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Biomedical subjects

W J Brawn

Publications and source records attributed to W J Brawn.

At least 19 recordsLinked to original sources

The modified Norwood procedure for hypoplastic left heart syndrome: early to intermediate results of 120 patients with particular reference to aortic arch repair.

BACKGROUND: Classic first-stage Norwood repair of hypoplastic left heart syndrome uses a homograft patch enlargement to obtain an unobstructed aorta and coronary arteries. Because of possible disadvantages of the homograft, such as lack of growth, degeneration and calcification, and availability, we have tried to repair the aorta without patch supplementation. METHODS: Between February 1993 and September 1997, 120 patients, aged birth to 47 days (median 4 days) and weighing 1.7 to 4.4 kg (median 3.1 kg), underwent first-stage palliation for hypoplastic left heart syndrome. The diameter of the ascending aorta ranged from 1.5 to 8.0 mm (median 3.0 mm). Eight patients had an aberrant right subclavian artery arising from the descending thoracic aorta. In 95 patients (group I), all duct tissue was excised and the descending aorta was anastomosed to the aortic arch, which had been opened back into the ascending aorta. Then to this confluence was anastomosed the proximal main pulmonary artery. In the remaining 25 patients (group II), continuity of the aortic arch was maintained and the repair was performed with a Damus-Kaye-Stansel anastomosis. The size of the systemic-to-pulmonary shunt was 3 mm in 48 patients, 3.5 mm in 70, and 4.0 mm in 2. RESULTS: Circulatory arrest time ranged from 19 to 105 minutes (median 54 minutes). A homograft patch was necessary for the arch reconstruction in 18 patients (15%); 9 group I patients (10%) and 9 group II (36%) (P =.001). There were 82 hospital survivors (68%); 69 group I patients (73%) and 13 group II (52%) (P =.04), 71 patients without a patch (70%) and 11 with a patch (61%) (P >.2). By multiple logistic regression, the aberrant right subclavian artery was a significant risk factor for hospital death (P =.008). There were 6 late deaths. Sixteen of 71 patients (23%) who underwent second-stage palliation had a neoaortic arch obstruction develop, with a peak gradient greater than 10 mm Hg; 14 group I patients (23%) and 2 group II (22%) ( P >.2), 15 without a patch (23%) and 1 with a patch (17%) (P >.2). Overall survivals were 57% at 1 year and 55% at 2 years. CONCLUSION: The modified Norwood procedure for first-stage palliation of hypoplastic left heart syndrome is possible in the majority of patients without the use of exogenous materials and does not result in an increased incidence of neoaortic arch obstruction. Repair of the aorta without patch supplementation may improve the potential for long-term growth of the new aorta.

Anastomosis, Surgical

Divided left atrium in association with tricuspid atresia and discordant ventriculo-arterial connections.

Division of the morphologically left atrium is a rare abnormality, constituting around 0.1% of congenital heart disease. It may coexist with other cardiac abnormalities, and this association may obscure its recognition. We report an uncommon association with tricuspid atresia and discordant ventriculo-arterial connections, the latter dominating the clinical picture. Accurate diagnosis was made by transthoracic cross-sectional echocardiography, and the patient was referred to surgery without need for cardiac catheterisation.

Abnormalities, Multiple

Intraoperative ultrasonographic troubleshooting after the arterial switch operation.

BACKGROUND: Less than perfect coronary artery translocation accounts for the majority of perioperative deaths after the arterial switch procedure for transposition of the great arteries. Some types of coronary arterial anatomy are associated with a higher risk of death. METHODS: Prospective epicardial ultrasound examination of all neonates with failing left ventricle or difficulty in weaning off cardiopulmonary bypass was performed after completion of the arterial switch operation during a 2-year period from March 1994 to February 1996. The aim was to identify any mechanical, and potentially remediable, factors accounting for ventricular failure. RESULTS: Four neonates fulfilling the above criteria were identified during a 2-year period when epicardial echocardiography was routinely applied. In 2 patients coronary arterial problems in the form of kinking of the proximal left coronary artery (1 patient) and extrinsic compression of the artery by the neo-pulmonary trunk (1 patient) were identified and successfully corrected. In 2 other patients, supravalvar aortic stenosis was recognized, leading to prompt revision. CONCLUSIONS: Epicardial echocardiography has an important "troubleshooting" role in the subgroup of patients with a suboptimal hemodynamic result after the arterial switch operation. Patients with unusual coronary anatomy should routinely be candidates for such studies.

