Transcatheter closure of patent ductus venosus with the Amplatzer vascular plug in twin brothers.

We describe the transcatheter closure of a patent ductus venosus in twin brothers with an ill-defined systemic illness and respiratory failure using the Amplatzer vascular plug. To our knowledge, this is the first description of the use of the Amplatzer vascular plug for ductus venosus closure.

Recurrent arch obstruction after repair of isolated coarctation of the aorta in neonates and young infants: is low weight a risk factor?

BACKGROUND: Repair of aortic coarctation is often delayed in small infants because of the belief that such patients are at risk of recurrent arch obstruction and that growth will decrease this risk. To determine whether low weight was a risk factor for recurrent arch obstruction, we reviewed our experience with coarctation repair via left thoracotomy in infants less than 3 months of age. METHODS: From 1990 to 1999, 103 patients less than 3 months of age underwent repair of aortic coarctation through a left thoracotomy. Median age was 18 days (1-90 days), with 45 patients less than 2 weeks. Median weight was 3.3 kg (1.0-6.4 kg) and 14 patients were less than 2 kg. The method of repair was resection and end-to-end anastomosis in 64 patients, subclavian flap angioplasty in 34, and patch augmentation of the arch in 5. Demographic, echocardiographic, and operative variables were analyzed for correlation with recurrent arch obstruction. RESULTS: One early and 1 late death occurred, both in patients who had complications but no evidence of recoarctation. At median follow-up of 24 months, reinterventions for recurrent arch obstruction were performed in 15 patients. The median time to reintervention was 5 months and was less than 1 year in 12 patients. Kaplan-Meier freedom from arch reintervention was 88% at 1 year (95% confidence intervals: 82%-94%) and 82% at 5 years (95% confidence intervals: 72%-92%). Factors associated with shorter duration to arch reintervention by univariable Cox regression included younger age (continuous, P =.01; <2 weeks, P =.005), smaller transverse arch (absolute diameter, P <.001; indexed to weight, P =.03; indexed to ascending aortic diameter, P =.02), and smaller ascending aorta (absolute diameter, P =.02). Smaller absolute transverse arch diameter and younger age were the only independent predictors of shorter time to arch reintervention by multivariable Cox regression analysis. Weight and type of repair did not correlate with risk of recoarctation. CONCLUSIONS: Low weight is not a risk factor for recurrent obstruction after repair of coarctation of the aorta in infants less than 3 months of age. Rather, risk of recoarctation is more a function of the anatomy of the arch. Thus, it is not indicated to delay repair in low weight infants with the goal of achieving growth.

Effectiveness of pharmacomechanical thrombolysis in infants and children.

Between March 1995 and February 2000, 10 children with major thromboses were treated with local pharmacomechanical thrombolysis. Clinical improvement was found in 8 patients: follow-up angiography showed complete thrombus resolution in 5 patients and subtotal resolution in 4.

Frequency of restenosis after balloon pulmonary arterioplasty and its causes.

Restenosis has been described after balloon pulmonary arterioplasty (BPA), but litte is known about its frequency, settings, and time course. We undertook this study to (1) determine the incidence of restenosis after BPA, and (2) identify its potential determinants. We reviewed clinical data and measured pulmonary artery diameters from angiograms of 134 dilations on 75 patients (median 2.1 years, range 0.3 to 32) who had BPA from January 1990 to June 1998. Successful BPA was defined as a > or = 50% increase in predilation diameter, whereas restenosis was said to occur if there was a > or = 50% loss in initial diameter gain. The success rate after BPA by angiographic criteria was 64% (95% confidence interval 56% to 73%). Seventy-four percent of BPAs were successful by published standard criteria (angiographic criteria or > or = 20% change in right ventricular/aortic pressure). Baseline demographic variables and predilation parameters were not predictive of initial dilation success. Restenosis occurred in 35% (95% confidence interval 22% to 49%) of successfully dilated vessels. Only weight at follow-up (p = 0.02) was associated with an increased likelihood of restenosis. Predilation parameters, technical aspects of dilation, or immediate results of BPA were not predictive of restenosis. We therefore conclude that restenosis is unpredictable and more common after BPA than previously recognized.

Outcome following single-stage repair of coarctation with ventricular septal defect.

