Further studies on the effect of chloroquine on the uptake, metabolism and intracellular translocation of [35S]cystine in cystinotic fibroblasts.

The present study uses the lysosomotropic drug chloroquine to investigate the mechanisms by which exogenous [35S]cystine is able to label the intracellular (intralysosomal) cystine pool(s) in cystinotic fibroblasts. When cystinotic fibroblasts were labelled for short periods of time (8 h or less), chloroquine (20 microM) inhibited the labelling of the intracellular cystine pool(s). However, when the cells were labelled for longer periods of time (24 h or more) chloroquine stimulated the labelling of the intracellular cystine pool(s). The short-term effect was selectively abolished when the cells were washed free of chloroquine, while the long-term effect was selectively abolished when the medium was depleted of cystine. Two routes of translocation of exogenous cystine to the lysosomes could be defined. One route was fast, had a low capacity, was inhibited by chloroquine and increased with increasing medium pH, while the other route was slow, had a high capacity, was stimulated by chloroquine and was more active at low pH. The former pathway probably consisted of plasma membrane transport of cystine into the cytosol followed by direct or indirect transport into the lysosomes. The latter route possibly consisted of pinocytosis with fusion of the cystine-containing pinosomes with lysosomes.

Resolution of dilated cardiomyopathy after surgical ablation of ventricular tachycardia in a child.

Sustained tachycardia may be associated with dilated cardiomyopathy that may improve after medical management of the tachycardia. Ventricular tachycardia due to an ectopic focus is uncommon in children and rarely presents as congestive heart failure. This report documents that severe dilated cardiomyopathy in a child was caused by sustained ventricular tachycardia and that, after cryoablation of the tachycardia focus, ventricular function rapidly returned to normal.

Myocardial ischemia in patients with pulmonary atresia and intact ventricular septum.

Children who die after operation for pulmonary atresia and intact ventricular septum may have myocardial ischemia. The relation between histologic evidence of myocardial ischemic injury and the presence of a right ventricle to coronary artery fistula, coronary artery dysplasia and operation in 17 autopsy specimens was assessed. Age at death ranged from 1 day to 16 years (median, 11 days). Of the 17 hearts, 6 (35%) had right ventricle to coronary artery fistulas, 5 of which had coronary artery dysplasia. In three cases, there was segmental or complete absence of a coronary artery. Ischemia was present in four of these six hearts, two of which had right ventricular outflow reconstruction. Six of the 11 hearts without right ventricle to coronary artery fistulas also had myocardial ischemia. Of these six cases, four had right ventricular outflow reconstruction and two had shunt operations. Death occurred from 1 to 8 days (mean 3) after operation. Hearts with pulmonary atresia and intact ventricular septum may have myocardial ischemia with or without either right ventricle to coronary artery fistulas or coronary artery dysplasia. Myocardial ischemia may occur after right ventricular outflow reconstruction or shunt operations. Thus, myocardial ischemia occurs commonly in patients with pulmonary atresia and intact ventricular septum and is not always related to coronary abnormalities or operation.

Transesophageal echocardiography detects thrombus formation not identified by transthoracic echocardiography after the Fontan operation.

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

New approaches to treatment of incessant ventricular tachycardia in the very young.

It was assumed that the availability of new antiarrhythmic drugs and new surgical techniques might allow medical or nonexcisional surgical treatment in many young children with incessant ventricular tachycardia. Fourteen infants and young children less than 5 years of age were evaluated and treated for incessant ventricular tachycardia. Medical treatment was pursued up to the use of amiodarone with a type Ib or Ic antiarrhythmic drug unless the patient became hemodynamically unstable. Patients underwent surgery when these drug regimens failed or when moderate congestive heart failure was present. Seven patients were successfully treated medically and seven underwent surgical treatment. Of those treated surgically, five had cryothermic lesions and two had excisions. Five of the surgically treated patients required temporary additional medical treatment. Follow-up ranged from 12 to 53 months (mean 28). Eleven of the 14 patients are currently not taking any antiarrhythmic medication. No patient required a pacemaker, none received anticongestive medications and none died.

