Reno-portal anastomosis as an approach to pediatric kidney transplantation in the setting of inferior vena cava thrombosis.

In pediatric renal transplantation in the setting of IVC thrombosis, the retrohepatic IVC or gonadal veins are often used for outflow. However, if use of systemic venous outflow is unsuccessful, options become limited. We report the use of the portal vein for venous outflow in kidney retransplantation in the setting of IVC thrombosis. The patient is a 19-month-old male who developed end-stage renal failure at seven months of age secondary to hypotension after spontaneous rupture of an accessory renal vein. The IVC was occluded during emergent laparotomy, and the patient developed extensive IVC thrombosis. The first two transplant attempts used the retrohepatic IVC for venous outflow. Despite good initial flow, in both instances the renal vein thrombosed on post-operative day 1. In an unsuccessful salvage attempt of the second transplant, a reno-portal anastomosis was performed. With few options for vascular access, a third transplant was attempted. The reno-portal stump from the second transplant was used for outflow. The patient recovered well from his third transplant (creatinine 0.6 mg/dL 35 months post-surgery), demonstrating that the portal vein can be used for outflow in cases of extensive IVC thrombosis.

Multivisceral transplantation using a 2.9 kg neonatal donor.

Prematurity and very low birthweight have often been considered relative contraindications to neonatal organ donation. Organ procurement from neonatal donors is further complicated by unclear guidelines regarding neonatal brain death. We report a successful case of multivisceral transplantation using a graft from a 10-day-old, 2.9 kg, neonatal donor born at 36 6/7 wk in a 3.2 kg, three month old with intestinal and liver failure secondary to midgut volvulus. There was immediate liver graft function with correction of recipient coagulopathy, but delayed normalization of laboratory values and delayed return of bowel function. At six-yr post-transplant follow-up, the patient has normal intestine and liver function. Her last histologically confirmed rejection episode was 30 months prior to last follow-up. This case suggests that multivisceral grafts from very young or small neonatal donors may be transplanted successfully in selected cases. We propose a re-examination of the brain death guidelines for premature and young infants to potentially increase the availability of organs for infant recipients.

Congenital anomalies involving the coronary sinus.

A classification is presented of anomalies involving the coronary sinus. These anomalies are classified into four anatomic groups on the basis of (1) enlargement of the coronary sinus, (2) absence of the coronary sinus, (3) atresia of the right atrial coronary sinus ostium, and (4) hypoplasia of the coronary sinus. Anomalies involving the coronary sinus often are associated with other venous anomalies, either of the systemic or the pulmonary circulation. In some there is no basic disturbance of the circulation. Those conditions involving the coronary sinus which are of major functional significance participate in shunts, either left-to-right or right-to-left in nature. Enlargement of the coronary sinus in the absence of a shunt usually indicates that a systemic venous channel joins the coronary sinus anomalously.

Predictive value of lung biopsy in ventricular septal defect: long-term follow-up.

Although the Heath-Edwards classification has been used for more than 25 years to evaluate pulmonary vascular changes, its potential to predict the long-term course after successful ventricular septal defect closure has not been proved. Operative lung biopsy slides obtained at the time of closure from 57 infants and children who had been among the first survivors (between 1954 and 1960) of such surgery were graded in blinded fashion according to the Heath-Edwards classification system, and the resultant biopsy grade of each was compared with the eventual long-term outcome of each child. In 53 (93%) of the 57 cases, the Heath-Edwards system correlated well with long-term clinical or hemodynamic status of the patient. Grade IV changes were predictive of a usually fatal outcome, while grade I and II changes were generally benign. Death from pulmonary vascular disease occurred, however, in four children whose operative lung biopsy had been classified as either grade I or II, indicating that the focal nature of the higher Heath-Edwards grades, or human error, must be considered when this classification system is employed.

Lung growth after reduced size transplantation in a sheep model.

