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Biomedical subjects

R M Lauer

Publications and source records attributed to R M Lauer.

At least 91 records · Page 5Linked to original sources
PubMed1982

Repair of large ventricular septal defects in infants and small children.

It is possible to achieve excellent results for primary closure of ventricular septal defects regardless of the age of the patients when surgical intervention is required. Thirty-two severely symptomatic patients, age 1-24 months, with large ventricular septal defects (m Qp/Qs = 3.4, m R VSD = 4.0), had primary repair of the defects with one (3%) hospital death. Seven patients (22%) had increased pulmonary vascular resistance ranging from 5.4 to 12 units/m2. It was possible to close the ventricular septal defect through the right atrium in 26 patients (81%). Pulmonary artery banding was not performed in any patient with isolated ventricular septal defect during the period of this study. The 31 survivors have been followed an average of four years, and 30 of them are remarkably improved and remain New York Heart Association Class I or II. Only one patient, with obstructive pulmonary vascular disease (pulmonary resistance = 12 U/m2), died suddenly 16 months after operation. Follow-up catheterization was offered to all patients, and to date, 18 (60%) have been restudied. These hemodynamic data show that pulmonary vascular resistance after surgery is usually normal or only minimally elevated; except for one patient with a large residual ventricular septal defect, functionally significant left to right shunts were eliminated. These results and the analysis of results of combined series reported in the literature for primary and staged operations for the continued practice of primary repair of isolated large ventricular septal defects in infants and children who require surgery.

Age Factors↗
PubMed1982

Coronary artery disease mortality in relatives of hypertriglyceridemic school children: the Muscatine study.

From 2655 healthy school children participating in the 1973 and 1975 Muscatine Coronary Risk Factor School surveys, two groups of index cases were selected for a detailed family study of coronary mortality: a group with fasting triglyceride levels greater than the ninetieth percentile on both surveys (n = 75) and a group with triglyceride levels less than the tenth percentile on both surveys (n = 47). Coronary mortality in adult (age 30 years or older) first- and second-degree relatives was not different between the two groups. When the families of the high-triglyceride group was further subdivided based on the cholesterol percentile of the index child, greater coronary mortality was observed in the relatives of index cases with high cholesterol (higher than the seventy-fifth percentile). This study suggests that family members of children with elevated triglyceride and low cholesterol levels do not have excess coronary mortality.

Adult↗
PubMed1982

Electrocardiographic measures of left ventricular hypertrophy in children across the distribution of blood pressure: the Muscatine study.

We sought to test the effectiveness of the ECG as a measure of increased left ventricular wall mass in children with high blood pressure. One hundred eighty-one children, ages 9-18 years, were selected from the lowest, middle and highest quintile of systolic blood pressure from the Muscatine Study, based upon two biennial school screenings. After correction for age, sex, height, weight and skinfold thickness, children with the highest blood pressure had increased echocardiographic left ventricular wall mass (p less than 0.02). Voltage measurements of maximum R and S waves in the standard and precordial leads were measured by computer. We correlated blood pressure and echocardiographic measurements of the interventricular septum, left ventricular posterior wall and left ventricular wall mass to electrocardiographic combinations used to predict left ventricular hypertrophy in both children and adults. The electrocardiographic correlations ranged from -0.01 to + 0.17. Poor correlations were found between electrocardiographic measures and blood pressure, left ventricular wall thickness or left ventricular wall mass. Skinfold thickness and weight had negative correlations, suggesting a damping effect upon measured voltage. We conclude that the echocardiogram is a more sensitive measurement of increased left ventricular mass than the ECG in children with elevated blood pressure.

Adolescent↗
PubMed1982

Forearm vascular resistance in the upper and lower quintiles of blood pressure in adolescent boys: The Muscatine Study.

