Perinatal and early surgical outcome for the fetus with hypoplastic left heart syndrome: a 5-year single institutional experience.

OBJECTIVES: To review our experience with the prenatal diagnosis of hypoplastic left heart syndrome (HLHS). Our goal was to establish the benchmark for perinatal and early surgical outcome in the current era, from a center with an aggressive surgical approach and a cohort with a high level of intention-to-treat. METHODS: Outcome was assessed in fetuses with HLHS following stratification into high-risk and standard-risk categories. High risk was defined as the presence of any of the following: extracardiac, genetic or chromosomal anomalies; prematurity of < 34 weeks' gestation; additional cardiac findings such as intact or highly restrictive atrial septum, severe degree of tricuspid regurgitation or severe ventricular dysfunction. Standard risk was defined as absence of these risk factors. RESULTS: Of 240 fetuses evaluated over 5 years, 162 (67.5%) were in the standard-risk group and 78 (32.5%) were in the high-risk group. Of the 240 sets of parents, 38 (15.8%) chose termination or non-intervention at birth at initial prenatal counseling and 185 of the neonates (77.1%) underwent first-stage Norwood surgery with 155 surviving and 30 deaths, giving an overall Norwood operative survival of 83.8%. Breakdown by risk class reveals a significant Norwood operative survival advantage for the standard-risk group (92.8%) over the high-risk group (56.5%) (P < 0.001). CONCLUSIONS: Following prenatal diagnosis of HLHS, families should be strongly encouraged to undertake comprehensive prenatal evaluation in order to obtain an accurate prognosis. One-third have additional risk factors that limit survival outcome, however two-thirds do not and have an excellent chance of early survival.

Tricuspid valve dysplasia with severe tricuspid regurgitation: fetal pulmonary artery size predicts lung viability in the presence of small lung volumes.

Congenital tricuspid valve disease (Ebstein's anomaly, tricuspid valve dysplasia) with severe tricuspid regurgitation and cardiomegaly is associated with poor prognosis. Fetal echocardiography can accurately measure right atrial enlargement, which is associated with a poor prognosis in the fetus with tricuspid valve disease. Fetal lung volumetric assessments have been used in an attempt to predict viability of fetuses using ultrasonogram and prenatal MRI. We describe a fetus with tricuspid dysplasia, severe tricuspid regurgitation, right atrial enlargement and markedly reduced lung volumes. The early gestational onset of cardiomegaly with bilateral lung compression raised the possibility of severe lung hypoplasia with decreased broncho-alveolar development. Use of fetal echocardiography with measurement of pulmonary artery size combined with prenatal MRI scanning of lung volumes resulted in an improved understanding of this anomaly and directed the management strategy towards a successful Fontan circulation.

Exercise performance and quality of life following surgical repair of anomalous aortic origin of a coronary artery in the pediatric population.

OBJECTIVE: We sought to evaluate exercise performance and quality of life in children after surgical repair of anomalous aortic origin of a coronary artery with an interarterial course. METHODS: Patients who had surgery from October 2001 to January 2007 were eligible for inclusion. Exercise performance and quality of life were prospectively assessed by maximal exercise tests and age-appropriate questionnaires, respectively. We used t tests to compare pre- and postoperative exercise data and quality-of-life scores to published normative data. We performed linear regression analyses to assess associations between demographic, anatomic, and exercise variables and quality-of-life score. RESULTS: Of 25/27 patients, 64% were boys, 68% had anomalous right coronary, 32% were asymptomatic. Average age at surgery was 10.8 (+/-4.1) years; median follow-up was 14.5 (2 to 48) months. Postoperative percent-predicted exercise values were: peak heart rate 97 (+/-6), working capacity 91 (+/-15), maximal oxygen consumption 82 (+/-16). In those who had preoperative exercise testing (n = 11), resting and maximal heart rates decreased significantly without significant change in exercise performance. Average child quality of life was 85/100 (+/-13) and parent-proxy 88 (+/-11) compared with normal scores of 83 (+/-15) and 88 (+/-12), respectively. CONCLUSION: There is mild chronotropic impairment in children and adolescents following anomalous coronary artery repair without a decline in exercise performance. This does not appear to impair their overall quality of life. Because long-term effects on heart rate, exercise performance, and quality of life are unknown, serial exercise tests should be included as routine care of these patients.

What factors are important to parents making decisions about neonatal research?

