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Biomedical subjects

J M Loggie

Publications and source records attributed to J M Loggie.

At least 19 recordsLinked to original sources
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↗
PubMed1998

Prevalence and correlates of blood pressure elevation in children with Guillain-Barré syndrome.

While there have been case reports describing blood pressure elevation in adults and children with Guillain-Barré syndrome (GBS), no previous systematic study has explored the prevalence of hypertension in children with this condition. In a retrospective review, blood pressure elevation was seen in 20 of 30 (66.7%) patients with GBS admitted to a children's hospital during a 10-year period. There was a significant correlation between highest GBS stage and deviation of systolic blood pressure from age- and gender-specific norms (r = 0.93, p < 0.05). Since blood pressure may be markedly elevated in GBS, the clinician caring for a child with this condition should be aware of this complication.

Adolescent↗
PubMed1993

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

OBJECTIVES: The aim of this study was to determine if left ventricular preload, afterload or contractility is a correlate of left ventricular mass index in hypertensive pediatric patients. BACKGROUND: It is believed that decreased contractility and increased preload are associated with left ventricular hypertrophy in adult hypertensive patients. METHODS: Ninety pediatric hypertensive patients underwent echocardiography to assess left ventricular mass, preload (diastolic dimension and volume) and afterload (end-systolic wall stress, vascular resistance and blood pressure). Contractility was assessed by 1) the end-systolic stress/volume ratio, and 2) the difference between measured and predicted velocity of circumferential fiber shortening. Univariate and multivariate analyses were performed. RESULTS: Univariate analysis showed significant correlations between left ventricular mass and 1) body mass (r = 0.33, p < 0.001), 2) black race (r = 0.37, p < 0.0003), 3) diastolic dimension (r = 0.26, p < 0.01), 4) diastolic volume (r = 0.20, p < 0.05), and 5) stress/volume ratio (r = -0.53, p < 0.0001) but not the difference between measured and predicted velocity of circumferential fiber shortening. A multivariate model included body mass, age at diagnosis, diastolic dimension, wall stress and vascular resistance but not the difference between measured and predicted velocity of circumferential fiber shortening. CONCLUSIONS: Contractility is not significantly related to left ventricular mass. The positive correlation between mass and stress/volume may be due to the dependence of the latter variable on loading conditions. We speculate that both elevated preload and systemic vascular resistance may have a role in the development of hypertrophy in hypertensive pediatric patients.

Adolescent↗
PubMed1993

Blood pressure nomograms for children and adolescents, by height, sex, and age, in the United States.

Because height is a more appropriate index of maturation than weight for use with normative blood pressure (BP) data, we developed normative BP levels for children, by sex, while accounting for age and height simultaneously. Eight U.S. studies used in the Report of the Second Task Force on Blood Pressure Control in Children and one additional study of BP in U.S. children were reanalyzed to develop age-sex-height-specific values for normative BP values among 56,108 children, aged 1 to 17 years, seen at 76,018 visits. Height percentiles were computed on the basis of standard National Center for Health Statistics growth charts. When height is taken into account, more short children (10th age-sex-specific height percentile) and fewer tall children (90th age-sex-specific height percentile) are likely to be classified as hypertensive than when the current age-sex-specific percentiles of BP alone are used. Tables are provided for boys and girls separately, by single year of age (1 to 17 years) and by the 90th and 95th percentiles of systolic blood pressure and diastolic blood pressure (fifth phase of Korotkoff sounds) for selected age-sex-specific height percentiles based on standard U.S. growth charts.

Adolescent↗
PubMed1993

Distribution and correlates of creatinine clearance in children and adolescents with blood pressure elevation.

The kidney has been implicated as both an etiologic factor and as a target organ in patients with essential hypertension. Renal function has not been studied extensively in children and adolescents with essential hypertension. Eighty-eight subjects, aged 6 to 23 years, with blood pressure persistently above the 90th percentile for age were studied. Creatinine clearance was determined from a single 24-hour urine collection. The mean creatinine clearance was 129.3 +/- 55.3 ml/min per 1.73 m2. Multiple regression analysis was used to investigate potential correlates of creatinine clearance. Because creatinine clearance was not normally distributed, the logarithm of creatinine clearance was used as the dependent variable. Body mass index, resting heart rate, and basal supine plasma renin activity were significant direct independent correlates. Peripheral vascular resistance at maximal exercise was an inverse correlate of the logarithm of creatinine clearance. These findings are consistent with previous studies of adults and may provide the basis for strategies to identify young patients with essential hypertension who are at risk for the development of renal dysfunction.

