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Biomedical subjects

A R Castaneda

Publications and source records attributed to A R Castaneda.

At least 145 records · Page 8Linked to original sources
PubMed1980

Left ventricular function after repair of tetralogy of fallot and its relationship to age at surgery.

Left ventricular (LV) work-function curves were used to assess LV performance in eight postoperative tetralogy of Fallot (TOF) patients who underwent repair before 2 years of age (group 1) and 12 patients who underwent repair after 2 years of age (group 2). All patients were without significant residual shunts or pulmonary stenosis. Results were compared with those in seven control patients. Left- and right-heart hemodynamics were measured at various levels of afterload induced by methoxamine while heart rate was maintained constant. Cardiac output was serially measured. The slope (m) for each patient's LV end-diastolic pressure (EDP) vs LV minute-work index (MWI) relationship was determined. There were no significant differences in resting cardiac index, LV systolic pressure, LVEDP, aortic oxygen saturation or MWI among the groups. However, with afterload stress, group 2 patients had abnormal work-function curves with depressed slopes (m = 0.21 +/- 0.04) compared with the values for group 1 patients (m = 0.89 +/- 0.13, p less than 0.001) or the control group (m = 1.13 +/- 0.12, p less than 0.001). Thus, LV dysfunction unmasked by an afterload stress was present in the older TOF patients but not in the patients repaired during infancy. These findings raise the possibility that early, definitive repair of TOF may help preserve postoperative LV function.

Adolescent↗
PubMed1980

Surgical management of multiple ventricular septal defects.

Between Jan. 1, 1973, and June 1, 1979, 29 patients underwent surgical closure of multiple ventricular septal defects (VSDs). Included are 19 patients with VSDs only (one death), five with tetralogy of Fallot (TF) (0 deaths), two with transposition of the great arteries and VSD (TGA/VSD) (one death), two with complete atrioventicular (AV) canal (one death), and one with common atrium (one death). The overall hospital mortality rate was 14% (4/29) and was significantly related to the complexity of the underlying malformation (p = 0.01) and the presence of major associated cardiac lesions (p = 0.005). The incidence of reoperation for overlooked VSDs was 28% (8/29) and was significantly related to the presence of muscular VSDs (all overlooked defects were muscular) and the failure preoperatively to diagnose multiple VSDs (p = 0.05). Of patients with shunt data available after the final operation, 85% (17/20) had a Qp/Qs less than or equal to 1.5, and no patient had a final Qp/Qs > 2.0. This experience indicates that satisfactory results usually can be achieved after operation for multiple VSDs and emphasizes the value of early assessment for residual shunting and reoperation when indicated.

Child↗
PubMed1980

Early pulmonary vascular changes in congenital heart disease studied in biopsy tissue.

Patients with congenital heart defects who had or were at risk for developing pulmonary artery hypertension underwent lung biopsy at the time of intracardiac repair. In 95 consecutive patients with either ventricular septal defect, d-transposition of the great arteries, or a defect of the atrioventricular canal, the pulmonary arteries were evaluated microscopically by quantitative morphologic techniques, and the findings were correlated with hemodynamic data obtained at a recent preoperative cardiac catheterization. Three grades of severity of early pulmonary vascular changes were identified, which correlated with hemodynamic evidence of progressive functional impairment. Grade A denotes cases with abnormal extension of muscle into peripheral arteries only; pulmonary blood flow is increased but pulmonary artery pressure is normal. In grade B an increased medial wall thickness of the normally muscular arteries is also present, and in these cases pulmonary artery pressure is also increased. Grade C denotes cases in which in addition to the findings in grade B disease there is a reduction in the number of small peripheral arteries; in these cases pulmonary vascular resistance is increased. Follow-up postoperative hemodynamic evaluation will reveal the significance of these changes in reflecting irreversible functional impairment of the pulmonary vascular bed.

Adolescent↗
PubMed1979

Double outlet from chambers of left ventricular morphology.

This series of 5 cases with double outlet of morphologically left ventricular chamber includes 4 found during a review of 1700 heart specimens (incidence 0.23%) and 1 found at operation and successfully corrected. Abnormal atrioventricular connection precluding total correction was present in the 4 anatomical cases. Clinical diagnosis may be difficult and it is suggested that axial cineangiography may make anatomical diagnosis easier. Absence of the infundibular septum and aortic laevoposition are frequent. As some cases can be surgically corrected, accurate information is required on the size of the right ventricle, the morphology and function of the atrioventricular valves, the presence, size, and position of the ventricular septal defect, and the degree and type of outflow tract obstruction.

Heart↗
PubMed1979

Intraoperative recording of specialized atrioventricular conduction tissue electrograms in 47 patients.

