Recombinant porcine factor VIII for high-risk surgery in paediatric congenital haemophilia A with high-titre inhibitor.

INTRODUCTION: High-titre factor VIII (FVIII) inhibitors complicate peri-operative haemostasis. Recombinant porcine FVIII (r-pFVIII) may provide an alternative haemostatic agent for high-risk procedures and allow FVIII activity monitoring. AIM: Devise an effective haemostatic plan for repair of a progressively symptomatic aortic coarctation in a 5-year-old male with immune tolerance induction (ITI) refractory high-titre FVIII inhibitors. METHODS: Preprocedure human FVIII inhibitor titre was 58 Bethesda Units mL-1 (BU) and cross-reacted to neutralize porcine FVIII at 30 BU. Daily ITI with plasma-derived FVIII concentrate was supplemented with anti-B-cell and anti-plasma cell immunotherapy to reduce FVIII inhibitor titres. Potential haemostatic agents were evaluated in comparative ex vivo thrombin generation assays (TGA). RESULTS: Four weeks after immunosuppression, human and porcine inhibitor titres declined to 16 and 2 BU respectively. TGA with r-pFVIII was less robust than with activated prothrombin complex concentrate (aPCC); however, r-pFVIII was selected for cardiac surgery to secure the ability to assay FVIII levels throughout this high-bleeding risk procedure. Haemostasis with r-pFVIII was excellent; initial trough FVIII activity levels ranged from 0.81-1.17 IU mL-1 . On postoperative day 3, peak and trough levels markedly declined suggesting a rising porcine inhibitor titre. Postprocedure prophylaxis was transitioned to aPCC, informed by TGA. CONCLUSIONS: R-pFVIII provided effective peri-procedural haemostasis with no adverse events. Rapid neutralization of r-pFVIII after the first 60 hours, despite intensive immune suppression, accentuates the importance of careful monitoring. Use of TGA can support bypassing agent selection for convalescence. The comparative cost of r-pFVIII may limit its use to high morbidity clinical scenarios.

Biventricular repair in patients with heterotaxy syndrome.

OBJECTIVE: Complex intracardiac and extracardiac anatomy is often confronted during biventricular repair in patients with heterotaxy syndrome. We examined factors affecting surgical outcomes in these patients. METHODS: Between January 1990 and July 2007, 371 patients received a diagnosis of heterotaxy syndrome; 91 (91/371, 24.5%) underwent biventricular repair. Left atrial isomerism was present in 73% (66/91) and right atrial isomerism in 10% (9/91), with indeterminate atrial anatomy in 17% (16/91). Median age at biventricular repair was 6.8 months (5 days to 22.3 years). Systemic venous anomalies were present in 75 patients, pulmonary venous anomalies in 26, and endocardial cushion defects in 36. Transposition complexes were present in 15 patients with atrioventricular discordance in 10; 8 underwent double switch, 2 received a physiologic repair, 2 underwent arterial switch, and 3 underwent the Rastelli operation. Other conotruncal anomalies included double-outlet right ventricle in 10 patients, tetralogy of Fallot in 3, and hemitruncus in 2. Separation of systemic from pulmonary venous return included intra-atrial baffling in 48 patients and extracardiac grafting in 2. Combined lesions were common, occurring in 99% (90/91). Statistical analysis with Kaplan-Meier and Cox proportional hazards models were performed. RESULTS: Average follow-up was 44.9 +/- 57.5 months (3 days to 189.3 months). Kaplan-Meier estimated survival was 93.4% at 10 years; unbalanced complete atrioventricular canal was the only risk factor for mortality (P = .006). Subsequent procedures were common with a 10-year freedom from reoperation or reintervention of 38% +/- 7.5%. Arrhythmias occurred in 36 (39.6%) patients; bradyarrhythmia in 27 (29.7%) and tachyarrhythmia in 15 (16.5%). Freedom from any arrhythmia was 53.9% +/- 6.7% at 10 years. CONCLUSIONS: Excellent survival for patients with heterotaxy undergoing biventricular repair can be expected, even for multiple, complex lesions. Reintervention is common, and arrhythmia is a long-term concern. This experience shows that patients with heterotaxy syndrome and complex cardiac anatomy can be considered for biventricular repair. Patients with unbalanced complete atrioventricular canal are a high-risk group for which selection criteria are particularly important.

