Effects of early vesicostomy in obstructive uropathy on bladder development

Purpose

Creation of a vesico-amniotic shunt for obstructive uropathy removes the normal fetal urination cycle. It is unclear how this affects bladder function at term. The authors measured the bladder volume and reviewed the bladder histology after fetal vesicostomy.

Methods

The authors created an obstructive uropathy in fetal lambs at 60 days’ gestation by ligating the urethra and urachus. Vesicostomy (female) or urethrostomy (male) were performed 21 days after obstruction to release the obstruction. The fetuses were killed at term (145 days).

Results

Thirteen fetuses were shunted. Seven fetuses miscarried after shunting. Six survived, and 3 had a successful shunt with a very small bladder (5 to 7 mL). Two had incomplete shunts that failed some time after shunting. These both had huge bladders (399 mL). In one, the obstruction was unsuccessful. Histologic examination showed that the obstruction caused bladder muscle hypertrophy. Shunted lambs had severe fibrosis of the bladder wall and very poor bladder compliance.

Conclusions

Shunt operations after obstructive uropathy may salvage the kidney but fail to preserve bladder function. The fetus needs a normal urination cycle for normal bladder development. This requirement exists even when the obstruction is successfully bypassed.     

Is a vesicoamniotic shunt intrinsically bad? Shunting a normal fetal bladder

Introduction

We previously demonstrated that in utero vesicoamniotic shunting of obstructive uropathy in fetal lambs produces a shrunken noncompliant bladder. We hypothesized that the normal fetal bladder filling and emptying cycle in fetal life is critical to the development of normal bladder function.

Materials and Methods

We placed vesicoamniotic shunts in 4 normal fetal lambs at 74 days' gestation. The fetuses were delivered at term (145 days), and bladder volume and compliance were measured and compared with those measurements in 3 normal term fetuses. The lambs were then killed and the renal tracts and bladders removed submitted to histologic examination.

Results

All shunted lambs survived to term. Three normal control lambs were delivered at term. The mean bladder volume in shunted lambs was 4 ± 2.8 mL (n = 4) compared with 60 ± 17 mL (n = 3) in control lambs (P < .05). Bladders in the shunted lambs had very poor compliance compared with normal lambs' bladders. Histologic examination of the shunted bladders showed increased fibrosis and distortion of the muscle layers compared with control bladders.

Conclusion

Even in the absence of obstruction, preventing normal bladder filling and emptying in fetal life produces fibrotic bladders with poor compliance.     

Can a pressure-limited vesico-amniotic shunt tube preserve normal bladder function?

Introduction

We have previously shown that a vesico-amniotic shunt (V-A shunt) produces fibrotic bladders with poor compliance in normal fetal lambs. We hypothesized that using a ventriculo-peritoneal shunt (V-P shunt) as a V-A shunt in normal bladders may preserve the filling/emptying cycle and normal bladder development.

Materials and methods

The V-A shunting in normal fetal lambs was performed at 74 days of gestation using a V-P shunt (group A) and a free-draining shunt tube (group B). Sham-operated lambs were used as controls (group C). They were all delivered at term (145 days), and the pressure-volume curve, bladder volume, and histologic features of the bladder wall were compared.

Result

The mean bladder volume in group B (n = 5), 5 ± 2.4 mL, was significantly smaller (P < .01) than that in group A (n = 6), 53 ± 14 mL, and group C (n = 10), 57.3 ± 12 mL. The bladder wall thickness in group A was 338 + 94.2 μm; group B, 741 ± 128 μm; and group C, 374 ± 120 μm. Group B bladders had very poor compliance with thick bladder wall (P < .01). Histologically, group B bladders showed prominent submucosal fibrotic change, but group A bladders were similar to controls.

Conclusion

This study shows that a pressure-limited shunt tube for V-A shunting preserves the normal fetal bladder development.     

Vesicoamniotic shunt for complete urinary tract obstruction is partially effective

Purpose

The long-term outcome for children after antenatal intervention for obstructive uropathies is disappointing. We reported that renal dysplastic changes are well established 3 weeks after obstruction in a fetal lamb model. We used this model to explore renal development and bladder function after fetal intervention.