Cardiopulmonary Bypass

Complete atrioventricular septal defects: the influence of associated cardiac anomalies on surgical management and outcome.

OBJECTIVE: Major associated cardiac anomalies are known to increase the risk of repair of complete atrioventricular septal defects (CAVSDs). The purpose of this study was to examine the effects of such anomalies on the current surgical management of CAVSDs and their influence on outcome following repair. METHODS: We performed a retrospective review of a 100 consecutive non-isomeric patients undergoing repair of CAVSD at our institution, between January 1989 and December 1994; patients with partial or intermediate defects were excluded. Complete atrioventricular septal defect patients with other major cardiac abnormalities (complex) were then compared to those with isolated CAVSDs. RESULTS: There were 15 patients (15%) with associated anomalies; 3 had tetralogy of Fallot, 1 patient had pulmonary atresia, 6 had hypoplastic left or right ventricle, 1 had tetralogy of Fallot and hyperplastic right ventricle, 2 patients had double outlet right ventricle, 1 had hypoplastic aortic arch and 1 patient had aortic coarctation. The median age at operation was similar for both groups (4.2 months), while the median weight was not significantly different for isolated CAVSDs compared to complex (4.2 months vs 3.4 months, P = 0.89), but there was a higher incidence of trisomy 21 (70/85, 82% vs 8/15, 53.3%, P = 0.01). Two of the 85 isolated CAVSD patients (2.3%) had undergone palliative pulmonary artery banding, while 5 of the 15 complex patients (33.3%) had either banding or Blalock-Taussig shunts performed. The technique of CAVSD repair was identical in each group. All complex patients had standard repair of their associated anomalies. Hospital mortality was higher in the complex group (3/15, 20% vs 2/85, 2.3%, P = 0.004); all early deaths in the complex group occurred in patients with a hypoplastic ventricle. Reoperation for left atrioventricular valve regurgitation was required in six isolated CAVSD patients (7.1%) and in one complex (6.6%). CONCLUSIONS: In the absence of significant ventricular hypoplasia, the early results of surgical repair in patients with CAVSDs and associated cardiovascular anomalies are similar to those achieved in patients with isolated CAVSD.

Aorta, Thoracic

Management and outcome of infants and children with right atrial isomerism.

OBJECTIVES: To assess the current results and outcome of surgery in infants and children with right atrial isomerism and complex congenital heart disease. SETTING: Tertiary referral centre. METHODS: 20 consecutive children with right atrial isomerism and complex congenital heart disease underwent surgery over a 6 year period between August 1987 and July 1993. The results and outcome were analysed according to age, presentation, and surgical procedures. RESULTS: Patients were divided into two groups depending on age at presentation and initial surgery: group A comprised 11 patients who required surgical intervention in the first month of life (mean age 5 days); and group B comprised nine patients who required initial surgical intervention after the first month of life (mean age 6.8 months). Seven (64%) of the 11 patients in group A had obstructed pulmonary venous drainage and ten (91%) had pulmonary atresia. There were seven early deaths (64%), including the five patients who required systemic to pulmonary artery shunt and simultaneous repair of obstructed pulmonary veins. The long-term survival rate in this group was 18% (two of 11). Pulmonary venous obstruction was present in two (22%) of the nine patients in group B and four (44%) had pulmonary atresia. There were no early deaths. One patient died after a second palliative procedure. There was one late sudden death. Four patients had a Fontan operation with no deaths. Two of the remaining three patients meet the Fontan criteria. The long-term survival rate in this group was 78% (seven of nine). CONCLUSIONS: Surgical management of patients with right atrial isomerism who have complex congenital heart disease carries a high mortality and remains palliative. The overall survival rate was 45% (nine of 20); 18% in patients requiring surgery in the first month of life (group A) and 78% in patients requiring surgery after the first month of life (group B) (P < 0.001). Of the total of 20 patients, nine were potential candidates for a Fontan operation. Seven of these have undergone a Fontan procedure with five survivors.

