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Biomedical subjects

C L Backer

Publications and source records attributed to C L Backer.

At least 37 records · Page 2Linked to original sources
PubMed1999

Impact of arrhythmia circuit cryoablation during Fontan conversion for refractory atrial tachycardia.

Refractory atrial arrhythmias in late postoperative Fontan patients are usually associated with residual hemodynamic abnormalities and result in significant morbidity and mortality. Surgical revision of the Fontan anastomosis may improve hemodynamics without eliminating tachycardia. This study sought to assess the impact of surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion on the clinical recurrence of tachycardia. Sixteen consecutive atriopulmonary Fontan patients with refractory atrial arrhythmias underwent surgical conversion to lateral tunnel total cavopulmonary anastomosis (15) or Fontan revision (1 patient). The initial 4 patients underwent Fontan conversions alone, without specific arrhythmia surgery. The subsequent 12 patients underwent electrophysiologically guided cryoablation of the tachycardia circuits at the time of surgical conversion. The mean age at Fontan revision was 15.6 +/- 3.8 years. Cryoablation was directed to 3 identified major tachycardia circuits: the inferomedial right atrium, the superior rim of the prior atrial septal defect patch, and along the lateral right atrial wall. Transmural antitachycardia pacemakers were implanted in 11 of the 16 patients. There was no surgical mortality in either group, and all patients improved in functional classification. All patients not undergoing cryoablation experienced recurrent symptomatic tachycardia requiring antiarrhythmic therapy (median follow-up, 54 months) versus 2 of 12 patients receiving cryoablation (median follow-up, 25 months; p <0.02). Thus, surgical cryoablation of the arrhythmia circuit at the time of Fontan conversion is highly effective in the management of refractory atrial arrhythmias, and is superior to Fontan conversion alone.

Adolescent↗
PubMed1999

The use of balloon-expandable metallic stents in the treatment of pediatric tracheomalacia and bronchomalacia.

OBJECTIVE: To evaluate the use of balloon-expandable metallic stents in the treatment of children with tracheomalacia and bronchomalacia in whom conventional therapy has failed. DESIGN: Retrospective case series. SETTING: Tertiary pediatric otolaryngology and cardiothoracic surgery referral center. PATIENTS: Six patients were identified as having undergone bronchoscopic placement of metallic balloon-expandable stents between 1994 and 1997. The age at stent placement, prior surgical interventions, and indications for and sites of stent placement were noted. Also, the complications related to stent placement and the current airway status of the patients were reviewed. INTERVENTIONS: Twelve balloon-expandable metallic angioplasty stents (Palmaz; Johnson & Johnson Interventional Systems Co, Warren, NJ) were placed bronchoscopically in 6 patients. Six stents were placed in the lower trachea, and 6 were placed in the main bronchi. The stents were balloon expanded under fluoroscopic guidance. MAIN OUTCOME MEASURE: Discontinuation of mechanical ventilation. RESULTS: The age at stent placement ranged from 1.5 to 38 months (mean age at placement, 10 months). The indications for stent placement were (1) tracheomalacia or bronchomalacia, (2) pericardial patch or slide tracheoplasty failure, and (3) bronchomalacia caused by tetralogy of Fallot and large pulmonary arteries. The primary complication of stent placement was postoperative granulation tissue formation. One patient required the removal of 2 tracheal stents because of granulation tissue formation. There were 2 deaths in the series, 1 possibly related to stent placement. Four of the 6 patients were weaned from mechanical ventilation, and 3 experienced prolonged relief of airway obstruction. CONCLUSIONS: Metallic balloon-expandable stents are effective in relieving lower tracheomalacia and bronchomalacia in select patients. Only patients in whom conventional therapy has failed should be considered for stent placement.

Airway Obstruction↗
PubMed1999

A 26-year review of pectus deformity repairs, including simultaneous intracardiac repair.