Adolescent↗
PubMed1993

Determinants of retinal vascular abnormalities in children and adolescents with essential hypertension.

The predictors of retinal vascular abnormalities in patients with elevated BP have not been studied extensively in children or adults. The purpose of this study was to investigate potential correlates of arteriolar narrowing, tortuosity and arteriovenous nicking in a population of children and adolescents with essential hypertension. A total of 97 subjects, aged 6-23 years, were studied. Retinal vascular abnormalities were determined by photographs of the optic fundus which were interpreted independently by two opthalmologists. In 50 subjects (51%) there were one or more abnormalities. Potential correlates of retinal abnormalities included: (1) demographic factors, (2) body size, (3) level of BP and duration of hypertension, (4) family history of cardiovascular disease, (5) treatment with antihypertensive medication, (6) dietary sodium intake, (7) laboratory analyses, (8) the reactivity of BP and heart rate to playing a video game, and (9) cardiovascular reactivity to exercise. Using stepwise multiple logistic regression, the variables that were independently associated with the presence of retinal vascular abnormalities were family income, dietary sodium intake, fasting blood glucose, pulse pressure during mental stress and the change in SBP from rest to maximum exercise. In addition, subjects with more than one retinal vascular abnormality had higher average DBP during follow-up in the Hypertension Clinic and a smaller rise in SBP from rest to maximum exercise. Identification of these independent predictors of retinal vascular abnormalities and factors associated with more than one abnormality may provide insight into the pathogenesis of hypertensive vascular disease.

Adolescent↗
PubMed1991

The prevalence of retinal vascular abnormalities in children and adolescents with essential hypertension.

We studied 97 children and adolescents with essential hypertension by evaluating photographs of the optic fundus and fluorescein angiography. Photographs were examined for the presence of arteriolar narrowing, tortuosity, and arteriovenous nicking. Intraobserver and interobserver variability in determination of abnormalities was low with agreement of 75% for narrowing, 90% for tortuosity, and 100% for arteriovenous nicking. The prevalence of abnormalities was 41% (95% confidence interval, 31% to 50%) for arteriolar narrowing, 14% (95% confidence interval, 19% to 21%) for tortuosity, and 8% (95% confidence interval, 5% to 11%) for arteriovenous nicking. Of 97 patients, 50 (51%) had one or more abnormality. Retinal abnormalities are relatively common in young patients with essential hypertension.

Adolescent↗
PubMed1990

Determinants of cardiac involvement in children and adolescents with essential hypertension.

Left ventricular hypertrophy is often found in association with systemic hypertension and may be an independent risk factor for cardiovascular disease morbidity and mortality. Few studies have investigated the determinants of left ventricular mass (LVM) in young patients with essential hypertension. Therefore, we studied 104 children and adolescents with blood pressure persistently greater than the 90th percentile for age and sex and with no known cause of blood pressure elevation. LVM was determined by echocardiography and was indexed by height to account for body size. The mean LVM index was 90.2 +/- 26.0 g/m. Using the gender-specific 95th percentile from normal children, 40 subjects (38.5%) had left ventricular hypertrophy. Using multiple regression analysis, the significant independent direct correlates of LVM index were male sex, body mass index, dietary sodium intake, age at diagnosis, and systolic blood pressure at maximum exercise. The significant independent inverse correlate of LVM index was resting heart rate (p less than 0.05). These variables accounted for a substantial portion of the LVM index variance in this population (multiple R2 = 0.56, p less than 0.001). The results indicate that left ventricular hypertrophy is prevalent in children and adolescents with essential hypertension. The direct association of LVM index with body mass index and dietary sodium intake suggests weight reduction and dietary salt restriction might be useful to prevent or treat the development of left ventricular hypertrophy in pediatric patients with essential hypertension.

Adolescent↗
PubMed1990

Distribution of target-organ abnormalities by race and sex in children with essential hypertension.

