Juan A. Tovar

Ambulatory 24-hour manometric and pH metric evidence of permanent impairment of clearance capacity in patients with esophageal atresia

Dysphagia and gastroesophageal reflux (GER) probably caused by structural disorganization of the esophagus occur frequently after repair of tracheoesophageal fistula (TEF), and the extent to which they may improve beyond childhood is not known. The aim of the present study is to assess by combined ambulatory 24-hour manometry and pH-metry the esophageal peristaltic activity and acid clearing capacity in adolescents and adults who had been operated on for TEF at birth. Twenty-two patients, aged 17.1 +/- 4.5 years (mean +/- SD), were examined with combined three-channel manometry and two-channel pH-metry followed by endoscopy and biopsy. Although they considered themselves healthy, on careful interrogation, 16 (72%) were found to have dysphagia, 13 (59%) had heartburn, 10 (45%) had foreign body impaction, and 7 (31%) had chronic respiratory tract disease. GER was detected in 12 (54%) patients (5 with histological esophagitis), 10 of whom had a pattern of prolonged nocturnal episodes with very slow clearance. All patients had diminished contractile activity with low-amplitude and short-duration waves that decreased from 0.53 +/- 0.35 waves per minute to 0.28 +/- 0.2 waves per minute during sleep. Propulsive activity was uniformly disorganized, with peristaltic sequences being few (less than 50% overall) and incomplete (above 80%). Finally, the acid-clearing capacity was nil; the proportions of ineffective sequences were above 90% for all periods considered, including sleep and mealtimes. The motor behavior of nonrefluxing and refluxing patients was identical despite the differences in esophageal acid exposure.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital Diaphragmatic Hernia

Congenital Diaphragmatic Hernia (CDH) is defined by the presence of an orifice in the diaphragm, more often left and posterolateral that permits the herniation of abdominal contents into the thorax. The lungs are hypoplastic and have abnormal vessels that cause respiratory insufficiency and persistent pulmonary hypertension with high mortality. About one third of cases have cardiovascular malformations and lesser proportions have skeletal, neural, genitourinary, gastrointestinal or other defects. CDH can be a component of Pallister-Killian, Fryns, Ghersoni-Baruch, WAGR, Denys-Drash, Brachman-De Lange, Donnai-Barrow or Wolf-Hirschhorn syndromes. Some chromosomal anomalies involve CDH as well. The incidence is < 5 in 10,000 live-births. The etiology is unknown although clinical, genetic and experimental evidence points to disturbances in the retinoid-signaling pathway during organogenesis. Antenatal diagnosis is often made and this allows prenatal management (open correction of the hernia in the past and reversible fetoscopic tracheal obstruction nowadays) that may be indicated in cases with severe lung hypoplasia and grim prognosis. Treatment after birth requires all the refinements of critical care including extracorporeal membrane oxygenation prior to surgical correction. The best hospital series report 80% survival but it remains around 50% in population-based studies. Chronic respiratory tract disease, neurodevelopmental problems, neurosensorial hearing loss and gastroesophageal reflux are common problems in survivors. Much more research on several aspects of this severe condition is warranted.

Cardiovascular malformations in congenital diaphragmatic hernia: Human and experimental studies

BACKGROUND/PURPOSE Cardiovascular malformations (CVM) associated with congenital diaphragmatic hernia (CDH) account in part for the high mortality caused by this defect. The aim of this study is to examine the nature of these malformations in a large series of autopsies and to assess if similar defects are also present in rat fetuses with experimental CDH. METHODS The incidence of CVM and their nature were examined in the autopsy records of 136 stillborns and neonates with CDH admitted to our institution in the last 30 years. Experimental CDH was induced in rat fetuses by giving 100 mg of nitrofen to their mothers on gestational day 9.5, and the fetuses were harvested on day 21 (near full term). The presence of CDH and the anatomy of the heart and great vessels were studied under dissecting microscope after formalin fixation. Unexposed fetuses were used as controls. RESULTS Thirty-three newborns with CDH (24%) had CVM, either isolated or associated with other defects, and 7 had heart hypoplasia. Most CVM (ventricular septal defect, tetralogy of Fallot, transposition of the great vessels, double-outlet right ventricle) involved the outflow tract. In our animal experiments, no malformations were found in 21 control pups. Conversely, 80 of 130 nitrofen-exposed fetuses (61%) had CDH, and 59 of them (74%) had CVM. A significant association (Fishers Exact test, P<.01) was found between CDH and CVM because only 25 of the 50 exposed animals without CDH (50%) had CVM. Again, most defects involved the outflow tract and were similar to those seen in human CDH (tetralogy of Fallot, persistent truncus, ventricular septal defect, double-outlet right ventricle, aberrant right subclavian artery, agenetic ductus, and interrupted aortic arch). Animals with CDH had significantly decreased heart weight to fetal weight ratio in comparison with controls and with those without CDH. CONCLUSIONS The similar nature of the cardiovascular defects found in babies succumbing to CDH and in nitrofen-exposed rats suggests that a similar disturbance of the regional organogenesis related to the neural crest might be involved in both settings, and further validates the use of this animal model for clarifying the cellular and molecular pathogenetic mechanisms.

