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Biomedical subjects

D G Human

Publications and source records attributed to D G Human.

At least 19 recordsLinked to original sources
PubMed2000

Early and intermediate-term complications of self-expanding stents limit its potential application in children with congenital heart disease.

OBJECTIVES: We report on the early and intermediate-term follow-up results of self-expanding Wallstent (Schneider, Switzerland) implanted in children with congenital heart disease. BACKGROUND: The inherent shortcomings of balloon-expandable stents prompted the trial of an alternative stent. METHODS: Twenty patients underwent 22 implantations of 25 self-expanding Wallstents between December 1993 and June 1997 in two institutions. The mean age and weight were 10.8+/-4.5 years and 30.5+/-14.2 kg, respectively. The patients were divided into two groups: 1) Group I comprised 17 patients with pulmonary arterial stenoses, 2) Group II comprised four patients with venous stenoses (one belonged to both groups). Sixteen patients underwent recatheterization at a median of 5.8 months (range 0.5 to 31, mean 8.1 months) after stenting. Hemodynamic and angiographic changes after the interventional procedures and complications were documented. RESULTS: All the stents were successfully deployed in the intended position. In Group I, the narrowest diameter of the stented vessel increased from 4.1+/-1.5 to 8+/-2 mm (95% increase, p < 0.0001) while the systolic pressure gradient across decreased from 24.6+/-15.8 to 12.1+/-11.4 mm Hg (51% decrease, p = 0.001). In Group II, the dimensional changes of the narrowest segment increased from 4.3+/-0.5 to 7.5+/-0.4 mm (75% increase, p = 0.003), and the pressure gradient reduced from 5.0+/-2.9 to 0.9+/-1.0 mm Hg (82% decrease, p = 0.04) across the stented venous channel. Distal migration of two optimally positioned stents occurred within 24 h of implantation. At recatheterization, significant neointimal ingrowth (>30% of the expanded diameter) was noted in 7 (28%) of the 25 implanted stents. This responded poorly to balloon dilation. Predisposing factors for the neointimal ingrowth included stents of smaller diameter (<9 mm) and longer period after implantation. CONCLUSIONS: Self-expanding Wallstent could be deployed easily and safely to relieve vascular stenoses in children. The complications of distal migration, significant neointimal ingrowth and its unyielding design to overdilation limit its application to this patient group.

Adolescent↗
PubMed1998

Kawasaki disease in the older child.

OBJECTIVES: To determine the prevalence of Kawasaki disease in older children and to evaluate its clinical presentation, time to diagnosis, and outcome in comparison with younger patients with the disease. METHODOLOGY: A retrospective analysis of all patients discharged with a diagnosis of Kawasaki disease at a pediatric tertiary care hospital over a 12-year period. RESULTS: A total of 133 patients were included in this study; 7.5% were 9 years of age or older at the time of illness. Patients were grouped by age: infants included children age 1 to 8 years of age and children 9 years of age or older. Older children had a higher frequency of abnormal cardiovascular physical examination (50%) versus children (6%) and infants (10%). The older age group and the infants had a higher prevalence of coronary artery abnormalities and poor left ventricular function than did the 1- to 8-year-olds. Eighty percent of the older children had coronary arteries that were either dilated or aneurysmal, and 30% demonstrated left ventricular dysfunction on initial echocardiography. The number of days to diagnosis after meeting the diagnostic criteria was 5.8 +/- 2.3 for infants, 5.2 +/- 1.5 for older children, and 1.9 +/- 0.3 for children. Older children had a complicated course of Kawasaki disease compared with younger patients. CONCLUSION: We found a higher prevalence of older children with Kawasaki disease at our center than has previously been reported. Older patients, as well as infants, had a higher rate of coronary artery abnormalities than did the children between 1 and 8 years of age. Older age at the time of illness or a delay in treatment may be important factors in determining cardiac involvement in Kawasaki disease.

Age Distribution↗
PubMed1995

Technology assessment of nonsurgical closure of patent ductus arteriosus: an evaluation of the clinical effectiveness and costs of a new medical device.

