Microwave Ablation vs Radiofrequency Ablation in the Management of Complicated Monochorionic Pregnancies：A RCT Study

Study Overview
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Brief Summary
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Complicated pregnancies refer some special complications, including twin to twin transfusion syndrome(TTTS), twin reverse arterial perfusion(TRAP), selective intrauterine fetal growth restriction(sIUGR), twin anemia-polycythemia sequence(TAPS), one fetal death or structural abnormalities, etc. Complicated twins are often associated with high perinatal morbidity and mortality. Severe complicated twins can be treated with fetal-reduction surgery during pregnancy, which can improve the survival rate of retained fetuses and reduce the disability rate. The managements include mechanical umbilical cord ligation or thermal coagulation obliteration, such as bipolar coagulation (BCC), radiofrequency ablation (RFA), and laser coagulation.Nowadays radiofrequency ablation reduction is the most common, which processes a higher survival rate and fewer maternal and fetal complications compared with other ways.Latest experience suggests that microwave ablation(MWA) is also easy to be used and the therapeutic effect is similar with RFA, but there is no convincing evidence. Compared with radiofrequency ablation, MWA has the advantages of simple operation and time, and avoids the problems of tissue carbonization, drying and heat sink effect. For fetation reduction surgery, the main advantage is that the endothermic effect near the blood vessels is smaller, which enables microwave fetation reduction to have a larger ablation range and a higher thermal effect. This study is comparing Microwave Ablation(MWA) and radiofrequency ablation (RFA) methods for selective fetal reduction in the treatment of complicated monochorionic (MC) multifetal gestations. This is a pilot randomised controlled trial(RCT) of 60 patients who undergo selective fetal reduction. The subjects of this study were all pregnant women and their offspring who underwent reduction surgery in the third hospital of Beijing University, and patients are randomly assigned 1:1 to different intervention groups by parallel design. The outcome evaluators were blind. Collecting their surgery, clinical information and maternal and fetal complications at a week and a month after surgery, 42 days and 6 months after delivery, to verify the safety and efficacy of MWA, and find a better treatment plan for complicated monochorionic pregnancies .The primary outcome was neonatal survival rate.

Detailed Description
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Medical charts were reviewed for the details of surgery and the pregnancy outcomes if the patient delivered at the authors'institution. In the event of delivery at distant locations, patients were contacted by telephone to obtain delivery and neonatal information. Patients are randomly assigned 1:1 to different intervention groups by parallel design. Chorionicity was assessed by the referring physicians during the ﬁrst trimester. All patients underwent comprehensive ultrasound examination to confirm the fetal diagnosis, chorionicity, amnionicity and cervical length upon arrival at Peking University Third Hospital. Monochorionicity was confirmed through the ultrasound findings of a single placenta, a thin intervening membrane, lack of a lambda sign and concordance for fetal gender. Patients were counseled about the risks and benefits of expectant management vs. selective reduction. Written informed consent was obtained. Statistical analysis was performed using the statistical software Statistical Product and Service Solutions(SPSS), for comparison of entry and outcome variables using the chi-square test, Fisher's exact test and the Student's t-test, where appropriate. P < 0.05 was considered as statistically significant.

Official Title
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Microwave Ablation Versus Radiofrequency Ablation for the Treatment of Severe Complicated Monochorionic Pregnancies in the Peking University Third Hospital : A Pilot Randomised Controlled Trial

Conditions
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Twin; Complicating Pregnancy, Microwave Ablation

Intervention / Treatment
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* Procedure: Microwave ablation
* Procedure: Radiofrequency ablation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Complicated monochorionic pregnancies women; Having the indication of selective reduction;(TTTS III or IV, TRAP, severe sIUGR, Twin malformation inconsistency or stillbirth，three or more fetuses with monochorionic pregnancies requiring reducing the number of fetuses） The reduction surgery should be done after 15 weeks of gestation; Willingness to participate in the trial and having provided written consent. Exclusion Criteria: Preoperative examination shows that patient is not appropriate to undergoing reduction surgery, such as acute infection of the organ system, especially the urinary system. Patients need to perform acute reduction surgery due to the progress of the disease and the surgery cannot be scheduled. Other diseases that may affect the experimental results: neuropsychiatric diseases and congenital diseases.
Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Microwave ablation group<br>Microwave ablation is used for the treatment of Complicated Monochorionic Pregnancies | Procedure: Microwave ablation<br>* Use of microwave energy to ablate tissue surrounding fetal umbilical cord. All the procedures are performed percutaneously under ultrasound guidance.<br>|
| Active Comparator: Radiofrequency ablation group<br>Radiofrequency ablation is used for the treatment of Complicated Monochorionic Pregnancies | Procedure: Radiofrequency ablation<br>* Use of radiofrequency energy to ablate tissue surrounding fetal umbilical cord. All the procedures are performed percutaneously under ultrasound guidance.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neonatal survival rate | The proportion of live births at 28 days postpartum | a month after delivery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Surgical injury to fetal | Using MRI to assess postoperative thermal injury and nerve injury of fetus | at 28 weeks gestation | 
| Postoperative complications | Frequency of PPROM, premature delivery, frequency of infection, procedure-to-delivery interval, <28 weeks of intrauterine fetal death/abortion, >28 weeks of intrauterine fetal deat and <32 weeks premature delivery | at delivery | 
| Perinatal outcomes | Using Apgar Score to assess neonatal asphyxia（Heart rate, respiration, muscle tone, laryngeal reflex and skin color within one minute after birth are taken as the basis, each item is 0 2 points, the full mark is 10 points. 8 10 belong to normal newborns. 4 7 can be classified as mild asphyxiation, 0 3 as severe asphyxiation） | a week after delivery | 
| Growth of the children | The height of the surviving fetus at 6 months | 6 months postpartum | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Complicated Monochorionic Pregnancies, Selective feticide