OBJECTIVE: A recent multi-institutional study suggested improved survival (97%) after staged repair of coarctation with ventricular septal defect (VSD) compared with single-stage repair. The current study was undertaken to determine outcome and need for reintervention following single-stage repair of coarctation and VSD at our institution. METHODS: Retrospective review of patients undergoing single-stage repair of coarctation with VSD between October 1, 1994 and August 15, 1999. RESULTS: Single-stage repair of coarctation with VSD was performed in 25 infants (12 males, 13 females) at a median age of 12 days (range 1-87 days) and median weight of 3.3 kg (range 1.3-4.4 kg). The VSD was conoventricular in ten patients, malalignment type with posterior deviation of the infundibular septum in ten, muscular in four and conal septal hypoplasia in one. Arch hypoplasia was present in all patients and bicuspid aortic valve in 13. At least moderate subaortic narrowing was present in six patients (secondary to prolapse of tricuspid valve tissue across the VSD in four). Repairs were performed via a median sternotomy with a mean circulatory arrest time of 38+/-12 min. Overall patient survival was 96% with one operative death and no late deaths at a median follow-up of 16 months (range 1-50 months). Reinterventions included balloon dilatation of recurrent coarctation (five), closure of residual VSD (one) and Ross-Konno procedure (two). Actuarial freedom from reintervention for the hospital survivors was 81% (95% confidence limit (CL) 61%, 92%) at 6 months, 71% (95% CL 47%, 87%) at 1 year and 59% (95% CL 31%, 82%) at 2 years following surgery. CONCLUSION: Single-stage repair of coarctation with VSD can be performed with low operative mortality and good midterm survival equivalent to reported results for staged repair.

Optimization of adenoviral vector-mediated gene transfer to pulmonary arteries in newborn swine.

Efficient pulmonary vascular gene transfer in neonates would aid in understanding the pathophysiology of, and ultimately allow the development of specific therapies for, pulmonary vascular diseases. The purpose of this study was to optimize efficiency, and evaluate the duration, of catheter-based adenoviral vector-mediated pulmonary artery gene transfer in newborn pigs. An adenovirus vector encoding LacZ was infused via percutaneously placed catheters that were advanced to segmental pulmonary arteries under fluoroscopic guidance. Optimal viral dose and duration of expression were determined by histochemical evaluation of gene transfer efficiency 72 hr, 2 weeks, and 1 month after gene delivery. The effect of protamine on the efficiency of gene transfer was studied by assaying transgene protein in lung at 72 hr. The optimal viral dose was 2 x 10(10) plaque-forming units (PFU). Seventy-two hours after infusion, expression predominated in medium-sized artery endothelial cells, 40% of which expressed beta-galactosidase. At 2 weeks, the distribution of expression had changed such that the majority of transduced cells were seen not in arteries but in gas exchange units of lung. No histochemical evidence of transgene expression was seen 1 month after virus infusion. The addition of protamine to virus infusate resulted in a fivefold increase in transgene protein product in lung tissue assayed 72 hr after gene transfer. Adenoviral vector-mediated gene transfer in neonatal swine results in high-efficiency transduction of arterial endothelial cells. However, the time course of gene transfer is not significantly prolonged compared with the adult. The addition of protamine results in a significant improvement in transduction efficiency, permitting lower doses of virus.

The hypoplastic left heart syndrome with intact atrial septum: atrial morphology, pulmonary vascular histopathology and outcome.

OBJECTIVES: The purpose of this study was to investigate the outcome in infants with hypoplastic left heart syndrome and intact atrial septum and to evaluate the relationship of atrial morphology, left atrial decompression pathway and lung histopathology to outcome. BACKGROUND: In the hypoplastic left heart syndrome, severe restriction at the atrial level results in marked systemic hypoxemia after birth. Infants with intact atrial septum may be at high risk for mortality after Norwood operation. METHODS: Of 316 infants with hypoplastic left heart syndrome seen at our center over a 6.5-year period, 18 (5.7%) had intact atrial septum. Medical records and echocardiograms were reviewed. RESULTS: On echocardiography, three types of intact atrial septal morphology were identified: 1) large left atrium, thick prominent septum secondary with thin septum primary adherent (type A, n = 12); 2) small left atrium with thick, muscular atrial septum (type B, n = 4), and 3) giant left atrium, thin atrial septum with severe mitral regurgitation (type C, n = 2). Seven infants had left atrial decompression pathways that were severely obstructed (3/12 type A, 4/4 type B). Norwood operation was performed in 17 infants; one underwent emergency balloon atrial septostomy and died. Of six early survivors, all with type A atrial morphology and unobstructed decompression pathway, three died after subsequent cavopulmonary surgery. Lung histopathology revealed severely dilated lymphatics and "arterialization" of the pulmonary veins in those with the severest degree of obstruction to left atrial egress (type B atrial morphology). CONCLUSIONS: Despite aggressive intervention, outcome for infants born with hypoplastic left heart syndrome and intact atrial septum is poor. Maldevelopment of the pulmonary vasculature contributes to the high mortality seen. Atrial morphology can be used as a marker for the severity of pulmonary vascular disease.

