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Biomedical subjects

C L Backer

Publications and source records attributed to C L Backer.

At least 91 records · Page 5Linked to original sources
PubMed1992

Ventricular volume growth after cardiac transplantation in infants and children.

BACKGROUND: Intermediate-term survival after pediatric cardiac transplantation continues to improve. However, little is known about cardiac function and especially ventricular growth in young patients after cardiac transplantation. The purpose of this study was to evaluate serially the hemodynamics, left ventricular (LV) volume, and ventricular function after cardiac transplantation in infants and children. METHODS AND RESULTS: Indications for cardiac transplantation were dilated cardiomyopathy (eight patients), hypoplastic left heart syndrome (six patients), and postoperative structural congenital heart disease (three patients). The age at time of transplant ranged from 7 days to 15 years (median, 3.5 years). The mean follow-up was 30.3 months (range, 13-46 months). Serial annual cardiac catheterizations were performed 1 year (17), 2 years (15), and 3 years (seven) after transplant. Measurements included right and left heart pressures, cardiac index, and LV volume and ejection fraction (Lange). Cumulative results (expressed as mean +/- SD) were pulmonary artery pressure, 14.9 +/- 3.2 mm Hg; LV end-diastolic pressure, 7.7 +/- 2.6 mm Hg; cardiac index, 3.5 +/- 0.52 l/min.m-2; and pulmonary vascular resistance, 2.02 +/- 0.76 units/m2. LV end-diastolic volume increased as patients grew, so that left ventricular end-diastolic volume remained 90 +/- 14% of that predicted for body surface area. The ejection fraction was 99 +/- 6% of that predicted. There was no evidence of chronic rejection by endomyocardial biopsy. No accelerated coronary artery atherosclerosis was identified. CONCLUSIONS: Serial studies in these young patients demonstrate normal hemodynamics and LV function after cardiac transplantation. Cardiac transplantation is associated with normal LV volume growth despite immunosuppression and denervation.

Adolescent↗
PubMed1992

Fenestrated Fontan with delayed catheter closure. Effects of volume loading and baffle fenestration on cardiac index and oxygen delivery.

BACKGROUND. The fenestrated Fontan operation has been applied to high-risk patients with univentricular hearts, resulting in improved survival. The purpose of this study was to determine the hemodynamic factors responsible for these improved results. METHODS AND RESULTS. We performed the fenestrated Fontan operation in 17 high-risk patients with univentricular hearts (median age, 3 years; age range, 1.2-25 years). High-risk characteristics were depressed ventricular function and/or hypertrophy (n = 12), atrioventricular valve insufficiency (n = 5), pulmonary artery distortion (n = 6), elevated pulmonary vascular resistance (> 2 units/m2) (n = 4), previously failed Fontan operation (n = 2), or associated Wolff-Parkinson-White syndrome (n = 1). Intraoperative hemodynamic measurements (n = 8) included cardiac index (by aortic flow probe), peripheral arterial O2 saturations, and left and right atrial pressures during inflow occlusion, followed by volume loading with open versus closed fenestration. Mean baffle fenestration was 3.5 mm (range, 2.7-5.0 mm). Multiple regression analysis (cardiac index versus atrial pressure) revealed cardiac index was greater with open than with closed fenestration (p < 0.001) during volume loading. Oxygen delivery (cardiac index multiplied by oxygen content) was also greater with open than with closed fenestration (p < 0.001). Survival was 100% with a mean follow-up of 10.4 months; pleural drainage was high in two patients. Subsequent transcatheter fenestration closure resulted in increased O2 saturation (87 +/- 1% to 96 +/- 0.3%, p < 0.05). CONCLUSIONS. The fenestrated Fontan operation improves survival in high-risk patients by increasing cardiac index and maintaining oxygen delivery, despite mild arterial O2 desaturation. Subsequent transcatheter fenestration closure can be performed after hemodynamic assessment.

Cardiac Catheterization↗
PubMed1992

Pulmonary artery sling. Results of surgical repair in infancy.

