Amniotic fluid index and fetal bladder outlet obstruction. Do we really need more?
ABSTRACT With the constant advances in technology and expertise of prenatal diagnosis, necessity of early counseling in cases of bilateral obstructive uropathy has become of paramount importance. To better evaluate fetal renal function new biochemical (serum and urine) fetal markers have been introduced in the literature. However, they are only available at select centers and always requiring an invasive approach. Furthermore, paucity of normal controls sometimes makes interpretation of results difficult. Owing to this growing interest towards biochemical evaluation of fetal renal function, assessment of amniotic fluid, which is mostly expression of fetal urination, has progressively fallen into disrepute, and studies comparing the amount of amniotic fluid with renal function are scant.
In a 3-year period 28 cases of bilateral obstructive uropathy were seen prenatally at the Artemisia Medical Center. All cases were initially reviewed at 17 to 20 weeks of gestation when a distended fetal bladder with thickened wall and enlarged kidneys were visualized. At the same time ultrasonographic assessment of amniotic fluid was performed by calculating the amniotic fluid index. An amniotic fluid index less than the 25th percentile was considered below average and an index less below the 5th percentile was considered oligohydramnios, whereas an index between 50th and 75th percentiles was considered normal. All cases were subsequently evaluated for renal function up to age 1 year. Impaired renal function was defined as a serum creatinine greater than 1.2 mg/dl before age 1 year.
Of the 28 cases 18 had an index of oligohydramnios (group 1) and 10 had a normal index (group 2). No significant variations were observed in amniotic fluid index at repeated consultations throughout pregnancy. Two cases in group 1 and 1 case in group 2 were lost to followup while in the other group 1 cases intrauterine death occurred. Bilateral obstructive uropathy was confirmed in all instances after birth as valves in 18 cases and urethral atresia in 3. Of the 12 surviving group 1 cases there were 3 neonatal deaths from severe lung hypoplasia, and in the remaining 9 cases mean serum creatinine at each evaluation before age 1 year was 1.3 +/- 0.2 mg/dl. All patients in group 2 survived with a mean serum creatinine at each evaluation of 0.6 +/- 0.1 mg/dl (p <0.05).
Despite widespread use of prenatal biochemistry, evaluation of amniotic fluid by the amniotic fluid index remains a reproducible and inexpensive method to predict renal function in cases of bilateral obstructive uropathy of any origin. It retains its validity not only in severe, but also in milder reductions. Conversely, intact amniotic fluid mostly invariably predicts normal renal function at long-term evaluation. For a better understanding of the disease such information is to be promptly conveyed to the prospective parents at each prenatal consultation.
Article: Oligohydramnion[Show abstract] [Hide abstract]
ABSTRACT: Zusammenfassung Eine angeborene Niereninsuffizienz ist selten. Häufigste Ursachen sind Fehlbildungen der Nieren und ableitenden Harnwege sowie autosomal-rezessive Zystennieren. Die Nierenfunktionseinschränkung kann sich bereits intrauterin mit verminderter/fehlender Diurese manifestieren und zu einem renal bedingten Oligohydramnion führen, welches oft eine Lungenhypoplasie verursacht. Während ältere Serien die Prognose der Feten mit renalem Oligohydramnion als schlecht bis infaust einschätzten, überlebt neueren Daten nach die Mehrzahl der Betroffenen. Die pränatale Beratung sollte deshalb interdisziplinär und in einem spezialisierten Zentrum unter Beteiligung von Kindernephrologen erfolgen; die Indikation zur Interruptio ist u. E. derzeit nicht mehr grundsätzlich gegeben. Da die Mortalität und Morbidität in der Neonatalphase am höchsten sind, sollte die Entbindung in einem Zentrum erfolgen, in dem sowohl eine Intensivtherapie auf neuestem Stand als auch eine Nierenersatztherapie vorgehalten werden können. Im späteren Verlauf kommt aufgrund der chronischen Nierenbeteiligung der Kindernephrologie die entscheidende Bedeutung zu. Viele intrauterin mit Oligohydramnion aufgefallene Kinder benötigen keine Nierenersatztherapie bei überwiegend guter Lebensqualität.Monatsschrift Kinderheilkunde 12/2010; 158(12):1224-1230. DOI:10.1007/s00112-010-2247-8 · 0.28 Impact Factor