Methods

We created an obstructive uropathy in fetal lambs at 60 days gestation by ligating the urethra and urachus. A vesicostomy (female) or urethrostomy (male) were performed 21 days later. The fetuses were killed at term (145 days) and bladder volume and compliance were measured. The urinary tract was processed for histologic examination.

Results

Twenty two fetuses were shunted. Nine were miscarried or were still-born. Thirteen survived, and 11 had a successful shunt with a small bladder (8 ± 5 mL) compared with controls (71 ± 19 mL) (P < .05). Shunted bladders had poor compliance. Histologically, they had thickened submucosal connective tissue with hypertrophied muscle. Histology of the renal tissue demonstrated relatively well-preserved renal architecture with reduced nephron mass (oligonephronia) in 2 lambs and multicystic dysplastic change in 3. Six (55%) had normal nephrogenesis.

Conclusions

In our model, shunt operations after obstructive uropathy fail to preserve bladder function. Shunting ameliorated the development of cystic dysplasia, but half of the lambs had oligonephronia or multicystic dysplastic kidney. These might develop renal failure later in life.     

Prenatal urinary matrix metalloproteinase profiling as a potential diagnostic tool in fetal obstructive uropathy

Background/Purpose

The diagnostic evaluation, patient stratification, and prenatal counseling for congenital obstructive uropathy remain sub-optimal. Matrix metalloproteinase (MMP) expression profiles are emerging as a valuable diagnostic tool in assorted disease processes. We sought to determine whether congenital obstructive uropathy impacts MMP expression in fetal urine.

Methods

Fetal lambs (n = 25) were divided in two groups: group I (n = 12) underwent a sham operation and group II (n = 13) underwent creation of a complete urinary tract obstruction. Gelatin zymography panels for 4 MMP species were performed on fetal urine in both groups at comparable times post-operatively. Statistical analysis was by the Fisher's exact test (P < .05).

Results

Overall fetal survival was 80% (20/25). A variety of significant differences in MMP expression between the two groups were identified. The following profiles were present only in obstructed animals: any MMP other than MMP-2 (P = .029), including any MMP other than 63 kDa and 65 kDa (P = .009); 2 or more MMPs excluding MMP-2s (0.029); and 3 or more MMPs (P = .029).

Conclusions

Limited matrix metalloproteinase expression is present in the urine of normal ovine fetuses. Fetal obstructive uropathy impacts urinary MMP expression in various distinguishable patterns. Prenatal urinary MMP profiling may become a practical and valuable diagnostic tool in the evaluation of congenital obstructive uropathy.     

The early effects of urinary tract obstruction on glomerulogenesis

Purpose

Our obstructive uropathy model in fetal lambs showed that renal cystic changes appeared 3 weeks after obstruction. In this study, the authors investigated the changes resulting from complete urinary tract obstruction in the first 7 days after obstruction.

Methods

An obstructive uropathy was created in fetal lambs at 60 days’ gestation by ligating the urethra and urachus. They were delivered 48 hours, 3 days, 5 days, and 7 days later by cesarian section. The kidneys were removed and processed for histologic examination.

Results

Eighteen fetuses were operated on and 15 (4 at 48 hours, 4 at 3 days, 2 at 5 days, and 5 at 7 days; 83%) survived. Macroscopically, bladder dilatation and slightly dilated ureters were identified from 48 hours. Microscopically, dilatation of proximal tubules started from 48 hours after obstruction and increased by 7 days. Glomerular cysts in the nephrogenic zone also were identified from 48 hours. Dysplastic changes were not found.

Conclusions

The first areas in the developing kidney that suffer damage after obstructive uropathy are the proximal tubule and the nephrogenic zone. This change started 48 hours after obstruction. Shunting procedures need to be performed considerably earlier than previously thought.     

