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Biomedical subjects

C L Backer

Publications and source records attributed to C L Backer.

At least 109 records · Page 6Linked to original sources
PubMed1989

Transposition of the great arteries: a comparison of results of the mustard procedure versus the arterial switch.

Sixty infants with transposition of the great arteries and intact ventricular septum underwent primary surgical correction in the first 3 months of life. Twenty-three patients had a Mustard procedure (group 1) and 37 patients, an arterial switch operation (group 2). The mean age at the time of repair was 42 +/- 31 days for group 1 and 8 +/- 6 days for group 2 (p less than 0.001). The mean weight at the time of repair was 3.6 +/- 0.7 kg for group 1 and 3.4 +/- 0.5 kg for group 2 (p = not significant). Operative mortality was 8.7% (2/23) in group 1 and 8.1% (3/37) in group 2 (p = not significant). The incidence of arrhythmias in the early postoperative period was 39% (9/23) in group 1 and 11% (4/37) in group 2 (p less than 0.01). All patients were followed a mean of 4.8 +/- 2.4 years in group 1 and 2.6 +/- 1.4 years in group 2 (p less than 0.001). Postoperative catheterization has been performed in 86% (18/21) of group 1 operative survivors and 50% (17/34) of group 2 operative survivors. Ejection fraction of the systemic ventricle was 79% +/- 15% of predicted normal in group 1 and 98% +/- 6% in group 2 (p less than 0.005). The incidence of late arrhythmias was 57% (12/21) in group 1 and 3% (1/34) in group 2 (p less than 0.001). There have been 2 late deaths in group 1 and 1 late death in group 2 (p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrhythmias, Cardiac↗
PubMed1989

Vascular anomalies causing tracheoesophageal compression. Review of experience in children.

Two hundred four infants and children (mean age 13 months) have undergone operation for the relief of tracheoesophageal obstruction resulting from vascular anomalies. One hundred thirteen patients had complete vascular rings (group I), 61 with double aortic arch and 52 with right aortic arch with a left ligamentum. Nine patients had a pulmonary artery sling (group II), 71 had innominate artery compression (group III), and 11 had miscellaneous anomalies (group IV). Patients were admitted with respiratory distress, stridor, apnea, dysphagia, or recurrent respiratory infections. Diagnosis was established by barium esophagogram in group I; barium esophagogram, bronchoscopy, and computed tomography or angiography in group II; bronchoscopy in group III; and barium esophagogram or angiography in group IV. The operative approach was through a left thoracotomy in group I, II and IV (93% of these patients) and through a right thoracotomy for group III (96% of these patients). The operative mortality rate was 4.9% and there were seven late deaths (3.4%). There have been no operative deaths in patients with isolated vascular anomalies in the past 28 years. Follow-up data from 1 month to 20 years (mean 8.5 months) were available on 159 patients; 141 (92%) were essentially free of symptoms, and 12 (8%) had residual respiratory problems. Five of six patients in group II having a lung scan postoperatively had a patent left pulmonary artery. A strong index of suspicion is necessary to avoid the complications of vascular rings in children. Barium swallow is the best single diagnostic technique for patients with complete vascular rings. A bronchoscopic study is required to diagnose innominate artery compression. Angiograms or computed tomographic scans are used to confirm the diagnosis of pulmonary artery sling. Left thoracotomy provides excellent exposure for all vascular rings except the displaced innominate artery, for which a right thoracotomy is the best approach.

Aorta, Thoracic↗
PubMed1988

Comparison of single versus multidose blood cardioplegia in arterial switch procedures.

