate left ventricular mass (LVM) in children and adolescents at the initiation of dialysis and to assess its changes during chronic dialysis therapy. In this longitudinal analysis, 29 patients aged 4-18 years had an echocardiographic evaluation within 90 days of starting dialysis therapy and a follow-up study at least 6 months later. LVH was defined as LVM index (g/m2.7) > 95th percentile for normal children and adolescents. On the initial echocardiogram 20 of 29 (69%) patients had LVH and 24 patients (83%) had abnormal LV geometry (38% eccentric LVH, 31% concentric LVH, and 14% concentric remodelling). Patients with LVH were more likely to be on antihypertensive medications (16/20) than patients without LVH (3/9) (P = 0.005). Repeat echocardiogram, performed after 10 +/- 3 months on chronic dialysis, showed no significant difference in the mean LVM index (49.6 +/- 17.5 g/m2.7 and 49.7 +/- 16.1 g/m2.7, respectively) or in the prevalence of LVH or LV geometric pattern. However, 14 of 29 patients had a progressive increase in LVM index and 15 patients had regression. Multiple regression analysis showed that baseline LVM index (P = 0.005) and interval change in indexed systolic blood pressure (P = 0.027) were independent predictors for LVM index changes. In summary, LVH and abnormal LV geometry are already prevalent in children and adolescents with renal failure at the time of initiation of dialysis therapy, indicating that LVH develops during the pre-ESRD course. Early intervention to control blood pressure may be an important factor to improve and prevent progression of LVH in pediatric patients with ESRD.

Adolescent↗
PubMed2001

A phase I and pharmacologic study of capecitabine and paclitaxel in breast cancer patients.

BACKGROUND: Based on preclinical studies demonstrating that treatment with paclitaxel upregulates intratumoral thymidine phosphorylase (dTHdPase), which catalyzes the final step in the conversion of the oral fluoropyrimidine capecitabine to 5-fluorouracil (5-FU), as well as the overlapping spectra of activity for these agents, particularly in metastatic breast cancer, this phase I study evaluated the feasibility of administering capecitabine on an intermittent schedule in combination with paclitaxel in previously-treated patients with locally advanced or metastatic breast cancer. The study also sought to recommend doses for subsequent disease-specific studies, identify clinically significant pharmacokinetic interactions, and detect preliminary antitumor activity. PATIENTS AND METHODS: Nineteen previously treated women with metastatic breast cancer whose prior treatment included neither paclitaxel or capecitabine received one hundred one courses of capecitabine and paclitaxel. Paclitaxel was administered as a three-hour intravenous (i.v.) infusion at a fixed dose of 175 mg/m2 and capecitabine was administered as 2 divided daily doses for 14 days followed by a seven-day rest period every 3 weeks. The dose of capecitabine was increased from a starting dose of 1650 mg/m2/d. The plasma sampling scheme in the first course permitted characterization of the pharmacokinetics of each agent given alone and concurrently to detect major pharmacokinetic interactions. RESULTS: Palmar plantar erythrodysesthesia (hand foot syndrome) and neutropenia were the principal dose-limiting toxicities (DLT). Other toxicities included diarrhea and transient hyperbilirubinemia. Three of eight new patients treated with capecitabine 2000 mg/m2/d and paclitaxel 175 mg/m2 experienced DLT in the first course, whereas none of eleven new patients treated with capecitabine 1650 mg/m2/d and paclitaxel 175 mg/m2 developed DLT. Pharmacokinetic studies indicated that capecitabine did not grossly affect the pharmacokinetics of paclitaxel, and there were no major effects of paclitaxel on the pharmacokinetics of capecitabine and capecitabine metabolites. However, AUC values for the major 5-FU catabolite, fluorobeta-alanine (FBAL), were significantly lower in the presence of paclitaxel. Two complete and seven partial responses (56% response rate) were observed in sixteen patients with measurable disease; four of six patients whose disease was previously treated with high-dose chemotherapy and hematopoietic stem-cell support had major responses. Seven of nineteen patients had stable disease as their best response. CONCLUSIONS: Recommended combination doses of capecitabine on an intermittent schedule and paclitaxel are capecitabine 1650 mg/m2/d orally for 14 days and paclitaxel 175 mg/m2 i.v. every 3 weeks. The favorable preclinical interactions between capecitabine and paclitaxel, as well as the acceptable toxicity profile and antitumor activity in patients with metastatic breast cancer, support further clinical evaluations to determine an optimal role for the combination of capecitabine and paclitaxel in breast cancer and other relevant malignancies.

