Intra-aortic balloon pumping in children with dilated cardiomyopathy as a bridge to transplantation.

Children with dilated cardiomyopathy awaiting transplantation who fail maximal pharmacologic therapy may benefit from intra-aortic balloon pumping. Between July 1993 and August 1999, a total of 4 children with dilated cardiomyopathy underwent pre-transplant balloon pumping for 6.0 +/- 5.8 (1 to 12) days. One child (pumped for 12 days) died awaiting transplant, and the remaining 3 were successfully transplanted. Intra-aortic balloon pumping timed precisely with M-mode echocardiographic markers offers a relatively simple and safe intermediate level of mechanical support for children with dilated cardiomyopathy who fail pharmacologic support.

Can Doppler systemic venous flow indices predict central venous pressure in children?

Tricuspid valve, superior vena cava (SVC), and hepatic vein Doppler patterns may be abnormal in right heart anomalies and have been used to predict high central venous pressure (CVP) in adults. The purpose of this study was to evaluate the relationship of these systemic venous flow indices to CVP in children. Children undergoing cardiac catheterization were studied prospectively using simultaneous recordings of mean CVP with pulsed-Doppler tracings of SVC, hepatic vein, and tricuspid valve flow. Systemic venous Doppler measurements included peak velocities and velocity time integrals for ventricular systole (S), ventricular diastole (D), and ventricular systole (B), and atrial systole (A). Tricuspid inflow Doppler E and A waves were recorded also. Patients with significant tricuspid stenosis or regurgitation, systemic venous obstruction, and nonsinus rhythm were excluded. The 42 patients ranged in age from 0.2 to 21.0 years and in weight from 3.0 to 68.0 kg. Mean CVPs ranged from 1 to 17 mmHg. Catheterization indications included hemodynamic evaluation (25 patients), transplant biopsy, (11 patients), and interventional procedures (6 patients). No SVC or tricuspid valve Doppler measurement correlated with CVP. Hepatic vein peak D, peak B, and peak A significantly correlated with CVP (r = 0.34 - 0.55; P < 0.05, linear regression). For all correlations, the r values were low with significant overlap among patients. Thus, in children, only hepatic vein peak velocities correlate with CVP. Because of the low r values and significant overlap among patients, the currently used Doppler indices have a low sensitivity for predicting CVP in this age group.

Randomized controlled study of inhaled nitric oxide after operation for congenital heart disease.

BACKGROUND: Inhaled nitric oxide selectively decreases pulmonary vascular resistance. This study was performed to determine whether inhaled nitric oxide decreases the incidence of pulmonary hypertensive crises after corrective procedures for congenital heart disease. METHODS: Patients with a systolic pulmonary arterial pressure of 50% or more of the systolic systemic arterial pressure during the early postoperative period were randomized to receive 20 parts per million inhaled nitric oxide (n = 20) or conventional therapy alone (n = 20). Acute hemodynamic and blood gas measurements were performed at the onset of therapy. The efficacy of sustained therapy was determined by comparing the number of patients in each group who experienced a pulmonary hypertensive crisis. RESULTS: In comparison to controls, there were no significant differences in the baseline and 1-hour measurements of patients who were treated with nitric oxide. Four patients in the control group and 3 patients in the nitric oxide group experienced a pulmonary hypertensive crisis. CONCLUSIONS: Nitric oxide did not substantially improve pulmonary hemodynamics and gas exchange immediately after operation for congenital heart disease. Nitric oxide also failed to significantly decrease the incidence of pulmonary hypertensive crises.

Spectrum and influence of hypoplasia of the left heart in neonatal aortic coarctation.

