Cardiovascular mortality in children and young adults with end-stage kidney disease.

OBJECTIVE: To analyze cardiovascular death in a national end-stage renal disease (ESRD) population. STUDY DESIGN: This retrospective, observational study with data from the US Renal Data Systems analyzed 1380 deaths from 1990 to 1996 among patients who started ESRD therapy as children and died before 30 years of age. RESULTS: Percentage of cardiac deaths (n = 311) varied by age and was higher among black patients (0-4 years, 36%; 5-9 years, 18%; 10-14 years, 35%; 15-19 years, 22%; 20-30 years, 32%) than white patients (18%, 12%, 17%, 14%, and 23%, respectively). Among black patients, cardiac deaths occurred in 11% of transplant recipients, 34% of dialysis patients, and among white patients 9% and 25%, respectively. Black patients were 1.6 times more likely to die of a cardiac death (P <.001) than white patients. Transplant recipients had 78% lower risk of cardiac death than dialysis patients (odds ratio = 0.22; P =.0001). The cardiac death rate among dialysis patients was 21.4 per 1000 patient-years in black patients compared with 20.5 in white patients. Transplantation cardiac death rates were lower in black patients, 2.1 per 1000 patient-years, and 1.3 in white patients. CONCLUSIONS: Cardiovascular death accounts for 23% of pediatric and young adult ESRD deaths. Black patients and dialysis patients are at higher risk of a cardiac death compared with white patients and transplant recipients. Further studies are needed to identify risk factors associated with cardiovascular death in patients with ESRD.

Distribution of uidA gene sequences in Escherichia coli isolates in water sources and comparison with the expression of beta-glucuronidase activity in 4-methylumbelliferyl-beta-D-glucuronide media.

The uidA gene, which encodes the beta-glucuronidase enzyme, was detected in 97.7% of 435 Escherichia coli isolates from treated and raw water sources by DNA-DNA hybridization; 92.4% of the strains expressed the translational product in 4-methylumbelliferyl-beta-D-glucuronide-containing media after reinoculation. Upon initial isolation from water samples, the minimal medium o-nitrophenyl-beta-D-galactopyranoside-4-methylum-belliferyl -beta-D-glucuronide preparations failed to detect more than 50% of the E. coli isolates that possessed uidA gene. Treated water gave the lowest recovery, with Colilert producing 26% positive samples and Coliquik producing 48% positive samples. There appears to be no relationship between the intensity of the autoradiographic signals of the uidA gene and the expression of beta-glucuronidase activity. Therefore, another variable such as physiological condition of the bacteria could be responsible for the nonexpression of the enzyme activity.

Maximal voluntary work and cardiorespiratory fitness in patients who have had Kawasaki syndrome.

To assess the natural history of Kawasaki syndrome and its effect on maximal voluntary work and cardiorespiratory fitness, we performed cycle ergometry testing in 47 patients who had had the syndrome. Forty-one patients performed maximal effort as judged by achievement of 95% predicted heart rate response. Oxygen consumption, carbon dioxide production, and minute ventilation were performed in 23 patients. There was no difference in maximal voluntary work (total work, mean power) or maximal oxygen consumption between case subjects and control subjects. There were no differences between patients with and those without aneurysms. Serial exercise studies were performed in 10 patients; of these, two with initially normal exercise study findings had decreased maximal voluntary work and oxygen consumption with ischemic changes, and both were at high risk for the development of stenotic or occlusive coronary arteries. The other eight patients had normal cardiorespiratory reserve and no ischemic changes with serial studies. These results suggest that patients have normal cardiorespiratory fitness after Kawasaki syndrome. With the development of ischemic heart disease, they may have decreased cardiorespiratory reserve. Serial evaluation of cardiorespiratory fitness may demonstrate ischemic heart disease.

Normal aerobic and anaerobic exercise data for North American school-age children.

The purpose of this study was to establish normative data for untrained, healthy North American children by means of the James protocol for bicycle ergometry. Data were obtained on 151 of 185 children (70 girls and 81 boys). Their ages ranged from 7 years 6 months to 12 years 9 months. All subjects were divided into groups by gender and body surface area (BSA). Maximum heart rates were greater in girls. The mean difference between maximum and recovery heart rates differed significantly by gender, girls taking longer to recover than boys. Maximum oxygen consumption (measured in cubic centimeters per minute per kilogram body weight) did not differ in boys and girls. Ventilatory anaerobic threshold (VAT) occurred when there was an isolated increase in the slope for ventilatory equivalent for oxygen consumption (VE/VO2) with no change in the slope for ventilatory equivalent for carbon dioxide production (VE/VCO2) when both were plotted against time. Absolute oxygen consumption (VO2) at VAT increased with BSA in both sexes, and, when normalized to body size and expressed as a percent of VO2 maximum, no significant difference was observed between the sexes. These data may be used in the fitness evaluations of preadolescent children from North America.

Autoantibodies to SS-A/Ro in infants with congenital heart block.

Antibodies to SS-A/Ro have been proposed to be a serologic marker for the neonatal lupus syndrome, which is characterized by congenital heart block or cutaneous lupus or both. The antibodies occur in the mother and are transiently found in the child's serum. We examined an unselected series of 12 children with idiopathic CHB, isolated in 10 children and with cutaneous lupus lesions in two. Six of these children and their mothers were studied during the child's neonatal period, and six were studied retrospectively. All six neonates had SS-A/Ro autoantibodies. Nine of 12 mothers had SS-A/Ro autoantibodies. Of the seropositive mothers, one had systemic lupus erythematosus, two had sicca syndrome, one had photosensitivity, one had arthralgias, and four were asymptomatic. We propose that congenital heart block may be related to transplacental passage of maternal SS-A/Ro antibodies and that neonatal lupus may be the most common cause.

The natural history of hypertrophic cardiomyopathy in infants of diabetic mothers.

Eleven infants of diabetic mothers with hypertrophic cardiomyopathy have been followed for 30 to 40 months. All infants presented with cardiorespiratory distress and were found to have disproportionate septal hypertrophy on echocardiogram. Cardiac catheterization was done in four infants; three had significant subaortic obstruction. One infant had remarkable improvement after treatment with propranolol. Two infants who received digoxin did poorly and responded favorably to cessation of therapy. The natural history of HCM-IDM appears to be benign, with a resolution of symptoms within two to four weeks and a resolution of septal hypertrophy within two to 12 months. Most of the infants need only supportive care; if pharmacologic intervention is deemed necessary, propranolol appears to be the drug of choice. The natural history of this entity is that of spontaneous regression of symptoms and septal hypertrophy irrespective of therapy.

The silent ductus arteriosus.

Preterm infants at risk of developing a patent ductus arteriosus were followed sequentially by physical examination, echocardiographic determinations of the LA/AO ratio, and chest roentgenograms. The results show that a significant number of infants who have no clinical signs or symptoms of a PDA have large left-to-right shunts. The presence of this shunt was suggested by acute increase in left atrial size by ECHO determination and confirmed by retrograde single-film aortography. Clinical signs and symptoms often developed several days after documentation of the left-to-right shunt.