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Biomedical subjects

W G Williams

Publications and source records attributed to W G Williams.

At least 145 records · Page 8Linked to original sources
PubMed1992

Late results after repair of aortic insufficiency associated with ventricular septal defect.

The late results of 70 patients aged 1.96 to 35.9 (mean 10.1) years who had repair of ventricular septal defect and aortic insufficiency from 1968 to 1988 were reviewed. The ventricular septal defect was subcristal in 50 and subpulmonary in 20 patients. Two thirds were situated immediately below some part of the right coronary leaflet with prolapse of that leaflet. Most of the remainder were below the right commissure or the anterior part of the noncoronary leaflet with prolapse of one or both adjacent leaflets. Associated structural defects, usually including some fusion at a commissure, were present in 18 of the 70 patients and occurred more often with a ventricular septal defect in or below the commissure between the right and noncoronary leaflets (p less than 0.001). Follow-up ranged from 1.9 to 19.6 (mean 9.8) years. There were no early deaths or cases of atrioventricular block, but there were two late deaths. Patient survival rate was 96% at 10 years. Freedom from valvuloplasty failure and freedom from reoperation were 76% and 85%, respectively, at 10 years. The major predictor for failure by multivariate analysis was the presence of an associated structural defect (p less than 0.01). Age at repair and position of the ventricular septal defect were not significant risk factors. We conclude that aortic valvuloplasty produces good palliation in most children. The few failures occurred early and chiefly in patients with associated structural valve defects that occurred more frequently in children who had a ventricular septal defect in the right commissure, where both the right and noncoronary leaflets may be affected.

Adolescent↗
PubMed1991

Analysis of survival in patients with pulmonic valve atresia and ventricular septal defect.

This study reviews the clinical course of 104 consecutive patients with pulmonic valve atresia and ventricular septal (VSD) defect who were diagnosed in the first year of life and followed for a mean period of 4.95 years (range 2 days to 13.75 years). Specific attention was paid to the nature of the pulmonary blood supply and to its influence on patient outcome. Confluent pulmonary arteries supplied by a single ductus arteriosus were present in 72 patients (69%, group I), whereas 32 patients (31%, group II) had a pulmonary blood supply that was partially or exclusively dependent on systemic collateral arteries. An estimate of the probability of survival for 10 years was 69% in the entire cohort, with no different between patients in group I and group II. Definitive surgical repair was performed in 33 of 72 group I patients (46%), compared with 5 of 32 group II patients (16%). Arborization and distribution abnormalities of the pulmonary arteries as well as intrapulmonary stenoses that were exclusively present in patients with systemic collateral arteries (p less than 0.00001) accounted for the significantly lower probability of undergoing corrective surgery in group II patients.

Analysis of Variance↗
PubMed1991

Repair of coarctation of the aorta in children: postoperative morphology.

To determine the morphologic sequelae after surgical repair of coarctation of the aorta, the authors retrospectively reviewed angiograms and hemodynamic and clinical data on 215 patients who underwent cardiac catheterization after surgical repair of coarctation of the aorta during a 13-year period. Ninety-seven patients (45%) underwent coarctation resection with end-to-end anastomosis; 92 (43%), subclavian-flap angioplasties; and 26 (12%), synthetic-patch repairs. Sixty-four patients (30%) had an "aneurysm," defined as a measurement ratio of repair site to diaphragmatic aorta greater than 1.5. Transverse-arch or isthmic hypoplasia or recoarctation was detected in 86 patients (40%) and was most commonly associated with septal defects or obstruction of the left ventricular outflow tract. Pullback systolic pressure gradients at catheterization were significantly higher (P = .0001) in the patients with transverse-arch hypoplasia and recoarctation than in those with ratios of transverse arch to diaphragmatic aorta greater than 0.9. Significant postoperative arch obstructions can be predicted with measurement ratios on the basis of the diameter of the abdominal aorta.

Adolescent↗
PubMed1991

Expression of ventricular myosin subunits in the atria of children with congenital heart malformations.

The presence of ventricular myosin light chains in the atria of children with congenital heart disease was demonstrated by two-dimensional polyacrylamide gel electrophoresis, peptide mapping, and Western blot analysis. Ventricular myosin light chains were present in 27% of biopsies from 91 children with different forms of congenital heart disease. Perimembranous ventricular septal defects and tetralogy of Fallot were associated with the presence of ventricular myosin light chains in 50% of patients. The presence of ventricular myosin light chains in these atria did not correlate with pressure or volume overload. Analysis of myosin heavy chain isotype in the same biopsies by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, peptide mapping, and Western blot analysis indicated that there was no detectable expression of ventricular myosin heavy chain (beta-subunit), suggesting that the genes for the myosin heavy chains and light chains are not expressed coordinately.