BACKGROUND: The growth of mature allografts is a critical issue in pediatric lung transplantation. This study explores the architectural changes of mature sheep lung when submitted to two different compensatory growth forces: either transplantation into a neonatal host or expansion in an otherwise empty adult hemithorax. METHODS: Right upper lobes (RUL) (mean+/-SEM, 66.7+/-1.9 kg) from 4- to 5-year old (adult sheep) were transplanted into newborn (n=6) lambs (5.4+/-0.3 kg, 5+/-2 days old) that were then allowed to survive for 45 days. Changes in pulmonary volume and architecture were measured before and after transplantation. Allografts were compared with both normal adult RUL (n=10) and adult (65.8+/-2.2 kg and 4 to 5 year old) RUL that remained in situ for 45 days after resection of the corresponding middle and lower lobes (n=6). Statistical differences were analyzed using two-sample and paired t tests. RESULTS: In adult animals, RUL remaining in the otherwise empty hemithorax compensated by an 85% increase in volume (251.5+/-18.7 ml vs. 466+/-32.8 ml) (P<0.0001). Concomitant increases in total internal alveolar surface area (48%) and alveolar size were prominent. The number of alveoli per volume decreased proportionately to the increases in volume (P<0.0001). There was no significant change in the calculated number of alveoli (345.6+/-40.5 x 10(6)) compared with the normal adult RUL (402.4+/-40.7x10(6)) (P=0.37). Transplant recipients received a reduced-size normal adult RUL (49%) in volume (125.3+/-21.5 ml). Allografts 45 days after transplantation showed a 73% increase in volume (216.4+/-21.3 ml) (P<0.0001) with a parallel (83%) increase in total internal alveolar surface area (P=0.008). The number of alveoli per volume remained constant (P=0.21) despite the increase in volume. There was therefore a significant increase in the calculated number of alveoli from before transplantation (172.5+/-35.9x 106) compared with that observed 45 days after transplantation (389.7+/-77.7x10(6)) (P=0.012). CONCLUSIONS: We conclude that mature sheep RUL parenchyma compensates with dilation of the respiratory structures in the adult animal, whereas there is alveolar multiplication when transplanted into newborn recipients.

Prenatal detection of neuroblastoma: a ten-year experience from the Dana-Farber Cancer Institute and Children's Hospital.

OBJECTIVES: To assess the relative frequency of, the clinical and pathological correlates in, and the prognosis of the subset of infants with neuroblastoma who were identified initially by prenatal ultrasonography. DESIGN: Retrospective review of all patients with neuroblastoma evaluated between 1982 and 1992. SETTING: Large, urban, tertiary care children's hospital in Boston, Massachusetts. PATIENTS: Eleven infants with neuroblastoma initially detected with prenatal sonograms were identified. RESULTS: Nine patients had adrenal tumors; two had thoracic paraspinal tumors. Typical diagnostic evidence for neuroblastoma including a palpable abdominal mass and elevations in urinary catecholamines were not commonly seen postnatally. These patients had multiple favorable prognostic indicators including low stage of disease (10/11), favorable biological markers including cellular DNA content (5/5) and N-myc oncogene copy number (5/5), and histopathology suggestive for neuroblastoma in situ (7/11). All patients were treated by surgical resection. One patient exhibited progression of disease postoperatively, but demonstrated a complete clinical response to multiagent chemotherapy. Overall survival in our population was excellent with no deaths seen at a mean follow-up of 37 months (range 3 to 120 months). CONCLUSIONS: Patients with neuroblastoma identified by prenatal ultrasonography generally, although not exclusively, follow a clinically favorable course in which surgical resection is curative. Chemotherapy is not indicated unless substantial progression of disease occurs.

Extracorporeal membrane oxygenation and conventional medical therapy in neonates with persistent pulmonary hypertension of the newborn: a prospective randomized study.

Thirty-nine newborn infants with severe persistent pulmonary hypertension and respiratory failure who met criteria for 85% likelihood of dying were enrolled in a randomized trial in which extracorporeal membrane oxygenation (ECMO) therapy was compared with conventional medical therapy (CMT). In phase I, 4 of 10 babies in the CMT group died and 9 of 9 babies in the ECMO group survived. Randomization was halted after the fourth CMT death, as planned before initiating the study, and the next 20 babies were treated with ECMO (phase II). Of the 20, 19 survived. All three treatment groups (CMT and ECMO in phase I and ECMO, phase II) were comparable in severity of illness and mechanical ventilator support. The overall survival of ECMO-treated infants was 97% (28 of 29) compared with 60% (6 of 10) in the CMT group (P less than .05).

Late results (30 to 35 years) after operative closure of isolated ventricular septal defect from 1954 to 1960.