BACKGROUND: We reviewed our operative experience and long-term results with repair of pectus excavatum and carinatum deformities through a vertical midline approach, including those cases with simultaneous intracardiac repair. METHODS: From 1972 through 1998, 120 children underwent pectus deformity repair. Operative technique used a vertical midline incision with subperichondrial resection of deformed cartilages and an anterior sternal osteotomy. Thirty-five patients had a temporary metal bar for retrosternal support for 6 months; 85 underwent repair without a bar. Patients and parents were asked to assess the outcome after pectus repair as poor, fair, good, or excellent. RESULTS: There were 94 male and 26 female patients (mean age, 8.4 years; range, 3 to 21 years). There were 111 cases of pectus excavatum and 9 of pectus carinatum. Fourteen children (11.5%) had an associated congenital heart defect; 9 patients had simultaneous pectus and intracardiac repair. One patient was referred for emergent open heart repair and pectus repair after attempted "Nuss" repair resulted in a perforated right atrium, perforated right ventricle, and partially disrupted tricuspid valve apparatus. There were no deaths and only one significant complication, which required a return to the operating room for bleeding. Morbidity was not higher in patients with simultaneous intracardiac repair. Long-term follow-up was established in 83% of patients. Results were classified as excellent in 64 patients (64%), good in 25 (25%), fair in 8 (8%), and poor in 3 (3%). Thirty (86%) of 35 patients with a sternal bar had excellent results versus 34 (52%) of 65 without a bar (p = 0.004); 97% of patients who underwent repair with a sternal bar classified the result as excellent or good. CONCLUSIONS: Long-term results of pectus excavatum and carinatum repair through a vertical midline approach are excellent. Outcome with a temporary sternal bar is superior to outcome without a bar. Concomitant repair of congenital heart defects and pectus deformity may be performed successfully without additional morbidity.

Adolescent↗
PubMed1999

Right aortic arch, right ligamentum, absent left pulmonary artery: a rare vascular ring.

A 5-month-old infant presented with respiratory failure secondary to severe right bronchial compression. Diagnostic imaging revealed a right aortic arch and absent left pulmonary artery. Surgical relief was obtained via median sternotomy by dividing a right ligamentum and pexing the enlarged right pulmonary artery to the ascending aorta.

Aorta, Thoracic↗
PubMed1999

Pulmonary artery sling: results with median sternotomy, cardiopulmonary bypass, and reimplantation.

BACKGROUND: The classic surgical approach to pulmonary artery (PA) sling has been through a left thoracotomy with division of the left PA and reimplantation into the main PA anterior to the trachea. Another approach is anterior left PA translocation with distal tracheal resection. Since 1985, we have repaired PA sling with a median sternotomy approach, cardiopulmonary bypass, and division and reimplantation of the left PA into the main PA with simultaneous repair of associated tracheal stenosis. The purpose of this review is to determine the outcome of that strategy. METHODS: From 1985 to 1998, 16 infants had surgical treatment of PA sling, 14 had left PA division and reimplantation into the MPA, 2 patients had repair using the translocation technique. Mean age at repair was 6.9 months, median age was 4 months. All infants, except 1 with an absent right lung, were operated on at the time of diagnosis. All had rigid bronchoscopy, which revealed associated complete tracheal rings in 12 patients. Seven patients had tracheal repair with pericardial tracheoplasty, 4 had repair using a tracheal autograft technique, and 2 had a distal tracheal resection (one for tracheomalacia). Of the 2 patients having the translocation technique, 1 had a severely hypoplastic right lung and the other had complete absence of the right lung. RESULTS: There has been no operative mortality. Hospital stay ranged from 5 to 188 days (mean 36 +/- 42 days). There was 1 late death 7 months postoperatively from respiratory complications of pericardial tracheoplasty. All left pulmonary arteries are patent and blood flow to the left lung by nuclear scan (n = 10) ranges from 24% to 46% (mean 35% +/- 9%). CONCLUSION: The strategy of median sternotomy, cardiopulmonary bypass, and left PA division and reimplantation into the main PA with simultaneous tracheal repair has resulted in a low operative mortality and excellent patency of the left pulmonary artery. Results with repair of the commonly associated complete tracheal rings has recently improved with the use of the free tracheal autograft technique.

Anastomosis, Surgical↗
PubMed1999

Supraarterial decompression myotomy for myocardial bridging in a child.

A 10-year-old boy presented with a history of exertional chest pain. An electrocardiogram demonstrated an inferior apical myocardial infarction. Cardiac catheterization revealed myocardial bridging of the left anterior descending coronary artery with evidence of intramyocardial obstruction during systole. The patient underwent successful treatment with supraarterial decompression myotomy and remains symptom free at 1 year.

Angina Pectoris↗
PubMed1999

Bidirectional Glenn shunt in association with congenital heart repairs: the 1(1/2) ventricular repair.