Blood Pressure↗
PubMed1991

Thromboexclusion of the right ventricle in children with pulmonary atresia and intact ventricular septum.

Twelve children with pulmonary atresia and intact ventricular septum underwent closure of the tricuspid valve as a part of a new surgical procedure. In two cases a concomitant Fontan operation was performed. In each patient the right ventricle was very small and right ventricular pressure was higher than systemic pressure. Ventricle-coronary connections provided flow of desaturated blood from the right ventricle into the coronary arteries in 11 of 12 cases. Five of the 12 children did not survive operation and postmortem examination of each revealed severe acute and chronic myocardial ischemic damage and high-grade obstruction or interruption of the proximal left anterior descending coronary artery. Preoperative angiography demonstrated occlusive changes in the coronary arteries, resulting in right ventricular dependent circulation, in all five children who died and in one child who survived operation. Seven children who survived operation are well 4 months to 3.5 years later. Two have undergone subsequent successful Fontan operation and two others are considered suitable candidates for this operation. Tricuspid valve closure is recommended for a carefully selected group of infants with pulmonary atresia and intact ventricular septum provided a right ventricular-dependent coronary circulation can be excluded on the basis of preoperative coronary cineangiography.

Child↗
PubMed1991

Effect of rapid cooling contracture on ischemic tolerance in immature myocardium.

Hypothermic perfusion before cardioplegic ischemic arrest is commonly used in neonatal cardiac surgery. However, perfusion cooling of the heart in the nonarrested state results in an inotropic response and may induce myocardial contracture secondary to a sustained elevation of intracellular calcium levels. The effect of prearrest cardiac cooling was examined in two groups of isolated parabiotic, blood-perfused neonatal rabbit hearts. Group C (cooling group, n = 12) was exposed to 15 minutes of cold perfusion to 12 degrees C before 1 hour of cardioplegic arrest. Group N (normothermia group, n = 11) underwent identical arrest conditions but without prearrest cold perfusion. Developed pressure at constant volume in group C fell from 109 +/- 8.7 mm Hg at baseline to 55.2 +/- 5.5 mm Hg after 30 minutes of reperfusion versus no significant change in group N. Diastolic compliance showed significant deterioration in group C, with marked elevation of diastolic pressure from 9.8 +/- 0.4 mm Hg at baseline to 22.0 +/- 4.4 mm Hg after ischemia and reperfusion. This experimental data demonstrates that profound hypothermic perfusion of the myocardium in the nonarrested state may induce a rise in resting myocardial tension and that cardioplegic ischemic arrest in the presence of cooling contracture may result in important myocardial injury.

Animals↗
PubMed1991

Assessment of myocardial perfusion in patients after the arterial switch operation.

In 21 patients who had undergone the arterial switch operation, the adequacy of myocardial perfusion was evaluated by thallium-201 computed scintigraphy 2.6 +/- 2 (0.3-7) yr after surgery. Fourteen patients had undergone the arterial switch procedure after pulmonary artery banding and seven as a primary repair. Isoproterenol stress increased the heart rate by at least 55%. Tomographic imaging was performed at peak stress and 3 hr later in the reperfusion phase. Nine patients had perfusion defects. The perfusion defects were located at the left ventricular apex in four (with extension to the inferolateral wall in one), left ventricular anterolateral wall in two, ventricular septum in one, left ventricular inferior wall in one, and right ventricular free wall in one. Some of these defects could be due to myocardial damage at the time of surgery, but these results also raise concern about long-term adequacy of myocardial perfusion following the arterial switch procedure.

Child↗
PubMed1990

Management of neonatal critical pulmonic stenosis in the balloon valvotomy era.

We evaluated our recent experience with management of neonatal critical pulmonic stenosis and intact ventricular septum between 1982 and 1988. Thirty-nine patients (aged less than 3 months) were treated initially by operation (group A, n = 19) or with balloon pulmonary valvotomy (group B, n = 20). Patients in group A were younger (5 +/- 1.3 versus 18 +/- 4 days in group B) (mean +/- standard error of the mean) and had a greater degree of hypoxia (oxygen tension, 55 +/- 4 versus 80 +/- 6 mm Hg) (p less than 0.05 for all variables). Ten patients in group A and 8 patients in group B had right ventricular hypoplasia, based on an angiographically determined index. Balloon pulmonary valvotomy was attempted in 20 patients at the time of the initial catheterization but was unsuccessful in 9 owing to inability to catheterize the hypoplastic right ventricular outflow tract (n = 8) and to recurrent infundibular stenosis (n = 1). Patients with failed balloon valvotomy were subsequently operated on within 24 hours. The early operative mortality (less than 30 days) was 25% (7 of 28); one death (9%) occurred after successful balloon valvotomy owing to associated critical aortic stenosis. The early postoperative gradient was 20 +/- 2 mm Hg; the post-balloon valvotomy gradient was 18 +/- 3 mm Hg. We conclude that balloon pulmonary valvotomy yields good results in patients with critical pulmonary stenosis with essentially normal-sized right ventricle, whereas surgical pulmonary valvotomy is required for patients with right ventricular hypoplasia.