Etiology, management, and outcome of pediatric pericardial effusions.

The objective of this study was to determine the contemporary etiologies, treatment, and outcomes of moderate and large pericardial effusions in pediatric patients. We reviewed pediatric patients with moderate or large effusions diagnosed at Children's Hospital Boston. Effusion size was determined in offline review of echocardiograms. One hundred sixteen patients with moderate or large pericardial effusions were identified. The age range was 1 day to 17.8 years (median 8.6). The size of the pericardial effusions ranged from 0.5 to 4.7 cm (median 2.1). Neoplastic disease was present in 39% of patients, collagen vascular disease in 9%, renal disease in 8%, bacterial infection in 3%, and human immunodeficiency virus (HIV) in 2%; 37% were idiopathic. Pericardial drainage procedures were performed in 47 patients (41%). Of these, 29 (63%) had recurrent effusions leading to repeat drainage in 12 (41%). Pericardial effusions resolved within 3 months in 83% of patients who underwent drainage and in 91% of patients who did not. In summary, pediatric pericardial effusions were rarely caused by bacterial infections in this study population and were more frequently idiopathic or associated with neoplastic disease. Pericardial effusions often reaccumulated after drainage. The majority of both drained and undrained effusions resolved within 3 months.

Changes in left heart hemodynamics after technically successful in-utero aortic valvuloplasty.

OBJECTIVE: Severe aortic stenosis in the mid-gestation fetus can progress to hypoplastic left heart syndrome (HLHS). @ In-utero aortic valvuloplasty is an innovative therapy to promote left ventricular growth and function and potentially to prevent HLHS. This study evaluated the effects of mid-gestation fetal balloon aortic valvuloplasty on subsequent fetal left ventricular function and left heart Doppler characteristics. METHODS: We reviewed fetuses with aortic stenosis that underwent attempted in-utero aortic valvuloplasty between 2000 and 2006. Pre-intervention and the latest post-intervention fetal echocardiograms were analyzed to characterize changes in left heart function and Doppler characteristics in utero. RESULTS: Forty-two fetuses underwent attempted aortic valvuloplasty during the study period, 12 of which were excluded from analysis secondary to inadequate follow-up data, termination or fetal demise. Study fetuses (n = 30) underwent pre-intervention echocardiography at a median gestational age of 23 weeks, and were followed for a median of 66 +/- 23 days post-intervention. In 26 fetuses, aortic valvuloplasty was technically successful. Among these 26, left heart physiology was abnormal pre-intervention and improved or normalized after intervention in most cases: biphasic mitral inflow was present in 5/25 (20%) cases pre-intervention and in 21/23 (91%) post-intervention (P < 0.001); moderate or severe mitral regurgitation was present in 14/26 (54%) cases pre-intervention and in 5/23 (22%) post-intervention (P = 0.02); bidirectional flow across the patent foramen ovale was present in 0/26 cases pre-intervention and in 6/25 (24%) post-intervention (P = 0.01); antegrade flow in the transverse arch was present in 0/25 cases pre-intervention and in 17/26 (65%) post-intervention (P < 0.001). The left ventricular ejection fraction increased from 19 +/- 10% pre-intervention to 39 +/- 14% post-intervention (P < 0.001). These changes were not observed in control fetuses (n = 18). CONCLUSION: Fetal aortic valvuloplasty, when technically successful, improves left ventricular systolic function and left heart Doppler characteristics.

Three-dimensional echocardiography in congenital heart disease: a continuum of unfulfilled promises? No. A presently clinically applicable technology with an important future? Yes.

Three-dimensional echocardiography has important clinical applications to congenital heart disease. Such applications include assessment of ventricular volumes, and unique imaging planes and projections of septae and atrio-ventricular and semi-lunar valves. Advances in ultrasound and computer technology will improve the process of three-dimensional echocardiography to continue to bring it to everyday clinical utility application.

Valve-sparing operation for balloon-induced aortic regurgitation in congenital aortic stenosis.