BACKGROUND: The bidirectional Glenn shunt has been used to incorporate a smaller tripartite ventricle into the circulation and create pulsatile pulmonary artery flow. We reviewed our operative experience and assessed hemodynamics of the bidirectional Glenn shunt in 1(1/2) ventricular repair or in conjunction with other repairs of congenital heart defects. METHODS: Between 1992 and 1998, 15 patients (mean age, 8.1+/-7.9 years) had bidirectional Glenn shunt in association with repair of congenital heart defects. Eighty-seven percent had at least one previous operation. All patients had simultaneous or previous intracardiac repair and had bidirectional Glenn shunt to volume unload the small right ventricle (group A, n = 7), to unload the poorly functioning right ventricle (group B, n = 2), to redirect superior vena cava-pulmonary venous atrial connection to treat cyanosis (group C, n = 2), or to unload the pulmonary left ventricle for residual intracavitary hypertension in patients with L-transposition of the great arteries, ventricular septal defect, and pulmonary stenosis (group D, n = 4). Intraoperative hemodynamic assessment was done in 2 patients in group A by selective use of inflow occlusion and flow probes. RESULTS: All patients survived. Four patients had successful, concurrent arrhythmia circuit cryoablation for Wolf-Parkinson-White syndrome (n = 1) or atrial reentry tachycardia (n = 3). Superior and inferior vena caval flow averaged 36% and 64% of cardiac output, respectively. Postoperative superior vena caval pressure (n = 13) was 13.7+/-4.0 mm Hg with pulmonary arterial flow pattern contributed by the ventricle in systole (pulsatile) and the superior vena cava in diastole (laminar). CONCLUSIONS: The bidirectional Glenn shunt is an effective adjunct to congenital heart repair to treat pulmonary ventricular pressure-volume problems and anomalous superior vena caval to left atrial connections.

Adolescent↗
PubMed1999

Pediatric coronary artery bypass for Kawasaki congenital, post arterial switch, and iatrogenic lesions.

BACKGROUND: Pediatric coronary artery bypass (PCAB) has been recently employed for expanding indications to treat acquired, congenital, post arterial switch, and other iatrogenic pediatric coronary artery problems. METHODS: Between 1987 and 1998, 3 infants and 13 children (n = 16, mean age 6.1 years, range 2 months-18 years) underwent one or more internal thoracic artery (ITA) to coronary artery (CA) bypass grafts for Kawasaki disease (n = 4), congenital lesions (n = 3), post arterial switch (n = 4), and other iatrogenic obstructions (n = 5). Proximal left main CA arterioplasty was performed concurrently with ITA-CA bypass in 4 patients. RESULTS: Survival is 93.8%. All bypass grafts in surviving patients are patent 2 months-11 years postoperation. The 11 elective patients are well (NYHA I-II). The 5 emergent operations were performed in 2 infants and 3 adolescents who had poor ventricular function prior to ITA-CA bypass due to iatrogenic injuries in 3, congenital critical left main stenosis in 1, and intraoperative iatrogenic coronary injury in 1. The 3 adolescents fared worse, resulting in death in the first, cardiac transplantation in the second, and full recovery in the third. The 2 infants have steadily improving ventricular function. CONCLUSIONS: ITA-CA bypass can be successfully performed in infants and children for expanding elective and life-saving indications with excellent results. Poor preoperative ventricular function often persists, especially in those older children with iatrogenic injuries, and may result in death or cardiac transplantation.

Adolescent↗
PubMed1999

Left ventricular growth in selected hypoplastic left ventricles: outcome after repair of coarctation of aorta.

BACKGROUND: Models that predict survival in neonates with left ventricular hypoplasia and critical aortic stenosis may not be applicable to neonates with left ventricular hypoplasia and coarctation. METHODS AND RESULTS: We report 8 infants with severe aortic coarctation and left ventricular hypoplasia. Mean age was 18 days (range 1-48 days), and mean weight was 3.5 kg (range 2.7-4.3 kg). Associated diagnoses included mild aortic stenosis (4), ventricular septal defect (2), and venous anomalies (2). All had coarctation repair as a primary procedure (3 of these had concomitant intracardiac procedures); 7 had subsequent operations. All are alive and well 1.1-6.7 years (mean 3.1 years) after the first surgery. Progressive increases were observed in aortic and mitral diameters, and in left ventricular dimensions, areas, and volumes when the preoperative, earliest postoperative, and most recent echocardiograms were compared. CONCLUSIONS: Despite severe left ventricular hypoplasia, a two-ventricle repair is possible in selected cases. The prognostic criteria for left ventricular hypoplasia in critical aortic stenosis may not be applicable to infant coarctation. Relief of coarctation may result in the growth of the very small left ventricle, especially when the aortic root and mitral diameters are satisfactory.

Aortic Coarctation↗
PubMed1999

Captopril and platelet-activating factor (PAF) antagonist prevent cardiac allograft vasculopathy in rats: role of endogenous PAF and PAF-like compounds.