Administration, Oral↗
PubMed2001

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.

Adolescent↗
PubMed2001

Noncircumferential myofiber function: impact on early diastolic filling in children.

Circumferential and noncircumferential myofiber contraction may have varying impact on systolic and diastolic function. The purpose of this study was to determine the relation of circumferential, longitudinal, and oblique fiber shortening to early diastolic filling in children. Twenty-five patients (8.1 +/- 5.6 years of age; 12 boys and 13 girls) with normal echocardiograms and no heart disease had prospective echocardiographic evaluation of circumferential (shortening fraction, fractional area change), longitudinal (left ventricular axial shortening), combined circumferential and longitudinal (left ventricular ejection fraction), oblique (left ventricular systolic twist [LVST]) shortening, and early diastolic filling. Mean LVST was 16 +/- 8 degrees. There was no relation between early diastolic filling indexes and indexes of circumferential or longitudinal shortening. However, there was a significant inverse relation between heart rate-corrected E-wave acceleration time and LVST (r = 0.63, P <.001). Oblique fiber shortening affects early diastolic filling in children. Describing the functional role of noncircumferential left ventricular myofibers may improve our understanding of global left ventricular function.

Adolescent↗
PubMed2000

Severe left ventricular hypertrophy in pediatric dialysis: prevalence and predictors.

Left ventricular hypertrophy (LVH) has been recognized as an independent risk factor for cardiovascular morbidity and mortality in adults with end-stage renal disease. However, the prevalence and severity of LVH in children on chronic dialysis therapy is not well established. Retrospectively, 64 chronic dialysis patients, aged 20 months to 22 years, on chronic dialysis had echocardiographic evaluation of LV mass (LVM) and geometry. Forty-eight (75%) children had LVH, including 22 of 26 (85%) on hemodialysis (HD) and 26 of 38 (68%) on peritoneal dialysis (PD). The prevalence of LVH in patients on HD was significantly higher than those on PD (P=0.02). Abnormal LV geometry was found in 51 of 64 (80%) patients: 25 patients (39%) had eccentric hypertrophy, 3 (5%) had concentric remodelling, and 23 (36%) had concentric LVH. Twenty-six children (41%) had severe LVH, defined as LVM index greater than 51 g/m2.7, which is associated with a fourfold greater risk for development of cardiovascular disease in adults. Patients with severe LVH had a significantly lower hemoglobin level (P=0.027) and longer duration of renal disease prior to the start of dialysis therapy (P=0.003) than patients without LVH. Multiple logistic regression analysis revealed HD as opposed to PD as a significant independent predictor for severe LVH (P=0.036). Higher systolic blood pressure remained in the final model as an independent predictor with a borderline level of significance (P=0.065). The results indicate that severe LVH and abnormal left ventricular geometry are common in young dialysis patients. Better control of blood pressure, anemia, and hypervolemia may be important in prevention or improving LVH.

Adolescent↗
PubMed1999

Serum glutathione in adolescent males predicts parental coronary heart disease.

BACKGROUND: Traditional risk factors account for only half of the morbidity and mortality from coronary heart disease (CHD). There is substantial evidence that oxidative injury plays a major role in the atherosclerotic process. Thus, antioxidants may protect against development of atherosclerosis. Glutathione, an intracellular tripeptide with antioxidant properties, may be protective. METHODS AND RESULTS: This case-control study compared total serum glutathione (tGSH) in 81 adolescent male offspring of parents with premature CHD (ie, before 56 years of age) and 78 control male offspring of parents without known or suspected CHD. Case offspring had significantly lower tGSH than control offspring. In multiple logistic regression with parental CHD status as the dependent variable, age entered as a covariate, and other CHD risk factors competing to enter the model as significant independent predictor variables, LDL cholesterol (odds ratio [OR], 2.15 [units=1.5 SD]; 95% CI, 1.21 to 3.82), tGSH (OR, 0.40; 95% CI, 0.22 to 0.71), HDL cholesterol (OR, 0.42; 95% CI, 0.22 to 0.78), and total serum homocysteine (OR, 2.6; 95% CI, 1.35 to 5.02) entered the model as significant predictors of parental CHD status. CONCLUSIONS: Low tGSH in adolescent boys is a significant independent predictor of parental CHD, in addition to elevated LDL cholesterol, low HDL cholesterol, and elevated total serum homocysteine concentrations.

Adolescent↗
PubMed1999

Association of body fat distribution and cardiovascular risk factors in children and adolescents.

