New radiofrequency ablation procedure for selective reduction in complicated monochorionic twin or triplet pregnancy using multistep, incremental expansion technique

Objectives: Radiofrequency ablation (RFA) is the preferred approach for selective reduction in complex monochorionic (MC) multiple pregnancies because of its ease of operation and minimal invasiveness. To optimize the RFA technique and reduce adverse pregnancy outcomes due to the heat-sink effect of RFA therapy, we used an innovative RFA method in which a needle, an expansion-type electrode, was expanded incrementally and stepwise. This study assessed the safety profile of this novel multistep incremental expansion (multistep) RFA method, including postoperative, maternal, and fetal complications. This study aimed to evaluate the efficacy of selective fetal reduction using multistep radiofrequency ablation (RFA) in multiple MC pregnancies. Methods: This single-center retrospective cohort study included all MC pregnancies treated with RFA between March 2016 and October 2022. The multistep RFA technique involved the use of an expandable needle for gradual dilation during the RFA procedure until the cord blood flow stopped. The traditional single-step RFA method was fully extended at the start of treatment. Results: In this study, 132 MC multiple pregnancies were treated with selective reduction using RFA: 50 with multistep RFA and 82 with single-step RFA. The overall survival rates were not significantly different between the two groups (81.1% vs. 72.3%, P = 0.186). Similarly, the rates of preterm premature rupture of the membranes within 2 weeks after RFA, procedure-related complications, spontaneous preterm delivery < 34 weeks, abortion < 28 weeks, gestational age at delivery, birth weight of the live fetus, and pathological cranial ultrasound did not differ between the groups. However, there was a trend toward a prolonged procedure-to-delivery interval (median, 109 vs. 99 days, P = 0.377) in multistep RFA compared with single-step RFA. Moreover, the fetal loss rate within 2 weeks after RFA in the multistep RFA group was significantly lower than that in the single-step RFA group (10.0% vs. 24.4%, P = 0.041). The ablation time was shorter (5.30 vs. 7.75 min, P < 0.001) and the ablation energy was less (10.2 vs. 18.0 kJ, P < 0.001) in multistep RFA than in single-step RFA. There were no significant differences in neonatal outcomes. Conclusions: Overall survival rates were similar between the two RFA methods. The multistep RFA technique resulted in significantly less ablation energy and shorter ablation time than single-step RFA in the selective fetal reduction of MC pregnancy. The multistep RFA technique was associated with a lower risk of fetal loss within 2 weeks after RFA. Additionally, there was a trend toward a prolonged procedure-to-delivery interval with the multistep RFA technique. This article is protected by copyright. All rights reserved.