Dynamic tracheal occlusion improves lung morphometrics and function in the fetal lamb model of congenital diaphragmatic hernia

Background

Congenital diaphragmatic hernia (CDH) is associated with significant neonatal morbidity and mortality. Although prenatal complete tracheal occlusion (cTO) causes hypoplastic CDH lungs to enlarge, improved lung function has not been demonstrated. Furthermore, cTO interferes with the dynamic pressure change and fluid flow associated with fetal breathing.

Purpose

The purpose of the study was to assess a novel dynamic tracheal occlusion (dTO) device that preserves pressure changes and fluid flow.

Methods

In this pilot study, CDH was created in fetal lambs at 65 days of gestational age (GA). At 110 days GA, a cTO device (n = 3) or a dTO device (n = 4) was placed in the fetal trachea. At 135 days GA, lambs were delivered and resuscitated. Unoperated lamb co-twins (n = 5), sham thoracotomy lambs (n = 2), and untreated CDH lambs (n = 3) served as controls.

Results

Tracheal opening pressure, lung volume, lung fluid total protein, and phospholipid were significantly higher in the cTO group than in the dTO and unoperated control groups. Maximal oxygenation and lung compliance were significantly lower in the cTO group when compared with the unoperated control and dTO groups.

Conclusion

Preliminary results suggest that in the fetal lamb CDH model, dTO restores normal lung morphometrics and function, whereas cTO leads to enlarged but less functional lungs.     

Correlation between prenatal urinary matrix metalloproteinase activity and the degree of kidney damage in a large animal model of congenital obstructive uropathy

Background/Purpose

We aimed to determine whether the profile of matrix metalloproteinase (MMP) activity in fetal urine correlates with the degree of kidney damage in the setting of congenital obstructive uropathy.

Methods

Fetal lambs underwent either a sham operation or creation of a complete urinary tract obstruction. Necropsies were performed before term, when urinary MMP profiling was performed by zymography; and kidney damage was assessed histologically by multiple semiquantitative analyses and histomorphometric measurements.

Results

There was a significant correlation between inner medullary thickness and MMP-9 (P = .005) and 63-kd MMP-2 (P = .019) activities. In like manner, the only MMPs associated with kidney fibrosis were MMP-9 and 63-kd MMP-2. Matrix metalloproteinase-9 activity was a highly significant independent predictor of the total combined kidney fibrosis score (P < .001) as well as of higher fibrosis grades in each of 6 kidney areas analyzed (all with P < .01). The activity of 63-kd MMP-2 correlated significantly with higher fibrosis in select areas.

Conclusions

In a fetal ovine model, urinary MMP activity correlates with the degree of kidney damage. The presence of MMP-9 (in particular) and that of 63-kd MMP-2 are independent predictors of severity. Prenatal urinary MMP profiling may enhance patient stratification and counseling in the setting of congenital obstructive uropathy.     

Investigation of histopathologic changes in the ureter walls in experimental congenital obstructive uropathy

Background/Purpose

The aim of this study is to determine the histopathologic changes in the ureter wall in experimental urinary bladder hypoplasia and agenesis.

Methods

Timed pregnant rats were randomly divided and received intraperitoneal Adriamycin (ADR) at 2 mg/kg on gestational days (GD) 6 to 9 (ADR group) and saline at 2 mL/kg on GD 6 to 9 (SF group). The control (C) group did not receive any medication in their pregnancy. Fetuses were harvested near term on GD 21 and dissected under a dissecting microscope and examined for urinary system abnormalities.

Results

Diameter of ureter lumen was significantly increased, but wall thickness, tunica muscularis, and epithelial thickness of the ureter were decreased in the ADR group as compared with the C and SF groups.

Conclusions

Diameter of the ureter lumen was increased, but wall thickness, tunica muscularis, and uroepithelium of the ureter were decreased in the ADR group in the intrauterine period. The diameter of the ureter lumen and wall thickness of ureter (tunica muscularis of ureter and uroepithelium) were increased following obstructive uropathy after the birth.     