Pulmonary artery sling is a rare congenital vascular anomaly in which the left pulmonary artery originates from the right pulmonary artery and encircles the right main-stem bronchus and distal trachea before entering the hilum of the left lung. This causes compression of the trachea and right main-stem bronchus, and most infants with this anomaly have severe respiratory distress within the first year of life. Between 1953 and 1990 12 infants (nine male, three female) underwent surgical repair of pulmonary artery sling. Ages ranged from 8 days to 9 months (mean age 5 months). Bronchoscopic examination was performed in all patients. Complete tracheal rings were the most common associated lesion (five patients). Nine patients had pulmonary angiography. Most recently, computed tomography and magnetic resonance imaging have been used to diagnose pulmonary artery sling and associated complete tracheal rings when present. Surgical repair consisted of transection of the left pulmonary artery at its origin and implantation into the main pulmonary artery anterior to the trachea via right thoracotomy (one), left thoracotomy (six), or median sternotomy (five). Three patients had simultaneous pericardial patch tracheoplasty for complete tracheal rings. There were no operative deaths. Two late deaths occurred, at 7 months and 2.5 years postoperatively. Of 10 long-term survivors nine have had postoperative studies to determine the patency of the left pulmonary artery. Seven anastomoses were patent (78%). Pulmonary artery sling can be repaired in infancy with low operative mortality and excellent long-term patency of the left pulmonary artery by dividing the left pulmonary artery and implanting it into the main pulmonary artery anterior to the trachea. Simultaneous pericardial patch tracheoplasty should be performed if complete tracheal rings are associated. We recommend repair at the time of diagnosis with median sternotomy and extracorporeal circulation.

Congenital Abnormalities↗
PubMed1992

Anomalous origin of the left coronary artery. A twenty-year review of surgical management.

Children with anomalous origin of the left coronary artery from the pulmonary artery are at risk for myocardial infarction and death. Surgical management of this condition in children has evolved significantly during the past 20 years. Between 1970 and 1990, a total of 20 of these patients underwent surgical intervention at two institutions. Age at operation ranged from 3 weeks to 11 years (mean, 26 months). Twelve patients had congestive heart failure, three were in cardiogenic shock, and two had cardiac murmurs. Operative techniques included ligation (n = 9), subclavian artery anastomosis (n = 5), aortic implantation (n = 3), internal mammary artery anastomosis (n = 1), intrapulmonary tunnel from aortopulmonary window to coronary artery (n = 1), and cardiac transplantation (n = 1). The three deaths in the series occurred at 3 weeks, at 2 months, and at 9 years after ligation. There have been no deaths after establishment of a two coronary artery system or after transplantation. Two of the five patients who had subclavian artery anastomosis to the anomalous coronary artery have severe anastomotic stenosis and collateralization. For patients with anomalous origin of the left coronary artery from the pulmonary artery, we recommend direct aortic implantation of the anomalous coronary artery at the time of diagnosis. Intrapulmonary tunnel from aortopulmonary window to coronary artery, or aorta-coronary bypass with internal mammary artery are recommended for children in whom aortic implantation is not anatomically feasible. Left coronary artery ligation is not indicated for these patients; those who have survived ligation should be considered for elective establishment of a two coronary artery system because of the risk of late death.

Anastomosis, Surgical↗
PubMed1992

Ventricular septal defect with tricuspid pouch with and without transposition. Anatomic and surgical considerations.

