Objective: The objective of this study was to compare alterations in the middle cerebral artery (MCA) pulsatility index (PI) and mean velocity (V (mean)) 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 V (mean) 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 V (mean) 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 V (mean) remained constant. These findings may suggest some autoregulatory capacity in the cerebral vessels of the mid-trimester fetus.