Complications of monochorionic twins

Predictive value of cardiovascular parameters in twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the prognostic value of the Children's Hospital Of Philadelphia (CHOP) cardiovascular score and the modified myocardial performance index (MPI), in determining the risk of recipient fetal loss in twin-to-twin transfusion syndrome (TTTS).

METHODS

This cohort study was based on data collected prospectively from 105 pregnancies complicated by TTTS (Quintero stages I-IV) and treated with laser photocoagulation between May 2008 and February 2013. Fetuses underwent detailed anatomical and Doppler ultrasonography with cardiac assessment as part of routine care. CHOP score and right MPI were calculated and cut-offs selected using receiver-operating characteristics curve analysis. These were compared according to loss of recipient fetus, using univariate and multivariate logistic regression. The correlation between CHOP score, MPI and Quintero stage was determined and we investigated differences in MPI before and after laser coagulation in a cohort of 90 recipient fetuses.

RESULTS

Rates of recipient fetal loss were significantly higher when the CHOP score was ≥ 3 (39.5% vs 12.9%, P = 0.002) and when MPI z-score was > 1.645 (34.5% vs 10.6%, P = 0.004). After adjustment for Quintero stage, the risk of recipient fetal loss remained significantly higher when the CHOP score was ≥ 3 (odds ratio, 3.09; 95% CI, 1.035-9.21). There was a positive correlation between CHOP score, MPI and Quintero stage. MPI was significantly lower after compared with before laser coagulation.

CONCLUSION

CHOP score and MPI are predictors of recipient fetal loss in TTTS and may be used to supplement Quintero's classification.

The use of ultrasound in fetal surgery

Obstetric ultrasound (US) is an integral part of fetal surgery for open and minimally invasive techniques. With advances in US imaging, the ability to refine diagnosis, predict prognosis, and contribute to fetal treatment continues to grow. Current research in fetal diagnosis and treatment includes identifying the most reliable sonographic features for determining prognosis before and after surgery.

Initial fetal cardiovascular profile score predicts recipient twin outcome in twin-twin transfusion syndrome

BACKGROUND

The aim of this study was to assess the relationship between cardiomyopathy and recipient twin (RT) outcome in twin-twin transfusion syndrome (TTTS).

METHODS

Fetal echocardiography and outcomes data in 62 consecutive pregnancies with TTTS were reviewed. The primary outcome was neonatal RT survival. The severity of RT cardiomyopathy at presentation was assessed by the cardiovascular profile score (CVPS). RT outcomes and odds of survival were compared between groups stratified by CVPS.

RESULTS

Overall neonatal survival for all fetuses was 61% (76 of 124). RT survival was 58% (36 of 62). Grouped by CVPS, RT survival was greater (50%) for those with CVPS > or = 9 and even higher (74%) for CVPS of 10. Among the components of the CVPS, atrioventricular valve regurgitation was associated with negative RT outcome. Other factors at presentation were not predictive of RT outcome.

CONCLUSIONS

A normal CVPS in the RT in TTTS is predictive of improved survival compared with an abnormal CVPS, even in RTs with minor deductions. Standard clinical staging did not predict outcome. Cardiac assessment by CVPS may improve clinical decision making and the timing of fetal interventions.

Why is it important to diagnose chorionicity and how do we do it?

Because the monochorionic (MC) placenta is designed for a singleton fetus, and might not provide adequate physiological support for twins, obstetric problems are more frequent in MC than dichorionic (DC) twins. Problems arise because asymmetric cord insertions cause growth discordance as a result of unequal sharing of placental tissue. Approximately 95% of MC twin placentas contain interfetal vascular connections of some kind, sometimes in several combinations. Such connections can cause twin-twin transfusion syndrome and twin reversed arterial perfusion. The survivor can also suffer damage if the co-twin dies spontaneously or from inappropriate methods of selective termination. These complications are progressive and often advanced by 18 weeks gestation. Monoamniotic twins carry greater risks than diamniotic twins, especially entangled cords. MC twins are often discordant for congenital anomalies. Diagnosis of MC twinning is optimal in the first trimester. Optimal management of these MC twin disorders is not yet established; long-term follow-up studies are unsatisfactory. In clinical practice, chorionicity is not always determined in the first trimester.

Invasive fetal testing

PURPOSE OF REVIEW

Research on prenatal diagnosis and invasive fetal testing has continued at a rapid pace. Several studies that will have a profound impact on the way prenatal care will be provided to pregnant women have been published in the literature during the last year. These publications will be reviewed and their impact described.

RECENT FINDINGS

The main areas of interest in the recent literature covered in this review are first-trimester screening for aneuploidy, recent information on loss rates due to amniocentesis and chorionic villus sampling, and current work on invasive fetal therapy.

SUMMARY

It appears that first-trimester screening is at least comparable if not superior in efficacy to second-trimester serum screening. This will be a test that will be utilized increasingly by both low and high-risk patients for aneuploidy. Of utility to a much smaller number of patients, invasive fetal therapy for meningomyelocele repair, twin-to-twin transfusion syndrome and fetal cardiac malformations is being evaluated in a scientifically more rigorous manner.