OBJECTIVE: Aortic regurgitation after balloon dilation of congenital aortic stenosis may be treated with valve repair as an alternative to replacement. METHODS: Charts and echocardiograms of all patients undergoing aortic valve operations after balloon dilation of congenital aortic stenosis at our institution between January 1988 and December 1999 were reviewed. RESULTS: Twenty-one patients underwent valvuloplasty for predominant aortic regurgitation 9 months to 15 years (mean, 6.1 years) after balloon dilation. The mean +/- SD age at the time of the operation was 11 +/- 7 years. Aortic regurgitation was caused by a combination of commissural avulsion (10), cusp dehiscence with retraction (9), cusp tear (5), central incompetence (2), perforated cusp (1), or cusp adhesion to the aortic wall (1). Repair techniques included commissural reconstruction with a pericardial patch (8), pericardial patch cusp augmentation (6), primary suture repair (6), raphae release and debridement (4), commissurotomy (4), commissural resuspension with sutures (3), and cusp release (1). There were no deaths. At a mean follow-up of 30.1 months (range, 9 months-8 years), all patients were asymptomatic, and the grade of aortic regurgitation had been significantly reduced (P <.001). Left ventricular end-diastolic dimension z scores and proximal regurgitant jet/aortic anulus diameter ratios were significantly reduced (P <.001) and remained so over time. Freedom from reoperation for late failure was 100%, and overall freedom from reintervention was 80% at 3 years. CONCLUSION: Aortic valve repair for balloon-induced aortic regurgitation is reproducible and durable at medium-term follow-up.

Three-dimensional echocardiography of the atrial septum.

This article details the important contribution of three-dimensional echocardiography for catheterization device closure of secundum atrial septal defects. Aspects presented include three-dimensional echocardiographic application in preselection of patients and in selection of the type and size of the atrial septal occluder devices. Unique three-dimensional echocardiographic imaging planes are shown that depict the size and shape of the defect, the important rim tissue surrounding the defect, and the images that demonstrate successful device placement. Details of the acquisition phase, digital reformatting, and the eventual rendering of standard three-dimensional echocardiographic imaging planes of the atrial septum are shown. Three-dimensional echocardiography not only provides important additional information, but also enhances understanding of standard two-dimensional studies.

Three-dimensional echocardiographic measurement of left ventricular stroke volume in children: comparison with Doppler method.

Three-dimensional echocardiography (3DE) allows calculation of ventricular volumes without geometric assumption on the ventricular shape. Our aim was to apply 3DE in a normal pediatric population and to compare the left ventricular stroke volume measurements to the Doppler method. Twenty-four normal patients (median age 7 years) underwent Doppler echocardiography and 3DE for left ventricular stroke volume calculation. The left ventricular stroke volume by Doppler method was calculated as the product of the aortic Doppler flow mean velocity and the area of the aortic annulus. The 3DE method was performed using a transthoracic rotational probe (TomTec) and left ventricular volumes were calculated using the Simpson's rule. The mean time for 3DE acquisition was 90 seconds without any sedation. 3DE correlated well with the Doppler method for left ventricular stroke volume measurements (y = 0.8x - 0.2, r = 0.94). The mean difference between the average values of left ventricular stroke volume obtained by Doppler method and 3DE was 5 +/- 4 ml. Intraobserver and interobserver variabilities in the left ventricular stroke volume measurement by 3DE were 2.6% and 4.4%. In conclusion, 3DE compared to the Doppler method is an accurate, noninvasive, and reproducible method to measure the left ventricular stroke volume in normal children.

Echocardiographic characteristics of successful deployment of the Das AngelWings atrial septal defect closure device: initial multicenter experience in the United States.

The AngelWings device is a newer transcatheter device used for closure of secundum atrial septal defects (ASD) and patent foramen ovale (PFO), which consists of a self-centering, 2-disk system. Transesophageal echocardiography (TEE) plays a pivotal role in the deployment of the 2 disks of this device, on the appropriate sides of the atrial septum. The objective of this study is to describe the echocardiographic findings associated with successful deployment of the AngelWings device for closure of ASD and PFO. We evaluated the TEE studies of 70 patients enrolled in 4 United States centers, for closure of ASD and PFO with the AngelWings device. The TEE characteristics of successful and unsuccessful deployments were analyzed. Residual shunts across the atrial septum were assessed by TEE at the end of the procedure, 24 hours later by transthoracic echocardiography, and at 6 months by TEE. The deployment of the device was successful in 65 patients (93%). In the unsuccessful group, ASD size by TEE was larger (13.4 +/- 3.1 vs 8.9 +/- 4.7 mm, p <0.05). TEE was successful in identifying snagging of the device by intracardiac structures and prolapse of corners of the left or right atrial disk through the ASD, features that were difficult to identify by fluoroscopy. The echocardiographic characteristics outlined here are important guidelines for successful deployment of the AngelWings device.

