Postoperative middle cerebral artery peak systolic velocity changes confirm physiological principles of the sequential laser technique for twin-twin transfusion syndrome

Introduction: Treatment of the twin-twin transfusion syndrome (TTTS) via sequential selective laser photocoagulation of communicating vessels (SQLPCV) mandates ablation of donor-to-recipient arteriovenous anastomoses first. It is hypothesized that SQLPCV facilitates intraoperative transfusion to the donor, thereby minimizing donor hypovolemia and anemia. We sought to determine if postoperative changes in fetal middle cerebral artery-peak systolic velocities (MCA-PSV) support this hypothesis. Materials and Methods: Patients undergoing preferential SQLPCV for TTTS had MCA-PSV measured 1 day before surgery and on postoperative day 1 (POD-1). Fetal anemia was defined as an MCA-PSV ≥1.5 multiples of the median (MoM). Exclusions included: POD-1 demise, missing MCA-PSV data, or gestational age <18 weeks. Results: Study criteria were met by 139 patients. Mean MCA-PSV in recipients increased from 0.97 to 1.15 MoM postoperatively (p < 0.0001). Donor mean MCA-PSV remained stable at 1.00 MoM preoperatively and 0.98 MoM postoperatively (p = 0.272). Nine fetuses, 6 donors and 3 recipients, had preoperative anemia; SQLPCV was not attempted in the 3 anemic recipients. Postoperatively, the proportion of donors with anemia remained stable (increase 3.6%, p = 0.419), and the proportion of recipients with anemia increased (increase 12.2%, p = 0.009). Discussion: Our findings confirm the presumed physiological basis for the SQLPCV treatment of TTTS.