The prevalence of left ventricular hypertrophy, glomerular hyperfiltration and retinovascular abnormalities was investigated in 43 black and 45 white children with essential hypertension. Whilst 36% of subjects had left ventricular hypertrophy, 49% had glomerular hyperfiltration and 50% had retinal abnormalities, no differences were found between blacks and whites. This pattern differs from that found in adult hypertensives.

Adolescent↗
PubMed1987

Correlates of resting and maximal exercise systolic blood pressure after repair of coarctation of the aorta: a multivariable analysis.

Repair of coarctation of the aorta may not prevent the subsequent development of elevated systemic blood pressure at rest or with exercise. The correlates of late postoperative resting systolic blood pressure and maximal exercise systolic blood pressure levels were investigated in a retrospective study of 42 patients who had graded exercise tests after correction of coarctation of the aorta. The independent variables studied included height, weight, body surface area, age at surgery, age at exercise testing, the time interval between surgery and exercise testing, the highest systolic blood pressure prior to surgery, gradient across the coarctation at preoperative catheterization, and the residual postoperative gradient across the coarctation. The same combination of independent variables provided the best regression model for explanation of the variance of both postoperative resting and maximal exercise systolic blood pressure. The models included height, highest preoperative systolic blood pressure, and residual gradient. None of the other variables added significant explanatory ability to either model. These findings suggest that the preoperative level of systolic blood pressure may be the best determinant of timing the corrective surgery. It may be possible to defer the operation, as long as blood pressure remains normal, until an age when repair is less likely to result in recurrent coarctation.

Adolescent↗
PubMed1987

Clinical spectrum of intrinsic renovascular hypertension in children.

In the past two decades, 853 children and adolescents have been evaluated for elevated BP as inpatients and outpatients by the hypertension service at Children's Hospital Medical Center, Cincinnati. Most children with hypertension secondary to coarctation of the aorta and all children with glomerulonephritis are managed by other services and are not included in that total. In a retrospective study, 27 children (3%) were identified as having hypertension secondary to intrinsic renal arterial stenosis. The age at presentation ranged from 5 months to 20 years. The mean BP at that time was 171.6/114.2 mm Hg. Ten categories of causes were identified, including fibromuscular dysplasia, arteritis, Williams syndrome, neurofibromatosis, congenital malformations, blunt abdominal trauma, surgical vascular trauma-irradiation, thrombosis, congenital rubella syndrome, and unknown. Overall, symptoms were not common. However, findings of end-organ response, such as left ventricular hypertrophy and retinal vascular abnormalities were prevalent. This is not surprising given the mean BP level at presentation. Physical examination, laboratory tests, and radiologic evaluations (exclusive of renal angiography) were not useful in detecting or identifying the location and extent of the renovascular lesions. Fourteen patients were treated surgically, and 13 were managed medically. The outcome was variable for both treatment modalities. The management of renovascular hypertension in children must be individualized depending on the cause, location, and severity of the lesion, as well as the size of the child. Some forms of renovascular pathology, particularly the arteritides, may resolve spontaneously, and children with these entities should have their BP treated medically until the inflammatory process has subsided.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Evaluation and management of childhood hypertension.

Hypertension in childhood is diagnosed according to age-adjusted values for each sex. It is more commonly diagnosed now than it was 2 decades ago because blood pressure is more frequently measured in children today. Surgically curable forms of hypertension are not common but usually present as moderate or severe hypertension (diastolic blood pressure greater than or equal to 110 mm Hg). Although many patients in this group are asymptomatic, some present with Bell's palsy, enlarged hearts, heart failure, encephalopathy, or stroke. Newer imaging techniques have proved particularly useful for localizing tumors, such as pheochromocytoma. Many antihypertensive drugs are now available, and therapy should be tailored to the patient's needs, with as few adverse or side effects as possible.

Adolescent↗
PubMed1984

Juvenile hypertension: highlights of a workshop.

The workshop was successful in achieving its two major goals: (1) the scientific updating of research issues in pediatric blood pressure determinants and in pediatric hypertension, and (2) the delineation of future research objectives. These objectives are itemized at the end of the workshop proceedings and, in brief, center around the need for better definitions of normal and abnormal blood pressures in youth, the identification of variables in childhood capable of indicating which children are at risk for developing hypertension as adults, and finally, a thoughtful list of additional research issues germane to the explanation of primary and secondary forms of hypertension.

Adult↗