Intraoperative mapping of the specialized atrioventricular conduction system was performed in 47 patients during cardiac surgery. Specialized conduction tissue electrograms were identified in 37, and atrioventricular conduction preserved in 92%. Specialized conduction tissue was identified in 27 patients with atrioventricular canal defect: complete heart block was avoided in 25. Conduction tissue was located in six of 12 patients with complex transpositions; atrioventricular conduction was preserved in all six. Other lesions in which the technique was useful were Ebstein's anomaly and single atrium. Limitations to the technique are 1) deep hypothermia and circulatory arrest; 2) interruption in atrioventricular conduction during mapping; 3) inadequate exposure and access to probable sites of conduction tissue; 4) variation of size and spatial relations of individual malformations; and 5) limited time for identification of unusually located conduction tissue. Indications for use of this technique include patients with both forms of atrioventricular canal, complex transpositions, atrioventricular discordance, single ventricle and single atrium.

Adolescent↗
PubMed1979

Cerebral anoxia: effect of deep hypothermia and pH.

Deep hypothermic circulatory arrest facilitates repair of congenital cardiac anomalies in infants. It is known empirically that hypothermia protects against central nervous system (CNS) ischemic damage. The Q10O2 is only 2.2 for brain and thus a decrease in metabolic rate does not fully account for protective effects of hypothermia. Since enthalpy of dissociation of H2O is high (approximately 7 kcal/mole), its pH is temperature dependent (7.0 at 25 degrees C, 7.4 at 20 degrees C) and hypothermia may in part protect by its influence on hydrogen ion concentration. A manifestation of CNS susceptibility to ischemia is an obstruction of the microcirculation [no-reflow lesion (NRL)] demonstrated by infusion of carbon black into the cerebral circulation after a period of circulatory arrest. White lesions (NRL) against a gray background on cut section of brain increase in size with increasing time of arrest. The effect of anoxia versus circulatory arrest, brain temperature, and extracellular brain pH on NRL was studied in 45 mongrel dogs, subjected to varying periods of N2-induced anoxia on cardiopulmonary bypass (CPB) at 37 degrees C or 20 degrees C. In some studies jugular venous pH was adjusted by infusion of NaHCO3 or HCl. Control groups included normothermic CPB without anoxic and normothermic CPB, anoxia, and equimolar NaCl infusion. NRL was quantified by planimetry of photographs of cut sections of brain. These results confirm that NRL is abated by hypothermia and suggest that (1) NRL is a function of anoxia and not arrested circulation since perfusion with N2 at 37 degrees C does not protect the brain (i.e., NRL is not solely related to "critical reopening pressure") and (2) NRL is in part a function of extracellular pH.

Animals↗
PubMed1979

Modified Senning operation for treatment of transposition of the great arteries.

Since February, 1978, 42 infants ranging in age from 15 days to 16 months (mean age 6 months) and weighing between 2.0 and 9.0 kg (mean weight 5.8 kg) underwent a modified Senning I operation. Eleven (26%) underwent operation during the first 3 months of life. Twenty-nine patients had dextro-transposition of the great arteries (d-TGA) and an intact ventricular septum (Group I), and 13 patients had d-TGA and a large ventricular septal defect (VSD) (Group 2). In addition to the Senning I procedure, 13 patients had transatrial closure of their VSD, eight had ligation of a patient ductus arterioses, two had removal of a pulmonary artery band, and four had trans-pulmonary artery resection of short-segment subpulmonary stenosis. Modification of the original Senning operation included (1) patch augmentation (pericardium or Gore-Tex) of the atrial septal flap and (2) pericardial patch enlargement of the pulmonary venous pathway. One patient in Group 1 (3%) and two patients in Group 2 (15%) died after operation. A 2-week-old infant (Group 1) was treated with prostaglandin E1 (PGE) for 2 weeks before operation. The other hospital deaths (Group 2) occurred in a 2-month-old infant with advanced ischemic damage to the right ventricle and a 4-month-old child with multiple VSDs and Grade IV pulmonary vascular disease. No caval gradients were found after modification of the right atrial incision. Two patients died later from pulmonary venous obstruction, one during attempted recatheterization and the other after repair of the pulmonary venous obstruction. One patient had transient complete heart block, and four were discharged in junctional rhythm. Thirty-four patients (87%) were in regular sinus rhythm when released from the hospital. Postoperative catheterizations in eight patients showed no significant gradients in six and severe pulmonary venous obstruction in two (late deaths). More late postoperative results are required, including postoperative catheterization and electrophysiological studies, before the relative merits of the Senning versus the Mustard operation can be assessed.

Cardiopulmonary Bypass↗
PubMed1978

Early and late results with the Mustard operation in infancy.