Long-term survival expectancy after liver transplantation in children

PURPOSE The aim of this study was to assess the long-term survival rate in children who have undergone orthotopic liver transplantation (OLT) in the last 13 years. METHODS The records of 198 consecutive patients under 18 years of age who underwent 249 OLTs between 1986 and 1998 were reviewed. Actuarial patient survival rates were assessed at 1, 3, 5, and 10 years in the whole series, in the last 5 years, and in patients surviving more than 1 year. Age, weight, and indications were analyzed, as well as type and incidence of posttransplant complications. The median follow-up period was 41 months (0 to 154 months). RESULTS Biliary atresia was the most common indication (41.9%) followed by alpha-1 antitrypsin deficiency (8.1%), Alagille syndrome (7.6%), and fulminant hepatic failure (6.6%). One hundred forty-six patients (58.6%) were below 5 years, and 46 patients were (18.5%) younger than 1 year at operation. Sixty-eight patients (27.3%) weighed less than 10 kg. One hundred seventy whole organs and 70 reduced, 5 living-related donor, and 4 split-liver allografts were used. Hepatic artery thrombosis (n = 18), primary nonfunction (n = 15), and chronic rejection (n = 14) were the most common causes for allograft failure. Fourteen patients (7%) had posttransplant lymphoproliferative disorders (PTLD) at a median time of 28 months (4 to 124 months) postoperation (3 died). The 1-, 3-, 5-, and 10-year actuarial patient survival rates are 80%, 76%, 74%, and 74%, respectively; over the last 5 years it is 88% at 1 year and 82% at 3 and 5 years. For patients surviving more than 1 year, 3-, 5-, and 10-year actuarial survival rates are 95%, 93%, and 93%, respectively. CONCLUSIONS (1) Overall results of OLT improve with increasing experience. (2) Children who survive more than 1 year after OLT have an excellent prognosis, although long-term complications of immunosuppression can be expected.

Colonic interposition for esophageal replacement in children remains a good choice: 33-year median follow-up of 65 patients

INTRODUCTION Gastric pull-up has become the predominant technique for esophageal replacement because of allegedly deficient results of colon grafts. This retrospective study examines the long-term results in a large series of colonic interpositions. PATIENTS AND METHOD One hundred six children (median, 2.9 years; range, 0.32-15 years) had their esophagus replaced between 1965 and 2008, of which 96 had colon grafts. Those survivors who were 18 years and older were contacted and, if willing, interviewed, examined, and had their functional ability rated using the Karnofsky index. RESULTS Ninety-six children had undergone a colon graft, and of these, 9 (9.3%) died. There were 65 long-term survivors whose indications for surgery included caustic injury (n = 32), failed tracheoesophageal fistula repair (n = 16), pure esophageal atresia (n = 14), and others (n = 3). The graft was either retrosternal (n = 49) or mediastinal (n = 16 patients). Twelve patients were unavailable for long-term assessment. After a median follow-up of 33.3 (11-41) years, 23 (43%) of 53 individuals experienced mild symptoms of reflux; scoliosis, 12 (22%) of 53, and/or other complications, 15 (27%) of 53 required further surgery. Thirty-two patients (60%) with Karnofsky indexes of 80% or higher felt healthy, 19 (36%) had mild life-style limitations (index, 40%-80%), and 2 had indexes less than 40%. Most patients live normal lives. CONCLUSIONS Colon conduits restored gastrointestinal continuity with limited mortality and considerable morbidity but good functional outcome and health perception in the long-term. Our study suggests that colon grafts are no worse than gastric pull-ups in the long-term.