Clinical outcomes with the Hancock II bioprosthetic valve

Background

The Hancock II bioprosthetic valve, which was first introduced to clinical use in 1978, differs from its predecessor in several ways. This study was designed to evaluate the durability and outcomes with this valve in patients who had isolated aortic or mitral valve replacements.

Methods

From 1991 to 1999, 459 patients underwent aortic valve replacement and 138 patients underwent mitral valve replacement with the Hancock II bioprosthesis (Medtronic Inc, Minneapolis, MN). The mean age was 73.2 ± 0.4 and 72.6 ± 0.8 years in the aortic and mitral groups, respectively. Most patients were in New York Heart Association Class III or IV (50% aortic group and 69% mitral group) and concomitant coronary artery bypass was performed in 49.4% and 52.8% of patients, respectively. Patients were assessed annually and follow-up was up to 129 months in the aortic group and 100 months in the mitral group.

Results

At 8 years, actuarial survival was 52% ± 5% in the aortic group and 57% ± 8% in the mitral group. Furthermore, the actuarial freedom from structural failure necessitating reoperation was 99% ± 0.5% in the aortic group and 98% ± 2% in the mitral group, and the actuarial freedom from repeat valve surgery due to all causes was 97% ± 2% and 96% ± 2%, respectively. Actuarial freedom from thromboembolic events was 89% ± 2% in the aortic group and 90% ± 5% in the mitral group.

Conclusions

The Hancock II valve has excellent midterm durability and clinical performance in older patients.     

Diaphragmatic repair through fetal tissue engineering: a comparison between mesenchymal amniocyte- and myoblast-based constructs

Purpose

We have previously shown that fetal tissue engineering is a preferred alternative to diaphragmatic repair in a large animal model. This study was aimed at comparing diaphragmatic constructs seeded with mesenchymal amniocytes and fetal myoblasts in this model.

Methods

Neonatal lambs (n = 14) underwent repair of an experimental diaphragmatic defect with identical scaffolds, either seeded with labeled autologous cells (mesenchymal amniocytes in group 1 and fetal myoblasts in group 2) or as an acellular graft (group 3). At 1 to 12 months postoperatively, implants were harvested for multiple analyses.

Results

Repair failure (reherniation or eventration) was significantly higher in group 3 than in groups 1 and 2, with no difference between groups 1 and 2. Seeded fetal myoblasts quickly lost their myogenic phenotype in vivo. All grafts contained cells with a fibroblastic-myofibroblastic profile. Elastin concentrations and both modular and ultimate tensile strengths were significantly higher in group 1 than in groups 2 and 3. There were no differences in glycosaminoglycans and type I collagen levels among the groups.

Conclusions

Diaphragmatic repair with a mesenchymal amniocyte-based engineered tendon leads to improved structural outcomes when compared with equivalent fetal myoblast-based and acellular grafts. The amniotic fluid is a preferred cell source for tissue-engineered diaphragmatic reconstruction.     

Serial amnioinfusions prevent fetal pulmonary hypoplasia in a large animal model of oligohydramnios

Background/Purpose

Severe neonatal pulmonary hypoplasia incurs mortality rates approaching 71% to 95%. We sought to determine the utility of serial amnioinfusions through a subcutaneously implanted intraamniotic catheter to prevent pulmonary hypoplasia in fetal obstructive uropathy.

Methods

Fetal lambs (n = 32) were divided into 3 groups. Group I (n = 12) underwent a sham operation, group II (n = 15) underwent a complete urinary tract obstruction via ligation of the urachus and urethra with a subcutaneous tunneled intraamniotic port-a-cath without amnioinfusions, and group III (n = 5) underwent a creation of a complete urinary tract obstruction with a port-a-cath as described in group II with serial amnioinfusions. Lung tissue was analyzed by lung volume to body weight ratios and stereology. Statistical analysis was performed by analysis of variance and Bonferroni comparisons (P < .05).

Results

Obstructed fetuses grossly had smaller lungs than treated and control animals. Lung volume to body weight ratios were statistically significant between groups. Airspace fractions were comparable between groups I and III (average = 0.53 and 0.55, respectively), although both were significantly greater than group II (average = 0.48) (P = .049).