Transoesophageal echocardiography during scoliosis repair: comparison with CVP monitoring.

PURPOSE: Accurate haemodynamic assessment during surgical repair of scoliosis is crucial to the care of the patient. The purpose of this study was to compare transoesophageal echocardiography (TEE) with central venous pressure monitoring in patients with spinal deformities requiring surgery in the prone position. METHODS: Twelve paediatric patients undergoing corrective spinal surgery for scoliosis/kyphosis in the prone position were studied. Monitoring included TEE, intra-arterial and central venous pressure monitoring (CVP). Haemodynamic assessment was performed prior to and immediately after positioning the patient prone on the Relton-Hall table. Data consisted of mean arterial blood pressure (mBP), heart rate (HR), CVP, left ventricular end-systolic and end-diastolic diameters (LVESD and LVEDD respectively) and fractional shortening (FS). Right ventricular (RV) function and tricuspid regurgitation (TR) were assessed qualitatively. Analysis was performed using descriptive statistics, Student's t test, sign rank, and correlation analysis. RESULTS: There was an increase in CVP (8.7 mmHg to 17.7 mmHg; P < .01), and decreases in LVEDD (37.1 mm to 33.2 mm; P < .05), and mean blood pressure (75.0 mmHg to 65.7 mmHg; P < .05) when patients were placed in the prone position. Fractional shortening, LVESD, and HR did not change from the supine to the prone position. Right ventricular systolic function and tricuspid regurgitation were unchanged. CONCLUSION: These data indicate that the CVP is a misleading monitor of cardiac volume in patients with kyphosis/scoliosis in the prone position. This is consistent with previous studies. In this clinical situation, TEE may be a more useful monitoring tool to assess on-line ventricular size and function.

Neonatal radiofrequency catheter ablation of junctional tachycardias.

Junctional tachycardias comprise several arrhythmia types with differing mechanisms, principally involving the region of the atrioventricular (A-V) junction. Neonatal radiofrequency catheter ablation has typically been reserved for life-threatening, drug-refractory cases due to the unique concerns regarding patient size and development. We performed radiofrequency catheter ablation on two neonates with incessant, rapid junctional tachycardias and hemodynamic compromise after failing conventional medical therapy. This report describes 2 neonates who underwent emergent radiofrequency catheter ablation, and compares these two patients to a larger pediatric catheter ablation patient cohort. Both neonates had an acutely successful outcome and were able to be discharged within a week of the ablation procedure. Fluoroscopy time and total procedure time were shorter in these two patients than in the course of the average pediatric catheter ablation. Though long-term developmental consequences of neonatal catheter ablation are yet unknown, in unique extreme situations, radiofrequency catheter ablation can be performed in neonates, as in older children and adults, without excessive acute morbidity.

Cardiac dysfunction in twin-twin transfusion syndrome: a prospective, longitudinal study.

OBJECTIVE: To use serial echocardiography to evaluate prospectively the cardiac dysfunction in twin-twin transfusion syndrome and determine its clinical course and outcome. METHODS: Twin pregnancies presenting in the second trimester with sonographic evidence of twin-twin transfusion syndrome were managed with therapeutic reduction amniocenteses. Gestational age at diagnosis and delivery, number of amniocenteses performed, volume of amniotic fluid withdrawn, placentation, birth weight, hemoglobin at delivery, and perinatal outcome were recorded. Serial fetal echocardiography was carried out in a single tertiary center. Echocardiographic assessments included cardiac anatomy, chamber size, cardiothoracic ratio, interventricular septal thickness, ventricular systolic function, and the presence and severity of atrioventricular valve regurgitation. Postnatal echocardiograms were obtained on the surviving twins. RESULTS: Twelve cases of twin-twin transfusion syndrome were evaluated with serial echocardiography. Evidence of cardiac dysfunction was present prenatally in 10 recipient twins. All of the donor twins had normal fetal echocardiographic assessments. The most common abnormalities detected prenatally in recipient twins were decreased ventricular function, tricuspid regurgitation, and cardiac chamber enlargement. A deterioration of cardiac function was observed in seven recipient twins with increasing gestational age. Four of the eight surviving recipient twins had persistent postnatal echocardiographic abnormalities on follow-up examinations after the first 28 days of life. CONCLUSION: Prenatal cardiac dysfunction is common in recipient twins and can be transient, progressive, or persistent beyond the neonatal period.