Eighty-one patients, ranging in age from 36 hours to 24 months and in weight from 2.5 to 12 kg had a Mustard operation for D-transposition of the great arteries (D-TGA) (20 with complex D-TGA) using either deep hypothermic circulatory arrest (68 patients) or conventional cardiopulmonary bypass (13 patients). A Dacron patch was used for the intraatrial baffle and pericardium for augmentation of the pulmonary atrium. Ten patients died following operation. Thirty-two patients had cardiac catheterization 1 year after operation. Of 24 patients with D-TGA and intact ventricular septum, 23 had normal pulmonary artery pressures. In 20 patients left ventricular outflow tract gradients decreased from a mean of 32 mm Hg to a mean of 18 mm Hg after operation. Five patients who had D-TGA and ventricular septal defect and systemic pressures in the left ventricle before operation, had a notable decrease in left ventricular pressures after the procedure. Seven patients required reoperation for baffle obstruction. Mortality following Mustard repair was primarily related to the complexity of the lesion, maturity of the infant, and degree of pulmonary vascular changes. Caval obstruction was related to the configuration of the baffle used in the early part of this series.

Blood Pressure↗
PubMed1978

Growth after surgical repair of simple D-transposition of the great arteries.

The effect of the Mustard procedure on growth was assesed in 45 patients with simple D-transposition of the great arteries (DTGA) surviving for at least one year after operation. Growth failure (below the third percentile for height, weight, or both) was found in 25 of the 45 patients preoperatively and in 8 patients postoperatively. The principal factors associated with poor growth before repair were advancing age, increased pulmonary and systemic flow, and subpulmonic stenosis. In those patients without postoperative growth failure, growth had returned to the normal range within two years. All patients wit retarded growth after the Mustard procedure had had preoperative growth failure as well. In addition, all 8 patients with postoperative growth failure had one or more amjor residual hemodynamic abnormalities, whereas residual lesions were present in only 10 of 37 patients with normal postoperative growth.

Age Factors↗
PubMed1978

Left ventricular function following attempted surgical repair of tetralogy of Fallot.

Left ventricular function was assessed by angiographic methods in 40 patients (ages 3-27), 1-12 years following repair of tetralogy of Fallot. Twenty of the 40 patients (group A) had a satisfactory repair with a pulmonary-systemic flow ratio (Qp/Qs) less then or equal to 1.5 and a right ventricular systolic pressure of less than or equal to 60% of the left ventricular value. The other 20 patients (group B) had a Qp/Qs greater than 1.5 and/or a right ventricular systolic pressure greater than 60% of the left ventricular value. Group A patients had a normal left ventricular end-diastolic volume (LVEDV), end-diastolic pressure (LVEDP), ejection fraction (LVEF), and mass (LVM), while the group B patients had significantly elevated LVEDV, LVEDP, LVM, and a significantly depressed LVEF. These findings indicate that patients with a satisfactory hemodynamic repair of tetralogy of Fallot have normal left ventricular function while patients with postoperative unsatisfactory hemodynamics have significantly impaired left ventricular function.

Adolescent↗
PubMed1978

Lung biopsy in congenital heart disease: a morphometric approach to pulmonary vascular disease.

Fifty patients with congenital heart disease, ages 2 days-30 years (median 12 months) at cardiac surgery, underwent lung biopsy to assess pulmonary vascular disease (PVD). Twenty-six had ventricular septal defects (VSD), 17 d-transposition of the great arteries (D-TGA), and seven, defects of the atrioventricular canal (AVC). Quantitative morphologic data was correlated with hemodynamic data. Three new grades of PVD were observed. Abnormal extension of muscle into peripheral arteries (grade A) was found in all patients; all had increased pulmonary blood flow. In addition, 38 of 50 patients had an increase in percentage arterial wall thickness (grade B); this correlated with elevation in pulmonary artery (PA) pressure (r = 0.59). Another 10 of 50 patients had, in addition to A and B, a reduction in the number of small arteries (grade C); nine of 10 were patients with elevated PA resistance greater than 3.5 mu/m2 (P less than 0.005). All three patients with Heath-Edwards changes of grade III or worse also had grade C. Reduction in peripheral arterial number probably precedes obliterative PVD and may identify those patients in whom, despite corrective surgery, PVD will progress.

Adult↗
PubMed1978

Chylous reflux syndrome involving the pericardium and lung.

A ten-year-old boy with symptom-free pulmonary interstitial edema and pericardial effusion was found to have a chylous reflux syndrome involving the pericardium and lung. Evidence suggests that unlike patients with isolated primary chylopericardium in whom pericardial window and/or ligation of the thoracic duct is curative, those with chylous reflux should be managed medically since the morbidity and mortality of surgical treatment is high in this syndrome.

Child↗