Conclusions

Serial amnioinfusions through an intraamniotic port-a-cath prevented pulmonary hypoplasia in an ovine model of complete obstructive uropathy. The use of an easily accessible device for amnioinfusions may be a viable option to treat oligohydramnios.     

Outcome after aortic valve replacement in octogenarians

Background

The advancing age of the population in the western world and improvements in surgical techniques and postoperative care have resulted in an increasing number of very elderly patients undergoing cardiac operations. Therefore, the aim of this study is to evaluate the surgical outcome in 115 octogenarians after aortic valve replacement.

Methods

We retrospectively identified 115 patients (47 men, 68 women) aged 82.3 ± 2.1 years (mean, 80 to 92 years) who underwent aortic valve replacement alone (71 patients, 62.1%) or in combination with coronary artery bypass grafting (44 patients, 37.9%), between January 1992 and April 2003. These patients had significant severe aortic stenosis with a mean valve area of 0.62 ± 0.15 cm² and a mean gradient of 88.62 ± 24.06 mm Hg.

Results

The in-hospital mortality rate was 8.5%. The late follow-up was 100% complete. Actuarial survival at 1 and 5 years was 86.4% and 69.4%, respectively. Predictors of late mortality were ejection fraction (p < 0.01), preoperative heart failure (p < 0.03), and the type of prosthesis (p < 0.03).

Conclusions

The outcome after aortic valve replacement in octogenarians is excellent; the operative risk is acceptable and the late survival rate is good. Therefore, cardiac surgery should not be withheld on the basis of age alone.     

Bladder development following bladder outlet obstruction in fetal lambs: optimal timing of fetal therapy

Background

Lower urinary tract obstruction causes both renal failure and bladder dysfunction after birth. This study examined the early bladder wall changes after creating an obstructive uropathy focusing on bladder wall thickness and muscle integrity.

Methods

We created obstructive uropathy in fetal lambs at 60 days' gestation, ligating the urethra and urachus. The fetuses (n = 28) were delivered at 48 hours and 3, 4, 5, 7, and 14 days after obstruction and at term (145 days' gestation). Sham-operated lambs were used as controls (n = 20). Histology samples were stained using α-smooth muscle actin) immunohistochemistry and also hematoxylin-eosin, Masson trichrome, and colloidal Fe stain.

Results

The bladder wall initially expanded and stretched. By day 4, the bladder wall became thicker. Histologically, the bladder in obstructed lambs demonstrated a prominent submucosal fibrotic change by 7 days. The mean bladder wall thickness at 14 days after obstruction was thicker than controls, and fibrosis was prominent.

Conclusion

The initial changes in the bladder wall were expansion of the muscle component followed by fibrosis. The bladder wall thickness dramatically increased 4 to 7 days after obstruction. We conclude that shunting operations to preserve bladder function may be needed earlier than expected.     

Appendicitis in the child with a ventriculo-peritoneal shunt: a 30-year review

Purpose

Each year, about 270 children are treated at our hospital for appendicitis, and there are 200 ventriculo-peritoneal (VP) shunt procedures. The incidence of primary peritonitis after a VP shunt is 8% to 12%. The purpose of this article is to try and differentiate these 2 entities.

Methods

From 1973 to 2003 inclusive, appendicitis was diagnosed in 8 children with a VP shunt at our hospital; there were 7 boys and 1 girl with 5 acute appendicitis and 3 ruptured appendices. The first case was diagnosed on purely clinical grounds, whereas the last 7 were confirmed by ultrasonography and/or computed tomography.

Results

All 8 had appendectomy and the shunt was exteriorized in the 3 children with a ruptured appendix. There were no postoperative problems, and the 8 children remained well.

Conclusion

Acute appendicitis can and does rarely occur in children with VP shunts; however, in such situations, the correct diagnosis can be confirmed by imaging. The shunt must be temporarily exteriorized if the appendix is ruptured.     

