P12.21: Permanent feto‐fetal transfusion from the recipient to the donor twin. A complication of laser surgery in twin‐to‐twin transfusion syndrome (TTTS)

Abstract

We report on a specific complication of endoscopic laser surgery in TTTS. 174 cases of severe TTTS were treated by laser in two referring centers. Of these, 8 recipients (9.3%) showed increased mean cerebral artery peak systolic velocity (MCA PSV) suggesting anaemia (2.02 MoM [1.5-4.1] without any other features of recurrence of TTTS. All recipient fetuses underwent fetal blood sampling (FBS) and were found to be anaemic with a mean hemoglobin of 4.5 gr/dl (range: 2.5gr/dl -10 gr/dl) and were treated with intrauterine transfusion. All donors showed low MCA PSV (mean 0.55: range: 0.43 Mom-0.78MoM) suggesting polycythemia which was confirmed at FBS or at delivery. A 2nd laser was performed in 2 patients. Patent anastomoses were identified and coagulated. Cord coagulation was performed in 3 cases for cerebral atrophy, severe cardiopathy and hydrops with severe acidosis. Post partum injection of the placenta' was performed in 2 cases. In 1 case managed by serial blood transfusion, there were clearly one remaining uncoagulated anastomoses. In the other cases managed by a single transfusion, no clear anastomoses were seen, although there were 2 small veins and 1 small artery from the donor reaching within 1 cm from the vascular territory of the recipient. Kleihauer Betke test performed on donor's blood obtained by FBS confirmed the presence of adult blood after transfusion of the recipient, confirming the mechanism of feto-fetal transfusion. Worsening or reversal of the feto-fetal transfusion process is a potential complication of laser coagulation in TTTS. Follow-up of double survivors with MCA PSV is therefore indicated as intrauterine blood transfusion, repeat-laser coagulation of the chorionic vessels or cord coagulation may prevent some of the previously unexplained late fetal losses.