This study was designed to determine the clinical status, cause of death, and effects of pulmonary vascular disease and conduction abnormalities 30 to 35 years after surgery in 296 consecutive surviving patients of closure of ventricular septal defect. Of the 296 patients, current status was determined by contact with patient and physician in 290 cases, with 6 (2%) lost to follow-up (7,912 patient years are included). Cardiac catheterization after surgery in 168 patients showed complete closure of the defect in 80%. Death occurred in 59 patients (20%), with higher mortality rates in those operated on after the age of 5 years, those with pulmonary vascular resistance greater than 7 units (51%), and those with complete heart block (78%). Of 37 patients with transient heart block after surgery, 8 (22%) have died (3 pulmonary vascular disease, 2 sudden death, 2 unknown causes and 1 complete heart block). Twenty other patients had a dysarrhythmia after surgery, and none of these died. Nine episodes of endocarditis occurred (11.4/10,000 patient years). Nine of 296 (3%) offspring had cardiac malformation. Most patients are in New York Heart Association class I, 57% attended college and 15% received an advanced degree. The data show good results for this group of patients operated on during an early era (1954 to 1960) of open cardiac surgery. They support the current trend toward operation in patients with ventricular septal defects at an early age and with low pulmonary vascular resistance.

Role of extracorporeal membrane oxygenation in selected pediatric respiratory problems.

Between 1984 and 1988, 89 infants and children with severe respiratory failure were supported by extracorporeal membrane oxygenation. Major clinical diagnoses included congenital diaphragmatic hernias (34), meconium aspiration syndrome (26), and sepsis (8). Extracorporeal membrane oxygenation was used for patients with a predicted mortality rate of at least 80% based on an oxygenation index greater than 0.4. Venoarterial bypass was accomplished by way of right cervical cannulation of the common carotid artery and internal jugular vein. Overall survival was 71% but varied widely by diagnosis and progressively improved over time. The average extracorporeal membrane oxygenation run was 5.7 days. Intracranial hemorrhage was the most serious complication occurring in 16% of patients. Mechanical circuit complications were seen in 22% but rarely related to significant morbidity. Extracorporeal membrane oxygenation appears to provide effective cardiopulmonary support for selected pediatric respiratory problems. It affords those with potentially reversible pathophysiology the temporal opportunity for successful medical or surgical therapies.

Mitral valve replacement: a comparison of two prostheses.

Between November, 1965 and June, 1970, 175 patients underwent mitral valve replacement with the Smeloff-Cutter prosthesis (109 patients) or the toroidal valve (66 patients). The early mortality for patients with a toroidal mitral prosthesis was 18.2 percent (12 patients) and the late mortality 34.8 percent (23 patients). Among patients in whom Smeloff-Cutter mitral valves were inserted, the early mortality was 15.6 percent (17 patients) and the late mortality 23.9 percent (26 patients). During a follow-up period extending at least five years, thromboembolic complications occurred in 25.9 percent (14) of patients with toroidal valves and 7.6 percent (7) of patients with Smeloff-Cutter valves. Reoperation was necessary because of thrombosis of the prosthesis in seven patients with toroidal valves and two patients with Smeloff-Cutter valves. The incidence of endocarditis was the same in both groups. In this study, the Smeloff-Cutter mitral prosthesis proved to be superior to the toroidal valve because of a lower incidence of thromboembolism.

Regional analgesia on pediatric medical and surgical wards.

Regional anesthetic approaches to pain management were examined in 72 children and young adults (ages 3 weeks to 31 years) who were observed on the surgical or medical wards of a children's hospital separate from intensive care areas. A protocol was devised to permit safe conduct of these techniques on the ward. Full resuscitation supplies were kept at each bedside. All patients receiving epidural narcotics had an apnea monitor, hourly counting of respiratory rates, and restriction of systemic analgesics. All bolus re-injections into the catheters were performed by an anesthesiologist who monitored the patient for 20 min. Minor side-effects, including pruritus, nausea, and urinary retention were common, but manageable. Significant complications included: one case of decubitus ulcers requiring skin-grafting, one episode of mild hypotension in a patient with terminal malignancy, requiring ephedrine and phenylephrine, and one mild toxic reaction on test dosing due to presumed intravascular migration of a lumber sympathetic catheter. Regional analgesic techniques can provide excellent analgesia on the wards for selected children and young adults, provided precautions are taken. Further study is required to define specific indications, risks and benefits relative to simpler techniques.