Outcome of antenatally diagnosed sacrococcygeal teratomas: single-center experience (1993-2004)

Aims

Sacrococcygeal teratomas (SCTs) are the commonest neonatal tumors with an incidence of approximately 1:30,000. There are few large single-center series and even fewer describing both their antenatal and postnatal course. We report the outcome of all fetuses investigated at a tertiary fetal medicine center with this diagnosis.

Method

Demographic details were obtained from a prospectively maintained database. Patient records were examined for additional data including antenatal and postnatal interventions. Data were described as median (range).

Results

Forty-one SCTs were diagnosed antenatally during the period 1993 to 2004. Twelve were excluded from subsequent analysis (single antenatal visit or attending for second opinion [n = 6] and termination of pregnancy [n = 6]). Twelve underwent fetal intervention (laser vessel ablation [n = 4], alcohol sclerosis [n = 3], cyst drainage [n = 2], amniodrainage [n = 2], vesicoamniotic shunt [n = 1]) for fetal hydrops and polyhydramnios to aid in delivery and to prevent obstructive uropathy developing in the fetus. Of these, 3 died in utero and 9 survived to be born (median gestational age, 33 weeks [27-37 weeks]). A further 3 died in the neonatal period. There are 6 long-term survivors (50%) from this group. Seventeen infants, without intervention, were born at median gestational age 38 weeks (26-40 weeks). One infant with severe cardiac anomalies died on the day of birth. All surviving infants had definitive excisional surgery at a median of 2 days (1-16 days). Current median follow-up of survivors is 39 months (8-86 months). There have been no recurrences. One child has mild constipation, and 3 are awaiting cosmetic revision of their scars.

Conclusions

The overall survival of antenatally diagnosed SCT is approximately 77%, with the development of hydrops and others requiring in utero intervention carrying a poor prognosis. Otherwise, the outcome after surgical excision is excellent.     

Portoumbilical Anastomosis as a Simple Method of Transient Portosystemic Shunt During Liver Transplantation

Background

This article describes a new method of transient intraoperative portosystemic shunting, Splachnic edema after portal cross-clamping can be a dangerous complication during the anhepatic phase of the liver transplant operation. The current method seeks to avoid this problem, without the use of external venovenous bypass pump, by a temporary portocaval shunt, with retrohepatic cava preservation as first described experimentally in dogs by Fonkalsrud et al in 1966.

Methods and Results

Among 227 liver transplant operations, we utilized a transient portosystemic shunt in 29 cases. The indication to perform a temporary shunt in all cases was the development of splachnic edema. In 3 instances, we performed a portoumbilical anastomosis using a prominent umbilical vein. The other 26 procedures employed the usual portocaval shunts. In these cases, splachnic congestion and onset of edema developed after cross-clamping of the round ligament and the portal vein, which resolved after the portoumbilical anastomosis.

Discussion

The flow in the shunt was in all cases greater than 1 L/min. The most important risk factor for the development of splachnic edema was the presence of a patent umbilical vein, which occurred in 34.5% of shunted patients.

Conclusion

The use of a patent umbilical vein to perform a portoumbilical shunt was an effective, easy method to decompress the splachnic area, avoiding dangerous congestion and edema.     

Rapidly polymerizing hydrogel prevents balloon dislodgement in a model of fetal tracheal occlusion

Background/purpose

This study examined whether an injectable hydrogel could buttress the balloon used in fetal tracheal occlusion, thus preventing its displacement.

Methods

Fetal lambs (n = 11) underwent tracheal occlusion through local delivery of a detachable silicone balloon and were divided in 2 groups: group I had no further manipulations, and group II received an intratracheal injection of a rapidly polymerizing hydrogel, cranially to the balloon. Near term, balloon placement was examined, the lung volume—to—body weight ratio (LV:BW) was determined, and tracheal histology was performed. Statistical analysis was by the Fisher’s Exact test, with significance set at P < .05.

