Fetal middle cerebral artery Doppler fluctuations after laser surgery for twin–twin transfusion syndrome

Objective:the objective of this study was to compare alterations in the middle cerebral artery (mca) pulsatility index (pi) and mean velocity (vmean) after laser surgery for twin–twin transfusion syndrome (ttts).study design:mca doppler studies were conducted 1 day before and after laser surgery for ttts. the pre- and postoperative mean (standard deviation) of the mca pi and vmean z-scores of the recipient and donor fetuses were calculated and compared. data were analyzed using paired testing and multivariable linear regression models.results:a total of 103 patients met the study criteria. recipients’ mca pi increased from −1.29 (1.20) preoperatively to 0.14 (1.52) postoperatively (p<0.0001), whereas the donors’ pi did not change significantly (−0.31 (1.67) to −0.67 (1.29); p=0.12). there was no significant difference between preoperative and postoperative mca vmean in donors (0.39 (0.83) and 0.38 (0.93), respectively; p=0.5048) or recipients (0.60 (0.74) and 0.63 (0.90), respectively; p=0.5324).conclusions:despite the changes in the mca pi after laser surgery for ttts, the mca vmean remained constant. these findings may suggest some autoregulatory capacity in the cerebral vessels of the mid-trimester fetus.