OBJECTIVE: To assess the clinical efficacy and cost impact of a new medical device for the nonsurgical closure of patent ductus arteriosus (PDA). METHODS: This was a before-after study comparing the most recent 20 surgical procedures with the first 20 nonsurgical procedures for PDA using a new medical device. Clinical outcome, hospital stay, device cost, and physician fees were compared. RESULTS: Surgical closure was effective in all 20 patients, with an average cost of $4667. In a similar patient group, nonsurgical closure was achieved in 18 of 20 patients (90%), with an estimated average cost per successful procedure of $4690. A clinically insignificant PDA leak persisted beyond 12 months in four nonsurgically managed patients. CONCLUSION: Nonsurgical closure of PDA can be recommended as an effective new medical technique that is not associated with a measurable increase in direct costs and that provides significant indirect and intangible cost advantages.

Cardiac Catheterization↗
PubMed1994

Trends in the prevalence of congenital heart disease: comprehensive observations over a 24-year period in a defined region of Canada.

OBJECTIVE: To determine the prevalence of congenital heart disease (CHD) in the three Maritime provinces, and to study prevalence differences among provinces and defined regions within these provinces. DESIGN: Each province was divided by counties into regions. All cases of CHD who were born alive in the study area between 1966 and 1989 were entered in a registry. Prevalences were analyzed for each province and for selected regions per year, per 1000 live births, and by diagnosis made by one year of age and by the 16th birthday. Comparison was then made with prevalences of a group who had severe lesions. INTERVENTIONS: Excepting a small number of CHD cases who were diagnosed by autopsy only, diagnosis was made by pediatric cardiologists using appropriate procedures, including cardiac ultrasound and cardiac catheterization. SETTING: The only tertiary care centre for children's heart disease in the provinces of Nova Scotia, New Brunswick and Prince Edward Island, areas of relative geographic isolation (combined population of 1.75 million people). MAIN RESULTS: A statistically significant positive linear trend occurred in these provinces during the study. The recorded prevalence of CHD in New Brunswick was significantly lower. Pooled prevalences by the first and 16th birthdays (8.0 and 12.5 per 1000 live births, respectively) of two regions of highest prevalence for 1980-86 were significantly higher (P < 0.05) than the pooled prevalence rate of all the remaining regions. Prevalence rates of a group with severe lesions were stable for 1976-86 in all regions. CONCLUSIONS: Differences in prevalence of CHD among provinces and regions were related to ascertainment levels. Prevalence of CHD with diagnosis by the first and 16th birthdays were approximately 8.0 and 12.5 per 1000 live births, respectively. The prevalence rate of a severe lesion group was a stable measure.

Adolescent↗
PubMed1992

Assessment of blood pressures and gradients by automated blood pressure device compared to invasive measurements in patients previously operated on for coarctation of the aorta.

The aim of the study was to compare invasive and non-invasive blood pressure measurements and gradients. Twenty-two children and 16 adults previously operated for coarctation of the aorta were included. Invasive blood pressures were recorded proximally and distally close to the former operation site and non-invasive systolic blood pressures were recorded by an automated sphygmomanometer on right arm and leg. The adults were investigated at rest and during supine exercise. The correlation between invasive and non-invasive measurements of proximal blood pressures in adults at rest and children were the following, r = 0.92, SD 7.6 mmHg (n = 16) and r = 0.85, SD 11 mmHg (n = 22) respectively. The corresponding correlation for the distal blood pressures were the following for adults at rest 0.64, SD 11.9 mmHg and in children r = 0.82, SD 9.2 mmHg. During exercise in adults we found a low correlation when comparing invasive and non-invasive proximal and distal blood pressures and a poor correlation regarding the gradients, r = 0.50, SD 16 mmHg, r = 0.45, SD 15.9 mmHg and r = 0.30, SD 22.9 mmHg respectively (n = 16). We also measured the time interval between cessation of exercise and completion of the blood pressure recordings, which gave a mean interval of 73 sec (range 45-115 sec). During that interval the mean fall in the proximal blood pressure was 37 mmHg (range 20-80 mmHg), and the mean fall of the gradient was from 41 mmHg (range 20-76 mmHg) to 23 mmHg (range 6-56 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Doppler echocardiographic and morphologic evaluation of patients following operative repair of aortic coarctation.