Late surgical fenestration for complications after the Fontan operation.

BACKGROUND: Significant morbidity after Fontan operation results in either takedown, heart transplantation, or death. Initial creation of a fenestration results in less morbidity and mortality; however, the role of late creation of a fenestration in aiding patients manifesting morbidity after an initial nonfenestrated Fontan operation is unclear. METHODS AND RESULTS: We reviewed our experience with late creation of a surgical fenestration in 9 patients (5.2 +/- 3.1 years old) exhibiting chronic effusions (n = 4) or protein-losing enteropathy (PLE) (n = 5) after lateral tunnel-type Fontan operation. Patients with effusions had creation via coronary punch of two or three 3-mm defects; patients with PLE had creation of a large, 5-mm defect. One child with effusions and multisystem organ failure before fenestration died 7 weeks after surgery secondary to low cardiac output; the other 3 had resolution of effusions within 4 to 6 weeks. Of the 5 with PLE, 3 had normalization of serum proteins and resolution of symptoms at 2 to 6 weeks. The 2 failures had arterial saturations > 89% after surgery. Follow-up was from 25 to 30 months. Spontaneous closure of defects occurred in all 3 with effusions. No return of symptoms was noted in 2; however, the third reaccumulated effusions and has undergone refenestration with a large defect. All 3 patients with PLE have remained asymptomatic with patency of the fenestration (4 to 5 mm on echocardiography) and arterial saturation < or = 85% for > 2 years. CONCLUSIONS: Late surgical creation of fenestration results in resolution of morbidity after Fontan operation. Improvement is related to the degree of right-to-left shunt created.

Early reduction of the volume work of the single ventricle: the hemi-Fontan operation.

BACKGROUND: In hearts with a functional single ventricle, cavity volume and myocardial muscle mass increase as a consequence of the excessive volume work associated with parallel pulmonary and systemic circulations. The hemi-Fontan operation was conceived as a means of accomplishing early reduction of the volume work of the single ventricle. METHODS: All patients presenting in infancy with single-ventricle physiology were managed by early hemi-Fontan operation in anticipation of a subsequent completion Fontan operation. Between May 1989 and August 1995, 400 patients less than 2 years of age underwent hemi-Fontan operations. Mean age at operation was 8.5 months (range, 2 months to 24 months). The hemi-Fontan operation included association of superior vena(e) cava(e) with the branch pulmonary arteries, augmentation of the central pulmonary arteries, occlusion of the inflow of the superior vena cava into the right atrium, and elimination of other sources of pulmonary blood flow. RESULTS: Operative mortality ( < 30 days) was 31 of 400 patients (7.8%). For the last 200 patients, operative mortality was 8 of 200 (4.0%). Younger age at operation was not an independent risk factor for operative mortality. Urgent operation in the presence of a hemodynamic burden requiring concomitant procedures was associated with increased mortality. CONCLUSIONS: The hemi-Fontan operation can be accomplished with low operative mortality in young patients, achieving early reduction of the volume work of the single-ventricle heart.

In vivo adenovirus-mediated gene transfer via the pulmonary artery of rats.

Gene transfer into the pulmonary vasculature has the potential to be a powerful technique for both investigation of pulmonary pathophysiology and development of genetic therapies for pulmonary vascular disease. To evaluate the potential for in vivo pulmonary arterial gene transfer, we infused adenoviral vectors into the left pulmonary artery of Sprague-Dawley and cotton rats. Access to the left pulmonary artery was obtained by a percutaneous transcatheter approach or through thoracotomy and pulmonary arteriotomy. With the thoracotomy approach, both pulmonary arterial inflow and pulmonary venous outflow were occluded during vector influsion and throughout a subsequent 20-minute dwell period. The success of gene transfer was assessed by staining for evidence of recombinant gene expression in lungs excised at time points ranging from 48 to 72 hours after virus infusion. With the thoracotomy technique, pulmonary gene transfer was successful in 15% of surviving Sprague-Dawley rats and 30% of surviving cotton rats. Percutaneous catheter-based pulmonary gene transfer was not successful. In rats with pulmonary gene transfer, 1% to 8% of total left lung cells expressed the recombinant gene. Recombinant gene expression was found in endothelial cells (0.2% to 18% of total transduced cells), smooth muscle cells (0% to 3%), macrophages (1% to 7%), airway epithelial cells (2% to 50%), and alveolar epithelial cells (38% to 94%). Investigation of the low rate of successful gene transfer in individual animals suggested that insufficient physical contact between the virions and pulmonary cells was the most likely cause. In vivo gene transfer into the rat pulmonary vasculature can be accomplished with adenovirus vectors.(ABSTRACT TRUNCATED AT 250 WORDS)

Indications for echocardiography in the diagnosis of infective endocarditis in children.