Obstruction of the left ventricular outflow tract may be associated with hypoplasia of the left heart, which importantly influences the options for treatment. Although the influence of the size of the left heart on the outcome for critical aortic stenosis has been described, less is known about the spectrum of such hypoplasia seen with neonatal aortic coarctation, and how this influences outcome. To determine, first, the spectrum and influence of hypoplasia of the left heart in neonatal coarctation, second, if the previously described critical values for adequacy of the left heart in neonates with critical aortic stenosis are applicable to neonates with coarctation, and, third, if any of the variables or associated abnormalities are risk factors for recoarctation, we studied 63 neonates who underwent repair of coarctation. From the initial echocardiogram, we measured multiple structures in the left heart, and calculated a score for adequacy as has been done for critical aortic stenosis. The sizes were compared to previously reported minimal values. We then analyzed the influence of the variables and the associated anomalies on outcome. There were no deaths. There was a broad spectrum of sizes that did not correlate with the need for re-intervention. The calculated score for adequacy would have predicted survival in only 56% of the patients, and 73% of the neonates had at least one parameter measured in the left heart below the previously reported minimal values. There is, therefore, a broad spectrum of sizes for the left heart in neonates with aortic coarctation that is not predictive of outcome. Minimal sizes, and the score for adequacy used for critical aortic stenosis, are not applicable to neonates with coarctation.

Pulmonary vein stenosis with normal connection: associated cardiac abnormalities and variable outcome.

BACKGROUND: Pulmonary vein (PV) stenosis with anatomically normal connection is considered rare, unresponsive to treatment, progressive, and usually fatal. METHODS: We reviewed the records of 13 children with this diagnosis at our center since 1990. RESULTS: The number of stenosed PVs ranged from all PVs (n = 5); three PVs (n = 1); two PVs (n = 5); and one PV (n = 2). All patients had associated congenital cardiac abnormalities. Operation on PV stenosis was attempted in 7 patients (54%), 2 of whom have done well and 5 of whom have not. Two patients underwent heart transplantation for inoperable associated cardiac lesions. Significantly more patients with three or four stenosed PVs died (83%) compared with patients with one or two stenosed PVs (0%). CONCLUSIONS: (1) Pulmonary vein stenosis with anatomically normal connection is associated with other congenital cardiac abnormalities, (2) presentation and outcome are contingent on the number of stenosed PVs, (3) surgical palliation may be helpful in some patients, and (4) heart transplantation for inoperable associated cardiac abnormalities may be an option in patients with only one or two stenosed PVs.

Beta-blocker treatment of dilated cardiomyopathy with congestive heart failure in children: a multi-institutional experience.

BACKGROUND: Dilated cardiomyopathy is the primary indication for heart transplantation in children beyond infancy. Although beta-blockers improve symptoms, ejection fraction, and survival in adults with congestive heart failure, little is known of their effects in children. METHODS: This study reviews our pediatric experience with the beta-blocker, metoprolol, at 3 institutions. We gave metoprolol to 15 children, age 8.6 +/- 1.3 years (range 2.5 to 15 years), with idiopathic dilated cardiomyopathy (n = 9), anthracycline cardiomyopathy (n = 3), and Duchenne muscular dystrophy cardiomyopathy, postmyocarditis cardiomyopathy, and post-surgical cardiomyopathy (n = 1 each). All had been treated with conventional medications (digoxin, diuretics, and ACE inhibitors) for 22.5 +/- 9 months before starting metoprolol. Metoprolol was started at 0.1 to 0.2 mg/kg/ dose given twice daily and slowly increased over a period of weeks to a dose of 1.1 +/- 0.1 mg/kg/day (range 0.5 to 2.3 mg/kg/day). RESULTS: Between the time point of stabilization on conventional medications and the initiation of metoprolol therapy, there was no significant change in fractional shortening (13.1 +/- 1.2% vs 15.0 +/- 1.2%) or ejection fraction (25.6 +/- 2.1% vs 27.0 +/- 3.4%). However, after metoprolol therapy for 23.2 +/- 7 months, there was a significant increase in fractional shortening(23.3 +/- 2.6%) and ejection fraction (41.1 +/- 4.3%) (p < 0.05). CONCLUSIONS: Metoprolol improves ventricular function in some children with dilated cardiomyopathy and congestive heart failure. Further study is warranted to better define which children may benefit most from beta-blocker therapy and which beta-blockers are most efficacious.

Doppler evaluation of aortic regurgitation in children.