Right ventricular outflow reconstruction with cryopreserved homografts in pediatric patients: intermediate-term follow-up with serial echocardiographic assessment.

OBJECTIVES: This study was performed to assess by echocardiography the intermediate-term outcome of cryopreserved homografts employed in pulmonary outflow reconstruction in children and to validate the reliability of Doppler echocardiography in their evaluation. BACKGROUND: Cryopreserved homografts have become the most widely used pulmonary conduits. Previous reports have shown the occurrence of homograft regurgitation in the immediate postoperative period and the propensity of regurgitation to progress. Although Doppler echocardiography has been useful in assessing extracardiac valved conduit stenosis, its reliability in assessing a large series of cryopreserved homografts has not been documented. METHODS: Echocardiograms of 41 patients (43 homografts) who underwent operations between December 1986 and October 1992 were retrospectively reviewed. The median age of patients at operation was 37.5 months (range 3 to 333), and the median duration of follow-up was 28.5 months (range 1 to 68). Homograft regurgitation was classified on a scale of 0 to 4+. Pressure gradients across the homografts measured in 23 catheterizations were correlated with corresponding echocardiographic gradients. RESULTS: Regurgitation: Homograft regurgitation occurred in 100% of patients at follow-up. Progression of severity > 2 grades occurred during follow-up in 35% and was associated with operation before age 18 months (p < 0.002) and stenosis progression (p < 0.05) but not with homograft type (aortic or pulmonary). These data predict that 50% of patients operated on before 18 months of age will have severe regurgitation by 15 months postoperatively compared with only 15% operated on after 18 months. Stenosis: At follow-up, 51% of homografts had a stenotic gradient > or = 25 mm Hg predominantly at the distal anastomosis, and stenosis progression was related to young age at operation (< 18 months, p < 0.005) and small conduit size (p < 0.01). Fifty percent of conduits implanted before age 18 months could be predicted to stenose by 21.8 months compared with only 5% of those implanted after age 18 months. The gradient measured from Doppler echocardiography correlated well with the catheterization gradient (r = 0.86). CONCLUSIONS: Cryopreserved homograft dysfunction is frequent and progressive. Young age at operation (< 18 months) predicts more rapid deterioration. Doppler echocardiography is reliable in assessing the systolic gradients across homografts. Serial echocardiographic assessment in the follow-up of these patients accurately characterizes these problems.

Continuous wave Doppler determination of right ventricular pressure: a simultaneous Doppler-catheterization study in 127 patients.

Simultaneous continuous wave Doppler echocardiography and right-sided cardiac pressure measurements were performed during cardiac catheterization in 127 patients. Tricuspid regurgitation was detected by the Doppler method in 117 patients and was of adequate quality to analyze in 111 patients. Maximal systolic pressure gradient between the right ventricle and right atrium was 11 to 136 mm Hg (mean 53 +/- 29) and simultaneously measured Doppler gradient was 9 to 127 mm Hg (mean 49 +/- 26); for these two measurements, r = 0.96 and SEE = 7 mm Hg. Right ventricular systolic pressure was estimated by three methods from the Doppler gradient. These were 1) Doppler gradient + mean jugular venous pressure; 2) using a regression equation derived from the first 63 patients (Group 1); and 3) Doppler gradient + 10. These methods were tested on the remaining 48 patients with Doppler-analyzable tricuspid regurgitation (Group 2). The correlation between Doppler-estimated and catheter-measured right ventricular systolic pressure was similar using all three methods; however, the regression equation produced a significantly better estimate (p less than 0.05). Use of continuous wave Doppler blood flow velocity of tricuspid regurgitation permitted determination of the systolic pressure gradient across the tricuspid valve and the right ventricular systolic pressure. This noninvasive technique yielded information comparable with that obtained at catheterization. Approximately 80% of patients with increased and 57% with normal right ventricular pressure had analyzable Doppler tricuspid regurgitant velocities that could be used to accurately predict right ventricular systolic pressure.

