Characterization of diastolic dysfunction in twin-twin transfusion syndrome: association between Doppler findings and ventricular hypertrophy

Background: Twin-twin transfusion syndrome (TTTS) complicates 10% to 15% of monochorionic twin pregnancies. Cardiovascular changes of variable severity, such as ventricular hypertrophy, atrioventricular valve regurgitation, and systolic dysfunction, occur predominantly in recipient twins (RTs). It was the purpose of this study to perform a detailed assessment of ventricular geometry and diastolic function between controls, donor twins (DTs), and RTs.

Methods: In this prospective, case-control study, two-dimensional, pulsed-wave, and Doppler tissue imaging were used to evaluate biventricular geometry and diastolic function in controls, DTs, and RTs. RTs were divided into two groups, severe and mild, on the basis of evidence of high central venous pressure. Specific variables evaluated included relative wall thickness, mitral valve and tricuspid valve E/A velocities, diastolic filling time corrected for heart rate, isovolumic relaxation time, and early (E') and late (A') diastolic myocardial velocities.

Results: A total of 120 fetuses (39 TTTS twin pairs and 42 controls) were compared. Increases in relative wall thickness and isovolumic relaxation time were seen in the mild group. In the severe group, further increases in relative wall thickness and isovolumic relaxation time as well as decreased diastolic filling time corrected for heart rate were accompanied by the appearance of a monophasic Doppler inflow profile and elevations in the E/E' ratio, consistent with elevated ventricular filling pressures.

Conclusions: Concentric hypertrophy is observed in RTs affected by TTTS and is associated with impaired ventricular relaxation and shortened filling time. In severe cases, further decreases in diastolic filling time and Doppler signs of elevated ventricular filling pressures are present.