Ramesha Papanna

Objective To determine the association of high middle cerebral artery peak systolic velocity (MCA‐PSV) with fetal demise in donor twins among pregnancies complicated by twin‐to‐twin transfusion syndrome (TTTS) in the absence of twin anemia polycythemia sequence (TAPS). Methods This prospective cohort study included TTTS cases that underwent laser surgery between 2011 and 2022 at a single center. TAPS cases were excluded from the study. The primary objective was to explore the association of high MCA‐PSV (>1.5 multiples of the median) with fetal demise of the donor twin among pregnancies complicated by TTTS. Secondary objectives were: 1) to evaluate if donor or recipient MCA‐PSV is associated with an increased risk for their corresponding fetal death using receiving operator characteristic curve analysis; and 2) to compare the proportion of fetuses with low MCA pulsatility index among donor twins with high MCA‐PSV and in those with normal MCA‐PSV to evaluate the contribution of blood flow redistribution to high MCA‐PSV. Multivariable and Poisson regression analysis were performed to explore the association of isolated high donor MCA‐PSV and fetal demise, adjusted for TTTS stage, selective fetal growth restriction (sFGR), and other confounders. p<0.05 was considered significant. Results Out of 660 TTTS cases, donor MCA‐PSV was unavailable in 48 (7.3%) cases. Of the remaining 612 patients, 9 (1.5%) were lost to follow‐up, and 96 TAPS cases were excluded. High donor MCA‐PSV was seen in 6.5% (33/507) of the study population. High donor MCA‐PSV was an independent risk factor for donor fetal demise (adjusted relative risk (aRR) of 4.52; 95% CI: 2.72‐7.50), adjusted for confounders. Regression analysis restricted to each Quintero TTTS stage demonstrated that high donor MCA‐PSV was an independent risk factor for donor fetal demise in Quintero stage II (aRR of 14.21; 95% CI: 1.09‐186.2) and Quintero stage III (aRR of 3.41; 95% CI: 1.82‐6.41). Donor MCA‐PSV was associated with donor fetal demise (AUC: 0.69; p<0.001), but recipient MCA‐PSV was not associated with its corresponding fetal demise (AUC: 0.54; p=0.44). A higher proportion of donor twins in the group with high MCA‐PSV had a low MCA pulsatility index than in those with normal MCA‐PSV (33.3% vs. 15.5%; p=0.016). Conclusions Elevated donor MCA‐PSV without TAPS prior to laser surgery is associated with a 4‐fold increased risk for donor fetal demise, adjusted for sFGR, TTTS stage, and other confounders. Doppler evaluation of donor MCA‐PSV prior to laser surgery can further stratify TTTS staging to evaluate the risk for donor fetal demise. This article is protected by copyright. All rights reserved.