New insights and observations in three-dimensional echocardiographic visualization of ventricular septal defects: experimental and clinical studies.

BACKGROUND: The positions, sizes, and shapes of ventricular septal defects (VSDs) can be difficult to assess by 2-dimensional echocardiography (2DE). Volume-rendered 3-dimensional echocardiography (3DE) can provide unique views of VSDs from the left ventricular (LV) side, allowing complete assessment of their circumference and spatial orientations to other anatomic structures. METHODS AND RESULTS: Seventeen experimentally created defects of various locations, sizes, and shapes were imaged and reconstructed in 9 explanted porcine hearts. From an en face projection, major and minor axis diameters of the defects were measured, and these data were compared with direct anatomic measurements. Optimal reconstructions of the VSDs were obtained in all heart specimens, accurately depicting their positions and shapes. The correlations between 3DE and anatomy for the VSD major and minor axis diameters were y=1.0x+0.3 (r=0.88, P<0.001) and y=1.0x-1.4 (r =0.89, P<0.001), respectively. Good agreement between the 2 methods was demonstrated for all measurements. Our experience from the in vitro model was then applied to patient studies. Optimal LV en face reconstructions were obtained in 45 of 51 patients, permitting detailed assessment of the positions, sizes, and shapes of the VSDs. In the 25 patients with comparative surgical measurements, the correlations between 3DE and surgery for the VSD major and minor axis diameters were y =0. 81x+2.1 (r=0.92, P<0.001) and y=0.73x+2.0 (r=0.91, P<0.001), respectively. Good agreement was demonstrated between measurements made by 3DE and those obtained at surgery. CONCLUSIONS: 3DE provides excellent visualization of various types of VSDs. From an LV en face projection, the positions, sizes, and shapes of VSDs can be accurately determined. Such precise imaging will be beneficial for surgical and catheter-based closure of difficult perimembranous and singular or multiple muscular VSDs.

MRI and echocardiography in children: how do they compare?

Clearly, both echocardiography and MRI play vital roles in the diagnosis and management of children with congenital heart defects. 2-D Doppler echocardiography is very easy to use in a vast array of clinical situations. The accuracy of the anatomic and hemodynamic findings are well accepted. In comparative studies, 2-D Doppler echocardiography appears preferable for intracardiac anatomy, whereas MRI appears preferable for extracardiac anatomy. In certain patients, Doppler echocardiography may not be able to optimally obtain the anatomic or hemodynamic information, and MRI should be used in these particular cases.

Effect of pulmonary artery stenoses on the cardiopulmonary response to exercise following repair of tetralogy of Fallot.

Data from exercise tests, echocardiograms, and lung perfusion scans were analyzed to determine whether the excessive minute ventilation (VE) often encountered among patients with tetralogy of Fallot is due to ventilation-perfusion mismatch secondary to branch pulmonary artery stenoses. Patients with branch PA stenoses had lower peak oxygen consumptions and higher VE during exercise than did patients without stenoses, and a strong correlation existed between the degree of pulmonary blood flow maldistribution on lung perfusion scan and the amount of excessive VE during exercise.

Transcoronary ethanol ablation of the atrioventricular node in a young patient with tricuspid atresia.

Catheter ablation of AV conduction with radiofrequency energy can be challenging in the presence of structural abnormalities of the AV junction, either congenitally or after reconstructive surgery. We used transcoronary ethanol to ablate the AV node in a patient with classic tricuspid atresia and refractory intraatrial reentry tachycardia. This approach provides an alternative means of creating complete heart block with catheter-based techniques, when radiofrequency catheter ablation is technically impossible or ineffective.

Fate of mitral regurgitation following repair of atrioventricular septal defect.