Accelerated coronary artery disease (CAD) is the leading cause of late mortality following cardiac transplantation. The vascular lesions are characterized by myointimal proliferation and perivascular mononuclear inflammatory infiltrates. Platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a potent phospholipid mediator produced by inflammatory cells and activated endothelial cells. Angiotensin II is known to activate phospholipase A2, a critical enzyme in PAF synthesis. Using a rat heterotopic cardiac transplant model known to induce graft CAD, we previously reported that chronic administration of captopril, an angiotensin converting enzyme inhibitor, reduces intimal proliferation and maintains luminal patency. The purpose of the current study was to determine if captopril regulates vascular remodeling by suppressing PAF synthesis and whether administration of a PAF antagonist ameliorates graft CAD. Captopril was found to decrease levels of PAF and PAF-like compounds as well as reduce intimal lesions, decrease cellular rejection grade, and diminish allograft heart weights. Treatment with a PAF antagonist significantly decreased proliferation of the intimal component of the vasculopathy and caused regression of the cardiac hypertrophy, but had no significant effect on cellular rejection. In contrast, untreated animals had elevated plasma PAF levels, elevated heart weights, and severe myointimal proliferation with luminal stenosis 21 days post-transplantation. These observations suggest that graft CAD is mediated, in part, by PAF and PAF-like compounds, and suppression of endogenous PAF may prevent cardiac allograft vasculopathy.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1999

Dobutamine stress echocardiography: experience in pediatric heart transplant recipients.

BACKGROUND: Transplant coronary arteriopathy causes late death and is difficult to detect noninvasively. Dobutamine stress echocardiography is being used for risk stratification in adult recipients at some transplant centers, thus we investigated its role in a pediatric population. METHODS: We performed 46 stress echo studies (mean age = 11.8 years; mean years post transplantation = 4.3). An atropine/dobutamine protocol (5-40 mcg/kg/min) was used to attain a predicted target heart rate. Serial echocardiographic images were acquired at baseline and at each increment of dobutamine and recovery, and were digitized online. Data were correlated with endomyocardial biopsy (n = 23), coronary angiography (n = 26) or autopsy (n = 6). All studies were well tolerated. RESULTS: Target heart rate was achieved in 41/46 (89%) studies. The mean heart rate significantly increased from 95 to 169 beats/min and mean systolic blood pressure from 123 to 153 mm Hg (p<.05). The mean peak pressure-rate product was 23,041 beats-mm Hg/min. Coronary arteriopathy was confirmed in 5 patients by angiography (n = 3) explanted heart (n = 1) or autopsy (n = 4). In this group, abnormalities included a new reversible wall motion abnormality (n = 2), left ventricular cavity dilation with stress (n = 3), ischemia (n = 2), increased mitral insufficiency (n = 1) and marked diastolic dysfunction (n = 1). A positive study predicted death or graft failure (p< .0005). CONCLUSIONS: Echocardiographic abnormalities during stress correlated with coronary arteriopathy in this small cohort of patients; however, larger multi-center studies are warranted to assess the utility of dobutamine stress echocardiography for risk stratification for coronary disease in pediatric transplant recipients.

Adolescent↗
PubMed1999

Transmural atrial pacing in patients with postoperative congenital heart disease.

INTRODUCTION: Some patients with postoperative congenital heart disease require permanent cardiac pacing, but the use of transvenous or epicardial pacing leads may be limited by type of cardiac malformation, venous connections, body size, or fibrosis. Transmural atrial pacing may provide an alternative in difficult patients, but to date has been described in only a few articles with small patient numbers, and data from lead performance are lacking. METHODS AND RESULTS: Records were reviewed in 18 consecutive patients (4 months to 21 years old) with postoperative congenital heart disease receiving transmural atrial pacing leads from July 1994 to December 1996. Implantation materials and techniques were described. Lead sensing and capture thresholds obtained acutely and during short-term follow-up (mean: 11.0 months) were evaluated, and comparisons were made between patients with postoperative Fontan anatomy and non-Fontan patients, and between patients receiving steroid-eluting and nonsteroid leads. Overall, the median acute sensing and capture thresholds of transmural leads were 4.1 m V and 0.7 V at 0.5 msec, respectively. Median follow-up thresholds were 2.8 m V and 0.8 V, respectively. Performance of leads in Fontan patients was similar to those in non-Fontan patients. Steroid-eluting leads had a chronic capture threshold of 0.6 V versus 0.9 V for nonsteroid leads (P = 0.038). CONCLUSION: Transmural atrial pacing leads were successfully implanted in patients with diverse ages and types of postoperative congenital heart disease. Lead performance was acceptable both acutely and during the first year of follow-up.