Doppler indexes have been used successfully to determine the severity of aortic regurgitation (AR) in adults but have not been evaluated systematically in children. To evaluate the accuracy of specific Doppler echocardiographic indexes in assessing the degree of AR in children, 30 children underwent 2-dimensional and Doppler echocardiography within 24 hours of angiography. Patients were divided into 4 groups based on the degree of angiographic AR. Color Doppler jet width, short-axis jet area, jet length, and maximum jet area were measured. AR slope was measured using continuous-wave Doppler. Flow in the abdominal aorta was evaluated using pulsed Doppler. Doppler indexes were compared with the angiographic grade of AR. Jet width and short-axis jet area were significantly different between groups and showed strong correlation with the angiographic grade. Holodiastolic flow reversal in the abdominal aorta separated 1+ to 2+ from 3+ to 4+ AR (100% sensitivity and 100% negative predictive value for 3+ to 4+ AR). Jet length, maximum jet area, and the ratio of reverse to forward abdominal aortic velocity time integrals correlated with angiography but showed little difference between groups that differed by only 1 angiographic grade. AR slope did not correlate with the angiographic grade. We conclude that in children, color Doppler jet width, short-axis jet area, and holodiastolic abdominal aortic flow reversal are the best predictors of angiographic severity. Use of these indexes may obviate the need for angiography to determine the degree of AR in children.

Cost and efficacy of surgical ligation versus transcatheter coil occlusion of patent ductus arteriosus.

OBJECTIVE: The purpose of this study was to compare cost and efficacy of surgical closure of patent ductus arteriosus using new critical pathway methods with outpatient transcatheter coil occlusion of patent ductus arteriosus. METHODS: Surgical techniques included a transaxillary, muscle-sparing thoracotomy, triple ligation of the patent ductus arteriosus, no chest tube, and discharge from the hospital within 24 hours. Transcatheter coil occlusion of patent ductus arteriosus was done as an outpatient procedure. Costs were compared with inclusion of all hospital and professional charges. RESULTS: From July 1994 until March 1996, 20 patients underwent coil occlusion of patent ductus arteriosus and 20 patients underwent surgical closure of patent ductus arteriosus. Duration of hospitalization was significantly less for the patients receiving coil occlusion (11 +/- 6 hours) as compared with that for the patients having surgical ligation (28 +/- 7 hours, p < 0.05). Total charges were similar for surgical ligation ($7101 +/- $408) as compared with those for coil occlusion ($7104 +/- $886, p > 0.05). Morbidity in coil occlusion included inability to occlude the patent ductus arteriosus in two patients (2/20, 10%) and residual patency in two patients (2/18, 11%). Morbidity in the surgical group included nausea and vomiting necessitating hospitalization for more than 36 hours in one patient (1/20, 5%), transient left recurrent laryngeal nerve palsy in one (1/20, 5%), and pneumothorax in two patients (2/20, 10%). There were no instances of residual patency in the surgical group. CONCLUSIONS: Transaxillary thoracotomy without tube thoracostomy and with critical pathway methods allows safe and effective ligation of a patent ductus arteriosus with early hospital discharge. This surgical method has similar cost, higher efficacy rate, and applicability in all patients as compared with newer transcatheter coil occlusion techniques for closure of a patent ductus arteriosus.

Etiology and outcome of outpatient fevers in pediatric heart transplant patients.

We reviewed 74 outpatient febrile episodes in 22 pediatric heart transplant patients in order to determine etiologies, rates of serious and nonserious illness, and factors predictive of serious disease. Twenty-two febrile episodes (30%) resulted in hospital admission. Only three variables were predictive of serious illness: longer duration of fever, shorter time since transplant, and lower febrile episode number. We conclude that at least 70% of outpatient febrile episodes are nonserious and can be managed safely in an outpatient setting. The duration of fever may be predictive of serious disease but is not useful at initial presentation.

Aortic valve repair and replacement after balloon aortic valvuloplasty in children.