In a 10-year review, patients operated on for ventricular septal defect and tricuspid valve pouch were divided into two groups, because the effect of the tricuspid valve pouch is influenced by which ventricle has the higher pressure. Group I comprised patients with ventricular septal defect without transposition of the great arteries and group II, ventricular septal defect with transposition. In 72 of 392 group I patients, the septal tricuspid valve leaflet was incised to expose the edges of the hidden ventricular septal defect to accomplish proper anatomic repair. Forty-eight patients had a tricuspid valve pouch, the diagnosis being established by angiography, echocardiography, or at operation. Ages at operation ranged from 5 months to 22 years and the pulmonary-systemic flow ratio ranged from 1 to 3.4, with 16 being less than 1.5. In one patient the pouch produced a 40 mm Hg pressure gradient in the right ventricular outflow tract. At operation, through a transatrial approach, the tricuspid valve pouch was opened radially, the actual ventricular septal defect patched, and the tricuspid valve leaflet repaired. There were no deaths, no significant intraoperative or postoperative morbidity, and no tricuspid valve dysfunction. The average postoperative hospital stay was 4.8 days. In group II, six of 83 patients operated on for transposition with ventricular septal defect had significant left ventricular outflow tract obstruction from the tricuspid valve pouch. Five of six had a Mustard procedure, two requiring a left ventricular-pulmonary artery conduit, and in two of the six the ventricular septal defect was closed through the pulmonary artery. One patient had heart transplantation after a Mustard repair and tricuspid valve replacement. The sixth patient in group II had a successful arterial switch at 9 years of age, after the presence of left ventricular outflow tract obstruction was proved to be due to the pouch. The presence of a tricuspid valve pouch in group I may lead the surgeon to close false small openings produced by the pouch rather than the actual ventricular septal defect. Incising the pouch is safe and essential for proper exposure and secure closure of the true defect. In group II, the systemic right ventricular pressure can push the pouch into the left ventricular outflow tract, causing significant obstruction, and may contribute to tricuspid valve insufficiency after atrial baffle repair. Arterial switch is preferred because it returns the obstructive tricuspid valve pouch and abnormal tricuspid leaflet to the lower pressure pulmonic right ventricle.

Child↗
PubMed1991

Pericardial patch tracheoplasty for severe tracheal stenosis in children: intermediate results.

Between 1982 and 1990, 15 children have undergone pericardial patch tracheoplasty, 13 for complete tracheal rings and 2 for acquired tracheal stenosis. Eleven had complete tracheal rings from the thoracic inlet or the cricoid to the carina. Diagnosis was by bronchoscopy (15), computed tomography (10), and magnetic resonance imaging (3). As first described by Idriss in 1984, the surgical technique uses a median sternotomy approach, extracorporeal circulation, bronchoscopic guidance, and the use of pericardium as a tracheal patch. There was one perioperative death of mediastinitis (operative survival, 93%). There were two late deaths caused by complications of tracheostomy (1) and direct laryngoscopy and bronchoscopy (DLB) (1). Follow-up is complete in 12 intermediate-term survivors and ranges from 0.4 to 8.2 years (mean, 4.2 +/- 2.9 years). Five children required multiple DLBs with dilation and excision of granulation tissue; one of these patients underwent tracheoplasty revision 5 months after the initial procedure for residual tracheal rings, and four of these children have had tracheostomies, two temporary and two currently (4 months, 7 years). Seven children had widely patent tracheas observed at follow-up DLB with little or no residual stenosis after tracheoplasty. All survivors are currently asymptomatic, except for the two children with tracheostomies. Pericardial patch tracheoplasty offers effective therapy with relatively low operative mortality for infants and children with severe long segment tracheal stenosis. On intermediate-term follow-up, nearly all survivors are essentially free of symptoms of residual tracheal stenosis.

Child, Preschool↗
PubMed1991

Living-related lobar lung transplantation in beagle puppies.