Adolescent↗
PubMed1998

Repair of mitral valve and subaortic mycotic aneurysm in a child with endocarditis.

Endocarditis requiring surgical intervention in children is uncommon. Individualized operative therapy must be fashioned to the particular pathology of each case. In this case we describe mitral anterior leaflet homograft patch augmentation valvuloplasty, subaortic homograft patch closure of a large mycotic aneurysm, and homograft aortic root replacement in a 3-year-old patient with endocarditis after remote repair of complete atrioventricular canal.

Aneurysm, Infected↗
PubMed1998

Traumatic left ventricular aneurysm and tricuspid insufficiency in a child.

We describe a rare combination of left ventricular aneurysm and severe tricuspid valve insufficiency in a 9-year-old boy who sustained blunt chest trauma in a motor vehicle accident. The child underwent successful aneurysmorrhaphy and tricuspid valve replacement 9 months after the accident.

Accidents, Traffic↗
PubMed1998

Axillary thoracoscopy.

Thoracoscopy can be done safely and effectively through working ports placed in the axilla in patients whose pathology is in the upper half of the thorax. We have used this technique successfully in 37 patients with no complications. Advantages include superior cosmesis, optimal access to the apex of the chest, and, if necessary, easy conversion to axillary thoracotomy.

Adolescent↗
PubMed1998

Does banding the pulmonary artery affect pulmonary valve function after the Damus-Kaye-Stansel operation?

BACKGROUND: The Damus-Kaye-Stansel (DKS) operation can be an effective palliation in patients who have single-ventricle physiology and systemic outflow obstruction. Pulmonary artery banding (PAB) may be used as a preliminary procedure in these patients to limit overperfusion of the pulmonary circulation. In some series, the DKS operation has been associated with pulmonary insufficiency (PI). We retrospectively analyzed medical records of our patients who had PAB and later DKS to determine the incidence of PI in these patients. METHODS: Between 1982 and 1996, 15 patients underwent PAB before DKS. Median age at PAB placement was 7 days and median duration of PAB was 7 months. Echocardiograms obtained before PAB, before DKS, and at the most recent post-DKS follow-up were reviewed. RESULTS: Follow-up ranged from 1 to 15 years (mean follow-up, 7.5 years). One patient had trivial PI before PAB, which progressed to moderate PI at the last follow-up. Only 1 other patient had mild PI, but only at the last follow-up after DKS. CONCLUSIONS: These findings suggest that prior PAB does not appear to cause significant PI in patients slated for DKS, and the incidence of significant PI after the DKS operation is relatively low.

Cardiac Surgical Procedures↗
PubMed1998

Repair of coarctation with resection and extended end-to-end anastomosis.

BACKGROUND: Our surgical strategy for infant coarctation changed from subclavian flap aortoplasty to resection with extended end-to-end anastomosis in 1991. The purpose of this review was to evaluate the results of that strategy. METHODS: From 1991 through 1997, 55 infants underwent repair of coarctation of the aorta using resection with extended end-to-end anastomosis. Isolated coarctation of the aorta was present in 26 patients, 20 patients had a ventricular septal defect, and 9 patients had other associated intracardiac lesions. Mean age at surgery was 0.20+/-0.24 years (median, 21 days). In 34 patients (62%), arch reconstruction was performed through a left thoracotomy. Twenty patients (36%) had median sternotomy with simultaneous repair of coarctation of the aorta and intracardiac repair of associated lesions. One patient had recoarctation repair through a median sternotomy. All coarctation and ductal tissue was resected and the anastomosis was constructed starting opposite the left carotid artery with running polypropylene suture. RESULTS: There was one early death 26 days after coarctation of the aorta and ventricular septal defect repair in a child on extracorporeal membrane oxygenation for meconium aspiration and 2 late deaths owing to pneumonia and pulmonary hypertension (1) and interventricular hemorrhage (1). There were no instances of paraplegia. Follow-up in survivors ranges from 10 to 76 months (mean, 39.8+/-17.2 months). Recoarctation has developed in 2 patients, who have had successful balloon dilation 6 and 14 months after the operation. This yields a low recoarctation rate of 3.6%. CONCLUSIONS: Resection with extended end-to-end anastomosis yields a low mortality and particularly a low recoarctation rate and is our procedure of choice for infants with coarctation of the aorta.

Anastomosis, Surgical↗