Nineteen 16 year old white boys whose systolic blood pressures were in the upper (r = 9) and lowest (r = 10) quintile of the distribution in two school surveys in 1975 and 1977 were selected. In 1979 forearm blood flow, blood pressure and heart rate were measured at rest, and during peak reactive hyperemia. Minimal forearm vascular resistance during peak reactive hyperemia was used to assess the structural contribution to vascular resistance. At rest the high quintile group again had significantly higher blood pressures than the low quintile group but their forearm vascular resistance was not significantly different. The high quintile group showed significantly higher minimal forearm vascular resistance at peak reactive hyperemia. The latter observation suggests that there is a difference in the structural contribution to forearm vascular resistance in adolescents with blood pressure in the upper versus lower quintile of the distribution.

Adolescent↗
PubMed1981

Vasectomy and coronary disease in men less than 50 years old: absence of association.

Because recent experiments in primates suggest a relationship between vasectomy, and the development and promotion of atherosclerosis a case control study was performed to explore this possibility in humans. The prevalence of prior vasectomy was determined in 55 men less than 50 years old with onset of documented coronary disease and in a matched control group of close relatives (45 brothers and 10 first cousins) free of coronary disease. The prevalence was the same in each group, 25.5 per cent (14 of 55), and there was no significant difference between study groups in the mean interval since vasectomy. Thus, within the limitations of this study no association of coronary disease with prior vasectomy was found. Further work is needed to evaluate whether the animal findings pertain to humans.

Coronary Disease↗
PubMed1981

Effect of mitral valvular regurgitation on transthoracic impedance cardiogram.

Mitral valvular regurgitation consistently modified the wave form of the first derivative of the transthoracic impedance cardiogram. The transthoracic impedance cardiogram was recorded in 23 control subjects (group 1), and 23 patients with isolated mitral regurgitation (group 2). Simultaneous transthoracic impedance cardiogram, electrocardiogram, and mitral valve echocardiograms in group 1 showed that the primary diastolic wave ("O") of the transthoracic impedance cardiogram occurred synchronously with the maximal opening of the mitral valve. In group 2, the primary systolic wave (dZ/dt max) was diminished, and the "O" of the transthoracic impedance cardiogram was raised. The area under the systolic wave of the transthoracic impedance cardiogram (S) and the area under the diastolic opening of the transthoracic impedance cardiogram (D) were measured and the ratio D/(D + S) calculated. This ratio, called the mitral regurgitation fraction was (0.50 +/- 0.14) in group 2 which was higher than that found in group 1 control subjects (0.11 +/- 0.08). The mitral regurgitation fraction (15 to 77%) determined by the impedance method was closely correlated with the mitral regurgitation fraction (20 to 74%) obtained during cardiac catheterisation; it also increased during isometric handgrip and decreased during amyl nitrite inhalation. In three mitral regurgitation patients the transthoracic impedance cardiogram returned to normal configuration after surgical implantation of a prosthetic mitral valve. These data suggest that the transthoracic impedance cardiogram is quantitatively altered in patients with mitral regurgitation.

Adolescent↗
PubMed1981

Coronary risk factors in children.

Arteriosclerosis and its complications are the leading cause of death in American adults today. There is ample evidence to show that the pathologic process begins process begins in childhood. In addition, coronary risk factors can be identified in childhood and may be maintained to some degree into adulthood. Thus, prevention should logically begin in the childhood years. A small reduction of serum cholesterol levels in all children by a modest change in diet has the potential for reducing coronary risk. More severe dietary restriction, in some cases in conjunction with medication, is recommended for high-risk pediatric populations only. In addition, surveillance of blood pressure, avoidance of cigarette smoking, weight control, and a program of regular physical exercise are prudent recommendations for all children.

Adolescent↗
PubMed1981

Single ventricle with aortic outflow obstruction: operative repair by creation of double outlet to the aorta and application of the Fontan principle.

A new operation is described which allows the Fontan procedure to be used in patients having single ventricle accompanied by aortic outflow obstruction. Connection of the proximal pulmonary artery and valve to the aorta via a tubular prosthesis provides a second outlet of the ventricle to the aorta in order to effectively bypass subaortic obstruction. Anastomosis of a distal pulmonary artery to the right atrium and closure of the atrial septum by patch (Fontan procedure) complete the establishment of unrestricted pulmonary and systemic circulations in series.

Adolescent↗
PubMed1981

Modified Fontan procedure. Methods to achieve direct anastomosis of right atrium to pulmonary artery.