Late biliary complications in pediatric liver transplantation

PURPOSE The aim of this study was to review the biliary complications occurring in late follow-up after liver transplantation in children. METHODS The medical records of 135 children who received orthotopic liver transplantations (OLT) and had graft survival of more than 1 year were reviewed. Technical variants using a reduced-size graft were applied in 32 (23.7%). For biliary reconstruction, 15 patients had choledochocholedochostomy and 120 a Roux-en-Y loop. Biliary reoperation in the early post-OLT period was needed in 24 patients (17.7%). Routine checking of liver function and duplex Doppler ultrasonography (DDS) were performed during the follow-up period, which averaged 58 months. Late biliary complication was defined as that occurring after the first hospital discharge. RESULTS Late biliary complications occurred in 18 children (13.3%); 16 showed symptoms or analytical disturbances in liver function tests. The Diagnoses included uncomplicated cholangitis (n = 6), anastomotic biliary stricture (n = 7), ischaemic damage of the biliary tree (n = 3) including one late (28 months) hepatic artery thrombosis leading to an intrahepatic biloma. and bile leak after T-tube removal (n = 2). The six children with uncomplicated cholangitis had no repeat episodes in follow-up despite persistent aerobilia. Six patients affected by anastomotic strictures were treated successfully with percutaneous dilatation and, if present, stone removal. Persisting dysfunction and cholangitis occurred in one case affected by ischaemic biliary disease. Biliary leaks after T tube removal settled spontaneously. Risk factors for late biliary complications were determined. There was no relation to the cold ischaemia time, type of graft or biliary reconstruction, or previous early post-OLT biliary reoperation. Aerobilia (affecting 21.5% of OLT patients) was related to cholangitis (P = .001). CONCLUSIONS Anastomotic strictures, reflux of intestinal contents via the Roux-en-Y loop, and residual ischaemic damage led to late biliary complications in 12% of paediatric OLT patients. Evidence of biliary dilatation on DDS may be delayed in anastomotic strictures; in these cases the results of percutaneous treatment were excellent. Children with aerobilia have and increased risk of cholangitis.

Heart hypoplasia in experimental congenital diaphragmatic hernia

BACKGROUND/PURPOSE Heart hypoplasia is associated with congenital diaphragmatic hernia (CDH) and decisively influences survival rate. This study examines whether nitrofen-exposed fetal rats have heart hypoplasia. METHODS Pregnant rats received either 100 mg nitrofen or vehicle on gestational day 9.5. The hearts recovered near full term were either formalin fixed for anatomic studies or snap-frozen for biochemical studies. Heart weight, ventricular chamber diameters and aortic-to-pulmonary root diameter ratios were measured in fixed hearts. Protein and DNA were determined in frozen hearts. Analysis of variance (ANOVA) and correlation-regression studies were used for statistical assessment. RESULTS All control fetuses were normal, whereas 61% of those exposed to nitrofen had CDH. Cardiovascular malformations were found in 73% of CDH and in 50% of non-CDH animals. Wet and fixed heart weights in percent of fetal weight, left-to-right ventricular diameter ratio, and aortic-to-pulmonary root diameter ratio were significantly decreased in fetuses with CDH in comparison with controls. Only wet heart was significantly decreased in nitrofen-treated fetuses without CDH, although all other variables showed a trend in the same direction. Protein to DNA ratios were similar in the three groups. The structure of the myocytes was histologically similar in all groups. CONCLUSIONS The spectrum of lesions in the nitrofen model of CDH encompasses heart hypoplasia, further validating its use for research on this condition. Heart hypoplasia is related to cardiopulmonary compression, but its presence in treated animals without CDH demonstrates that the teratogen itself participate directly in its pathogenesis, and this finding invites further research on this line.