Fifty-three patients with transposition of the great arteries and Taussig-Bing anomaly undergoing an arterial switch procedure were divided into two groups. Group 1 (N = 32) received multidose cardioplegia injected initially into the aortic root and subsequently into the coronary artery orifices and Group 2 (N = 21), single-dose cardioplegia injected into the aortic root. The mean aortic cross-clamp and bypass times were generally longer in Group 1 compared with Group 2. Group 1 patients with simple transposition undergoing primary repair (N = 15) had an aortic cross-clamp time of 80 +/- 8 minutes and a bypass time of 203 +/- 27 minutes versus 64 +/- 6 minutes (p less than 0.001) and 170 +/- 15 minutes (p less than 0.01), respectively, for similar patients in Group 2 (N = 10). Group 1 patients with simple transposition undergoing staged repair (N = 7) had an aortic cross-clamp time of 71 +/- 6 minutes and a bypass time of 201 +/- 24 minutes versus 66 +/- 4 minutes (p = not significant [NS]) and 226 +/- 25 minutes (p = NS), respectively, for Group 2 (N = 6). In Group 1 patients with complex transposition (N = 10), the aortic bypass time was 79 +/- 12 minutes and the bypass time was 261 +/- 40 minutes versus 64 +/- 11 minutes (p less than 0.05) and 225 +/- 16 minutes (p less than 0.1), respectively, for Group 2 (N = 5). Early mortality was 16% (5/32) in Group 1; there were no early deaths in Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1988

Coronary embolism following atrial septal defect repair.

To our knowledge, coronary embolism following repair of atrial septal defect has not been reported previously. A 29-year-old woman had an angiographically documented embolus to the circumflex coronary artery on the fifth postoperative day after pericardial patch repair of a secundum atrial septal defect. This complication might have been prevented by temporary postoperative anticoagulation.

Adult↗
PubMed1988

Transposition of the great arteries with intact ventricular septum. Arterial switch in the first month of life.

Twenty-three infants with simple transposition of the great arteries and intact ventricular septum were operated on from October 1983 to October 1986. The age at operation in 22 infants ranged from 2 to 21 days and in one was 35 days (mean 9.82 +/- 6.86 days). The infants were evaluated with cardiac catheterization at 1 to 27 days of age. Twenty-two infants had balloon atrial septostomy, and 22 received prostaglandin E1 infusion. The left ventricular diastolic wall thickness, assessed by M-mode echocardiograms, varied between 2.8 and 4 mm. There were two hospital deaths in this group of 23 infants (mortality 8.6%), and there were no late deaths. All surviving patients are doing well clinically. One patient had asymptomatic nonsustained ventricular tachycardia necessitating phenytoin. Postoperative echocardiographic assessment performed on 15 patients at 0.93 +/- 0.61 years of age and cardiac catheterization and angiographic studies on seven patients at 1.07 +/- 0.13 years after operation revealed excellent ventricular performance, good semilunar valve function, and mild gradient at the right ventricular outflow with a mean right ventricular pressure of 37.4 +/- 4.1 torr.

Aorta↗
PubMed1987

Selective preoperative evaluation for possible N2 disease in carcinoma of the lung.

The efficacy of computed tomography and surgical mediastinal exploration in determining tumor resectability were retrospectively evaluated in 92 consecutive patients with non-small cell lung carcinoma. Status of mediastinal nodes was ultimately determined by surgical mediastinal exploration or thoracotomy. Patients were divided into three groups on the basis of chest roentgenography: Group I comprised 30 patients with peripheral T1 or T2 lesions with normal hilar and mediastinal shadows. Only one patient was found to have an involved node. Chest roentgenography had an accuracy rate of 96% and computed tomography, 93%. Thoracotomy is recommended without either computed tomography or surgical mediastinal exploration in this group. Group II comprised 47 patients with T1 or T2 lesions with an abnormal hilus, an abnormal mediastinal shadow, or either the hilus or mediastinum obscured by overlying parenchymal disease. Computed tomography revealed mediastinal nodes 1 cm or greater in size (abnormal node group) in 21 patients (45%) and smaller than 1 cm (normal node group) in 26 patients (55%). Surgical mediastinal exploration was performed in the abnormal node group and involved nodes were found in 17 of 21 patients (81%). In the normal node group, thoracotomy only was performed and no involved nodes were found. Computed tomography is recommended in all patients in Group II. Patients in the normal node group may be subjected to thoracotomy only and those in the abnormal node group should undergo surgical mediastinal exploration as the next diagnostic step before thoracotomy. Group III comprised 15 patients with grossly abnormal mediastinal shadows. Findings from computed tomography were abnormal in all 10 patients in whom it was done. Surgical mediastinal exploration was done in all 15 and yielded abnormal results in 14. It is recommended in this group that computed tomography is unnecessary and surgical mediastinal exploration should be the only diagnostic procedure. Thus, in potentially resectable non-small cell lung carcinoma, the use of computed tomography and surgical mediastinal exploration should be selective and should be determined by appropriate initial interpretation of the chest roentgenogram.