Blood Pressure↗
PubMed1990

Common atrioventricular valve guarding double inlet atrioventricular connexion: natural history and surgical results in 76 cases.

We describe 76 patients in whom a double inlet atrioventricular connexion was guarded by a common atrioventricular valve. The atriums were connected to a dominant right ventricle in 42, to a left ventricle in 29 and to a solitary indeterminate ventricle in 5. The most common atrial arrangement was isomerism of the right atrial appendages, seen in 46% (35/76). Of these, there was associated anomalous pulmonary venous connexion in 72% and absence of the spleen in 63%. Double outlet right ventricle was the most frequent ventriculoarterial connexion, present in 37 cases. Abnormal atrioventricular valvar function could already be detected in 46% of cases at the time of initial presentation. A decrease of function was observed in 18 patients, in 14 of them 2 weeks to 16 years (mean 5.7 years) after palliative surgery. The majority of the palliative procedures were constructions of shunts, since 75% (57/76) of the patients showed obstruction to flow of pulmonary blood. Patients with double inlet ventricle guarded by a common atrioventricular valve have a high early mortality (37% died in the neonatal period). Management should be designed to protect the integrity of the pulmonary vascular bed. Definitive repair with a Fontan type procedure is the most suitable final approach.

Blood Vessel Prosthesis↗
PubMed1990

Early nosocomial infections in pediatric cardiovascular surgery patients.

All patients undergoing cardiovascular surgery between July 1, 1987 and February 29, 1988 were followed from admission to the pediatric ICU (PICU) daily by an intensivist/anesthetist. Patients were characterized by surgical procedure and PRISM score on ICU admission. Of 310 patients, 40 patients (nosocomially infected patient ratio 12.9) developed 78 infections (nosocomial infection ratio 25.2), of which 28% (n = 22) were wounds, within 2 months of surgery. Early wound infection followed 8% of closed, nonpump cases and 6.7% of open, pump cases. Wound infection was more likely if the sternum was open on the ward (elective or emergency) (27.6% open vs. 5.0% closed, p less than .001) or if the PRISM score was greater than or equal to 10 on PICU admission (10.7% greater than or equal to 10 vs. 2.3% less than 10, p less than .01). The causative agents in wound infections in closed cases were Staphylococcus aureus (70%) and coagulase negative staphylococci (CONS) (30%) while in open, pump cases the agents were CONS (33%), Pseudomonas aeruginosa (27%), Candida spp. (27%), and S. aureus (20%). Nonwound infections accounted for 72% of infections (n = 56). The number of bacteremias and other central and arterial line-related infections approximated wound infection in incidence at 6.8/100 patients. Wound infections are more likely if the sternum has been left open on the ward, if the patient has a high PRISM score on PICU admission, and after specific surgical procedures.

Cardiac Surgical Procedures↗
PubMed1990

Iliofemoral arterial complications of balloon angioplasty for systemic obstructions in infants and children.

The medical and radiological records of 64 consecutive infants and children who underwent transfemoral balloon dilation of the aorta or aortic valve were reviewed to determine the incidence, nature, and post-treatment outcome of acute iliofemoral complications. Balloon dilation angioplasty or balloon valvotomy was performed with 8F and 9F catheters without an arterial sheath. Patients ranged in age from 5 days to 15.4 years (mean, 6.4 years). Of 64 patients, 29 (45.3%) had an acute iliofemoral complication, including thrombosis (18 of 64), complete disruption (five of 64), incomplete disruption (three of 64), and arterial tear (three of 64). The arterial pathology was confirmed in 23 of 29 patients by one or a combination of surgical exploration and repair (18 of 29), angiography (six of 29), and magnetic resonance imaging (three of 29). Of eight patients, three with arterial disruption had acute hypotension requiring transfusion and immediate surgery; the other five had absent pedal pulses after the procedure. Of these five, three developed bleeding during thrombolytic therapy and underwent surgical exploration, and two were diagnosed by angiography after ineffective thrombolytic therapy. Angiography in three patients with iliac artery avulsion showed tapered occlusion in two and an aneurysm in one. In patients with iliofemoral thrombosis, angiography showed occlusion from the puncture site to the origin of the external iliac artery. Eleven patients (17% of the entire group and 38% of the group with acute iliofemoral complications) had reduced or absent pedal pulses at the time of discharge. A significant correlation was found between increased incidence of iliofemoral thrombosis and disruption (as well as abnormal pedal pulses at hospital discharge) and low patient weight.