BACKGROUND: Obesity is associated with increased risk of cardiovascular disease in adults and less favorable cardiovascular risk factor status in children and adolescents. In adults, fat distribution has been shown to be related to lipid and lipoprotein concentrations, blood pressure levels, and left ventricular mass. These relationships have not been extensively studied in young subjects. METHODS AND RESULTS: This was a cross-sectional study of 127 children and adolescents 9 to 17 years of age. Dual-energy x-ray absorptiometry was used to measure total and regional fat mass. The dependent variables were fasting lipid and lipoprotein concentrations, systolic and diastolic blood pressures, and left ventricular mass. There were significant (P<0.05) univariate correlations between fat distribution and log triglycerides (r=0.27), log HDL cholesterol (r=-0.23), systolic blood pressure (r=0.26), and left ventricular mass (r=0.37). Multiple regression analysis showed that the significant independent correlates for triglycerides and HDL cholesterol were age and fat distribution; for systolic blood pressure, height and fat distribution; and for left ventricular mass, height, race, sex, and fat distribution. CONCLUSIONS: These results demonstrate that fat distribution is a more important independent correlate of cardiovascular risk factors than percent body fat in children and adolescents. Greater deposition of central fat (an android fat pattern) is associated with less favorable plasma lipid and lipoprotein concentrations, blood pressure, and left ventricular mass.

Adipose Tissue↗
PubMed1998

Left ventricular geometry and severe left ventricular hypertrophy in children and adolescents with essential hypertension.

BACKGROUND: Left ventricular (LV) hypertrophy has been established as an independent risk factor for cardiovascular disease in adults. Recent research has refined this relationship by determining a cutpoint of 51 g/m(2.7) for LV mass index indicative of increased risk and defining LV geometric patterns that are associated with increased risk. The purpose of this study was to evaluate severe LV hypertrophy and LV geometry in children and adolescents with essential hypertension. METHODS AND RESULTS: A cross-sectional study of young patients (n=130) with persistent blood pressure elevation above the 90th percentile was conducted. Nineteen patients (14%) had LV mass greater than the 99th percentile; 11 of these were also above the adult cutpoint of 51 g/m(2.7). Males, subjects with greater body mass index, and those who had lower heart rate at maximum exercise were at significantly (P<.05) higher risk of severe LV hypertrophy. In addition, 22 patients (17%) had concentric LV hypertrophy, a geometric pattern that is associated with increased risk of cardiovascular disease in adults. Seven patients had LV mass index above the cutpoint and concentric hypertrophy. No consistent significant determinants of LV geometry were identified in these children and adolescents with hypertension. CONCLUSIONS: Severe LV hypertrophy and abnormal LV geometry are relatively prevalent in young patients with essential hypertension. These findings suggest that these patients may be at risk for future cardiovascular disease and underscore the importance of recognition and treatment of blood pressure elevation in children and adolescents. Weight loss is an important component of therapy in young patients with essential hypertension who are overweight.

Adolescent↗
PubMed1996

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.

Blood Pressure↗
PubMed1996

Fluconazole versus amphotericin B in the treatment of hematogenous candidiasis: a matched cohort study.

PURPOSE: To compare the efficacy and toxicity of fluconazole and amphotericin B in the treatment of hematogenous candidiasis in cancer patients. PATIENTS AND METHODS: A matched cohort study of cancer patients with hematogenous candidiasis was conducted. Forty-five patients with hematogenous candidiasis who received fluconazole (200 to 600 mg/day) in an open-label trial at the University of Texas M. D. Anderson Cancer Center, Houston, Texas, between February 1990 and June 1992 were matched to 45 patients treated with amphotericin B (0.3 to 1.2 mg/kg/day) for the same diagnosis. Criteria for matching included the following prognostic variables at the initiation of therapy: pneumonia, neutropenia (< 1,000 cells/mm3), number of positive blood cultures before therapy, infecting Candida species, underlying disease, and the simplified acute physiology score. Response and survival at 48 hours, after 5 days of therapy, and at the end of therapy, as well as toxicity rates were obtained. Other post hoc analyses were performed. Differences in outcomes were assessed by the McNemar, the sign, and the log rank tests. RESULTS: Patients were similar with respect to the matching criteria, age, sex, status of underlying disease, use of antibiotics and growth factors, duration of treatment, presence and removal of central venous catheters, disseminated disease, and concomitant infections. Response rates at 48 hours and 5 days were similar between the two study groups. Overall response rates at the end of therapy were 73% for patients treated with fluconazole and 71% for patients treated with amphotericin B (P = 0.78). There were no differences in survival rates or causes of death. Toxicity was observed in 9% of patients treated with fluconazole and in 67% of patients treated with amphotericin B (P < 0.0001). Toxic effects of amphotericin B included nephrotoxicity, hypokaliemia, and fever and chills. CONCLUSION: Fluconazole is effective and better tolerated than amphotericin B for the treatment of hematogenous candidiasis in cancer patients.