Pulmonary blood flow distribution during partial liquid ventilation.

Regional pulmonary blood flow was investigated with radiolabeled microspheres in four supine lambs during the transition from conventional mechanical ventilation (CMV) to partial liquid ventilation (PLV) and with incremental dosing of perfluorocarbon liquid to a cumulative dose of 30 ml/kg. Four lambs supported with CMV served as controls. Formalin-fixed, air-dried lungs were sectioned according to a grid; activity was quantitated with a multichannel scintillation counter, corrected for weight, and normalized to mean flow. During CMV, flow in apical and hilar regions favored dependent lung (P < 0.001), with no gradient across transverse planes from apex to diaphragm. During PLV the gradient within transverse planes found during CMV reversed, most notably in the hilar region, favoring nondependent lung (P = 0.03). Also during PLV, flow was profoundly reduced near the diaphragm (P < 0.001), and across transverse planes from apex to diaphragm a dose-augmented flow gradient developed favoring apical lung (P < 0.01). We conclude that regional flow patterns during PLV partially reverse those noted during CMV and vary dramatically within the lung from apex to diaphragm.

The high-risk liver allograft recipient. Should allocation policy consider outcome?

The Boston Center for Liver Transplantation has accumulated one of the larger series of liver allograft recipients. This review has provided an opportunity to examine recent pronouncements by Medicare regarding patient selection and survival and to question whether the current allocation scheme best utilizes a scarce supply of donor liver allografts. Patients with primary biliary cirrhosis, sclerosing cholangitis, and metabolic derangements have enjoyed excellent survival: in aggregate, 78.9% at 1 year. In contrast, patients suffering from acute hepatic failure, patients requiring life support, or patients with primary graft failure who need a second liver transplant did poorly compared with other recipient groups: 45% 1-year survival. This center's experience reflects a more realistic expectation of patient survival because it considers the high-risk recipient by diagnosis and urgency status. This study also suggests that assessment of outcome should be a component of allocation planning in the future.

The first open-heart repairs of ventricular septal defect, atrioventricular communis, and tetralogy of Fallot using extracorporeal circulation by cross-circulation: a 30-year follow-up.

From March 26, 1954, to July 19, 1955, 45 patients with major cardiac malformations not previously correctable underwent open repair utilizing cross-circulation between patient and donor without donor deaths. All operations were carried out at normothermia with lowered flow rates based on azygos flow studies. Twenty-seven patients, more than half of them infants, had ventricular septal defects closed. There were 8 hospital deaths, and there have been only 2 late deaths in 30 years. Fourteen (87.5%) of 16 who underwent recatheterization have closed defects. The 17 30-year-survivors are all in New York Heart Association Functional Class I. Five patients 4 months to 10 years old were operated on for atrioventricular canal (complete form). All had intractable failure, and 4 had pulmonary hypertension. Two of the 3 hospital deaths were due to heart block. The long-term survivor, a 15-month-old infant at the time of operation (severe pulmonary hypertension, 90/50 mm Hg), underwent repair 31 years ago and is now married with 3 children. Recatheterization disclosed normal pulmonary pressure (20/4 mm Hg), no shunts, and mild mitral regurgitation. Ten cyanotic tetrads 13 months to 14 years old were operated on with 5 hospital deaths. Of the 3 late deaths, 1 was accidental at 17 years, 1 occurred suddenly at home 13 years after operation in infancy for atresia, and the third occurred at reoperation 10 years later. The 2 remaining patients (1 the first patient operated on) are in excellent health. The surgical methods used and the physiological advantages of cross-circulation (temporary placenta) that made these results possible at a time when surgical knowledge was primitive are described.

15- to 30-year follow-up of patients undergoing repair of ruptured congenital aneurysms of the sinus of Valsalva.