Truncus arteriosus with single pulmonary artery: influence of pulmonary vascular obstructive disease on early and late operative results.

Nineteen patients with truncus arteriosus and single pulmonary artery had corrective operations at the Mayo Clinic from 1969 to 1983. At operation, their ages ranged from 4 months to 20 years (mean 8.1 years). The preoperative pulmonary resistance divided by 2 was used to predict the degree of pulmonary vascular obstructive disease at operation. The influence of elevated pulmonary resistance and the intraoperative postrepair ratio of pulmonary artery to left ventricular pressure on operative and late mortality were examined. The outcome of patients with single pulmonary artery was compared with the outcome of 148 patients with truncus arteriosus and two pulmonary arteries operated on during the same period. Patients with a single pulmonary artery had an operative mortality similar to that of patients with two pulmonary arteries (32 versus 28%, p greater than 0.05). Late mortality was, however, significantly greater (p less than 0.001) for patients with a single pulmonary artery. Elevated ratios of intraoperative postrepair pulmonary artery to left ventricular pressure were associated with significantly higher (p less than 0.02) operative and late mortality, but elevated preoperative pulmonary resistance was not (p greater than 0.10). Truncus arteriosus with single pulmonary artery is associated with poor postoperative survival, and although elevated pulmonary resistances preoperatively did not predict outcome, elevated intraoperative postrepair pulmonary artery to left ventricular pressure ratios were associated with increased operative and late survival, suggesting a deleterious role of pulmonary hypertension.

Instantaneous pressure gradient: a simultaneous Doppler and dual catheter correlative study.

To more precisely measure the beat to beat and instantaneous pressure gradients across outflow stenotic lesions, simultaneous Doppler and dual catheter pressure gradient measurements were performed in 95 patients (mean age 42 years, range 1.5 to 85). There were 38 right ventricular and 62 left ventricular outflow obstructive lesions. Forty-nine patients also had a nonsimultaneous Doppler study performed within 7 days before catheterization. The simultaneous pressure waveforms and Doppler spectral velocity profiles were digitized at 10 ms intervals deriving maximal, mean and instantaneous gradients (mm Hg). For simultaneous maximal Doppler and catheter gradient measurements, the correlation coefficient (r) was 0.95 (SEE = 10 mm Hg), for Doppler and catheter mean gradients it was 0.94 (SEE = 8 mm Hg) and for maximal Doppler and peak to peak catheter gradients it was 0.92 (SEE = 13 mm Hg). The correlation of maximal and mean Doppler gradients with the respective catheter gradients was similarly high when the right and left ventricular outflow lesions were analyzed separately. However, the maximal Doppler gradient was significantly higher than the peak to peak catheter gradient. This was more evident with left ventricular outflow stenotic lesions. The correlation of the outpatient maximal Doppler and catheter gradients (r = 0.80, SEE = 17 mm Hg) was significantly lower than the simultaneous correlation (r = 0.96, SEE = 10 mm Hg) in the 49 patients with two Doppler studies. Continuous wave Doppler echocardiography accurately measures the instantaneous pressure gradient across both left and right ventricular outflow obstructive lesions. The maximal Doppler gradient should not be equated with the peak to peak catheter gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis and management of fetal cardiac tumors: a multicenter experience and review of published reports.