Adult↗
PubMed1996

Determinants of resting energy expenditure in young black girls and young white girls.

OBJECTIVE: To identify determinants of resting energy expenditure (REE) in black girls and white girls and to evaluate racial differences in REE. STUDY DESIGN: Cross-sectional study of 98 girls (47 black and 51 white girls), ages 6 to 16 years. METHODS: Determinations of lean body mass, fat mass, and bone mass were made by dual-energy x-ray absorptiometry. Measurements of REE were made with the DeltaTrac metabolic monitor. Subjects fasted at least 3 hours before testing, had rested 30 minutes before the test, and had not engaged in strenuous activity for the previous 12 hours. Pubertal maturation was assessed with a three-stage scoring method: (1) prepubertal, (2) pubertal, but premenarcheal, and (3) postmenarcheal. RESULTS: There were no significant differences in height, weight, lean body mass, or fat mass between the black and white subjects. Racial differences in total REE were also not significant, but REE standardized by weight was significantly greater in white girls (40.3 kcal/day) compared with black girls (35.5 kcal/day) (p = 0.001). Resting energy expenditure was positively and significantly correlated with all measures of body composition. Multiple regression analysis identified lean body mass, sexual maturation, and race as significant main effects. After controlling for lean body mass and maturation, black girls had significantly lower REE. The race-maturation interaction was of borderline significance (p = 0.09); prepubertal black girls had significantly lower REE (1156 kcal/day) than prepubertal white girls (1399 kcal/day), but racial differences in stages 2 and 3 were not statistically significant. CONCLUSION: Lean body mass, maturation, and race are significant determinants of REE. Resting energy expenditure is significantly lower in black than white girls in the prepubertal stage. The cause of this racial difference in REE is not known; it is not explained by differences in anthropometric variables. Racial differences in REE could explain in part the earlier onset of puberty in black girls compared with white girls and could be a factor in the difference in obesity in black and white women.

Absorptiometry, Photon↗
PubMed1996

Correlates of the hemodynamic determinants of blood pressure.

The purpose of this study was to investigate the association of sex, race, lean body mass, and fat mass with the hemodynamic determinants of blood pressure, including stroke volume, heart rate, and total peripheral vascular resistance. The study included 201 subjects aged 6 to 17 years, 105 of whom were male and 98 of whom were black. Lean body mass and fat mass were both significant (P < .05) independent determinants of stroke volume, cardiac output, and total peripheral vascular resistance. However, the direction of the effect of lean body mass was opposite for stroke volume and cardiac output compared with that of total peripheral vascular resistance. The direct relationship of lean body mass with systolic blood pressure (SBP) and diastolic blood pressure (DBP) (regression coefficients, 0.55 +/- 0.05 for SBP and 0.47 +/- 0.05 for DBP) indicates that the effect of lean body mass on cardiac output may predominate. Lean body mass explained substantially more of the variance of the hemodynamic variables than did fat mass. After control for the effects of body size, male subjects had higher heart rate and cardiac output, and female subjects had higher vascular resistance. White subjects had higher stroke volume and cardiac output, and black subjects had higher peripheral vascular resistance. This study demonstrates that lean body mass is a more important correlate of the hemodynamic determinants of blood pressure than is fat mass and that sex and race have significant independent relationships with the hemodynamic determinants of blood pressure in children and adolescents.

Adolescent↗
PubMed1996

The impact of thrombolytic therapy on arterial and graft occlusions: a critical analysis.

