Maternal hemodynamic evaluation in monochorionic twin pregnancy complicated by twin-to-twin transfusion syndrome treated with fetoscopic laser surgery.

BACKGROUND: Maternal cardiovascular adaptations are amplified in twin pregnancies to support the metabolic request of the feto-placental unit. Few studies have evaluated the maternal hemodynamics changes after routine use of laser surgery in the treatment of twin-twin transfusion syndrome (TTTS).

OBJECTIVES: The aim of our study was to evaluate hemodynamic changes in monochorionic twin pregnancies complicated by TTTS before and after treatment with fetoscopic laser surgery.

STUDY DESIGN: A prospective observational study from 2020 to 2022, included monochorionic twin pregnancies complicated withTTTS undergoing laser surgery between 16 and 26 weeks 'gestation. To assess placental function and perfusion, uterine artery pulsatility index, hemoglobin, hematocrit, and soluble fms-like tyrosine kinase-1/placental growth factor (sFlt1/PlGF) ratio sampling pre and 24 hours post-laser were measured. Echocardiography by a single cardiologist evaluated maternal hemodynamics at pre-surgery, 24 hours, and one week post-laser Those data were crosswise compared with cardio-vascular indices of uncomplicated monochorionic pregnancies recruited at the same gestational age using non-parametric tests. Moreover, we fitted random-intercept linear regression models to investigate maternal hemodynamic changes accordingly to the amount of amniotic fluid drained during laser surgery.

RESULTS: Forty-two TTTS pregnancies with a median gestational age of 19.1 (17.4 - 20.9) and fifteen uncomplicated monochorionic pregnancies at the same gestational age were enrolled. Overall survival rate after laser was 72% with delivery at a median gestational age of 31.5 weeks (27-34). Significant changes in blood chemistry and placental function were observed in the TTTS group, along with alterations in arterial pressure, heart rate, cardiac output, and ventricular strain, eventually aligning with the uncomplicated group's values by one week post-laser. The amount of amniodrainage, with a 1000 mL cut-off, did not significantly impact hemodynamic parameters. Lastly, we detected a percentage of laser surgery complications in agreement with international literature and we did not record any maternal procedure-related problems.

CONCLUSIONS: Our analysis highlighted that maternal cardiovascular status in monochorionic twin pregnancy complicated by TTTS was more dynamic and, one week after fetoscopic laser ablation of placental anastomosis completed by amniodrainage, maternal hemodynamic parameters restored to values similar to uncomplicated monochorionic twin pregnancies.