Child, Preschool

Endocarditis with multiple intracardiac shunts: identification and repair.

An 8-year-old boy who suffered from Hirschsprung's disease had development of tricuspid valve endocarditis that progressed to aortic root abscess formation, development of a fistulous communication between aorta and right atrium, atrial and ventricular septal defects, and a left ventricle to right atrium defect. Several surgical procedures were required. Operation consisted initially of closure of the septal defects and aortic valve repair. This was followed by homograft replacement of the aortic valve for persistent infection, and further closure of a left ventricle to right atrium fistula.

Abscess

Neonatal pulmonary vascular disease in hypoplastic left heart syndrome.

A term neonate with hypoplastic left heart syndrome underwent surgical palliation using the Norwood procedure on day 2 of life. The postoperative course was complicated by recurrent systemic desaturation leading to death. Postmortem histologic examination of lung tissue confirmed the clinical impression of fixed pulmonary vascular disease. Some neonates with a restrictive interatrial communication may have pulmonary vascular disease at birth, which will negatively influence survival irrespective of the type of palliation undertaken.

Fatal Outcome

Univentricular heart with systemic outflow obstruction: palliation by primary Damus procedure.

In 24 consecutive infants (19 male and 5 female) with complex forms of single-ventricle physiology and systemic outflow obstruction, a modified Damus operation without the use of exogenous material was undertaken in conjunction with creation of an aortopulmonary shunt 3.5 mm in diameter. The median age at operation was 6 days (range, 1 to 170 days) and the median weight, 3.4 kg (range, 2.6 to 4.6 kg). There were nine early deaths. All 15 survivors (median follow-up, 6.5 months) were clinically well without major systemic ventricular dysfunction or atrioventricular or arterial valve regurgitation. Ten of them have undergone a superior vena cava-pulmonary shunt (one death), and 1 has required patch angioplasty of the aortic arch and innominate artery with revision of the aortopulmonary shunt. The 4 other survivors are awaiting a cavopulmonary shunt. Univariate analysis yielded the chronologic rank for an individual procedure (higher risk of death early in the series), presence of aortic arch atresia, and presence or absence of transposition of the great arteries as predictors of death. This aggressive surgical approach provides excellent early palliation, and because the operation prevents abnormal ventricular hypertrophy from pressure or volume overload, systemic ventricular function is optimally conserved for a future Fontan-type procedure.

Cardiac Surgical Procedures

Intraoperative epicardial echocardiography in assessing pulmonary artery banding procedures.

BACKGROUND: Accurate perioperative assessment of the adequacy of pulmonary artery banding has hitherto relied on oximetry and direct pressure measurements. We report the use of epicardial Doppler echocardiography for assessing banding procedures. METHODS: Six consecutive infants (3 male, 3 female; median age, 17 days) who underwent pulmonary artery banding for complex defects were studied by intraoperative epicardial Doppler echocardiography. RESULTS: Excellent visualization of the relation of the band to the pulmonary valve and branch arteries was obtained, enabling or confirming optimal positioning. Doppler echocardiographic estimation of the pressure drop across the band was possible in each patient and resulted in further tightening of the band in 2 patients (33%) with satisfactory increases in transband pressure gradients. Intraoperative echocardiographic estimates of the transband gradients (median, 57 mm Hg; range, 52 to 71 mm Hg; mean +/- standard deviation, 59 +/- 7 mm Hg) correlated well with those obtained at subsequent transthoracic echocardiography (median gradient, 66 mm Hg; range, 52 to 67 mm Hg; mean +/- standard deviation, 63 +/- 6 mm Hg). CONCLUSIONS: Epicardial echocardiography is a valuable adjunct to direct pressure and saturation measurements for adjustment of final band size and aids in confirming accurate band placement.

