Abstract 4554: Progression of Fetal Diastolic Dysfunction in Twin-Twin Transfusion Syndrome: Pathophysiologic Insights from Pulsed-Wave and Doppler Tissue Imaging
10 –15% of monochorionic twin pregnancies are complicated by twin-twin transfusion syndrome (TTTS). Cardiovascular changes in the recipient twin (RT) are associated with poor outcome and may provide guidance for optimal timing of intervention. We performed a detailed assessment of systolic and diastolic function using 2D, pulsed-wave and tissue Doppler techniques. Prospective, case-control study comparing RT in TTTS pregnancies with gestational age-matched normal fetuses. 2D, pulsed-wave and tissue Doppler imaging were used to evaluate RV/LV geometry (including relative wall thickness, RWT) as well as systolic/diastolic function. Doppler variables included MV and TV E/A velocities, isovolumic relaxation (IRT) and contraction times (ICT), and early (E’), late (A’) diastolic and systolic (S’) annular velocities. RT with (RTsevere) and without (RTmild) evidence of high central venous pressure, defined as presence of umbilical venous pulsation, were compared to control fetuses with ANOVA. 34 TTTS pregnancies and 37 normal fetuses were compared. Gestational age ranged from 15–26 weeks. Increases in RWT, IRT, and ICT with preserved systolic function were seen in RTmild (Table⇓). In RTsevere, further increases in RWT, IRT and ICT were accompanied by significant increases in E/E’ ratio, which is due to the appearance of a monophasic early diastolic inflow pattern (monoE). Excluding subjects with monoE, there were no significant group differences in E/A or E’/A’ ratio. Decrements in systolic function were seen only in RTsevere. In TTTS, progressive, concentric hypertrophy is noted in the RT. In mild cases, there is diastolic dysfunction due to impaired relaxation. RTsevere demonstrate decreased compliance and high filling pressures, which manifests primarily as monoE. This transition between impaired relaxation and poor compliance appears abrupt without “intermediate” pulsed-wave or tissue Doppler findings.