Intertwin cardiac status at 10-year follow-up after intrauterine laser coagulation therapy of severe twin-twin transfusion Syndrome :comparison of donor, recipient and normal values

BACKGROUND: In twin-to-twin transfusion syndrome (TTTS), genetically identical twins are exposed to different haemodynamic conditions during fetal life, which are considered to be the cause of prenatal and postnatal cardiovascular differences between the donor and the recipient.

OBJECTIVE: To assess intertwin differences on childhood cardiac outcome after intrauterine laser coagulation therapy (LC) of severe TTTS.

DESIGN AND PATIENTS: Prospective, detailed, echocardiographic follow-up of 31 twin pairs aged 9.95±0.8 years (mean±SD) with severe TTTS treated by LC, and the comparison with reference values.

RESULTS: Cardiac function was normal and did not show intertwin differences in twins without structural heart disease. Discordant birth weight or birth weight <3rd centile for gestational age had no influence on blood pressure and cardiac indices. Pulmonary stenosis was more common (5/62; 8.1%) than in the general population (prevalence 0.066%, relative risk 134.4, 95% CI 42.1 to 428.8, p<0.0001) and affected both donor and recipient. Intertwin differences in late diastolic right ventricular filling (peak velocities: recipient 0.51±0.11 m/s vs donor 0.45±0.10 m/s, mean difference 0.74 m/s, 95% CI 0.23 to 1.24, p=0.009) and early septal relaxation (mean myocardial velocities: recipient -8.2±1.5 cm/s vs donor -8.9±1.2 cm/s, mean difference 0.7 cm/s, 95% CI 0.02 to 1.38, p=0.044) were found only when twins with right heart disease were included.

CONCLUSIONS: Despite severe prenatal cardiac involvement, childhood cardiac function is normal in the majority of surviving donors and recipients after successful LC of severe TTTS. This underlines the favourable impact of intrauterine LC on postnatal cardiovascular performance.