OBJECTIVES: We sought to determine the prevalence and natural history of cardiac tumors in patients referred for fetal echocardiography. BACKGROUND: Cardiac tumors are rare; the prevalence, reported from autopsy studies of patients of all ages, varies from 0.0017% to 0.28%. Despite many case reports, the prevalence and natural history of fetal cardiac tumors are unclear. METHODS: Fourteen thousand fetal echocardiograms recorded over an 8-year period in seven centers were available for retrospective review. Medical records and echocardiograms were studied to determine the reason for referral, family history of tuberous sclerosis, prenatal and postnatal course and tumor description and type. RESULTS: Cardiac tumors were present in 19 pregnancies (0.14%). Gestational age at diagnosis ranged from 21 to 38 weeks. The most common indication for referral was a mass on an obstetric ultrasound study. The tumors were singular in 10 patients and multiple in 9. Tumor size ranged from 0.4 x 0.4 to 3.5 x 4 cm, and the majority of tumors were not hemodynamically significant. There were 17 patients with rhabdomyomas, 1 with a fibroma and 1 with an atrial hemangioma. Tuberous sclerosis complex was diagnosed in 10 patients. Partial or complete tumor regression was seen in eight patients; tumors were unchanged in five; and three required operation. CONCLUSIONS: Fetal cardiac tumors, a rare condition, are often benign. The majority of tumors are rhabdomyomas, but not all fetuses with rhabdomyoma have tuberous sclerosis.

Extracardiac conduit obstruction: initial experience in the use of Doppler echocardiography for noninvasive estimation of pressure gradient.

Extracardiac valved conduits are often employed in the repair of certain complex congenital heart defects; late obstruction is a well recognized problem that usually requires catheterization for definitive diagnosis. A reliable noninvasive method for detecting conduit stenosis would be clinically useful in identifying the small proportion of patients who develop this problem. Continuous wave Doppler echocardiography has been used successfully to estimate cardiac valvular obstructive lesions noninvasively. Twenty-three patients with prior extracardiac conduit placement for complex congenital heart disease underwent echocardiographic and continuous wave Doppler echocardiographic examinations to determine the presence and severity of conduit stenosis. In 20 of the 23 patients, an adequate conduit flow velocity profile was obtained, and in 10 an abnormally increased conduit flow velocity was present. All but one patient had significant obstruction proven at surgery and in one patient, surgery was planned. In three patients, an adequate conduit flow velocity profile could not be obtained but obstruction was still suspected based on high velocity tricuspid regurgitant Doppler signals. In these three patients, subsequent surgery also proved that conduit stenosis was present. Doppler-predicted gradients and right ventricular pressures showed an overall good correlation (r = 0.90) with measurements at subsequent cardiac catheterization. Continuous wave Doppler echocardiography appears to be a useful noninvasive tool for the detection and semiquantitation of extracardiac conduit stenosis.

Prognostic features of children with idiopathic dilated cardiomyopathy.

The presenting features and long-term outcome of 39 children (median age 6.5 months, range 1 day to 16 years) with idiopathic dilated cardiomyopathy (IDC) were reviewed to help determine the appropriate management of these patients. Four outcome groups were identified: those who died, improved, had IDC resolved or received transplants. Presenting clinical features of age, sex, race, congestive heart failure, cardiomegaly, and degree of systolic ventricular dysfunction did not predict final outcome. Left ventricular hypertrophy on the electrocardiogram was seen significantly more often in children who improved than in those who died or in whom IDC resolved (p = 0.002). A rhythm disturbance was also seen more often in those who died than in those who survived (p = 0.025). Of 36 patients treated medically, 12 (33%) died, 15 (42%) improved and 9 (25%) resolved. Eighteen of 26 (69%) patients presenting at age less than or equal to 2 years survived, whereas 6 of 10 patients greater than 2 years survived. There were no differences based on age at presentation, in the time to death or time of follow-up. Three patients received orthotopic heart transplants, 1 of whom died from graft failure. Thus, no clinical feature including age at presentation consistently predicts ultimate outcome in children with IDC.

Clinical and therapeutic aspects of Haemophilus influenzae pericarditis in pediatric patients.