Angioplasty, Balloon↗
PubMed1990

Coronary angiography of pulmonary atresia, hypoplastic right ventricle, and ventriculocoronary communications.

A retrospective study was undertaken to determine the spectrum of angiographic abnormalities of the coronary arteries in infants and children with pulmonary atresia, hypoplastic right ventricle, and right ventriculocoronary arterial communications. Twenty-nine patients with 67 angiographic examinations were reviewed; findings in seven patients were compared with those at autopsy. Twenty-seven (93%) of 29 patients had caliber abnormalities of the involved coronary arteries, including obstructive lesions in 20 (69%) of 29 and segmental dilatation in 16 (55%) of 29. Nine patients had interruption of the anterior descending artery and one had absent connection between the coronary arteries and the aorta. A single coronary artery was found in four of 29 patients. There was excellent correlation between clinical angiography and autopsy findings in seven patients. This study confirms the ability of high-quality clinical angiography to show significant abnormalities of the coronary arteries in infants and children with pulmonary atresia and ventriculocoronary communications.

Child↗
PubMed1990

William Glenn lecture. The cavopulmonary shunt. Evolution of a concept.

A bold and imaginative development, the cavopulmonary anastomosis, appeared to originate in several centers almost simultaneously. After extensive research on right heart bypass, Glenn was the first in North America to perform a successful experimental cavopulmonary shunt, and it became known by his name. In properly selected patients, palliation success was excellent, and mortality rates were low. From 1961 through 1988, we used a cavopulmonary anastomosis for palliation in 139 infants and children. There were eight hospital deaths, and most occurred early in the series. Palliation generally lasted 6-8 years-until the child outgrew the blood supply to the contralateral lung. Palliation could be restored by increased flow to that lung with another shunt. Six otherwise inoperable patients received benefit from the addition of an axillary arteriovenous fistula. Late pulmonary arteriovenous fistulas were identified in 11% of our patients by angiography, but with more sensitive testing, the incidence rate may be as high as 21%. The occurrence of pulmonary arteriovenous fistulas caused general concern and less frequent use of the shunt. Recent application of an end-to-side anastomosis, creating a bidirectional shunt, has restored interest. A major legacy of the cavopulmonary anastomosis was demonstration of the feasibility of partial right heart bypass, which paved the way for the Fontan operation, and it is frequently constructed as part of that operation. Currently, the Glenn shunt is most often used as a temporary or permanent alternative to a Fontan repair if there appears to be significant risk. The risk factors usually encountered include small pulmonary arteries, young age, poor ventricular function, atrioventricular valve incompetence, and myocardial hypertrophy-sometimes alone but often in combination.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1990

Morphological findings contributing to a failed Fontan procedure. Twelve-year experience.

A group of 37 patients (age range, 3 months to 29 years) who died after the modified Fontan procedure (within 2 months), representing 15% of the 245 patients undergoing this procedure from 1976 through 1988, was reviewed to determine the causes of death. The three morphological groups were 1) univentricular atrioventricular connection (n = 19), 2) tricuspid atresia (n = 9), and 3) other complex malformations (n = 9). Subaortic stenosis was present in 15 patients (40%) in this group compared with 31 of 208 early survivors (15%) (p = 0.008). Pulmonary artery banding, identified as a risk factor in our previous experience, was performed in 14 patients, nine of whom had subaortic stenosis. Nine palliative procedures for subaortic stenosis were performed in eight patients--before the Fontan procedure in three patients and concurrently with the Fontan procedure in five patients. Myocardial hypertrophy and signs of acute ischemic injury were common findings at autopsy (n = 25) and were particularly prominent in all patients with univentricular heart of left ventricular morphology associated with subaortic stenosis and previous pulmonary artery banding (n = 7). We conclude that the present majority of deaths occurring after the modified Fontan procedure are myocardial in nature and attributable to advanced myocardial hypertrophy that is potentiated by previous pulmonary artery banding and subaortic stenosis.