Carcinoma, Non-Small-Cell Lung↗
PubMedDate not supplied

Cardiac plasma cell granulomas: response to oral steroid treatment.

Plasma cell granulomas are lesions of uncertain histogenesis arising in a variety of locations, most commonly the lung. Treatment for these lesions is complete surgical excision if possible. Unresectable pulmonary lesions respond to oral corticosteroids and radiation therapy. We report the long-term outcome of two unusual pediatric cases of cardiac plasma cell granulomas originating within the right ventricle and posterior aspect of the left ventricle. The limited literature reports advocate surgical resection for this entity, with no discussion of alternative treatment strategies for unresectable lesions. We prospectively evaluated the response to postoperative oral steroid therapy, as complete surgical excision was not possible in either case. Sequential echocardiography demonstrated additional significant reduction in the size of the masses and the patients remain asymptomatic at 9 and 5.5 years follow-up, without evidence of obstruction or recurrence. Oral corticosteroids should be considered as a treatment option for any unresectable plasma cell granuloma.

Administration, Oral↗
PubMedDate not supplied

Alterations in the natriuretic hormone system related to cardiopulmonary bypass in infants with congestive heart failure.

This study examined changes in the natriuretic hormone system in five infants with congestive heart failure (CHF) due to intracardiac left-to-right shunting who were exposed to cardiopulmonary bypass (CPB) during surgical repair. Plasma concentrations of three hormones [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and dendroaspis natriuretic peptide (DNP)] and their secondary messenger, guanosine 3',5'-monophosphate (cGMP), were measured, and the biological activity of the system was quantified. At baseline, BNP and DNP concentrations were normal in our patients, a finding that is strikingly different from that of adult CHF patients, whereas ANP concentrations were elevated. Following CPB, ANP concentrations decreased (median, 175 vs 44 pg/ml; p = 0.043) and BNP concentrations increased (median, 25 vs 66 pg/ ml; p = 0.043), whereas DNP concentrations did not change. Following modified ultrafiltration, BNP concentrations increased (p = 0.043), but other natriuretic peptide concentrations did not change. The calculated biological activity of the natriuretic hormone system decreased following CPB [molar ratio, cGMP / (ANP + BNP + DNP); median, 213 vs 127; p = 0.043)]. Additional studies are needed to expand on these findings and identify patients with other types of congenital heart disease who have perioperative disturbances in the natriuretic hormone system and thus might benefit from pharmacologic intervention.

Atrial Natriuretic Factor↗
PubMedDate not supplied

New directions in surgical therapy of arrhythmias.

The success of the radiofrequency catheter ablation procedure for most types of supraventricular and ventricular tachycardia, particularly in young patients, largely eliminated the role of surgical therapy of arrhythmias. However, there remains a subset of arrhythmia patients in whom the catheter approach has not been successful and types of arrhythmias with high recurrence rates following initially successful catheter ablation procedures where surgery can provide more definitive therapy. In addition, the concepts of ablation therapy can be successfully incorporated into the concomitant repair of complex congenital heart disease, resulting in single-stage therapy for structural and rhythm abnormalities. Prospectively, knowledge of the role of anatomic barriers as substrates for future reentrant arrhythmia circuits provides the opportunity to alter these circuits prophylactically at the time of initial surgical repair of congenital heart disease in an attempt to avoid the late development of tachycardia. This article describes our experience during the past decade with 71 patients undergoing arrhythmia surgery using this approach.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Is surgical ligation of an accessory left superior vena cava always safe?

In patients considered for bidirectional Glenn or Fontan procedures, the association of left superior vena cava (LSVC) with ostial atresia of the coronary sinus should be diagnosed preoperatively in order to avoid surgical division or ligation of the LSVC and the negative effect of resulting coronary venous hypertension on myocardial perfusion. This report discusses the angiographic and hemodynamic features of LSVC when it is the only drainage route from a blind coronary sinus. A retrograde flow in the LSVC seen by Doppler ultrasonography should raise the suspicion of this diagnosis.

Angiography↗
PubMedDate not supplied

Testing of an intrathoracic artificial lung in a pig model.