Rupture of a congenital aneurysm of the sinus of Valsalva is a rare congenital cardiac malformation. Between 1956 and 1971, we operated on 14 patients aged 9 to 36 years (median, 20 years) for repair of a ruptured aneurysm of the sinus of Valsalva, and have followed each patient to the present. Two operative and 4 late deaths occurred, 3 following a second cardiac operation and the other from dysrhythmia. Late complications have included development of complete heart block in 2 patients (necessitating permanent pacemaker insertion 11 and 24 years after initial repair), progression of aortic regurgitation in 2 (necessitating valve replacement 9 and 13 years after initial repair), and endocarditis in 1 patient 20 years after repair. Four of the 8 remaining long-term survivors (followed for 15 to 30 years [mean, 23.6 years]) are in New York Heart Association (NYHA) Class I, and the other 4 are in NYHA Class II. Three of the 5 patients with suture closure (no pledgets or adjacent ventricular septal defect repair) of the ruptured aneurysm of the sinus of Valsalva sustained recurrent rupture and required repeat closure. Whether the lack of prosthetic material to bolster the repair or inadequate resection of redundant aneurysmal fibrous tissue was responsible for these recurrences cannot be stated. Operative management of patients with ruptured congenital aneurysms of the sinus of Valsalva is discussed.

Pediatric lung transplantation and "lessons from Green Surgery.".

During the past decade, lung transplantation has emerged as the definitive treatment for children with end-stage lung disease. Pediatric transplantation presents unique challenges with respect to diagnostic indications, donor-recipient size disparities, perioperative management, and growth. Lessons from the early development of cardiac surgery at the University of Minnesota (Green Surgical Service) provide a useful model for novel surgical challenges. Since 1990, 25 lung transplantations have been performed at our institution, including 4 heart-lung, 3 single-lung, 17 bilateral-lung, and 1 living-related lobar allograft. Age at transplantation ranged from 7 months to 27 years. The most common indication was cystic fibrosis. Given the limited donor pool, size disparities between donor and recipient were frequent. Excessive donor size was addressed by parenchymal reduction. Accommodation of small donor allografts was facilitated by elective cardiopulmonary bypass and pulmonary vasodilation using inhaled nitric oxide. Epidural anesthesia was routinely used for postoperative pain management and to enhance good pulmonary hygiene. Immunosuppression is presently achieved using cyclosporine, mycophenolate mofetil, and corticosteroids. Monitoring for rejection is accomplished with spirometry and transbronchial biopsies. Bronchial complications in 2 patients required placement of Palmaz stents. The living-related allograft was performed in a previous bone marrow transplant recipient obviating the need for long-term immunosuppression. The potential for growth of mature lung parenchyma postoperatively was studied and verified in a sheep model. Our experience parallels that of other frontiers such as early cardiac surgery in which medical and technologic innovations can be applied in a supportive environment to permit surgical progress.

Inhaled nitric oxide in the treatment of postoperative graft dysfunction after lung transplantation.

Pulmonary hypertension and transient graft dysfunction may complicate the postoperative course of patients undergoing lung transplantation. We report the acute effect of inhaled nitric oxide (80 ppm) on hemodynamics and gas exchange in 6 patients (median age, 14 years; range, 5 to 21 years) after lung transplantation as well as the effect of extended treatment over 40 to 69 hours in 2 patients. In 5 patients with pulmonary hypertension nitric oxide lowered mean pulmonary artery pressure (from 38.4 +/- 1.6 to 29.4 +/- 3.1 mm Hg; p < 0.05), pulmonary vascular resistance index (from 9.3 +/- 1.4 to 6.4 +/- 1.3 Um2; p < 0.05), and intrapulmonary shunt fraction (from 28.6% +/- 8.3% to 21.0% +/- 5.7%; p < 0.05). There was a 28.4% +/- 7.2% reduction in transpulmonary pressure gradient with only minor accompanying effects on the systemic circulation. Mean arterial pressure decreased only 2.7% +/- 5% (from 76.4 +/- 2.2 to 74 +/- 2.3 mm Hg; p = not significant), and systemic vascular resistance index by 4.2% +/- 9.7% (from 21.7 +/- 3.1 to 20.6 +/- 3.6 Um2; p = not significant). Cardiac index was unchanged (from 3.5 +/- 0.8 to 3.6 +/- 0.7 L.min-1.m-2; p = not significant). Nitric oxide caused a sustained improvement in oxygenation and pulmonary artery pressure during extended therapy at doses of 10 ppm. There were no major side effects. However, transient methemoglobinemia (9%) developed in 1 patient after 10 hours of nitric oxide treatment. Nitric oxide may be useful in the treatment of pulmonary hypertension and the impaired gas exchange that occurs after lung transplantation.

Interposed jejunal segment with nipple valve to prevent reflux in biliary reconstruction.