Echocardiography

Surgery for infants with a hypoplastic systemic ventricle and severe outflow obstruction: early results with a modified Norwood procedure.

OBJECTIVE: Prospective audit of the first year of implementation of a modified approach to palliation for infants with hypoplastic systemic ventricle and severe systemic outflow obstruction. SETTING: Tertiary referral centre for neonatal and infant cardiac surgery. PATIENTS AND METHODS: 17 of 19 infants (aged < 35 days) presenting to Birmingham Children's Hospital in 1993 with hypoplastic systemic ventricle and severe outflow obstruction underwent surgery. This was performed using a new modification of the Norwood-type arch repair, without the use of exogenous material, and a 3.5 mm Gore-tex shunt between the innominate and right pulmonary arteries. The Gore-tex shunt was replaced by a cavopulmonary shunt between 3 and 5 months later. Clinical, morphological, and functional determinants of outcome were examined. RESULTS: 10 (59%) infants survived initial surgery. All proceeded to cavopulmonary shunt without further loss. Significant atrioventricular valve regurgitation seemed to be the main risk factor for poor outcome. If this was excluded, the morphology of the dominant ventricle seemed to have little effect on the outcome of initial surgery. CONCLUSIONS: Early survival was achieved in 59% of patients in the first year of implementation of a protocol for surgery in infants with hypoplastic systemic ventricle and severe outflow obstruction. The construction of a neoaorta without the use of exogenous material may allow improved later growth of the neoaorta. Early cavopulmonary shunt can be performed safely and should reduce mid-term complications from cyanosis and systemic ventricular volume loading.

Female

Combined atrial and arterial switch procedure for congenital corrected transposition with ventricular septal defect.

OBJECTIVES: A combined atrial and arterial switch procedure was performed in selected patients with congenitally corrected transposition to establish the morphological left ventricle as the systemic ventricle. Immediate and early follow up results are presented. BACKGROUND: Progressive right ventricular dysfunction and tricuspid regurgitation are common in patients with congenitally corrected transposition who undergo repair of associated lesions. A surgical procedure which re-establishes the left ventricle as the systemic ventricle should improve functional results. METHODS: Four symptomatic children aged from 9 months to 3 years 1 month (mean 2 years 3 months) with congenitally corrected transposition and ventricular septal defect underwent both an atrial and arterial switch procedure and were followed up for a mean of 12 months (range 6-21 months). RESULTS: There were no early or late deaths. Conduction abnormalities worsened in two patients. Hospital stay ranged from 8 to 17 days (mean 13 days). The cardiothoracic ratio decreased from a mean (range) of 0.65 (0.6 to 0.71) to 0.58 (0.52 to 0.6). Currently, three patients are in functional class I and one child is in functional class II. CONCLUSIONS: The combination of an atrial and an arterial switch procedure in symptomatic children with congenitally corrected transposition establishes the left ventricle as the systemic ventricle. The initial experience is encouraging with excellent immediate and early follow up results.

Child, Preschool

The use of a glutaraldehyde-preserved ovine pulmonary valve, as a pulmonary valve substitute in infants.

Reconstruction of the right ventricular outflow tract with a valved conduit is often necessary to repair some forms of congenital heart disease. We have used a 12- to 13-mm sized glutaraldehyde-preserved lamb's (ovine) valve for this purpose. The valves were harvested from the local abattoir, dissected, and stored in glutaraldehyde at 4 degrees C for 2 weeks before use. The valve was placed in four infants, two with truncus arteriosus, one with aortic valve atresia and ventricular septal defect, and one with absent pulmonary valve syndrome. In three patients, the valve had to be replaced in the second year of life, and in one patient in the fourth year of life. All patients are alive and well at follow-up. In the short-term, this valve has functioned well and could be considered where commercially available conduits or homografts are not routinely available.