Unilateral lung transplantation has provided effective short-term therapy in adults with end-stage lung disease. Rejection continues to be the most common cause of transplant failure. Living-related lung transplantation may decrease the recipient immune response. The purpose of this study is to test the technical and physiological feasibility of living-related lobar lung transplantation from adult beagles into beagle puppies in a chronic model. Twenty purebred adult beagle donors underwent left thoracotomy with harvest of the left lower lobe using cold perfusion of the pulmonary artery and cold immersion. Twenty recipient purebred beagle puppies from the same colony underwent left thoracotomy, left pneumonectomy, and implantation of the donor adult lobe. Anastomoses were performed in sequence: pulmonary vein to left atrium, bronchus, pulmonary artery. Postoperative immunosuppression was with Cyclosporine. Respiratory function of the implanted lobe was evaluated by pulmonary angiography and during balloon occlusion of the right pulmonary artery with arterial blood gases 1 month after transplantation. Ten recipient puppies died of rejection (4), infection (3), or bronchial dehiscence (3) prior to angiography. Seventeen pulmonary angiograms in 10 surviving animals showed normal left pulmonary arterial blood flow (2), diminished left pulmonary arterial flow (5), and occluded left pulmonary artery (3). In two recipients balloon occlusion of the right pulmonary artery was performed and respiratory function was maintained solely by the transplanted lobe for 2 days in one recipient and for 30 minutes at 1 month and 2 months postimplant in a second recipient. Living-related lung transplantation of adult beagle lobes into pneumonectomized beagle puppies is technically feasible. High mortality rates in a chronic model are related to infection and rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Vascular rings: 10-year review of imaging.

Radiologic studies of 47 children with surgically proved vascular rings were retrospectively reviewed. On radiographs, a right-sided or bilateral aortic arch and the presence of tracheal narrowing were signs indicative of vascular rings. On barium esophagograms, a double or right aortic arch appeared as deep persistent posterior indentation of the esophagus. On computed tomographic (CT) scans and magnetic resonance (MR) images, the diagnosis of vascular rings was based on vascular branching patterns, the side of the aortic arch or presence of two arches, and narrowing of the airway. Although the diagnosis of a complete vascular ring can usually be established with certainty by means of radiography and esophagography, CT and MR imaging add valuable anatomic detail about exact arch configuration, tracheobronchial compression, and brachiocephalic vessel branching.

Adolescent↗
PubMed1991

Surgical management of the conal (supracristal) ventricular septal defect.

Surgical management of the conal (supracristal) ventricular septal defect differs significantly from the management of the perimembranous (infracristal) ventricular septal defect. The absence of a portion of the conal septum can lead to prolapse of the right cusp of the aortic valve, which predisposes these patients to aortic insufficiency. Between January 1980 and December 1989, 36 children with conal ventricular septal defect underwent intracardiac repair. Diagnosis was by echocardiography, cardiac catheterization, and intraoperative exploration. Preoperative evaluation showed that 26 patients (72%) had aortic valve prolapse and 16 (44%) had aortic insufficiency. Pulmonary-to-systemic flow ratios ranged from 1:1 to 3.5:1 (mean 2.0:1.0). Ten patients (27%) were believed to have clinical congestive heart failure. Age at the time of operation ranged from 2 weeks to 18 years (mean 5.5 years). Operative exposure was through the pulmonary artery (26), aorta (4), right ventricle (3), or right atrium (3). Simultaneous aortic valve suspension for aortic insufficiency was performed in four patients. Operative survival was 100%. Follow-up is complete in all patients and ranges from 0.5 to 9 years (mean 4.3 years). All patients are in normal sinus rhythm. No residual ventricular septal defects have been identified. Twenty-three of 36 patients (64%) have no evidence of aortic insufficiency; 12 of 36 (33%) have trivial or mild aortic insufficiency. One patient with initial severe aortic insufficiency underwent repeat aortic valvuloplasty 3 years after ventricular septal defect closure and aortic valve suspension. No patients have required aortic valve replacement. Surgical management of the conal ventricular septal defect differs from that of the perimembranous ventricular septal defect in two critical aspects. The operative approach should be through the pulmonary artery. This allows the best exposure of the remaining conal septum and the pulmonary and aortic valve leaflets, facilitating closure of the defect without injury to the valves or conduction system. Conal ventricular septal defects should undergo early closure, regardless of shunt volume, to prevent progressive aortic insufficiency.

Adolescent↗
PubMed1991

Intermediate term results of infant orthotopic cardiac transplantation from two centers.