BACKGROUND: The indications for intraarterial thrombolytic therapy of lower extremity native arterial and synthetic graft occlusions prior to vascular reconstructions requires further refinement before firm conclusions can be made. STUDY DESIGN: A retrospective review of 55 patients undergoing 81 lytic treatments with high dose urokinase from February 1989 to February 1993 was performed. The cases were divided into three groups: Group I: successful thrombolysis with residual defects followed by surgical reconstruction or percutaneous transluminal angioplasty (PTA); Group II: successful thrombolysis alone; and Group III: failure of thrombolysis requiring reconstruction or leading to amputation. No effort was made to analyze the particular type of reconstruction. Follow-up ranged from 1 to 1627 days (4 years and 5 1/2 months). RESULTS: One, two, and three year patency rates were 47%, 24%, and 8% for Group I; 57%, 46%, and 46% for Group II; and 24%, 10%, and 10% for Group III respectively. The one, two and three year limb salvage rates were 92%, 76%, and 76% for Group I; 82%, 82%, and 82% for Group II; and 48%, 37%, and 37% for Group III respectively. Forty-one complications occurred in 35 of the 81 (43%) lytic treatments. CONCLUSIONS: Intraarterial thrombolytic therapy can be regarded as a possible consideration in the initial management of acute lower extremity arterial and synthetic graft occlusions especially in patients with multiple prior vascular reconstructions. Unsuccessful thrombolysis results in a poor outcome despite surgical reconstruction in the majority of cases.

Aged↗
PubMed1995

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.

Absorptiometry, Photon↗
PubMed1995

Indexing left ventricular mass to account for differences in body size in children and adolescents without cardiovascular disease.

Left ventricular (LV) mass has been established as an independent risk factor for cardiovascular disease morbidity and mortality. To account for differences in body size, a variety of factors have been proposed for indexing LV mass. Dual energy x-ray absorptiometry provides a measure of lean body mass which can be used as a comparison with other more clinically applicable methods of standardization. The study included 192 subjects (100 male, 103 white) aged 6 to 17 years. Lean body mass was determined by dual energy x-ray absorptiometry and LV mass was calculated from M-mode echocardiographic measurements. There were significant differences by gender (males 98.7 g, females 80.3g, p < 0.001), but not race, for unindexed LV mass. Indexing LV mass by lean body mass eliminated the difference by gender. Log-log regression analysis revealed that the optimal height exponent for indexing LV mass was height3 (95% confidence interval, 2.8 to 3.1). LV mass/height3 provided the most consistently high intraclass correlation with LV mass/lean body mass versus indexing with body surface area, height, height2, and height2.7 across the 4 race/gender groups. LV mass indexed by height3 eliminated differences in LV mass by gender (males 26.1 +/- 4.72 g/m3, females 25.5 +/- 4.8 g/m3, p = NS). The proposed method for indexing LV mass by height3 should be useful in the clinical setting. The 90th and 95th percentiles of LV mass/height3 provide cutpoints for determining the presence of LV hypertrophy in children and adolescents.

Absorptiometry, Photon↗
PubMed1994

Persistent hyperdynamic cardiovascular state at rest and during exercise in children after successful repair of coarctation of the aorta.

OBJECTIVES: The purposes of this study were to evaluate left ventricular performance and contractility at rest and during exercise to determine mechanisms and correlates for alterations in performance and blood pressure in pediatric patients after successful repair of coarctation of the aorta. BACKGROUND: Blood pressure and left ventricular function are elevated in children despite successful repair. The mechanisms for these changes are not understood. METHODS: Thirty asymptomatic pediatric patients with successful coarctation repair (mean age [+/- SD] 12.5 +/- 4 years) underwent echocardiographic determination of left ventricular mass, performance (shortening fraction), preload (indexed diastolic dimension), afterload (end-systolic wall stress), contractility (velocity of circumferential fiber shortening/wall stress relation) and Doppler gradient at rest and during exercise. Data were compared with those of 24 control subjects (mean age 21.0 +- 4 years). Because of the age discrepancy between groups, age-dependent echocardiographic data were indexed by body surface area. RESULTS: The mean age at operation was 5 +/- 4 years, and the average follow-up period was 7.5 +/- 3 years. The average blood pressure gradient between upper and lower limbs was 4 mm Hg. Left ventricular mass was higher in the postoperative group than in the control group (1.58 vs. 1.31 g/ht2.7, p = 0.04), as were values at rest for performance (44% vs. 31%, p = 0.0001), preload (3.9 vs. 3.7 cm/body surface area0.5), indexes systolic blood pressure (1.05 vs. 0.91, p = 0.0001) and contractility (0.23 vs. -0.05 circumferences/s, p= 0.001). Afterload was lower at rest (36 vs. 52 g/cm2, p = 0.0004). These differences between groups persisted during and after exercise. Contractility underwent an exaggerated increase after exercise in the postoperative group. CONCLUSIONS: Left ventricular performance in children after coarctation repair is higher at rest and during exercise than in control subjects as a result of higher preload and contractility and lower afterload. These changes may be due to associated hypertrophy. Persistent postoperative hypertension may be due to a hyperdynamic, hypercontractile state caused by residual gradients manifested only during exertion.

Adolescent↗