Abstract 12589: Fetoscopic Selective Laser Photocoagulation of Placental Anastomoses Leads to Early Reduction of Cardiovascular Burden in the Twin-Twin Transfusion Syndrome

Abstract

Background: Twin-twin transfusion syndrome (TTTS) occurs with an incidence of 10-15% in monochorionic pregnancies. The Children’s Hospital of Philadelphia (CHOP) TTTS Cardiovascular Score (CVS) is a 20-point scale and encompasses evaluation of five domains: Recipient (R) abnormalities of 1) ventricular hypertrophy/systolic dysfunction, 2) atrioventricular valve insufficiency, 3) diastolic ventricular inflow, ductus venosus and umbilical vein flow patterns and 4) right ventricular outflow/pulmonary obstruction; Donor (D) abnormalities of 5) umbilical arterial (UA) flow. We explore the early impact of selective fetoscopic laser photocoagulation (SLPC) of placental anastomoses on fetal cardiovascular (CV) burden. Methods: Fetal echocardiograms performed prior to and one week post SLPC from 11/2012 to 6/2018 were reviewed. Pulsatility indices (PI) of the UA and middle cerebral artery (MCA), cerebroplacental ratio (CPR) and CHOP CVS elements were analyzed pre and post SLPC using paired t-tests. Results: SLPC was performed in 198 subjects; 17 excluded due to one twin demise post SLPC. Of the 181 analyzed, mean gestational age at SLPC was 19.8 (95% CI: ±0.3) weeks. Following SLPC, R demonstrated an increase in MCA PI and decrease in UA PI, with increase in CPR. D demonstrated a similar magnitude decrease in both MCA PI and UA PI, yielding no change in CPR. Following SLPC, mean CHOP CVS decreased. CHOP pre SLPC CVS was ≥6 in 62 (34%). The magnitude of change was greater in the subgroup with greater pre SLPC CV burden (CVS > 6). Most common elements to improve were systolic dysfunction, tricuspid inflow, ductus venosus and umbilical vein flow patterns; least likely to improve was ventricular hypertrophy. Conclusions: Improvement in CV burden is seen as early as 1 week post SLPC, which supports acute alteration of loading conditions as contributing to the disease. Further study of the trajectory of CV alterations may provide insight into the complex mechanisms underlying TTTS.