Orthotopic cardiac transplantation has become established for selected infants with severe forms of congenital heart disease. This study reviews the combined experience and intermediate term results of infants undergoing orthotopic cardiac transplantation from Children's Memorial Hospital, Chicago, and Kosair Children's Hospital, Louisville. From June 1986 through December 1989, 20 orthotopic cardiac transplantations were performed in 19 patients. Sixteen patients had variants of hypoplastic left heart syndrome. One infant had anomalous origin of the left coronary artery with severe ischemic cardiomyopathy. Two infants had aortic stenosis with endocardial fibroelastosis, and one had extracorporeal membrane oxygenation as a bridge to transplantation. Immunosuppression included cyclosporine, azathioprine (Imuran), and corticosteroids with an effort to wean the patients from steroids by 6 months to 2 years. Three early deaths resulted--from technical errors in two patients and from hyperacute rejection in one patient at 3 days. Four late deaths have occurred. Two patients died at 2 and 13 months of acute rejection. One patient died at 15 months of acute rejection after retransplantation. One patient died at 7 months of respiratory syncytial viral pneumonia. The remaining 12 patients are surviving 5 to 47 months (means 20 months) after orthotopic cardiac transplantation. Rejection surveillance in the first 6 months is by clinical signs supplemented by echocardiography, electrocardiography, and cell cycle analysis; endomyocardial biopsy is used after 6 months of age. For the cumulative series, 24 episodes of suspected rejection have been treated during 277 at-risk patient months with intravenous methylprednisolone (Solu-Medrol) (n = 18) and monoclonal antibody (OKT3) (n = 6), for an incidence of 1.04 episodes of rejection per patient per year. Serious posttransplantation infections including endocarditis, catheter sepsis, meningitis, and colonic perforation were successfully treated in four patients. Subjectively, their quality of life is excellent as shown by normal growth and developmental milestones and a low hospital readmission rate (1.4 episodes per patient per year). These encouraging intermediate term results warrant continued application of infant orthotopic cardiac transplantation for severe forms of congenital heart disease.

Antibodies, Monoclonal↗
PubMed1990

Massive primary chylopericardium: a case report.

A large pericardial effusion was discovered in an asymptomatic 12-year-old boy admitted for an elective orthopedic procedure. On physical examination, heart rate was 96 and blood pressure was 130/70 without paradox. The neck veins were not distended, but heart tones were distant. Chest roentgenogram (CXR) showed an enlarged cardiac silhouette. Echocardiogram showed a massive pericardial effusion compressing the right atrium, with depressed ventricular contractility. Pericardiocentesis yielded 450 mL of chylous fluid. A percutaneous pericardial drain was placed and drained another 400 mL of chyle. Pericardial fluid reaccumulated even though the patient was on a low-fat diet, and 1 week after admission left thoracotomy was performed with partial pericardiectomy and pericardial window. There was 1 L of chyle in the pericardial sac; frozen section of the pericardium showed lymphangiectasia. Chest tube drainage diminished rapidly and the patient was discharged. Follow-up CXR at 1 week showed fluid in both pleural spaces requiring bilateral tube thoracostomies again draining chyle. Even with total parenteral nutrition (TPN), 500 mL/d of chyle drained from the pleural tubes. Right thoracotomy with ligation of the thoracic duct was performed after 1 week of TPN. Pleural drainage abruptly dropped, and there has been no reaccumulation in either the pleural spaces or pericardium at 6-month follow-up. This case dramatically supports early thoracic duct ligation and partial pericardiectomy as the treatment of choice for primary massive chylopericardium.

Child↗
PubMed1990

Computed tomography in patients with esophageal perforation.