BACKGROUND: Although parents of neonates with congenital heart disease are often asked permission for their neonates to participate in research studies, little is known about the factors parents consider when making these decisions. OBJECTIVE: To determine the reasons for parents' decisions about participation in research studies. METHODS: Qualitative analysis of the unsolicited comments of 34 parents regarding reasons for agreeing or declining to participate in research studies. Parents' comments were offered spontaneously during interviews about clinical care decisions for neonates with congenital heart disease. RESULTS: Parents cited five types of reason for or against permitting their newborn to participate in research studies: societal benefit (n = 18), individual benefit for their infant (n = 16), risk of study participation (n = 10), perception that participation posed no harm (n = 9), and anti-experimentation views (n = 4). CONCLUSION: Addressing parental decision making in the light of these reasons could enhance the parental permission process for parents of critically ill neonates.

Paediatric lung transplantation.

Since 1990, lung transplantation has been performed in infants, children and adolescents in small numbers, and the numbers, in comparison with adult transplants, remain small today. The indications for lung transplantation are similar in childhood when compared with adults, but the disease entities are distinct. In children, severe pulmonary vascular disease is most commonly associated with developmental abnormalities or congenital heart disease, as opposed to idiopathic pulmonary hypertension. Cystic fibrosis is the dominant indication for lung transplantation in older childhood and adolescence. The operative approach to lung transplantation in early life differs from that in adults, in that cardiopulmonary bypass is more likely to be utilised and bilateral lung transplantation is strongly preferred to single lung transplantation. Living donor lung transplantation is proportionately more common in children and adolescents than in adults. Post-transplant complications related to viral infection and post-transplant lymphoproliferative disease are more common and more likely to be severe and life-threatening. Bronchiolitis obliterans is the most important complication after paediatric lung transplantation and limits both the quality of life and duration of survival, as in adults.

A case of congenitally protected d-transposition of the great arteries in a very low-birth-weight infant.

An arterial switch is the corrective procedure of choice for d-transposition of the great arteries but may be associated with increased morbidity and mortality when performed in low-birth-weight infants. Conversely, delaying surgery often leads to left ventricular "deconditioning" as pulmonary arteriolar resistance decreases. We present an infant with a birth weight of 940 g with d-transposition of the great arteries with an intact ventricular septum whose bilateral pulmonary artery branch stenosis allowed for maintenance of near systemic left ventricular pressure, thereby protecting against deconditioning. This case also represents the smallest reported patient to undergo a successful balloon atrial septostomy.

The incidence of arrhythmias in a pediatric cardiac intensive care unit.

A pediatric cardiac intensive care unit (CICU) manages critically ill children and adults with congenital or acquired heart disease. These patients are at increased risk for arrhythmias. The purpose of this study was to prospectively evaluate the incidence of arrhythmias in a pediatric CICU patient population. All patients admitted to the CICU at the Cardiac Center at The Children's Hospital of Philadelphia between December 1, 1997, and November 30, 1998, were evaluated prospectively from CICU admission to hospital discharge via full disclosure telemetry reviewed every 24 hours. Arrhythmias reviewed included nonsustained and sustained ventricular tachycardia (VT), nonsustained and sustained supraventricular tachycardia (SVT), atrial flutter and fibrillation, junctional ectopic tachycardia, and complete heart block. We reviewed 789 admissions consisting of 629 patients (age range, 1 day-45.5 years; median, 8.1 months). Hospital stay ranged from 1 to 155 days (total of 8116 patient days). Surgical interventions (n = 602) included 482 utilizing cardiopulmonary bypass. During the study period, there were 44 deaths [44/629 patients (7.0%)], none of which were directly attributable to a primary arrhythmia. The operative mortality was 5.1%. Overall, 29.0% of admissions had one or more arrhythmias the most common arrhythmia was nonsustained VT (18.0% of admissions), followed by nonsustained SVT (12.9% of admissions). Patients admitted to a pediatric CICU have a high incidence of arrhythmias, most likely associated with their underlying pathophysiology and to the breadth of medical and surgical interventions conducted.

Sarcoma of the mitral valve causing coronary arterial occlusion in children.