Animals

Post-operative blood loss following cardio-pulmonary bypass in children.

Significant post-operative bleeding may occur following cardio-pulmonary bypass, sometimes necessitating early re-exploration. Two questions were asked by this study. Firstly, in children undergoing cardio-pulmonary bypass, can pre-operative, operative and immediately post-operative variables be used to predict post-operative blood loss? Secondly, in the same patient group, can the same variables be used to predict the surgical intervention of re-exploration for excessive bleeding within 12 h of surgery? In a prospective study of patients operated on in a 9-month period, bleeding fell rapidly in the first 3 h after surgery and early re-exploration for bleeding was necessary in 8 of the 206 patients. The only significant predictor of post-operative blood loss was minimum oesophageal temperature, low values being associated with greater blood loss (correlation r = -0.19 (P < 0.05)). With regard to re-exploration for bleeding, a long bypass time (P < 0.05) and abnormal pre-operative coagulation indices (P < 0.01) were significant and independent predictors. The data were also used to create a practical nomogram relating re-exploration for bleeding to hourly post-operative blood loss.

Body Temperature

Interrupted aortic arch in infancy: a 10-year experience.

Fifty infants with interrupted aortic arch (IAA), admitted between 1979 and 1988, were reviewed. They usually presented early in severe cardiac failure or shock. In the initial 5-year period, 17 of the 21 infants underwent diagnostic or confirmatory cardiac catheterization, in contrast with the latter 5 years when only eight of the subsequent 29 patients underwent catheterization. Since 1987, all patients underwent surgery after cross-sectional echocardiography. Fifteen infants had a type A IAA and 35 had type B. All had associated cardiac anomalies. Four infants were not operated on. In the initial 5-year period, of 17 infants who were surgically treated, four had a one-stage total repair, the remaining had a two-stage repair with initial reconstruction of the arch and pulmonary artery banding. There was an overall surgical mortality of 65%, reflecting the precarious state of many of these infants before surgery with a significant contribution from unrelieved subaortic stenosis. In the latter 5-year period, 29 underwent surgery, 22 had a one-stage total repair. There were three deaths, all in infants whose active treatment was withdrawn. The outcome of the survivors has generally been good, subsequent surgery being mainly related to the associated anomalies (e.g., recurrent subaortic stenosis, conduit replacement). Over this 10 year period the greater accuracy of noninvasive diagnoses, and perioperative intensive care, have led to an improvement in the preoperative state of these infants. Single-stage total repair is our procedure of choice.

Aorta, Thoracic

Cardiac conduction abnormalities and rhythm changes after neonatal anatomical correction of transposition of the great arteries.

Seventy three infants who underwent neonatal anatomical correction for transposition of the great arteries with or without a ventricular septal defect were reviewed for evidence of conduction and rhythm abnormalities on preoperative and postoperative 12 lead electrocardiograms and during 24 hour Holter monitoring. There was a partial right bundle branch block pattern in 47% (29/62) of all patients and in 60% (24/40) of those with simple transposition. Complete right bundle branch block was noted in 21% including 5% with simple transposition. Holter monitoring showed sinus rhythm in all patients except three: one had episodes of supraventricular tachycardia, another an intermittent second degree heart block, and a third a complete heart block. Atrial extrasystoles were noted in 47% (29/62) of patients but were frequent in only three patients. Occasional unifocal ventricular extrasystoles were encountered in 37% (23/62) of patients and were frequent in a further 3% (2/62). Only one patient (2%) developed multifocal ventricular extrasystoles. The frequency of important cardiac arrhythmias after neonatal anatomical correction of transposition of the great arteries was 5%, significantly less than that reported after atrial inflow diversion for the same malformation.

Arrhythmias, Cardiac