The purpose of this study was to evaluate the fate of mitral regurgitation (MR) following repair of atrioventricular septal defects (AVSDs). Echocardiograms of all survivors of isolated AVSD surgery between 1986 and 1996, who had had > or =2 postoperative color Doppler studies (39 patients), were reviewed. On each study, MR severity was graded on a 1+ to 4+ scale, based upon the size of the MR jet. Median age at surgery was 9 months (range 3 to 169); median age at postoperative follow-up was 45 months (range 3 to 107). Mild deterioration of mitral valve function was fairly common. MR severity increased by > or =1 grade in 16 patients (41%) during the course of the study. However, the deterioration in mitral valve function occurred primarily during the early postoperative time intervals. After the initial 32 postoperative months, MR worsened on only 4 occasions and in each instance worsened by only 1 grade. Deterioration to 4+ MR occurred in only 3 patients, and was not observed after the initial 30 postoperative months. Survival curve analysis predicted a 90% probability of not having severe (4+) MR after 30 months (lower 95% confidence bound: 80%). Postoperative MR remains fairly stable following AVSD repair. Serious deterioration is rare, especially after the initial 30 postoperative months.

Two- and three-dimensional transesophageal echocardiography in patient selection and assessment of atrial septal defect closure by the new DAS-Angel Wings device: initial clinical experience.

BACKGROUND: Transcatheter closure of atrial septal defects (ASDs) has been feasible and successful. Two-dimensional echocardiography (2DE) was applied to patients before selection and during device deployment. Three-dimensional echocardiography (3DE) can provide unique anatomic perspectives that might aid in improving device closure of ASDs. METHODS AND RESULTS: Twenty-two consecutive patients were enrolled in an initial protocol for ASD device closure by the new DAS-Angel Wings occluder device. On the basis of transesophageal (TEE) 2DE and 3DE, 13 patients were considered eligible for device closure (9 secundum ASDs and 4 with patent foramen ovale associated with a cerebral vascular accident). Maximal ASD diameter and surrounding rim tissues were compared by TEE 2DE and 3DE and with balloon sizing measurements at catheterization. ASD size measured by TEE 2DE and 3DE correlated well (y = 1.0x + 0.049, r = .95), with good limits of agreement. However, balloon-stretched diameter measurements were systematically larger than echocardiographic measurements. Rim tissue measurements correlated well; however, TEE 3DE could demonstrate the entire shape and perimeter of the defect. Two-dimensional imaging provided reliable information during device deployment and for closure of small ASDs. However, 3DE was superior for imaging the device, especially when abnormally placed. CONCLUSIONS: Three-dimensional imaging provides unique images and projections that were essential for understanding the spatial relationship of the device to the atrial septum. Three-dimensional echocardiography significantly enhanced our understanding of two-dimensional images and provided an imaging conceptualization that should aid in future development of device closures.

Excessive anaerobic metabolism during exercise after repair of aortic coarctation.

OBJECTIVES: To determine whether survivors of surgery for coarctation of the aorta (CoA) have an excessive reliance on anaerobic metabolism during exercise. BACKGROUND: Patients with peripheral vascular disease cannot increase blood flow to their muscles normally during exercise. Consequently they acquire an early, excessive reliance on anaerobic metabolism and have depression of the ventilatory anaerobic threshold (VAT) and of the slope of the oxygen consumption-work rate relationship (delta VO2/delta WR). We speculated that the capacity to augment blood flow to the lower extremities during exercise may be impaired after CoA surgery and would result in similar metabolic disturbances. STUDY DESIGN: Progressive exercise tests were performed on 15 patients (ages 19 +/- 7 years; range, 10 to 32) after successful repair of CoA (residual resting gradient, 7.7 +/- 7.1 mm Hg; range, 0 to 18), 15 age- and sex-matched healthy control subjects, and 10 patients (ages 13 +/- 3 years; range, 10 to 20) who had undergone ligation of a patent ductus arteriosus. RESULTS: The CoA patients' VAT averaged 14.8 +/- 3.8 ml O2/kg per minute versus 19.3 +/- 3.1 ml O2/kg per minute for the control subjects (p < 0.01), and their delta VO2/delta WR averaged 8.2 +/- 1.8 ml/watt compared with 10.1 +/- 1.4 ml/watt for control subjects (p < 0.01). Furthermore, 10 of 15 CoA patients had a VAT of less than 40% of predicted maximal oxygen consumption, and 9 of 16 had a delta VO2/delta WR of less than 8.7 ml O2/watt (generally accepted abnormal values). Patients with patent ductus arteriosus resembled the healthy control subjects with regard to anaerobic metabolism during exercise. CONCLUSIONS: Patients who have had CoA repairs commonly manifest an excessive reliance on anaerobic metabolism during exercise. This phenomenon may result from persistent blood flow abnormalities across the aortic arch during exercise, which may be present even after apparently successful surgery.