Primary tumors of the cardiac valves are rare. One of the most common reasons that left-sided cardiac tumors come to clinical attention is embolization to the systemic circulation. We present two children who suffered left coronary arterial occlusion due to embolization of a sarcoma of the mitral valve. A 6-year-old female who had been admitted to the hospital after cerebrovascular embolization of a fragment of sarcoma of the mitral valve experienced sudden cardiovascular collapse due to occlusion of the left coronary artery. She was placed on extracorporeal membrane oxygenation, and underwent coronary embolectomy and resection of the tumor from the mitral valve and its tendinous cords. Left ventricular function did not improve, and she underwent orthotopic heart transplantation. On follow-up 32 months after transplant, the patient is well, with no evidence of recurrence of or metastasis from the tumor. The tumor arose from the leaflets and tendinous cords of the mitral valve, and was composed grossly of multiple white nodules. Histopathologic evaluation disclosed fragments composed predominantly of peripheral spindle cells in an extensive fibromyxoid stroma. The mildly pleomorphic cells of the tumor gradually blended with adjacent pieces of the mitral valvar leaflet and tendinous cords. Immunohistochemical studies revealed strong staining for vimentin, smooth muscle actin, muscle specific actin, and myoglobin, suggesting myogenic differentiation. The other patient was a 2 1/2-year-old female who died suddenly at home. Grossly and histologically, the tumor was essentially identical to the first case, and there was a 3 cm string-like extension passing into the orifice of the left coronary artery. To put the cases in context, we compare them with other descriptions of this rare type of tumor.

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.

Are outcomes of surgical versus transcatheter balloon valvotomy equivalent in neonatal critical aortic stenosis?

BACKGROUND: For neonates with critical aortic valve stenosis who are selected for biventricular repair, valvotomy can be achieved surgically (SAV) or by transcatheter balloon dilation (BAV). METHODS AND RESULTS: Data regarding 110 neonates with critical aortic valve stenosis were evaluated in a study by the Congenital Heart Surgeons Society from 1994 to 1999. Reduced left ventricular function was present in 46% of neonates. The initial procedure was SAV in 28 patients and BAV in 82 patients. Mean percent reduction in systolic gradient was significantly greater with BAV (65+/-17%) than SAV (41+/-32%; P<0.001). Higher residual median gradients were present in the SAV versus BAV group (36 mm Hg [range, 10 to 85 mm Hg] versus 20 mm Hg [0 to 85 mm Hg], P<0.001). Important aortic regurgitation was more often present after BAV (18%) than SAV (3%; P=0.07). Time-related survival after valvotomy was 82% at 1 month and 72% at 5 years, with no significant difference for SAV versus BAV, even after adjustment for differences in patient and disease characteristics. Independent risk factors for mortality were mechanical ventilation before valvotomy, smaller aortic valve annulus (z score), smaller aortic diameter at the sinotubular junction (z score), and a smaller subaortic region. A second procedure was performed in 46 survivors. Estimates for freedom from reintervention were 91% at 1 month and 48% at 5 years after the initial valvotomy and did not differ significantly between groups. CONCLUSIONS: SAV and BAV for neonatal critical aortic stenosis have similar outcomes. There is a greater likelihood of important aortic regurgitation with BAV and of residual stenosis with SAV.

Impact of inspired gas mixtures on preoperative infants with hypoplastic left heart syndrome during controlled ventilation.

BACKGROUND: Management strategies for preoperative infants with hypoplastic left heart syndrome (HLHS) include increased inspired nitrogen (hypoxia) and increased inspired carbon dioxide (hypercarbia). There are no studies directly comparing these 2 therapies in humans. This study compares the impact of hypoxia versus hypercarbia on oxygen delivery, under conditions of fixed minute ventilation. METHODS AND RESULTS: Ten anesthetized and paralyzed preoperative infants with HLHS were evaluated in a prospective, randomized, crossover trial comparing hypoxia (17% FIO(2)) with hypercarbia (2.7% FICO(2)). Each patient was treated in a random order (10 minutes per condition) with a recovery period (15 to 20 minutes) in room air. Arterial (SaO(2)) and superior vena caval (SvO(2)) co-oximetry and cerebral oxygen saturation (ScO(2)) measurements were made at the end of each condition and recovery period. ScO(2) was measured by near infrared spectroscopy. Hypoxia significantly decreased both SaO(2) (-5.2+/-1.1%, P=0.0014) and SvO(2) (-5.6+/-1.7%, P=0.009) compared with baseline, but arteriovenous oxygen saturation (AVO(2)) difference (SaO(2)-SvO(2)) and ScO(2) remained unchanged. Hypercarbia decreased SaO(2) (-2.6+/-0.6%, P=0.002) compared with baseline but increased both ScO(2) (9.6+/-1.8%, P=0.0001) and SvO(2) (6+/-2.2%, P=0.022) and narrowed the AVO(2) difference (-8.5+/-2.3%, P=0.005). Both hypoxia and hypercarbia decreased the balance between pulmonary and systemic blood flow (Qp:Qs) compared with baseline. CONCLUSIONS: In preoperative infants with HLHS, under conditions of anesthesia and paralysis, although Qp:Qs falls in both conditions, oxygen delivery is unchanged during hypoxia and increased during hypercarbia. These data cannot differentiate cerebral from systemic oxygen delivery.