Sixty-six patients operated on previously for coarctation of the aorta were included in the study. There were 50 children and 16 adults. Invasive and non-invasive gradients were recorded. Anatomical obstruction was evaluated by angiography in 54 patients and the numbers and size of collaterals were quantified. The closest correlation was found between Doppler-estimated gradients and invasive peak-instantaneous gradients (r = 0.87). The relation between anatomical obstruction and invasive peak-to-peak gradients, Doppler gradients and diastolic flow ere discouraging (r = 0.64, 0.54 and 0.35). Liberal indications for angiography or magnetic resonance tomography are recommended.

Adolescent↗
PubMed1991

Quantification of left to right shunts by echo Doppler cardiography in patients with ventricular septal defects.

Thirty-one patients with ventricular septal defect were evaluated with Echo Doppler cardiography and colour flow mapping. The ventricular septal defect area was estimated by measurement of the jet diameter by colour flow mapping. The ventricular septal defect flow was calculated as the product of the cross-sectional area of the ventricular septal defect and the velocity time integral of flow through the defect. In ten patients the diameter obtained by colour flow mapping was compared with the diameter obtained at angiography, r = 0.88 (SD = 0.14 cm). The aortic flow was calculated as the product of left ventricular outflow tract cross-sectional area and the corresponding velocity time integral. QP/QS ratio was estimated as (ventricular defect flow + aortic flow)/aortic flow and compared to estimates by a radionuclide or oximetric method. A correlation of r = 0.95 (SD = 0.23) was found.

Adolescent↗
PubMed1990

Noninvasive estimation of aortic valve areas in children with aortic stenosis.

Fifteen children with aortic stenosis were examined with Echo-Doppler cardiography in order to evaluate the use of the continuity equation to calculate the aortic valve area. The results were compared to invasive estimates of valve area calculated with the Gorlin's equation. A close correlation between the two methods, r = 0.94, was found and it is concluded that even in children an accurate estimate of valve area can be expected with the use of the continuity equation.

Adolescent↗
PubMed1990

Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot.

Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis.

Child↗
PubMed1989

Echocardiography by telephone--evaluation of pediatric heart disease at a distance.

A 24-hour telephone transmission service was established for pediatric echocardiography between a general hospital and a children's hospital 500 km distant. Studies were transmitted in real time for interpretation and diagnosis by a pediatric cardiologist. In the first 9 months of operation, studies were transmitted for 18 children with a median age of 5 months. Image and sound quality was excellent. Complete segmental diagnosis was made in 16 patients, and further study was needed in 2 others. In 8 of the 18 patients a new diagnosis was provided, and in 10 patients diagnosis was confirmed. Congenital heart disease was found in 12 patients, other heart disease in 2 and a normal heart in 4. The population included 2 fetuses whose echocardiograms showed hypoplastic left heart and intracardiac tumor. In 4 patients transport was avoided. This is the first report of echocardiographic transmission by telephone, which was shown to be clearly feasible, cost-effective and diagnostic. It provides emergency access to specialist expertise, and may avoid hazardous and expensive transport of ill children.

Echocardiography↗
PubMed1989

Infective endocarditis in South African children.

The clinical and laboratory findings in 29 children with infective endocarditis over the past 10 years are reviewed retrospectively. Twenty children (70 per cent) had congenital heart disease, five (16 per cent) had rheumatic heart disease, and four (14 per cent) had no underlying cardiac abnormality prior to presentation. Twelve (41 per cent) patients had undergone cardiac surgery prior to developing endocarditis. The most common causative organisms were Staphylococcus aureus, Staphylococcus epidermidis, and viridans streptococci none of which was associated with a significantly greater mortality. There was a high case fatality rate of 35 per cent of children below the age of 6 months and children without an underlying cardiac abnormality were particularly at risk. There is a need for standardization of diagnostic criteria for infective endocarditis to facilitate accurate collaborative epidemiological investigation.

Adolescent↗
PubMed1988

Circulating megakaryocytes and platelet production in children with congenital cardiac defects undergoing cardiac catheterisation.

The literature has recently focused attention on the lung as a source of platelet production. Thirty-two children with normal lungs admitted to hospital for investigation of congenital heart disease were studied with the intention of showing a relationship between left atrial platelet counts and pulmonary blood flow. This was not demonstrated. Mean platelet counts were 296 X 10(9)/l (right atrium) and 304 X 10(9)/l (left atrium). There was no significant difference between the two results. It is suggested that previous studies were performed on subjects with significant acquired disease and that in young children with no pulmonary disease the lung is not a major source of platelet production.