BACKGROUND: Little is known about the incidence, indications, and results of surgical repair or replacement of the aortic valve after balloon aortic valvuloplasty (BAV) for congenital aortic stenosis in children. This study was designed to evaluate patterns of failure requiring operation after BAV for congenital aortic stenosis and to review our experience with successful repair, rather than replacement, of selected aortic valves after BAV. METHODS: From March 1986 to June 1995, 60 patients with congenital aortic stenosis aged 1 day to 27 years (mean +/- standard deviation, 7.3 +/- 6 years) underwent BAV. Twenty-three patients (38%) required operation a mean of 44 +/- 37 months (range, 1 to 110 months) after BAV, because of severe aortic insufficiency in 13 patients and recurrent or residual aortic stenosis in 10 patients. Severe aortic insufficiency was invariably due to avulsion of a cusp from the annulus, with resulting cusp prolapse and insufficiency. Operative intervention consisted of valve replacement in 14 patients and valve repair in 9 patients. Repair techniques included reattachment of an avulsed cusp to the aortic annulus, relief of commissural fusion, and debridement of thickened cusps. RESULTS: Actuarial freedom from surgical intervention after BAV was 88% +/- 4% at 1 year, 70% +/- 6% at 5 years, and 51% +/- 12% at 9 years. The need for aortic valve operation was unrelated to age at the time of BAV, indication for operation (aortic insufficiency versus aortic stenosis), age of operation, or preoperative gradient. All patients survived aortic valve operation; there was one late death at an average follow-up of 27 +/- 20 months (range, 2 to 61 months) after aortic valve operation. Stenosis was well relieved in all patients undergoing valve replacement. The 9 valve repair patients have been followed for 22 +/- 14 months (range, 1 to 47 months). Echocardiographic follow-up of the valve repair patients revealed a mean residual aortic stenosis peak instantaneous gradient of 32 mm Hg and mild aortic insufficiency or less in all patients. CONCLUSIONS: Aortic valve operation is required in 5% to 7% of patients yearly after BAV. The need for operation appears to be unrelated to age at the time of BAV; aortic insufficiency predominates over aortic stenosis as an indication for operative intervention. Valve repair can be applied in some patients after BAV with good intermediate-term results and may delay the need for aortic valve replacement.

Reversal of flow in the left pulmonary artery after cavopulmonary connection.

The postoperative course of a 15-month-old girl who underwent a bilateral bidirectional cavopulmonary connection was complicated by a left chylothorax and left hemidiaphragm paralysis. Two-dimensional and Doppler echocardiography revealed complete flow reversal in the left pulmonary artery. This flow abnormality was confirmed by angiography. Multiple aortopulmonary collaterals had also developed and were coil embolized at the time of catheterization. Coil embolization of the collaterals, combined with relief of the chylothorax and diaphragmatic plication, reestablished forward flow in the left pulmonary artery.

Congenital heart disease with ductal-dependent systemic perfusion: Doppler ultrasonography flow velocities are altered by changes in the fraction of inspired oxygen.

BACKGROUND: An unfavorable balance in systemic and pulmonary perfusion may occur in neonates with ductal-dependent systemic perfusion while being treated with prostaglandin E1 before surgical palliation or transplantation. At our institution, we adjust the fraction of inspired oxygen, with supplemental nitrogen if needed, to control pulmonary vascular tone and maintain systemic oxygen saturations near 75%. METHODS: We performed a noninvasive Doppler ultrasound study in 10 patients to determine whether velocity time integrals in the descending aorta and middle cerebral arteries and the peak velocity at the foramen ovale were acutely altered by changes in the fraction of inspired oxygen. Measurements were performed after 10- to 15-minute intervals of breathing 14% to 19%, 21%, and 35% oxygen. RESULTS: Antegrade descending aortic velocity time integrals did not change significantly when these patients breathed different amounts of oxygen; however, the retrograde velocity time integral in the descending aorta and the peak velocity of left-to-right shunt at the foramen ovale increased with increasing amounts of inspired oxygen. The ratio of antegrade to retrograde velocity time integrals in the descending aorta was greater with supplemental nitrogen than with supplemental oxygen. Middle cerebral arterial velocity time integrals were not significantly greater with supplemental nitrogen than with supplemental oxygen (p = 0.061). CONCLUSIONS: Systemic and interatrial Doppler velocities are acutely influenced by the fraction of inspired oxygen in neonates with ductal-dependent systemic perfusion.

