Paul Lewi

The outcome of monochorionic diamniotic twin gestations in the era of invasive fetal therapy: a prospective cohort study

OBJECTIVE The purpose of this study was to document pregnancy and neonatal outcome of monochorionic diamniotic twin pregnancies. STUDY DESIGN This observational study describes a prospective series included in the first trimester in 2 centers of the Eurotwin2twin project. RESULTS Of the 202 included twin pairs, 172 (85%) resulted in 2 survivors, 15 (7.5%) in 1 survivor, and 15 (7.5%) in no survivors. The mortality was 45 of 404 (11%), and 36 of 45 (80%) were fetal losses of 24 weeks or less, 5 of 45 (11%) between 24 weeks and birth, and 4 of 45 (9%) were neonatal deaths. Twin-to-twin transfusion syndrome (TTTS) occurred in 18 of 202 (9%). The mortality of TTTS was 20 of 36 (55%), which accounted for 20 of 45 (44%) of all losses. Severe discordant growth without TTTS occurred in 29 of 202 (14%). Its mortality was 5 of 58 (9%), which accounted for 5 of 45 (11%) of all losses. Major discordant congenital anomalies occurred in 12 of 202 (6%). Of the 178 pairs that continued after 24 weeks, 10 (6%) had severe hemoglobin differences at birth. After 32 weeks, the prospective risk of intrauterine demise was 2 in 161 pregnancies (1.2%; 95% confidence interval, 0.3-4.6). CONCLUSION Of the monochorionic twins recruited in the first trimester, 85% resulted in the survival of both twins, and 92.5% resulted in the survival of at least 1 twin. Most losses were at 24 weeks or less, and TTTS was the most important cause of death. After 32 weeks, the risk of intrauterine demise appears to be small.

Clinical outcome and placental characteristics of monochorionic diamniotic twin pairs with early-and late-onset discordant growth

OBJECTIVE The purpose of this study was to examine the clinical and placental characteristics of monochorionic diamniotic twin pregnancies with early-onset discordant growth diagnosed at 20 weeks, late-onset discordant growth diagnosed at 26 weeks or later, and concordant growth. STUDY DESIGN We studied a prospective cohort that underwent an ultrasound scan in the first trimester, at 16, 20, and 26 weeks. We excluded pregnancies complicated by twin-to-twin transfusion syndrome, miscarriage, fetal death less than 16 weeks, or severe congenital anomalies. Placental sharing and angioarchitecture were assessed by injection of each cord vessel with dyed barium sulphate. The 2 territories were delineated on an X-ray angiogram. The diameter of each intertwin anastomosis was measured on a digital photograph. RESULTS We included 178 twin pairs. Early onset discordant growth, late-onset discordant growth, and concordant growth occurred in 15, 13, and 150 pregnancies, respectively. Twin pairs with early-onset discordant growth had lower survival rates and were delivered at an earlier gestational age than pairs with late-onset discordant and concordant growth. The degree of birthweight discordance was similar in early- and late-onset discordant growth. Severe intertwin hemoglobin differences at the time of birth occurred in 0%, 38%, and 3% of pairs with early-onset discordant growth, late-onset discordant growth, and concordant growth, respectively. The placentas of pairs with early-onset discordant growth were more unequally shared and had larger arterioarterial anastomoses and a larger total anastomotic diameter as compared with placentas of pairs with late onset-discordant or concordant growth. CONCLUSION Unequal placental sharing appears to be involved in the etiology of early-onset discordant growth, whereas a late intertwin transfusion imbalance may be involved in some cases with late-onset discordant growth.

Assessment of fetal cardiac function before and after therapy for twin-to-twin transfusion syndrome

OBJECTIVE We sought to assess fetal cardiac function in monochorionic twins before and after therapy for twin-to-twin transfusion syndrome (TTTS) and compare it with control subjects. STUDY DESIGN We conducted prospective longitudinal assessment of fetal cardiac function in cases undergoing curative fetal therapy for TTTS (n = 39) until 4 weeks postoperatively and in uncomplicated monochorionic twins (n = 23). Fetal cardiac function was assessed by the left and right ventricular myocardial performance index, atrioventricular valve flow pattern, ductus venosus a-wave, and umbilical vein pulsations. RESULTS Nomograms for the myocardial performance index were constructed. Fetal cardiac function was grossly abnormal in recipient twins of TTTS when compared with control subjects (P < .001 for all indices) but normalized by 4 weeks postoperatively. The donor developed abnormal ductus venosus flow and tricuspid regurgitation postoperatively that regressed within 4 weeks. CONCLUSION The cardiac dysfunction in the recipient twin of TTTS normalizes within 1 month after laser. The donor develops a transient impairment of cardiac function postoperatively.

The pregnancy and long-term neurodevelopmental outcome of monochorionic diamniotic twin gestations: a multicenter prospective cohort study from the first trimester onward

OBJECTIVES We sought to document the pregnancy and neurodevelopmental outcome in monochorionic diamniotic twin pregnancies and to identify risk factors for death and impairment. STUDY DESIGN We conducted a prospective cohort study of 136 monochorionic twins followed up from the first trimester until infancy. RESULTS A total of 122 (90%) pregnancies resulted in 2 survivors, 6 (4%) in 1 survivor and 8 (6%) in no survivor. In all, 230 (92%) of 250 surviving infants were assessed at a mean age of 24 months. Neurodevelopmental impairment was present in 22 (10%) infants. Death or impairment of 1 or both infants occurred in 28 (22%) of 126 pregnancies. Twin-to-twin transfusion syndrome and assisted conception increased the risk of both death and impairment, whereas early-onset discordant growth only increased the risk of death. CONCLUSION The mortality in this prospective series was 8% and neurodevelopmental impairment occurred in 10% of infants.