Two cases of Haemophilus influenzae type B pericarditis are presented which demonstrate the major clinical features and sequelae of this serious illness. These cases are analyzed together with 77 others from the literature to characterize the clinical features, natural history, and optimal therapy. H. influenzae pericarditis is an increasingly frequent disease of young children. A mild prodromal illness is often followed by rapid progression of cardiac compromise until death ensues, unless pericarditis is diagnosed and treated appropriately. The development of cardiomegaly in a febrile patient with a Haemophilus infection is an indication for echocardiography, which is diagnostic of the pericardial effusion. Initial cultures of pericardial aspirates will be positive in 75% of cases even when antibiotic therapy has been initiated. Use of appropriate parenterally administered antibiotics, in combination with early surgical pericardial drainage or partial pericardiectomy, should minimize morbidity and mortality and prevent acute constrictive sequelae.

Continuous-wave Doppler determination of the pressure gradient across pulmonary artery bands: hemodynamic correlation in 20 patients.

The feasibility and accuracy of continuous-wave Doppler echocardiography in measuring pressure gradients across the pulmonary artery band were assessed. Simultaneous continuous-wave Doppler and catheter pressure measurements were prospectively performed in 20 patients with complex congenital heart disease and prior pulmonary artery banding. In two other patients, adequate Doppler signals could not be obtained. Doppler velocity was converted to pressure gradient by using the modified Bernoulli equation. Simultaneous continuous-wave Doppler spectral envelopes and catheter pressure wave forms were digitized at 10-ms intervals to obtain maximal instantaneous, mean, and peak-to-peak pressure gradients. The maximal Doppler gradient ranged from 23 to 154 mm Hg, and the simultaneous maximal catheter pressure gradient ranged from 34 to 168 mm Hg. The correlation (r) between these two measurements had a coefficient of 0.98 and a standard error of the estimate (SEE) of 7 mm Hg. The peak-to-peak systolic gradient ranged from 17 to 156 mm Hg and correlated with the maximal Doppler gradient (r = 0.95; SEE = 11 mm Hg). The mean Doppler and mean catheter pressure gradients also were correlated (r = 0.93; SEE = 9 mm Hg). As Doppler echocardiography measures instantaneous velocity and therefore instantaneous pressure gradient, the more precise correlation was between Doppler gradient and maximal instantaneous catheter gradient rather than peak-to-peak systolic gradient. Continuous-wave Doppler echocardiography is an accurate noninvasive technique for measurement of pressure gradients across pulmonary artery bands. In combination with clinical evaluation and two-dimensional echocardiography, it should substantially aid clinical decision making.

Valve prostheses in children: a reassessment of anticoagulation.

We have previously published evidence that children with St. Jude Medical prostheses on the left side of the heart may not require anticoagulation. Between March 1979 and September 1986, we followed up 48 patients who had no anticoagulant therapy for up to 7 years after valve replacement, an aggregate of 122 patient-years. The 25 male and 23 female patients ranged in age at implantation from 5 months to 21 years (12 +/- 6 years, mean +/- standard deviation). Five patients (all with complex associated malformation) died in the hospital (10%), and nine died late (22%). None of the early and one of the late deaths was associated with a thrombosed prosthesis. During follow-up, seven thrombotic (one mitral, one aortic) or thromboembolic (two mitral, three aortic) events occurred (5.7 +/- 2.1 per 100 patient-years). Of these seven events, five occurred within the last 14 months of the study. There was no relation of these events to age of patient at implantation, age at the time of even, gender, or site of implantation. Concurrently, we have followed up 340 adult patients with St. Jude Medical prostheses who had warfarin sodium (Coumadin) anticoagulation for 875 patient-years. By the end of this study, the children who did not receive anticoagulants were significantly less free of thrombotic and thromboembolic events than the adults who did receive anticoagulants (p less than 0.01).

Preoperative prediction of postoperative pulmonary arteriolar resistance after surgical repair of complete atrioventricular canal defect.