The role of transthoracic echocardiography as a diagnostic tool in children suspected of having infective endocarditis (IE) has not been defined. We hypothesized that echocardiography is only useful in children in whom there is high clinical suspicion of IE based on physical examination findings or persistently positive blood cultures. Echocardiographic reports and medical records of all inpatients (n = 133) from 1990 to 1992 who underwent echocardiography for suspected IE were reviewed. Fifty-nine of the 133 patients (44%) identified had either persistently positive blood cultures (n = 48), physical examination findings of IE (n = 20), or both (n = 9). The echocardiogram was positive in 7 of these patients (12%) and negative in all 74 patients without positive physical findings or positive blood cultures (p = 0.003). A new or changing precordial murmur, embolic phenomena, congestive heart failure, mechanical ventilation, and positive blood cultures were predictive of positive echocardiograms for IE by univariate analysis. The presence of fever, immune deficiency, and central lines, alone or in combination, was not predictive of a positive echocardiogram. In the absence of physical findings or persistently positive blood cultures, echocardiography is a low-yield study and is unlikely to aid in the diagnosis of IE in children.

The role of catheter-directed therapies in the treatment of congenital heart disease.

Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart defects. These procedures may be broadly grouped as dilations (valvuloplasty, angioplasty, and endovascular stenting) or as closures (vascular embolizations and device closure of defects). Balloon valvuloplasty has become the treatment of choice for simple valvar pulmonic stenosis in all age groups and, although not curative, appears at least comparable to surgery for noncalcific aortic stenosis in newborns through young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although still investigational, devices have been successfully used for closure of large numbers of atrial and ventricular septal defects. In this review, the current role of each major catheter intervention is discussed and results are compared with alternative forms of therapy. Catheter-based therapeutics are then placed in context in a discussion of combined catheter-surgical treatment of patients with complex congenital heart defects.

Adenoviral vector-mediated gene transfer into sheep arteries using a double-balloon catheter.

The potential for catheter-based in vivo delivery of genetic material to the arterial wall is incompletely explored. We evaluated the level of recombinant protein production as well as the anatomic distribution and duration of gene expression following adenoviral vector-mediated gene transfer into sheep arteries via a double balloon catheter. Catheters were positioned in the carotid or femoral arteries of 20 sheep via a combined percutaneous and surgical approach, and virions infused over a 30-min period. Three days later, recombinant gene expression was identified in approximately 30% (range 0-80%) of the luminal endothelial cells within the targeted area of the artery. Persistent recombinant protein expression was identified histochemically for up to 4 weeks, although the number of positive cells decreased steadily. High levels of both beta-galactosidase (beta-Gal) activity and protein (mean 20 mU and 44 ng per vessel) were measured in vessel extracts 3 days after gene transfer, again decreasing significantly over a 4-week period. Transgene expression was limited almost entirely to the intima and adventitia; adventitial gene transfer occurred virtually exclusively along the vasa vasorum. In comparison to previous studies of catheter-based gene transfer, adenoviral vectors delivered by double balloon catheter resulted in a particularly high efficiency of endothelial cell gene transfer. The efficiency and amount of recombinant gene expression achieved in this study suggest that catheter-based gene delivery may eventually be applicable to the treatment of focal human arterial disease.

Anatomic barriers influence the distribution of in vivo gene transfer into the arterial wall. Modeling with microscopic tracer particles and verification with a recombinant adenoviral vector.