Epoetin alfa therapy in infants awaiting heart transplantation.

OBJECTIVE: To determine the safety and efficacy of epoetin alfa therapy in infants awaiting heart transplantation to minimize the need for blood transfusions. DESIGN: Prospective case series analysis. SETTING: Pediatric tertiary care center. PATIENTS: Eleven term infants (4 to 54 days old) awaiting heart transplantation. INTERVENTION: Infants received 16 courses of daily epoetin therapy and four subsequent courses of alternate-day epoetin therapy. RESULTS: Daily epoetin therapy was instituted at 23.6 +/- 4.5 days of age, and the duration of treatment was 13.8 +/- 3.9 days (mean +/- SEM). During daily epoetin therapy, the hematocrit increased from 0.42 +/- 0.015 to 0.50 +/- 0.019 (P < .001), and the reticulocyte count increased from 58 +/- 9 x 10(-3) to 105 +/- 16 X 10(-3) (P < .05). There were no significant changes in leukocyte count (13.4 +/- 1.0 X 10(9)/L vs 15.1 +/- 0.9 X 10(9)/L), platelet count (402 +/- 43 X 10(9)/L vs 387 +/- 39 X 10(9)/L), or creatinine (53 +/- 9 mumol/L [0.6 +/- 0.1 mg/dL] vs 53 +/- 9 mumol/L [0.6 +/- 0.1 mg/dL]) (not significant). Four patients received blood transfusions during daily epoetin therapy, but the amount of blood administered to patients was significantly less (0.9 +/- 0.5 mL/kg per day) than the phlebotomy losses (1.8 +/- 0.4 mL/kg per day) (P < .01). During alternate-day epoetin therapy, the hematocrit decreased from 0.53 +/- 0.014 to 0.43 +/- 0.019 (P < .05). CONCLUSIONS: Daily epoetin therapy appears to be effective in maintaining stable hematocrit in infants awaiting heart transplantation, who generally require multiple transfusions secondary to iatrogenic blood losses.

Methotrexate therapy in pediatric heart transplantation as treatment of recurrent mild to moderate acute cellular rejection.

We have used adjunctive therapy with methotrexate as treatment of recurrent mild-to-moderate acute cellular rejection and in an attempt to reduce rejection frequency and corticosteroid dosage. The purpose of this study was to review our experience with this treatment strategy. Eight patients, 13.1 +/- 1.1 years of age (mean +/- standard error of the mean) at the time of transplantation, were given methotrexate in addition to their standard triple therapy immunosuppression. Methotrexate was started at 6.2 +/- 2 months after transplantation after an average of 3.1 +/- 0.4 rejection episodes. Patients were given methotrexate weekly for 8 weeks at 2.5 or 5 mg orally every 12 hours for three doses (0.23 +/- 0.02 mg/kg/week). The time to resolution of rejection was 17.9 +/- 4 days after initiating methotrexate therapy. The number of rejections per month decreased significantly from the 2 months before methotrexate therapy (1.49 +/- 0.1) when compared with both the 2 months during methotrexate therapy (0.50 +/- 0.1) and the 2 months after methotrexate therapy was completed (0.44 +/- 0.3) (p < 0.005). Furthermore, when comparing total rejection frequency since transplantation and before methotrexate therapy to a follow-up period of 21.8 +/- 5 months after completion of methotrexate therapy, the rejection frequency was significantly less (0.81 +/- 0.2 versus 0.10 +/- 0.06 rejections/month) (p < 0.01). Prednisone dosage was also significantly less when comparing the time before methotrexate therapy to immediately after completion of methotrexate therapy (0.23 +/- 0.04 versus 0.15 +/- 0.03 mg/kg/day) (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Early and intermediate results of the Fontan procedure at moderately high altitude.