Experience with Fontan operations suggests that techniques which utilize autogenous structures exclusively to achieve right atrium-pulmonary circuit connection may be preferred. Valves probably are not required in the circuit and in some cases have become obstructive with time. A large-diameter direct anastomosis of the right atrium to the pulmonary artery nearly always is possible and provides a modification of the Fontan procedure which combines favorable qualities of simplicity, all autogenous material, and posterior position which is free of the risks of compression. There also may be improved hemodynamics with this modification. Options to achieve this anastomosis depending on relations of the great arteries, previous operations, and other anatomic variations are described in eight patients.

Adolescent↗
PubMed1980

Hypoplastic left heart syndrome: successful palliation with a new operation.

A new operative procedure is described for the palliation of hypoplastic left heart syndrome. The operation consists of anastomosis of a tubular prosthesis between the proximal pulmonary artery and the aortic arch. A calibrated opening in the graft is brought into continuity with the distal pulmonary artery to provide balanced pulmonary and systemic blood flow. The atrial septum is excised and the ductus arteriosus ligated. A successful case report documents that this operation satisfies criteria required to reverse heart failure in infants with hypoplastic left heart syndrome.

Aorta, Thoracic↗
PubMed1979

Measurement criteria for group echocardiographic studies.

This study reports the reproducibility achieved both within an observer and between observers measuring left heart echocardiographic dimensions using standard measurement criteria in school age children. These criteria define acceptable interfaces as: 1) a single dominant line; 2) continuity at the point of measurement of at least 5 mm in length; and 3) display of specific motion characteristics for the cardiac structure to be measured. The within observer intraclass correlation coefficient for interventricular septum, diastolic dimension, systolic dimension, left ventricular posterior wall, left atrium and aorta averaged 0.94 (range 0.87--0.98). The coefficient of variation averaged 3.6% (range 2--7.5%). The least reproducible dimension was left ventricular posterior wall. The day-to-day variability within a single subject of echocardiographic determined cardiac dimensions was small for all measurements. The standard deviation of error for all variables was no more than 0.3 mm. A system using screening criteria and standardized measurement techniques can provide the degree of precision necessary to begin investigating echocardiographic differences in group studies.

Adolescent↗
PubMed1979

Increased coronary mortality in relatives of hypercholesterolemic school children: the Muscatine study.

From 2,874 school children participating in the 1971 and 1973 Muscatine Coronary Risk Factor Survey, we selected three groups of index cases for detailed family study: the HIGH group (n = 56), with cholesterol levels greater than the 95th percentile twice; the MIDDLE group (n = 46), cholesterol levels between the 5th and 95th percentile; and the LOW group (n = 46), cholesterol levels less than the 5th percentile twice. Coronary mortality determined from death certificates was increased in the young relatives (ages 30-59) of the HIGH group index cases, as follows: twofold excess in HIGH male relatives compared with the MIDDLE or LOW group (p less than 0.05); tenfold excess in the HIGH female relatives compared with the MIDDLE and LOW group combined (p less than 0.01). After correction for years at risk, there was an approximately twofold significantly-increased coronary mortality. Stroke mortality was higher, although not significantly, in the older relatives (ages greater than or equal to 60) of the HIGH index cases. Cancer mortality was not significantly different among the relatives of the three groups of index cases. This study indicates that school children's cholesterol levels cluster with those of their family members and that persistent hypercholesterolemia in children identifies families at risk for coronary artery disease.

Adolescent↗
PubMed1979

Septation of the univentricular heart. Transatrial approach.

The technique of septation of the univentricular heart via a transatrial approach is described in detail. Clinical details of four patients having Type A-III univentricular heart document the feasibility of working through the right-sided atrioventricular valve to place a cloth prosthesis into the ventricle to divide it into approximately equal chambers. Improved hemodynamics were observed in the postoperative period, which probably were related to retaining the integrity of the ventricular wall. This approach seems best suited to the ventricular chamber estimated to be large by echocardiography without severe pulmonary outflow tract obstruction. Techniques for enlargement of the pulmonary outflow tract are also described.

Adolescent↗