Results

Complete tracheal occlusion was achieved in all fetuses intraoperatively. The rate of balloon dislodgement was significantly higher in group I (4 of 7, or 57.1%) than in group II (0 of 4). In group II, balloons were recovered in situ with a column of residual hydrogel reinforcing their cephalad position. Animals in which balloon occlusion was maintained had significantly higher LV:BW, with no evidence of tracheal damage.

Conclusions

Intratracheal delivery of a rapidly polymerizing hydrogel cephalad to detachable silicone balloons results in improved fetal tracheal occlusion, with no harmful effects to the trachea. This adjuvant principle may enhance minimally invasive balloon tracheal occlusion for treatment of severe fetal pulmonary hypoplasia.     

Renal Transplantation in Patients With “Valve Bladder”: Is Bladder Augmentation Necessary?

Introduction

Posterior urethral valve is a common cause of renal failure in children. This disorder often results in small bladder and low compliance, which frequently requires bladder augmentation. Herein, we report our experience in 5 children with “valve bladder” who underwent renal transplantation without preliminary bladder enlargement.

Materials and Methods

Thirteen children with valve bladder undergoing renal transplantation were considered candidates for bladder augmentation. All had oligoanuria at transplantation. In 8 children, bladder augmentation was performed before renal transplantation; in the remaining 5, the decision was postponed until after transplantation. These children underwent transplantation with a ureteral reimplant, and a suprapubic catheter was in place for 2 months. Periodically, renal function, bladder capacity, and compliance were assessed, and renal ultrasonography was performed.

Results

At 1-, 2-, 4-, and 6-month follow-up, the 5 children who did not undergo bladder augmentation demonstrated normal renal function, with improved bladder capacity and absence of hydronephrosis. No significant difference was evident between the 2 groups (augmented vs nonaugmented) insofar as renal function, bladder capacity, or hydronephrosis. After transplantation, bladder augmentation was not deemed necessary in any of the 5 children because of complete restoration of clinical and urodynamic parameters.

Conclusion

Renal transplantation can be performed safely without preemptive bladder augmentation. Ureteral reimplantation is recommended, even in patients with small valve bladders. The decision about the need for bladder augmentation should be made only after normal diuresis is restored.     

Measurement of the ductal L-R shunt during extracorporeal membrane oxygenation in the lamb

Objective

In neonates, initially a ductal shunt is often observed during veno-arterial extracorporeal membrane oxygenation (ECMO). Depending on the degree of pulmonary hypertension in these patients, the ductal shunt will be right to left (R-L), left to right (L-R), or bidirectional. A ductal L-R shunt will possibly lead to pulmonary hyperperfusion and interact with ECMO weaning. The aim of this study was to give more insight in this ductal L-R shunt during ECMO by quantification of this shunt in relation to cardiac output and ECMO flow.

Methods

In 7 lambs, closure of the duct was prevented by infiltration of the ductal wall with 10% formaline. This patent duct could be closed using a vesselloop around the duct. Ultrasound flowprobes were installed around the pulmonary artery, ascending aorta, and around the ECMO circulation tube. Right and left ventricular output and ECMO flow were measured. Ductus flow was defined as ductal left to right shunt (Qduct L-R) = flow in ascending aorta (Qao) − flow in central pulmonary artery (Qpa) and Qduct R-L = Qpa = Qao.

Results

In 6 of 7 lambs a ductal L-R shunt was observed with a mean shunt of 44% (range, 11 to 79) of left ventricular output (Qduct L-R/Qao). Comparison with ECMO flow (Qduct L-R/Qecmo) showed a mean shunt of 76% (range 15 to 230). When compared with the total systemic circulating volume (Qpa + flow in the ECMO circuit [Qecmo]), the mean ductal L-R shunt showed a percentage of 51% (range, 7% to 142%).

Conclusions

During ECMO, mostly a ductal L-R shunt is observed in this lamb model. This ductal shunt is hemodynamically important. The percentages of this shunt in comparison with left ventricular output, and total circulating volume will support the idea that a ductal L-R shunt during ECMO could be another deteriorating factor in the often critical circulation of the neonate on veno-arterial ECMO.