Arrhythmias after pediatric lung transplantation.

Atrial arrhythmias have been reported after congenital heart surgery involving extensive atrial suture lines. Experimental studies involving bilateral lung transplantation (Tx) suggest that the left atrial suture lines predispose to atrial flutter. The overall incidence and type of arrhythmias after pediatric lung Tx have not previously been described and therefore the purpose of this study was to prospectively screen and describe arrhythmias in a subset of our lung transplant population. Over a 1-yr study period, all recipients of bilateral lung Tx were admitted to a full-disclosure telemetry unit. Single-lead electrocardiograms were recorded continuously and reviewed daily via a beat-by-beat analysis. A total of 314 patient days (range 9-93, median 43 days) were recorded from seven patients. The incidence of arrhythmias observed per total patient days included junctional escape rhythm (4.8%), non-sustained ventricular tachycardia (4.1%), accelerated junctional (2.5%), sinus bradycardia (2.2%), non-sustained supraventricular tachycardia (1.3%), ectopic atrial tachycardia (1.0%), sustained ventricular tachycardia (0.3%), junctional ectopic tachycardia (0.3%), and second degree heart block (0.3%). No patient had sustained supraventricular tachycardia, atrial flutter, atrial fibrillation, or complete heart block. Arrhythmias were treated in two patients. During the follow-up period, one patient received amiodarone for ventricular tachycardia (which was also noted and treated prior to transplant). We conclude that among pediatric lung transplant recipients admitted for their transplant surgery, arrhythmia is uncommon and rarely requires therapy.

Atrioventricular valve regurgitation in patients with single ventricle: impact of the bidirectional cavopulmonary anastomosis.

BACKGROUND: It is not known whether atrioventricular valve regurgitation (AVVR) can improve in some patients after the bidirectional cavopulmonary anastomosis (BCPA) without undertaking concomitant valvuloplasty. METHODS: We retrospectively reviewed our experience with patients who underwent the BCPA between June 1989 and June 2000 with specific attention to those patients with moderate or severe AVVR. The degree of AVVR was determined by color Doppler echocardiography. During the study period there were 576 patients who underwent BCPA at a median age of 6.8 months (range, 1.3 months to 4.8 years). The majority of subjects (66%) had a tricuspid valve as the systemic atrioventricular valve. Significant (moderate or severe) AVVR before BCPA was noted in 36 of 576 patients (6%) and was significantly more prevalent (8 of 52 patients, 15%; p = 0.01) in patients with a common atrioventricular canal. RESULTS: Of the 36 subjects with moderate or severe AVVR, 8 had interventions (6 valvuloplasty, 2 aortic arch dilation) at BCPA. There was 1 hospital death (2.8%). Of the remaining 27 survivors who did not undergo additional interventions at BCPA, improvement in AVVR (mild or none) was noted in 6 (22%) at intermediate follow-up (median, 2 years; range, 0.5 to 3.1 years). The presence of significant AVVR before BCPA was not significantly associated with hospital survival or intermediate-term freedom from death or transplantation. CONCLUSIONS: We conclude that AVVR improves in some patients after BCPA and that valvuloplasty is not justified in all patients with moderate preoperative AVVR.

Metachronous Epstein-Barr virus-related smooth muscle tumors in a child after heart transplantation: case report and review of the literature.

Soft tissue tumors are uncommon manifestations of Epstein-Barr virus (EBV) infection in patients who have had transplants. The authors report 2 metachronous EBV-containing smooth muscle tumors in a child who had a heart transplant, and review the literature on posttransplant soft tissue tumors.

Atrioventricular valve replacement in patients with a single ventricle.

