Diagnosis of vasa previa with endovaginal color Doppler and power Doppler sonography: report of two cases

Variations in reported outcomes in studies on vasa previa: a systematic review

OBJECTIVE

To evaluate reported outcomes of published studies on the diagnosis and management of vasa previa in pregnancy.

MATERIALS AND METHODS

Databases such as MEDLINE, Embase, Cochrane, PubMed, and ClinicalTrials.gov were searched up to March 2018 for all published studies on vasa previa using combinations of the following medical subject headings and key words: vasa previa, placenta previa, low-lying placenta, succenturiate lobe or placenta, bilobed or bilobate placenta, and velamentous insertion. All original human research that described maternal, obstetric, placental, fetal or neonatal outcomes relating to pregnancies with vasa previa were included for analysis. Title and abstract screening and data extraction was conducted independently and in duplicate by 2 reviewers for all studies until total agreement for eligibility was achieved. Data extraction was also conducted in duplicate in approximately 50% of studies reviewed.

RESULTS

A total of 160 published studies (1004 pregnancies) were included. There was a wide range of reported outcomes, many of which were sparingly reported. The most commonly reported maternal outcomes included mode of delivery, presence of antepartum hemorrhage, time of diagnosis, and rupture of membranes. The presence of known risk factors for vasa previa such as a low-lying placenta, succenturiate or bilobed placenta, and (velamentous) cord insertion was incorrectly reported as "outcomes" in many studies. The most commonly reported fetal/neonatal outcomes included fetal heart rate, gestational age at delivery, birthweight, Apgar score, presence of neonatal anemia, cord blood gas measurements, need for blood transfusion, and death. Of note, only 3 studies reported outcomes related to life impact, maternal social and emotional functioning, perceived delivery of care, or resource utilization.

CONCLUSION

Despite the profound effect the diagnosis of vasa previa has on pregnant women, families, and healthcare systems, studies on vasa previa seldom report outcomes related to life impact and resource utilization. There is a need for the development of a core outcome set-a minimum standard set of outcomes deemed important by pregnant women and other stakeholders involved in their care-to standardize outcome reporting in future studies on vasa previa.

Vasa Praevia: a descriptive review of existing literature and the evolving role of ultrasound in prenatal screening

Introduction: Literature addressing the feasibility of prenatal detection of vasa praevia during the mid-trimester morphology ultrasound scan is scarce, as is a lack of consensus about the appropriate management of pregnancies once it is detected. Method: The following descriptive review will provide historical context about the clinical significance, epidemiology, diagnosis and outcomes of pregnancies complicated by vasa praevia. It will also examine the role of ultrasound in the diagnosis of vasa praevia, and will examine current evidence surrounding this debate of whether routine screening for vasa praevia is possible, beneficial, or cost-effective. Conclusion: Finally, it will highlight the need for increased research into effective management of pregnancies at high risk of, or affected by vasa praevia to reduce fetal mortality and maternal and fetal morbidity associated with the condition.

Velamentous Cord Insertion: Significance of Prenatal Detection to Predict Perinatal Complications

In the maternal and child health statistics of Japan for 2003, perinatal deaths were most frequent in pregnant women with abnormalities of the placenta, umbilical cord, and fetal membrane. Despite advances in perinatal medicine, approximately 2% of low-risk pregnant women still require an emergency cesarean section after the onset of labor. Because it is likely that half of these cases are associated with placental and umbilical cord abnormalities, it is thought that prenatal detection of such abnormalities would reduce the number of emergency cesarean sections in low-risk women. In our previous studies, some abnormalities of the placenta and umbilical cord were associated with abnormalities of cord insertion. Furthermore, we reported that prenatal detection of velamentous cord insertion (VCI) reduced the number of emergency cesarean sections in low-risk women. In this review, we describe the prenatal detection of abnormalities of umbilical cord insertion and the management of VCI based on our current clinical data.

Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcome in ten cases

OBJECTIVE

To assess the specificity of sonographic diagnosis of vasa previa and pregnancy outcome in sonographically diagnosed cases.

METHODS

We prospectively collected cases of vasa previa diagnosed by color Doppler sonography. Delivery by elective Cesarean section after demonstration of fetal pulmonary maturity and prior to the onset of labor was recommended unless obstetric complications supervened. Data regarding maternal obstetric courses and newborn status were collected.

RESULTS

Eleven cases of vasa previa without placenta previa were diagnosed among 33 208 women over an 8-year period. Ten patients had confirmation of the diagnosis by the delivering obstetrician and/or placental examination, giving a specificity of diagnosis of 91%. Among the 10 patients with confirmed vasa previa, two were delivered at 31.5 and 35.5 weeks' gestation prior to demonstration of lung maturity, and the remainder were delivered at 34-37.5 weeks, after lung maturity. All infants had normal Apgar scores and survived. One baby had Scimitar syndrome, which was not suspected from sonography.

CONCLUSIONS

The specificity of sonographic diagnosis of vasa previa at our center was 91%. Antenatal diagnosis permitted us to prevent the catastrophic outcomes commonly associated with vasa previa.

Identification of cardiac masses and abnormal blood flow patterns with harmonic power Doppler contrast echocardiography

Power Doppler is an ultrasound technique that color-encodes the change in amplitude of the ultrasound signal, which reflects changes in the position of scatterers between ultrasound pulses. Power Doppler can be used with echocardiographic contrast agents in a harmonic imaging mode to opacify a cardiac chamber. The opacification of a cardiac chamber can aid in visualizing the silhouette of intracardiac masses and displaying blood flow patterns. Four cases are presented that demonstrate the use of harmonic power Doppler to aid in the identification of a left ventricular apical thrombus, a left atrial thrombus, and a left ventricular pseudoaneurysm.