At higher elevations, alveolar hypoxia increases pulmonary vascular resistance and may limit the cardiac output of individuals without a subpulmonary ventricle. Thus, we reviewed the outcome of definitive palliation for tricuspid atresia and other forms of single ventricle in 60 consecutive Fontan patients living at a mean elevation of 1,370 m (range, 910 to 2,130 m). There were four early deaths (6.7%; 70% confidence limits, 4.1% to 10.7%) and six late deaths. Kaplan-Meier actuarial survival (+/- standard error) is 79.6% +/- 8.2% at 5 years. Survival was significantly decreased in patients with a preoperative mean pulmonary arterial pressure greater than or equal to 15 mm Hg unless the Fontan procedure was performed with a residual fenestration. Exercise tolerance was significantly worse at higher elevations in a subgroup of patients who have traveled to altitudes of 1,680 to 3,350 m. We conclude that the early and intermediate results of the Fontan procedure at moderately high altitude are similar to results reported at sea level. However, exercise tolerance may be impaired at higher elevations in many patients.

Mid-term results after bidirectional cavopulmonary shunts.

Despite the increasing use of the bidirectional cavopulmonary shunt, little is known about the late results, the duration of palliation, and the frequency with which this procedure allows later successful conversion to a Fontan type of procedure. We reviewed our experience (1984 to 1992) in 38 consecutive children, ages 4 months to 16 years (mean, 4.0 years), who underwent a bidirectional cavopulmonary shunt procedure. All had a single functional ventricle and represented high risks for the performance of a Fontan procedure based on anatomic and hemodynamic criteria. The oxygen saturation in these patients improved from a preoperative value of 75% +/- 7% to 82% +/- 7% (p < 0.05) at late cardiac catheterization by a mean of 24 months after operation. The actuarial survival, including early deaths and that associated with all secondary procedures, was 86% at 1 year and 81% at 6 years. Early deaths occurred in 5.3% (2/38) and late deaths in 11% (4/36). Late follow-up ranged from 5 to 90 months (mean, 37 months). Conversion to a Fontan or fenestrated Fontan procedure was accomplished in 21 early survivors (21/36; 58%) by a mean of 26 months after the bidirectional cavopulmonary shunt procedure, with one operative and no late deaths (1/21; 4.8%). Three additional patients have undergone late reoperation, including 2 requiring cardiac transplantation and 1 undergoing the late creation of an axillary artery-to-vein fistula for the treatment of cyanosis. The midterm survival after a bidirectional cavopulmonary shunt procedure appears to be excellent, and it serves as a good staging procedure for patients who represent high risks for a Fontan procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of angioplasty and surgery for unoperated coarctation of the aorta.

BACKGROUND: The use of balloon coarctation angioplasty instead of surgery as treatment for unoperated coarctation of the aorta is controversial. The efficacy and complications of the two procedures have not been studied before in a prospective fashion. METHODS AND RESULTS: Thirty-six patients were prospectively randomized to either angioplasty (20 patients) or surgery (16 patients). Immediate results and patient follow-up, including physical examination, angiograms, and magnetic resonance imaging, were compared between groups. Reduction in peak systolic pressure gradient across the coarctation was similar (86%) immediately after both balloon coarctation angioplasty and surgery. On follow-up, aneurysms were seen only in the angioplasty group (20%) and not in the surgery group (0%). No aneurysms have shown progression or required surgery. The incidence of other complications was similar in both groups, although two patients experienced neurological complications after surgery. Although not statistically different, the incidence of restenosis (peak systolic pressure gradient > or = 20 mm Hg) tended to be greater in the angioplasty group (25%) than in the surgery group (6%). Restenosis after angioplasty occurred more frequently in patients with an aortic isthmus/descending aorta diameter ratio < 0.65 and was associated with an immediate catheterization residual peak systolic pressure gradient across the coarctation > or = 12 mm Hg. CONCLUSIONS: Immediate gradient reduction is similar after balloon coarctation angioplasty and surgical treatment of unoperated coarctation of the aorta. The risks of aneurysm formation and possibly restenosis after angioplasty are higher than after surgery, although the risks of other complications are similar. Balloon coarctation angioplasty may provide an effective initial alternative to surgical repair of unoperated coarctation of the aorta in children beyond infancy, particularly in patients with a well-developed isthmus. Further follow-up is necessary to determine the long-term risks of postangioplasty aneurysms.