BACKGROUND: Resection is the accepted management of a choledochal cyst. However, the debate continues regarding the optimal method of biliary reconstruction. The Roux-en-Y limb is used most frequently, but concerns have been raised about this method due to associated peptic ulcer disease, cholangitis, and poor growth. A method of reconstruction using an interposed segment of jejunum with a nipple valve placed between the common bile duct and the duodenum has been proposed. STUDY DESIGN: We have reviewed a series of 12 children requiring biliary reconstruction for choledochal cyst (11 children) and biliary stricture (one child). All had reconstruction with a nipple valve, and ten had an interposed segment of jejunum. RESULTS: All of the children are alive and have had follow-up evaluation from six months to 8.5 years (median of three years). Sequential examinations with ultrasound and biliary excretion scans have shown no evidence of obstruction, and liver function tests have remained normal. Three children have had cholangitis. One child had a brief episode in the perioperative period. The second child had cholangitis 16 months postoperatively, and the third child had multiple episodes of cholangitis. These latter two children were unique. One had Alonso-Lej type IV choledochal cyst with intrahepatic dilatation, which persisted after reconstruction. The other had a prior diversion with a Roux-en-Y limb from the gallbladder after resection of a choledochal cyst and had multiple episodes of cholangitis before reconstruction. These episodes are now controlled with chronic antibiotic suppression. Postoperative complications were limited to two episodes of obstruction of the small bowel requiring lysis of adhesions. No child has had peptic ulcer disease. These children have grown well after reconstruction, except for three with multiple anomalies or chronic pancreatitis. CONCLUSIONS: Biliary reconstruction with a jejunal interposition containing a nipple valve can be performed safely with a low incidence of complications. It offers a more physiologic method of reconstruction and a low incidence of postoperative cholangitis.

New ideas and their acceptance. As it has related to preservation of chordae tendinea and certain other discoveries.

The significant benefits of preserving chordal-papillary muscle integrity in mitral valve replacement took some two decades to become widely accepted. Familiarity with history clearly tells us that this paradox between our dedication to "new ideas" on the one hand, and opposition to their acceptance on the other has existed for hundreds of years. Most "new ideas" have been surrounded by controversy and opposition before wide acceptance. Selected examples from history are cited beginning with Roger Bacon in the 13th century, and continuing with Galileo, Semmelweiss, Lister, and Forssmann. The author cites two notable examples from his personal experiences. They occurred during the development of open heart surgery, and another during the development of the rigid bileaflet cardiac prosthesis, now known as the St. Jude cardiac prosthesis. Some of the basic reasons for this inevitable opposition are: an innate skepticism over anything "new." Simplicity is often resented, as well as any need to change patterns of behavior/habits. Determination, persistence, stubbornness are the most important components for successful research. In addition, the successful innovator must learn to expect opposition and not be deterred by it, but rather must learn to take sustenance from it, and "learn to thrive upon opposition." In conclusion, these observations and suggestions are summarized in a satire on "The Seven Ages in the Evolution of an Idea--with particular reference to the critic."

Echocardiography in the preoperative evaluation of vascular rings.

Vascular rings may produce tracheal and/or esophageal compression in infants and children. Traditionally recognized fluoroscopically, the exact anatomy of the ring and appropriate surgical correction are determined intraoperatively. The role of preoperative echocardiography was examined. Twenty patients with symptomatic vascular rings were evaluated preoperatively with echocardiography at this institution. Their ages ranged from 10 days to 11 years (mean, 17 months). There were 9 boys and 11 girls. Most (17/20) presented with respiratory symptoms in the first year of life, although in 3 patients dysphagia was the primary complaint (at birth, 4 months, 9 years). All underwent initial evaluation with a barium esophagogram prior to the echocardiogram. Surgical correction was subsequently performed and the exact anatomy identified. All barium esophagograms were interpreted prospectively as demonstrating a "vascular ring." Although often suspected fluoroscopically, the actual type of ring was correctly identified by echocardiogram in all cases including determination of the dominant arch and associated anomalies. The types of vascular rings included double aortic arch (10), right aortic arch with left ligamentum arteriosum and/or aberrant left subclavian artery (6); aberrant right subclavian artery (2), and pulmonary artery sling (2). Barium esophagogram remains the best screening test for children in whom a vascular ring is suspected. However, echocardiography is a useful noninvasive complementary examination to confirm the diagnosis, clarify anatomy, and exclude other major intracardiac pathology prior to surgical correction.