The natural history of patients with complete atrioventricular canal defect is one of unrelenting development of pulmonary vascular obstructive disease. Corrective surgery, which can be performed with low mortality during infancy, reduces the time that the pulmonary vascular bed is exposed to excessively high pressure and blood flow. In some patients, however, advanced vascular disease may already be established at operation. Surgical intervention in these patients may not prevent the progression of obliterative pulmonary vascular disease and may in time even result in right ventricular failure, since after the corrective operation there is no ventricular septal defect to shunt away the right ventricular pressure overload. This article outlines a numeric method for predicting pulmonary vascular resistance after surgical correction; the method is based on age and hemodynamic data available from preoperative cardiac catheterization. Retrospective analysis of preoperative and postoperative data from 20 patients produced a regression equation in which a linear combination of inverse pulmonary/systemic blood flow ratio and age at operation predicted pulmonary vascular resistance after operation, with a multiple correlation coefficient of 0.85. This newly discovered relationship may provide valuable insight into the probable outcome of surgical intervention in cases in which pulmonary vascular obstructive disease is suspected as significant.

Fifteen-year experience with surgical repair of truncus arteriosus.

From 1965 until March, 1982, 167 patients underwent surgical repair of truncus arteriosus. The age at operation ranged from 18 days to 33 years (mean 6 years). There were 48 hospital deaths (28.7%). The following factors had a positive correlation with the possibility of a surgical death: age at operation less than 2 years (p less than 0.001), a postrepair pulmonary arterial/left ventricular pressure ratio greater than 0.5 for patients with two pulmonary arteries (p less than 0.001) and greater than 0.6 for patients with unilateral absence of a pulmonary artery (p less than 0.02), and a postrepair right ventricular/left ventricular pressure ratio greater than 0.8 (p less than 0.008). The 119 hospital survivors were followed up for a total of 829 person-years. Late survival rate at 5 years was 84.4% and at 10 years, 68.8%. Preoperative factors that correlated with a reduced long-term survival rate were as follows: increasing age at operation (p = 0.004), the presence of moderate or severe truncal valve insufficiency (p = 0.008), lower pulmonary/systemic flow ratio (p = 0.04), and unilateral absence of a pulmonary artery (p less than 0.001). Thirty-six patients required reoperation during the follow-up period (30%) primarily for replacement of the right ventricular-pulmonary arterial conduit and/or for truncal valve replacement. The long-term results obtained in these patients support the need for early repair of the anomaly, improvement in the methods for control or repair of the truncal valve insufficiency, and the continued search for better extracardiac valved conduits.

Reverse subclavian flap repair of hypoplastic transverse aorta in infancy.

BACKGROUND: Management of hypoplastic aortic arch associated with coarctation in infancy can be challenging. Reverse subclavian flap aortoplasty plus coarctation resection offers simplicity without needing foreign material or cardiopulmonary bypass. METHODS: Since 1988, 46 of 162 infants less than 3 months undergoing coarctation repair had hypoplastic arch enlargement with reverse subclavian flap aortoplasty. Median age was 11 days; mean weight was 3.2 kg. Thirty-seven patients (80%) had associated cardiac defects including single or multiple ventricular septal defects (14 infants), transposition of the great arteries (7), aortic or mitral stenosis (5), and complete atrioventricular septal defect (5 infants). Twenty-eight patients had pulmonary artery banding; 2 had an arterial switch operation through a separate median sternotomy. RESULTS: There were two hospital deaths: one 4 months postoperatively in a patient requiring a Norwood procedure the next day for underestimated left ventricular hypoplasia; the other of sepsis more than 1 month postoperatively. On follow-up from 1 to 129 months (mean, 38 months), there were five recurrent obstructions: three at the coarctation site treated with balloon dilatation and two at the arch site. Twenty-six children had their heart defects corrected with 29 subsequent operations including an arterial switch operation for transposition of the great arteries/ ventricular septal defect (3 infants), relief of aortic or mitral stenosis +/- ventricular septal defect closure (5), multiple ventricular septal defect closure (3), a bidirectional Glenn (2), complete atrioventricular septal defect (2), and anomalous left coronary with ventricular septal defect repair (1 infant). Four children await debanding and ventricular septal defect closure or Glenn anastomosis. There have been two late deaths (overall survival, 91%). CONCLUSIONS: Reverse subclavian flap aortoplasty is excellent for relief of arch hypoplasia and coarctation in infants with low recurrence rates and acceptable operative and intermediate survival.