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ABSTRACT: Antenatal hydronephrosis (ANH) is one of the most frequently detected abnormalities found on routine prenatal ultrasounds, affecting 1% to 4.5% of all pregnancies. Despite its prevalence, there continues to be uncertainty regarding the clinical impact after birth. Prognosis depends on the severity of the dilation. Expectant prenatal management is the rule with fetal intervention rarely needed in a few select cases. Ureteropelvic junction obstruction and vesicoureteral reflux are the most common postnatal diagnoses. A renal and bladder ultrasound is essential in the follow-up of patients with ANH and helps dictate further investigation with voiding cystourethrography and/or diuretic renography.Clinics in Perinatology 09/2014; 41(3). DOI:10.1016/j.clp.2014.05.013 · 2.13 Impact Factor
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ABSTRACT: Congenital lower urinary tract obstruction (LUTO) is a disease associated with high perinatal mortality and childhood morbidity. Fetal vesicoamniotic shunting (VAS) bypasses the obstruction with the potential to improve outcome. To determine the effectiveness, cost-effectiveness and patient acceptability of VAS for fetal LUTO. A multicentre, randomised controlled trial incorporating a prospective registry, decision-analytic health economic model and preplanned Bayesian analysis using elicited opinions. Patient acceptability was evaluated by interview in a qualitative study. Fetal medicine departments in the UK, Ireland and the Netherlands. Pregnant women with a male singleton fetus with LUTO. In utero percutaneous VAS compared with conservative care. The primary outcome was survival to 28 days. Secondary outcome measures were survival and renal function at 1 year of age, cost of care and cost per additional life-year and per disability-free survival at the end of 1 year. The trial stopped early with 31 women randomised because of difficulties in recruitment. Of those randomised to VAS and conservative management, 3/16 (19%) and 2/15 (13%), respectively, did not receive their allocated intervention. Based on intention-to-treat analysis, survival at 28 days was higher if allocated VAS (50%) than conservative management (27%) [relative risk (RR) 1.88, 95% confidence interval (CI) 0.71 to 4.96, p = 0.27]. At 12 months survival was 44% in the VAS arm and 20% in the conservative arm (RR 2.19, 95% CI 0.69 to 6.94, p = 0.25). Neither difference was statistically significant. Of survivors at 1 year, two in the VAS arm had no evidence of renal impairment and four in the VAS arm and two in the conservative arm required medical management. One baby in the conservative arm had end-stage renal failure at 1 year. VAS was more expensive because of additional surgery and intensive care. VAS cost £15,500 per survivor at 1 year and £43,900 per disability-free year. Elicited expert opinions showed uncertainty in the effect of VAS at 28 days. In a Bayesian analysis combining elicited opinion with the results, uncertainty of the benefit of VAS remained (RR 1.31, 95% credible interval 0.84 to 2.18). The acceptability study identified visualisation of the fetus during ultrasound scanning, perceiving a personal benefit, and altruism as positive influences on recruitment. Fear of the VAS procedure and the perceived severity of LUTO influenced non-participation. The need for more detailed information about the condition and its implications during pregnancy and following delivery was a further important finding of this research. Recruitment was hampered by logistical and regulatory difficulties, a lower incidence of LUTO and lower antenatal diagnosis rate [estimated to be 3.34 (95% CI 2.95 to 3.72) per 10,000 total births and 47%, respectively, in an associated epidemiological study] and high termination of pregnancy rates. In the registry women also demonstrated a clear preference for conservative management. Survival to 28 days and 1 year appears to be higher with VAS than with conservative management, but it is not possible to prove benefit beyond reasonable doubt. Notably, prognosis in both arms for survival and renal function is poor. VAS was substantially more costly and unlikely to be regarded as cost-effective based on the 1-year data. Parents should be counselled about the risks of pregnancy loss with or without VAS insertion. The National Institute for Health and Care Excellence interventional procedures guidance (IPG 202) should be updated to reflect this new evidence. Babies in the PLUTO trial should be followed up long term for the different outcomes. ISRCTN53328556. This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment ; Vol. 17, No. 59. See the NIHR Journals Library website for further project information.12/2013; 17(59):1-232. DOI:10.3310/hta17590