A low input impedance, intrathoracic artificial lung is being developed for use in acute respiratory failure or as a bridge to transplantation. The device uses microporous, hollow fibers in a 0.74 void fraction, 1.83 m2 surface area bundle. The bundle is placed within a thermoformed polyethylene terephthalate glucose modified housing with a gross volume of 800 cm3. The blood inlet and outlet are 18 mm inner diameter vascular grafts. Between the inlet graft and the device is a 1 inch inner diameter, thin-walled, latex tubing compliance chamber. These devices were implanted in Yorkshire pigs via median sternotomy with an end to side anastomosis to the pulmonary artery and left atrium. The distal pulmonary artery was occluded to divert the right ventricular output to the device. Pigs 1 and 2 were supported fully for 24 hrs and then killed. Pig 3 was supported partially for 20 hrs and died from bleeding complications. The first implant, in a 55 kg male pig, transferred an average of 176 ml/min +/- 42.4 of O2 and 190 ml/min +/- 39.7 of CO2 with an average blood flow rate of 2.71/min +/- 0.46. The normalized average right ventricular output power, Pn, was 0.062 W/(L/min) +/- 0.0082, and the average device resistance, R, was 3.5 mmHg/(L/min) +/- 0.62. The second implant, in a 60 kg male pig, transferred an average of 204 ml/min +/- 22.5 of O2 and 242 ml/min +/- 17.2 of CO2 with an average blood flow rate of 3.7 L/min +/- 0.45, Pn of 0.064 W/(L/min) +/- 0.0067, and R of 4.3 mmHg/(L/min) +/- 0.89. The third implant, in an 89 kg male pig, transferred an average of 156 ml/min +/- 39.6 of O2 and 187 ml/min +/- 21.4 of CO2 with an average blood flow rate of 2.5 L/min +/- 0.49, Pn of 0.052 W/(l/min) +/- 0.0067, and R of 3.4 mmHg/(L/min) +/- 0.74. These experiments suggest that such an artificial lung can temporarily support the gas transfer requirements of adult humans without over-loading the right ventricle.

Adult↗
PubMedDate not supplied

Ascending aortic extension for right pulmonary artery stenosis associated with ventricular-to-pulmonary artery conduit replacement.

BACKGROUND: Ventricular-to-pulmonary artery conduits in growing patients with congenital heart disease will require replacement from time to time due to somatic growth, neointimal hyperplasia, and pulmonary artery stenosis. The purpose of this article is to review our experience with ascending aortic extension for significant long-segment pulmonary artery stenosis in patients undergoing reoperation for right ventricular-to-pulmonary artery conduit replacement. METHODS: From 1989 to 1997, 8 patients had aortic transection, right pulmonary artery augmentation arterioplasty, and aortic interposition graft (Hemashield in 7 and Gore-tex in 1) in association with right ventricular-to-pulmonary artery conduit replacement in 7 patients and completion Fontan operation in 1 patient. Aortic cross-clamp time was 90 +/- 34 minutes, and the cardiopulmonary bypass time was 205 +/- 37 minutes. RESULTS: All patients survived. In those 7 patients who had conduit replacement, the RV/LV ratio declined from 0.78 +/- 0.15 to 0.45 +/- 0.05 postoperatively (P < 0.05). Average length of stay was 8.9 +/- 7.2 days. Follow-up range is 18 months to 8 years (mean 4 years). Two complications included cardiac transplantation for pre-existing poor left ventricular function and accelerated conduit stenosis leading to conduit re-replacement. CONCLUSION: Ascending aortic extension facilitates long-segment pulmonary artery augmentation arterioplasty and enlarges the retroaortic space, preventing future compression restenosis.

Adolescent↗
PubMedDate not supplied

Complete repair of Tetralogy of Fallot with absent pulmonary valve including the role of airway stenting.