Embryology of esophageal atresia in the adriamycin rat model

PURPOSE The aim of this study was to describe the dysmorphogenetic process leading to esophageal atresia and tracheoesophageal fistula (EA + TEF) in the recently developed Adriamycin model of the malformation. METHODS Time-mated pregnant rats were given either Adriamycin (1.75 mg/kg intraperitoneally) or saline on days 6 to 9 of gestation, and their embryos recovered on days 12, 12.5, and 13 were serially sectioned in the transversal plane and studied microscopically after H&E and PAS staining. The findings were compared with those of age-matched untreated embryos. RESULTS All untreated and saline embryos were normal, whereas 49% of Adriamycin embryos had foregut malformations. Tracheoesophageal separation was complete on day 12 in control embryos, whereas 9 of 10 Adriamycin-exposed embryos had a common esophagotrachea with low emergence of the bronchi at that stage. This pattern had evolved into that of a regular EA + TEF in all nine malformed embryos by day 13. On day 12.5, esophagotrachea was found in 6 of 13 and EA + TEF in 5 of 13 embryos. Two had less well-defined malformations. CONCLUSIONS Esophagotrachea equivalent to complete tracheoesophageal cleft is the first step leading to EA + TEF in this model. The full-blown malformation is finally acquired by partial loss of the posterior wall of the foregut, which tapers-off in the mediastinal mesenchyme and respiratory differentiation of the anterior wall down to the level of bronchial bifurcation, where it constitutes the fistula and the distal esophagus.

International survey on the management of esophageal atresia

INTRODUCTION Because many aspects of the management of esophageal atresia (EA) are still controversial, we evaluated the practice patterns of this condition across Europe. METHODS A survey was completed by 178 delegates (from 45 [27 European] countries; 88% senior respondents) at the EUPSA-BAPS 2012. RESULTS Approximately 66% of respondents work in centers where more than five EA repairs are performed per year. Preoperatively, 81% of respondents request an echocardiogram, and only 43% of respondents routinely perform preoperative bronchoscopy. Approximately 94% of respondents prefer an open approach, which is extrapleural in 71% of respondents. There were no differences in use of thoracoscopy between Europeans (10%) and non-Europeans (11%, p = nonsignificant). Approximately 60% of respondents measure the gap intraoperatively. A transanastomotic tube (90%) and chest drain (69%) are left in situ. Elective paralysis is adopted by 56% of respondents mainly for anastomosis tension (65%). About 72% of respondents routinely request a contrast study on postoperative day 7 (2-14). Approximately 54% of respondents use parenteral nutrition, 40% of respondents start transanastomotic feeds on postoperative day 1, and 89% of respondents start oral feeds after postoperative day 5. Pure EA: 46% of respondents work in centers that repair two or more than two pure EA a year. About 60% of respondents opt for delayed primary anastomosis at 3 months (1-12 months) with gastrostomy formation without esophagostomy. Anastomosis is achieved with open approach by 85% of respondents. About 47% of respondents attempt elongation of esophageal ends via Foker technique (43%) or with serial dilations with bougies (41%). Approximately 67% of respondents always attempt an anastomosis. Gastric interposition is the commonest esophageal substitution. CONCLUSION Many aspects of EA management are lacking consensus. Minimally invasive repair is still sporadic. We recommend establishment of an EA registry.

Neural crest-derived defects in experimental congenital diaphragmatic hernia

Abstract Congenital diaphragmatic hernia (CDH) is often associated with other malformations. This study tests the hypothesis that the heart and great vessels, thymus, parathyroids, and thyroid might be abnormal in the rat model of CDH as a result of disturbed neural-crest development. Time-mated pregnant rats were fed either 100 mg 2-4-dichlorophenyl-p-nitrophenyl ether (nitrofen) or vehicle on gestational day 9.5. Diaphragm, lung, heart, and thymic malformations were sought after dissection and the parathyroids and thyroid were histologically investigated in term fetuses. Ten control fetuses had no malformations, whereas 22 of 32 nitrofen fetuses had CDH and 20 had cardiovascular defects like narrow pulmonary outflow tract (n=7), aberrant right subclavian artery (n=7), ventricular septal defect (n=4), atrial septal defect (n=4), tetralogy of Fallot (n=2), double-outflow right ventricle (n=2), right ductus arteriosus (n=2), and others. The thymus was present but was significantly hypoplastic in all nitrofen fetuses and was ectopic or single-lobed in 28% of them while the parathyroid glands were unilaterally absent or ectopic in 50%. The thyroid was only minimally malformed or ectopic. In conclusion, malformations of structures derived from the pharyngeal arches are likely neural-crest related in rats exposed to nitrofen.