Contrast esophagram is the diagnostic procedure of choice in patients with clinically suspected perforation of the esophagus. In patients in whom the usual clinical signs or symptoms are unrecognized and in whom the diagnosis is obscure, the diagnosis of a perforated esophagus may be suggested by the finding of mediastinal fluid and air on CT. Three patients are reviewed. The perforations included one spontaneous, one from erosion of an esophageal carcinoma, and one iatrogenic. In two of the three patients, the diagnosis of perforated esophagus had not been made initially and in one patient the initial esophagram was interpreted as normal. Computed tomography of the chest in each patient led to the suspected diagnosis of perforated esophagus. Prompt appropriate surgical intervention followed. The findings of mediastinal fluid and more importantly mediastinal air on CT of the chest are strongly suggestive of esophageal perforation.

Adult↗
PubMed1990

Exit block in pediatric cardiac pacing. Comparison of the suture-type and fishhook epicardial electrodes.

Ninety-seven consecutive permanent epicardial pacemaker implantations were performed with either suture-type (group I, n = 52) or fishhook electrodes (group II, n = 45). In addition to epicardial fixation of the electrodes at the collar area, the suture-type was further secured in place by tying the electrode's suture at its exit to another nonabsorbable pledget-supported suture. Acute thresholds and slew rates were not significantly different between the two groups. Although the R wave was lower in group I (8.4 +/- 3.5 mV) than in group II (11.8 +/- 6, p less than 0.01), no sensing problems occurred. The larger surface area of suture-type electrode led to lower resistance in group I (271 +/- 61 omega) compared with group II (356 +/- 72, p less than 0.001); however, the difference in pacemaker generator longevity did not appear significant (group I, n = 12, mean 4.7 +/- 1.6 years; group II, n = 4, mean 5 +/- 0.6 years). The incidence of exit block was significantly higher in group II (40%, 18/45) than in group I (8%, 4/52, p less than 0.01). The length of the stimulation tip and better fixation of the suture-type electrode probably accounted for the observed difference in the incidence of exit block between the two electrodes.

Adolescent↗
PubMed1990

An alternative approach to the surgical management of physiologically corrected transposition with ventricular septal defect and pulmonary stenosis or atresia.

A modified approach to the surgical management of corrected transposition of the great vessels with ventricular septal defect and pulmonary stenosis or atresia was used successfully in two patients. The procedure consisted of performing a venous switch operation, directing the blood flow from the morphologically left ventricle (right-sided chamber) into the aorta through the ventricular septal defect and inserting a valved conduit between the left-sided morphologically right ventricle and the pulmonary artery. This approach has several advantages when compared with the traditional surgical management, which consists of closure of the ventricular septal defect and a left ventricular (right-sided chamber) to pulmonary artery conduit. It uses the morphologically left ventricle as the systemic pumping chamber, thereby minimizing long-term ventricular failure. It allows closure of the defect from the right ventricular side of the septum, thus decreasing the prevalence of complete atrioventricular block. It also avoids use of the tricuspid valve as the systemic atrioventricular valve and therefore decreases the chance of postoperative valve regurgitation.

Adult↗
PubMed1989

Direct tricuspid closure versus atrial partitioning in Fontan operation for complex lesions.

Thirty-three patients with complex lesions undergoing the Fontan operation needed either direct tricuspid closure (group 1, 14 patients) or atrial partitioning (group 2, 19 patients). In group 1, the tricuspid patch was sutured to the annulus leaving the coronary sinus draining to the systemic venous atrium. In group 2, atrial partitioning was accomplished with either a Dacron or a polytetrafluoroethylene patch, leaving the coronary sinus draining to the pulmonary venous atrium. Intraoperative distention of the left side was used to check for residual defects. In group 1, complete heart block developed in 5 patients (36%) and patch disruption, in 4 patients (29%). There were 3 late deaths (21%), which were due to sudden death, sepsis caused by Candida, and liver failure. In group 2, no patient had heart block, and patch disruption developed in 1 patient (5%). There was 1 early death (5%) and 2 late deaths (11%), which were due to sepsis caused by Candida and renal failure. Our experience suggests that atrial partitioning is a better approach than direct tricuspid patch closure in patients with complex lesions undergoing the Fontan operation.

Adolescent↗