Hemi-Fontan operation in surgery for single ventricle: a preliminary report.

Mortality after Fontan operation is related to risk factors like ventricular hypertrophy, pulmonary artery deformity, and young age (infancy). Preliminary procedures may improve Fontan results. The hemi-Fontan operation includes atriopulmonary anastomosis and correction of all anatomical risk factors, but an atriopulmonary patch directs superior vena caval flow into both pulmonary arteries and inferior vena caval flow into the ventricle, thus maintaining cardiac output (modified Glenn physiology). We performed 17 hemi-Fontan procedures in 16 patients, 14 primarily (median age, 9 months) and 3 for takedown of a Fontan operation. The 14 primary operations were for hypoplastic left heart syndrome (5), pulmonary atresia with intact ventricular septum (4), and other (5). All patients had multiple risk factors. Extubation was at 18 hours (median), chest tube removal was at 3 days, and hospital discharge was at 8 days postoperatively. Important complications included subglottic stenosis, transient diaphragmatic paralysis, pulmonary artery stenosis and thrombosis requiring reoperation, and transient ventricular fibrillation. One patient required hemi-Fontan takedown, and this patient later (3 months postoperatively) became the only death. Fontan take-downs have had a high mortality rate. In 3 patients who tolerated Fontan operation poorly, converting Fontan to hemi-Fontan abruptly reversed the downhill course. For these patients, the operation was life-saving. Hemi-Fontan operation is safe and well-tolerated, even in infants, provides the advantages of modified Glenn physiology before Fontan operation, and may be especially useful for Fontan takedown after failed Fontan.

Successful biventricular repair after initial Norwood operation for interrupted aortic arch with severe left ventricular outflow tract obstruction.

BACKGROUND: Management of newborns with interrupted aortic arch (IAA) remains challenging. Associated severe left ventricular outflow tract obstruction (LVOTO) have often led to increased mortality with neonatal biventricular repair. We review our experience with an alternative approach for this complex surgical problem. METHODS: From May 1991 to June 1999, 28 neonates were treated for IAA. Thirteen of 28 neonates (46%) had type B IAA, ventricular septal defect (VSD) and severe LVOTO (Z value -2 to -7; mean -5 +/- 1.7). Mean age was 8 days (3 to 23 days old) with average weight of 3.3 kg (2.4 to 4.2 kg). Eight of 13 (62%) had anomalous right subclavian artery. Ten of 13 (77%) had thymic aplasia and chromosome 22 region qll deletion. All 13 patients were treated initially with a modified Norwood procedure. RESULTS: There were no perioperative deaths. Complications included 2 patients with recurrent arch stenosis treated with balloon dilatation. Two patients had systemic arterial shunt revision. Follow-up ranged from 2 to 99 months old (mean 39 months). There were 2 late deaths unrelated to any operation. Nine of 12 patients had a second stage palliation consisting of a bidirectional Glenn shunt. Six patients went on to have biventricular repairs (3 Ross-Konno, 2 Rastelli, 1 VSD closure with LVOT resection). One patient had a modified Fontan operation and 5 patients are awaiting potential biventricular repair. CONCLUSIONS: Children with IAA and severe LVOTO may be managed by initial Norwood palliation with an excellent outcome likely. This initial "univentricular" approach has enabled eventual successful biventricular repair despite severe LVOTO.