The role of ultrasound examination in the first trimester and at 16 weeks' gestation to predict fetal complications in monochorionic diamniotic twin pregnancies

OBJECTIVE The purpose of this study was to determine the value of ultrasound examination in the first trimester and at 16 weeks to predict fetal complications in monochorionic diamniotic (MCDA) twin pregnancies, defined as the occurrence of either twin-to-twin transfusion syndrome, severe discordant growth, or intrauterine death. STUDY DESIGN We identified risk factors to predict a complicated fetal outcome in the first trimester and at 16 weeks in a prospective cohort of 202 twin pregnancies recruited during the first trimester in 2 centers of the EuroTwin2Twin project. RESULTS Significant predictors in the first trimester were the difference in crown-rump length (odds ratio [OR], 11) and discordant amniotic fluid (OR, 10). At 16 weeks, significant predictors were the difference in abdominal circumference (OR, 29), discordant amniotic fluid (OR, 7), and discordant cord insertions (OR, 3). Risk assessment in the first trimester and at 16 weeks detected 29% and 48% of cases with a complicated fetal outcome, respectively, with a false-positive rate of 3% and 6%, respectively. Combined first-trimester and 16 week assessment identified 58% of fetal complications, with a false-positive rate of 8%. CONCLUSION Of the MCDA twin pregnancies classified as high risk on the combined first trimester and 16 weeks assessment (n = 41), 73% had a complicated fetal outcome with a survival rate of only 69%. In contrast, of the pregnancies classified as low risk (n = 154), 86% had an uneventful fetal outcome with a survival rate of 95%.

Validation of the fetal myocardial performance index in the second and third trimesters of gestation

To test the validity of the myocardial performance index (MPI) and its components against the more conventional methods of fetal cardiac function assessment: the ejection fraction (EF) for systolic function and the E/A index (ratio of transmitral flow during early (E) ventricular filling to flow during atrial (A) contraction) for diastolic function, both in a normal population and in a population at risk for cardiac failure because of volume overload (recipient fetuses in cases of twin–twin transfusion syndrome (TTTS)).

Preterm Prelabor Rupture of Membranes and Fetal Survival after Minimally Invasive Fetal Surgery: A Systematic Review of the Literature

Objective: Iatrogenic preterm prelabor rupture of membranes (iPPROM; <37 weeks of gestation) is a major complication of fetal surgery. Little information is available about risk factors and incidence. Methods: We systematically reviewed reported iPPROM rates, gestational age at delivery and fetal survival after representative minimally invasive antenatal procedures. Results: A total of 1,146, 36 and 194 cases with mean iPPROM rates of 27, 31 and 26% were included for placental laser in twin-twin transfusion syndrome, shunting in lower urinary tract obstruction and interventions for twin-reversed arterial perfusion, respectively. In the statistical analysis, the maximum diameter of the instrument predicted iPPROM rate and was significantly related to gestational age at birth as well as fetal survival. Information on duration of the respective procedures was scarce and did not allow for meaningful analysis. Conclusions: iPPROM occurs in about 30% of cases treated by minimally invasive fetal surgery. The maximum diameter of the instrument explains iPPROM rate, gestational age at birth and fetal survival. Great variations in the reporting of iPPROM make data analysis difficult.

Technical aspects of fetal endoscopic tracheal occlusion for congenital diaphragmatic hernia

In isolated congenital diaphragmatic hernia, prenatal prediction is made based on measurements of lung size and the presence of liver herniation into the thorax. A subset of fetuses likely to die in the postnatal period is eligible for fetal intervention that can promote lung growth. Rather than anatomical repair, this is now attempted by temporary fetal endoscopic tracheal occlusion (FETO). Herein we describe purpose-designed instruments that were developed thanks to a grant from the European Commission. The feasibility and safety of FETO have now been demonstrated in several active fetal surgery programs. The most frequent complication of the procedure is preterm premature rupture of the membranes, which is probably iatrogenic in nature. It does have an impact on gestational age at delivery and complicates balloon removal. FETO is associated with an apparent increase in survival compared with same severity controls, although this needs to be evaluated in a formal trial. The time has come to do so.

Results of Fetal Endoscopic Tracheal Occlusion for congenital diaphragmatic hernia and the set up of the randomized controlled TOTAL trial

In isolated congenital diaphragmatic hernia, lung size and/or the position of the liver are predictive of neonatal outcome. Percutaneous Fetal Endoscopic Tracheal Occlusion (FETO) by a balloon can be undertaken to prompt lung growth in the worst cases. The feasibility and safety of FETO is no longer at stake, and it is associated with an apparent increase in neonatal survival. The gestational age at birth, the pre-existing lung size, the ability to remove the balloon prior to birth, and the lung response are predicting outcome. The most frequent complication is preterm premature rupture of the membranes, and as a consequence preterm delivery, which also complicates balloon removal. We have set up a randomized trial for the formal evaluation of FETO in Europe, including criteria for fetoscopy centers. Training of European as well as North American centers is taking place, so that the procedure could be safely and more widely offered.

Predictors of neonatal morbidity in fetuses with severe isolated congenital diaphragmatic hernia undergoing fetoscopic tracheal occlusion

To investigate neonatal morbidity in fetuses with severe congenital diaphragmatic hernia (CDH) treated with fetoscopic endoluminal tracheal occlusion (FETO) and compare it with historical controls with less severe forms of CDH that were managed expectantly.