Cardiac Catheterization↗
PubMed1988

Immunological abnormalities in children with acute rheumatic carditis and acute post-streptococcal glomerulonephritis.

Immunological functions were investigated in 10 children with acute rheumatic fever and 11 children with acute nephritis to try and elucidate the cause of heart damage in acute rheumatic fever. Children with acute rheumatic fever and carditis showed an increase in serum IgG, IgA and antistreptococcal antibodies during the acute stage. Lymphocyte transformation responses to phytohaemagglutinin and streptococcal antigens were reduced but this was due to a serum suppressor effect. After recovering from acute rheumatic fever a lymphocytosis and an increased lymphocyte blastogenic response to streptococcal antigen were found. T-cells, T-helper cells and T-suppressor cells showed some changes in acute rheumatic fever but these were not statistically significant in our study. None of the changes in immunological responses that were seen in acute rheumatic fever were found in acute nephritis. These results support the hypothesis that an abnormal immune response to streptococcal products is involved in the development of carditis and the other phenomena observed in acute rheumatic fever.

Adolescent↗
PubMed1988

Management of pulmonary atresia or critical pulmonary stenosis and intact ventricular septum with a small or hypoplastic right ventricle.

Twenty-one neonates and infants less than 3 months old undergoing cardiac surgery for an obstructed right ventricular outflow tract, intact ventricular septum and a small or hypoplastic right ventricle were retrospectively analyzed, in order to assess the effects of a change in management protocol. Seven of the 8 patients with critical pulmonary stenosis survived surgery using a transannular outflow patch, whereas only 1 of the 8 patients with pulmonary atresia survived the same operation. Two patients in the latter group died 2 and 3 months after surgery but with complications arising from surgery. Of 5 patients with pulmonary atresia who had a modified Blalock Taussig shunt, 3 patients survived the surgery and were discharged home. These results significantly indicate that there is an unacceptably high mortality for the relief of pulmonary atresia (with intact septum) using a transannular outflow patch, and a Blalock Taussig shunt is the preferred operation. The transannular outflow patch is a safe operation for neonates with critical pulmonary stenosis, irrespective of the size of the right ventricle.

Cardiac Catheterization↗
PubMed1988

Effect of kwashiorkor on the cardiovascular system.

In kwashiorkor the heart is clinically and radiologically small. This study utilises echocardiography, a tool not previously used in this disease, to show that this is due to decreased muscle mass.

Child, Preschool↗
PubMed1987

The problem of compliance in rheumatic fever.

During a 12-month period 115 patients defaulted from a rheumatic fever clinic, so a study was undertaken to identify factors related to non-compliance by comparing defaulters with a group of 50 regular attenders. Those defaulting were significantly more likely to be coloured, male, and over 12 years old. They lived 10-99 km from the hospital, were on several drugs and despite more frequent appointments, usually had a record of poor attendance. The severity of the underlying heart disease and use of parenteral penicillin did not affect compliance. Since the use of regular penicillin prophylaxis for the secondary prevention of rheumatic fever is an essential step in reducing the prevalence of rheumatic heart disease, rheumatic fever clinics should be structured to address the needs of adolescents. Furthermore, the use of neighbourhood clinics for routine therapy between visits to a rheumatic fever clinic is essential to improve compliance.

Adolescent↗
PubMed1987

Hypertrophic cardiomyopathy in infancy and childhood.

Hypertrophic cardiomyopathy (HCM) presented in 10 children under 2 years of age (group 1) and in 5 between 3 and 8 years (group 2). The clinical, ECG, chest radiographic and echocardiographic features are reviewed and prognosis over a mean follow-up period of 3.5 years is reported. Patients in group 1 had more symptoms and 7 had evidence of heart failure at some stage; all had ECG abnormalities. Group 2 patients presented with murmurs and only 1 had heart failure. Medical management of these patients is discussed and the importance of accurate diagnosis stressed, since HCM may have a poor prognosis in childhood; 3 out of 15 patients have died.

Cardiac Catheterization↗