We evaluated the extent to which anatomic barriers to vector penetration might influence the distribution of successful in vivo gene transfer into the normal arterial wall. A double-balloon catheter technique with infusion pressures of 100 to 400 mm Hg was used to infuse microscopic tracer particles of the size range of liposomes and viral vectors into normal elastic arteries of sheep. Localization of the tracer particles in tissue sections by light, fluorescence, and electron microscopy suggested that vector-sized particles were delivered to the intima by direct infusion and to the adventitia via the arterial vasa vasorum. Particles were virtually absent from the arterial media. To test the predictions made from the particle studies, we repeated the infusion protocol with high-titer adenoviral vectors. Gene transfer occurred at high levels in the intima and along the adventitial vasa vasorum but again was virtually absent within the media. The ability of medial smooth muscle cells to be transduced was established in separate experiments with a high-pressure (5 atm) porous balloon infusion catheter. We conclude that (1) the anatomy of the normal elastic arterial wall imposes significant limitations on the penetration of particles in the size range of most gene-transfer vectors and (2) the distribution of in vivo gene transfer with adenoviral vectors is correctly predicted by the distribution of inert tracer particles. These findings have important implications for the design of arterial gene-transfer and gene-therapy protocols.

Tetralogy of Fallot with pulmonary atresia. Rehabilitation of diminutive pulmonary arteries.

BACKGROUND: Patients with tetralogy of Fallot, pulmonary atresia, and diminutive pulmonary arteries are a high-risk group for whom there is no consensus on the correct approach to medical management. The purpose of this report is to review a 14-year experience in the treatment of these patients comparing management schemes. METHODS AND RESULTS: Between January 1978 and August 1988, 91 patients with tetralogy of Fallot and pulmonary atresia had an adequate evaluation of their pulmonary artery anatomy before any surgical management. Forty-eight of these patients had diminutive pulmonary arteries (38 to 104 mm2/m2) supplied by aortopulmonary collaterals and were managed in four different fashions. Of the 9 patients repaired primarily, 7 died early and the two survivors had poor hemodynamic outcome. Of the 9 patients conservatively managed with no intervention before 5 years of age, 4 died and only 1 had a satisfactory hemodynamic result after repair. Of 10 shunted patients, 3 died and 3 had satisfactory repairs. Since 1984, we have rehabilitated pulmonary arteries with (1) right ventricle to pulmonary artery surgical graft, (2) balloon dilation of residual pulmonary artery stenoses and embolization of collaterals, and (3) surgical closure of ventricular septal defect and repair of remaining obstructions. Of 20 patients so managed, 7 died after various stages, but 10 of 20 had complete repairs. All repaired patients with subsystemic right ventricular pressures had at least one successful pulmonary artery dilation. CONCLUSIONS: A combined catheter-surgery approach begun at an early age in patients with tetralogy of Fallot and pulmonary atresia with diminutive pulmonary arteries appears to enhance the chances of satisfactory complete repair.

Transcatheter umbrella closure of valvular and paravalvular leaks.

OBJECTIVES: Our aim was to adapt the technique of transcatheter umbrella closure of intracardiac defects for closure of valvular and paravalvular defects. BACKGROUND: The double-umbrella device developed by Rashkind and Cuaso has been safely and effectively delivered across a host of intracardiac defects, but transcatheter closure of valvular and paravalvular leaks has not been reported. METHODS: Between February 1987 and September 1990, eight patients who were believed to be poor operative candidates were taken to the catheterization laboratory for transcatheter double-umbrella closure of a valvular or a paravalvular leak. Four patients had a paravalvular leak around a prosthetic aortic valve. The other four patients had a valvular leak: one patient with a regurgitant native aortic valve after a Stansel procedure and three patients with a regurgitant porcine valve in a left ventricular apex to descending aorta conduit. RESULTS: Placement of a double-umbrella device was attempted in seven of the eight patients and was successful in all seven. Device placement was not attempted in one patient because of the crescentic shape of his defect. Two patients required two devices for each closure; the other five required only one device each. Angiography, performed on six patients after device closure, demonstrated that three patients had a completely occluded defect, two had trivial residual flow and one patient had mild residual flow through the device. All significant complications occurred in one patient who had hemolysis and oliguria that resolved when the initial umbrella was replaced by a larger device. In addition, two devices migrated to the patient's pulmonary arteries but were retrieved in the catheterization laboratory without difficulty. No other early or late complications occurred in 21 to 50 months of follow-up. Of the four patients with a paravalvular leak, the one who did not receive a device died at operation, one patient died at operation for an associated defect (in the operating room the umbrella was found securely in place across the paraaortic defect) and two patients are clinically well at home after 21 and 32 months, respectively. Of the four patients with closure of a valvular leak, one patient remains well at home 50 months later, one patient died at operation for associated defects and two patients had additional successful surgical treatment and remain well 29 months after device placement. CONCLUSIONS: Transcatheter umbrella closure appears to be a reasonable alternative for closure of a valvular or paravalvular leak in patients who are poor operative candidates.