Tetralogy of Fallot (TOF) with absent pulmonary valve (APV) represents an extreme form of tetralogy where pulmonary insufficiency and mild annular stenosis often results in massive pulmonary arterial (PA) dilatation. The aneurysmal left and right PAs often compress the adjacent trachea and bronchi, leading to airway obstruction and respiratory failure in infancy. Between 1991 and 1997, 11 patients underwent a single stage repair of TOF and APV using a valved (10 patients) or nonvalved (1 patient) homograft conduit and PA reduction arterioplasty. There was one (1/11 [9.1%) perioperative and one (9.1%) late death. Both deaths were related to airway complications. Morbidity associated with postoperative respiratory complications and ventilator-dependency due to underlying tracheobronchomalacia is an important problem. Intermediate follow-up shows a high incidence of reintervention for conduit stenosis and/or insufficiency and tracheobronchial compression. These infants also required multiple hospitalizations for recurrent respiratory infections secondary to their tracheobronchomalacia. Stenting of the right and left main bronchi with balloon expandable metallic stents is a new experimental therapy that has been useful in two recent patients with respiratory failure despite satisfactory intracardiac repair. It may provide an attractive alternative therapy to prolonged mechanical ventilation with positive end expiratory pressure in patients with severe tracheobronchomalacia. Complete repair with a valved homograft conduit and reduction pulmonary arterioplasty in infancy at the time of diagnosis is the procedure of choice for infants with TOF with APV. With this approach the patient outcome is essentially determined by their airway status and airway management.

Bronchi↗
PubMedDate not supplied

A comparison of steroid-eluting epicardial versus transvenous pacing leads in children.

OBJECTIVE: To evaluate the acute and chronic performance of steroid-eluting (SE) epicardial (EPI) pacing leads as compared to SE transvenous (TV) pacing leads in children. METHODS: From 1989 through 1997, 55 children with congenital heart disease received a total of 85 SE pacing leads, of which 38 were EPI and 47 TV. The mean age of children receiving EPI leads was younger than those receiving TV leads (7.7 months vs 15.1 years, p = 0.001), and they had shorter follow-up (17.2 months vs 36.2 months, p < 0.001). All leads were evaluated for acute and chronic sensing and capture thresholds, and impedance. RESULTS: Acute and in particular chronic atrial and ventricular sensing and capture thresholds in SE EPI and TV leads were essentially equivalent. [table: see text]. The chronic impedance of TV leads (atrial 525 ohms, ventricular 520 ohms) was consistently higher than EPI leads (atrial 404 ohms, ventricular 386 ohms). CONCLUSION: At intermediate follow-up, SE EPI leads are functionally equivalent to SE TV leads. We recommend the use of SE EPI leads as long as practically feasible prior to using the TV approach in children who will require a life-time of pacing.

Adolescent↗
PubMedDate not supplied

Risk factors for recoarctation and results of reoperation: a 40-year review.

BACKGROUND: We analyzed a single institution 40-year experience with children that had coarctation repair to define risk factors for recoarctation and to evaluate the results of reoperation for recoarctation. MATERIAL AND METHODS: Between 1957 and 1998, 271 patients had primary surgical repair of coarctation of the aorta. Techniques for primary repair included Gore-tex patch aortoplasty (PATCH; n = 118), resection with extended end-to-end anastomosis (RXEEA; n = 69), subclavian flap aortoplasty (SFA; n = 61), resection with simple end-to-end anastomosis (ETE; n = 18), resection and interposition graft (n = 4), and extra-anatomic graft (n = 1). Techniques for recoarctation repair included PATCH, interposition graft, and extra-anatomic graft. RESULTS: Median age at initial repair was 156 days. Major associated cardiac anomalies were present in 96 patients (35%). A hypoplastic aortic arch was present in 37 patients (14%). There were three early deaths (1%) and six late deaths (2%). One patient had paraplegia (0.4%). Recoarctation occurred in 29 patients (11%) and was most frequent with ETE and SFA repairs (33% and 20%, respectively). Multiple logistic regression analysis revealed ETE repair (p = 0.0002), SFA repair (p = 0.049), and aortic arch hypoplasia (p = 0.0001) to be risk factors for recoarctation. Using PATCH as the covariate, the odds ratio to develop recoarctation was 3.5 for SFA, 17.2 for ETE, and 15.2 for hypoplastic aortic arch. There was no mortality or paraplegia after recoarctation repair (n = 23). Six patients had seven balloon angioplasties; two of these patients later required reoperation. Three patients required a second reoperation for persistent coarctation. CONCLUSIONS: In our 40-year review, simple end-to-end anastomosis and subclavian flap repair had the highest incidence of recoarctation, especially when associated with aortic arch hypoplasia. We recommend resection with extended end-to-end anastomosis for repair of neonates and infants and Gore-tex patch aortoplasty for children over the age of 1 year. Surgical repair of recurrent coarctation is safe, effective, and has a low incidence of persistent coarctation.