BACKGROUND: Significant atrioventricular valve (AVV) insufficiency has been associated with increased mortality and morbidity in patients with single ventricle. Although many patients can be managed with valvuloplasty alone, some patients require AVV replacement. The optimal timing, outcome, and risk factors for AVV replacement in this population have not been described. METHODS: We retrospectively reviewed our experience with AVV replacement in patients with single ventricle from January 1984 to August 2000. Outcome variables included mortality and valve-related complications. RESULTS: Seventeen patients required AVV replacement. Prosthetic valve types included: St. Jude's valve in 14, Bjork-Shiley in 1, Hall-Kaster in 1, and Carpentier-Edwards in 1. Valve size ranged from 17 to 33 mm, Median age at valve replacement was 3.0 years (range 7 days to 17.3 years). Of the 16 subjects with normal atrioventricular conduction preoperatively, 7 (44%) developed postoperative complete heart block. Hospital mortality was 29%. Hospital mortality decreased significantly from 56% in 1984 to 1993 to no deaths from 1994 to 2000 (p = 0.03). Younger age (less than 2 years) at operation was also a risk factor for hospital mortality (p = 0.03). There were four late deaths in this series and 1 patient underwent heart transplantation. Of the surviving patients, none has required replacement of the prosthetic valve. No patients have had cerebrovascular accident subsequent to AVV replacement. Functional status is New York Heart Association functional class I in 5, class II in 1, and Class III in 1. CONCLUSIONS: Atrioventricular valve replacement can be performed in patients with single ventricle with acceptable morbidity and mortality. The development of postoperative complete heart block is common. Survival after AVV replacement has improved in recent years, and intervention before patients develop ventricular dysfunction and atrial arrhythmias may further improve outcome.

Cerebral oxygen saturation before congenital heart surgery.

BACKGROUND: In congenital heart disease (CHD), neurologic abnormalities suggestive of hypoxia-ischemia are often apparent before cardiac surgery. To evaluate preoperative cerebral oxygenation, this study determined cerebral O2 saturation (ScO2) in CHD and healthy children. METHODS: Ninety-one CHD and 19 healthy children aged less than 7 years were studied before surgical or radiologic procedures. Arterial saturation (SaO2) and ScO2 were measured by pulse-oximetry and near infrared cerebral oximetry. Cerebral O2 extraction (CEO2) was calculated (SaO2-ScO2). SaO2, ScO2, and CEO2 were compared among diagnoses. Multivariable regression was performed between ScO2 and clinical variables. RESULTS: In healthy subjects, ScO2 (68%+/-10%) and CEO2 (30%+/-11%) were similar to patients with ventricular septal defect, aortic coarctation, and single ventricle after Fontan operation. ScO2 was significantly decreased in patients with patent ductus arteriosus (53%+/-8%), tetralogy of Fallot (57%+/-12%), hypoplastic left heart syndrome (46%+/-8%), pulmonary atresia (38%+/-6%), and single ventricle after aortopulmonary shunt (50%+/-7%), or bidirectional Glenn operation (43%+/-6%). CEO2 was significantly different only in patent ductus arteriosus (46%+/-8%) and hypoplastic left heart syndrome (38%+/-12%). In multivariable regression, only SaO2 was related to ScO2 (R = 0.63, p < 0.001). CONCLUSIONS: Cerebral oxygenation in CHD varies with anatomy and arterial saturation, and in some patients, it is very low compared with healthy subjects.

Allopurinol neurocardiac protection trial in infants undergoing heart surgery using deep hypothermic circulatory arrest.