Aortic Valve Stenosis↗
PubMed1990

Warm induction blood cardioplegia in the infant. A technique to avoid rapid cooling myocardial contracture.

The use of profound hypothermia and total circulatory arrest for repair of heart defects in neonates usually involves a period of systemic and myocardial bypass cooling. Rapid cooling of muscle (skeletal, smooth, and myocardial) can result in contracture through elevation of cytosolic calcium levels. The increased myocardial tone caused by cooling might render the heart more vulnerable to a subsequent period of cardioplegic ischemic arrest. Infants may be more susceptible to contracture because their small body mass allows more rapid myocardial temperature change when prearrest bypass cooling is used. The influence of avoiding rapid myocardial cooling before induced cardioplegic arrest was analyzed in a group of infants weighing less than 6 kg at the time of open cardiac operation. Myocardial ischemic arrest by warm (37 degrees C) induction blood cardioplegia was used in 57 infants and compared with results in 440 infants treated with standard blood cardioplegia. Multivariate logistic regression analysis revealed that patient diagnosis, weight, and age at operation were significant risk factors for operative mortality. The use of warm induction blood cardioplegia had a strongly positive independent effect on survival (p = 0.0003) for any patient weight, age, or diagnostic group. We recommend the avoidance of rapid myocardial cooling on bypass in all patients before induction of cardioplegic ischemic arrest.

Blood↗
PubMed1990

Single lung transplantation and closure of patent ductus arteriosus for Eisenmenger's syndrome. Toronto Lung Transplant Group.

A case report of the first single lung transplantation and closure of a patent ductus arteriosus for Eisenmenger's syndrome is presented. The operation was performed on Sept. 28, 1988. The patient was extubated on postoperative day 8, discharged from the intensive care unit on postoperative day 13, and discharged from the hospital on postoperative day 43, free of symptoms and without supplementary oxygen. Subsequent symptoms of dyspnea, presyncope, and fatigue recurred in association with subvalvular right ventricular outflow tract obstruction. Symptomatic improvement occurred gradually in association with reduction of the outflow tract obstruction. The patient is in New York Heart Association class I-II 12 months after the operation. The rationale, methods, and management of this patient are discussed, as well as the potential for application of this operation in similar settings.

Adult↗
PubMed1990

Rapid cooling contracture of the myocardium. The adverse effect of prearrest cardiac hypothermia.

Hypothermic total circulatory arrest for repair of congenital heart lesions in neonates requires a period of rapid core cooling on cardiopulmonary bypass during which the myocardium is also exposed to hypothermic perfusion. Myocardial hypothermia in the nonarrested state results in an increase in contractility due to elevation of intracellular calcium levels. This study was designed to test the hypothesis that rapid myocardial cooling before cardioplegic ischemic arrest results in damage, with impaired recovery during reperfusion. Two groups of 10 rabbit hearts were perfused on an isolated Langendorff apparatus. Group N (normothermia) was perfused at 37 degrees C before 2 hours of cardioplegic ischemic arrest at 10 degrees C. Group C (cooling) was perfused at 15 degrees C in the unarrested state for 20 minutes before the same cardioplegic arrest conditions as group N. Left ventricular isovolumic pressure measurements, biochemical measurements from right ventricular biopsy specimens, and ventricular necrosis as defined by tetrazolium staining were used to compare the groups at 30 and 60 minutes of normothermic reperfusion. Developed pressure at a constant volume was preserved in group N at 90.7 +/- 4.5 mm Hg versus 76.9 +/- 6.3 in group C after reperfusion (p less than 0.05). Diastolic compliance showed significant deterioration in group C, with marked elevation of diastolic pressure during reperfusion (group N = 6.8 +/- 2.5 mm Hg versus group C = 38.9 +/- 6.1 after reperfusion; p less than 0.001). Adenosine triphosphate levels were significantly higher in group N both at end-ischemia and after reperfusion versus group C (group N = 17.0 +/- 1.1 nmol/mg protein versus group C = 7.7 +/- 1.0 after reperfusion; p less than 0.001). Group N had 0.4% +/- 0.4% necrosis of ventricular mass versus 19.3% +/- 2.2% with prearrest cooling in group C (p less than 0.0001). These results indicate that, when combined with cardioplegic ischemic arrest, rapid myocardial cooling in the unarrested state results in significant damage. The mechanism may be related to the cytosolic calcium loading effect of hypothermia that is not relieved during the subsequent period of cardioplegic arrest. Although hypothermia is an essential component to ischemic preservation, rapid cooling contracture can adversely influence cardioplegic myocardial protection.

Animals↗