Anastomosis, Surgical↗
PubMedDate not supplied

Heart transplantation in neonates and in children.

Between May 1988 and July 1991, 28 neonates and children underwent orthotopic heart transplantation at Children's Memorial Hospital in Chicago. Indications for heart transplantation were hypoplastic left heart syndrome (10), dilated cardiomyopathy (13), aortic stenosis with endocardial fibroelastosis (1), complex D-transposition of the great arteries after Senning repair (1), L-transposition of the great arteries with single ventricle after shunt (1), cor biloculare, pulmonary atresia, and situs inversus after Fontan (1), and chronic rejection after heart transplantation for hypoplastic left heart syndrome (1). The age at time of transplantation ranged from 2 days to 17 years (mean, 5.3 +/- 6.1 years). Early deaths were from intraoperative donor right ventricular failure (2) and acute rejection after a second transplant procedure at 21 days (1), for an in-hospital mortality rate of 10.7%. Immunosuppression was with cyclosporine, azathioprine, and prednisone, with an attempt to discontinue the prednisone in neonates at age 6 months as guided by endomyocardial biopsy. Rejection episodes were treated with methylprednisolone pulse (34) or with OKT3 (4). Endomyocardial biopsy (in patients older than 6 months) was used extensively, and acute rejection was diagnosed in 29 of 301 biopsies. Three late deaths occurred (mean follow-up, 16.3 +/- 11.8 months): one of acute rejection at 13 months, one of viral pneumonia at 7 months, and one of intraabdominal sepsis as a complication of peritoneal dialysis at 5 months. Actuarial survival at 2 years is 77% +/- 9% (standard error of the estimate). Heart transplantation for neonates and for children can be performed with acceptable operative mortality. Intermediate results with triple therapy immunosuppression and an intensive rejection surveillance regimen relying on endomyocardial biopsy are encouraging.

Actuarial Analysis↗
PubMedDate not supplied

Influence of gender on allograft rejection in a rat heart transplant model.

BACKGROUND: Clinical studies have reported increased rejection in female heart transplant recipients. Conflicting data exist as to whether rejection is increased with male donors or female donors in these female recipients. METHODS: We investigated in this study allograft rejection in four sets of gender combinations with and without immunosuppression with the use of a heterotopic rat heart transplant model: male donor heart to female recipient, female donor heart to female recipient, male donor to male recipient, and female donor to male recipient. To examine the possible effect of androgens as an immunosuppressant, we orchiectomized a group of male recipient rats before transplantation. The rats that were not immunosuppressed were evaluated for length of graft survival (palpation). In the immunosuppressed rats (cyclosporine, 10 mg/kg x 7 days) in each gender combination half of the grafts were evaluated for length of survival (palpation) and half for cellular rejection grade at day 14 (microscopy). RESULTS: When rats that underwent transplantation were not immunosuppressed, no difference in graft survival time was found among the four sets of gender combinations. With immunosuppression, median graft survival time was 23 days in female recipients versus 32 days in male recipients (p < 0.05). Mean cellular rejection grade at day 14 was 2.95 +/- 0.7 in female recipients and 0.8 +/- 0.4 in male recipients (p < 0.01). No significant difference was found in graft survival time or cellular rejection grade with respect to donor gender. The graft survival times and cellular rejection grades of the male rats undergoing orchiectomy were not different from those of normal male recipients (p = NS). Cyclosporine levels on day 7 in both male and female recipients were high, female levels (1039 +/- 411 ng/ml) were less than male levels (2029 +/- 379 ng/ml) (p < 0.01). CONCLUSIONS: Female recipients of heterotopic rat heart transplants had shorter graft survival time and increased cellular rejection as compared with male recipients. Donor gender had no influence on graft survival or cellular rejection grade. Orchiectomy had no influence on graft survival time or grade of rejection. Results of this model suggest that female recipients may require increased immunosuppression and rejection surveillance, regardless of donor gender.

Animals↗