OBJECTIVE: This pharmacologic protection trial was conducted to test the hypothesis that allopurinol, a scavenger and inhibitor of oxygen free radical production, could reduce death, seizures, coma, and cardiac events in infants who underwent heart surgery using deep hypothermic circulatory arrest (DHCA). DESIGN: This was a single center, randomized, placebo-controlled, blinded trial of allopurinol in infant heart surgery using DHCA. Enrolled infants were stratified as having hypoplastic left heart syndrome (HLHS) and all other forms of congenital heart disease (non-HLHS). Drug was administered before, during, and after surgery. Adverse events and the clinical efficacy endpoints death, seizures, coma, and cardiac events were monitored until infants were discharged from the intensive care unit or 6 weeks, whichever came first. RESULTS: Between July 1992 and September 1997, 350 infants were enrolled and 348 subsequently randomized. A total of 318 infants (131 HLHS and 187 non-HLHS) underwent heart surgery using DHCA. There was a nonsignificant treatment effect for the primary efficacy endpoint analysis (death, seizures, and coma), which was consistent over the 2 strata. The addition of cardiac events to the primary endpoint resulted in a lack of consistency of treatment effect over strata, with the allopurinol treatment group experiencing fewer events (38% vs 60%) in the entire HLHS stratum, compared with the non-HLHS stratum (30% vs 27%). In HLHS surgical survivors, 40 of 47 (85%) allopurinol-treated infants did not experience any endpoint event, compared with 27 of 49 (55%) controls. There were fewer seizures-only and cardiac-only events in the allopurinol versus placebo groups. Allopurinol did not reduce efficacy endpoint events in non-HLHS infants. Treated and control infants did not differ in adverse events. CONCLUSIONS: Allopurinol provided significant neurocardiac protection in higher-risk HLHS infants who underwent cardiac surgery using DHCA. No benefits were demonstrated in lower risk, non-HLHS infants, and no significant adverse events were associated with allopurinol treatment.congenital heart defects, hypoplastic left heart syndrome, induced hypothermia, ischemia-reperfusion injury, neuroprotective agents, allopurinol, xanthine oxidase, free radicals, seizures, coma.

Patterns of right aortic arch and mirror-image branching of the brachiocephalic vessels without associated anomalies.

It is unusual to have a right aortic arch with mirror-image branching of the brachiocephalic vessels and no associated congenital cardiac anomalies. Pathogenetic factors of this anomaly, and associated development of the derivatives of the pharyngeal arches, have not been explored extensively. Eleven patients with a mirror-image right aortic arch and no intracardiac anomalies have undergone evaluation at our institution since 1987. Of these, 4 had stenosis (n = 2) or atresia (n = 2) of the proximal left pulmonary artery. These included 2 with bilateral ductus arteriosus. Six patients had a vascular ring formed by a ductus arteriosus or ligamentum arteriosum from the descending aorta to the left pulmonary artery. Six patients were evaluated for deletion within the DiGeorge critical region of chromosome 22q11. All 6 of the patients with a vascular ring underwent division of the ductus arteriosus or ligamentum through a left lateral thoracotomy. None of the patients with stenosis or atresia of the LPA have undergone intervention. Two of the 6 patients who underwent evaluation for chromosome 22q11 deletion were found to have the deletion. At a median follow-up of 7 years (15 months to 12 years), the patients who underwent division of the ring are all alive and asymptomatic. Two of these patients have undergone repeat magnetic resonance imaging, 1 of whom had mild residual tracheal compression. A right aortic arch with mirror-image branching of the brachiocephalic vessels and no associated intracardiac anomalies is extremely uncommon. We have observed two basic patterns of this lesion: (1) with associated abnormalities of the proximal left pulmonary artery, (2) with a vascular ring formed by a ductus arteriosus or ligamentum from the descending aorta to the left pulmonary artery. Pathogenetic considerations are explored, with a focus on flow-related vascular development and the role of deletions within chromosome 22q11.

Thrombus formation after the Fontan operation.

BACKGROUND: Thrombus formation is common after a Fontan operation. We investigated the frequency and location of thrombus in our population of children based on the type of Fontan operation performed. METHODS AND RESULTS: Between January 1987 and January 1999, 592 patients underwent echocardiography after Fontan operation and 52 (8.8%) had intracardiac thrombus. Median age at Fontan operation was 1.9 years (range 0.8 to 35.1). Freedom from thrombus was 92%, 90%, 84% and 82% at 1, 3, 8, and 10 years after Fontan operation, respectively. There was no difference in freedom from thrombus, based on type of operation (atriopulmonary vs. lateral tunnel) or presence of fenestration. Thrombus was detected in the systemic venous atrium in 26 (48%), in the pulmonary venous atrium in 22 (44%), in both atria in 1 (2%), in the hypoplastic left ventricular cavity in 2 (8%), and in the ligated pulmonary artery stump in 1 (2%). CONCLUSIONS: Thrombus formation occurs with equal frequency in all types of modifications and is seen in the pulmonary, as well as the systemic venous atria. Our study suggests that thrombus formation is inherent to the physiology after Fontan operation and is not related to the type of modification performed.