Stage I twin-twin transfusion syndrome with intermittent umbilical artery Doppler abnormalities

Twin-to-twin transfusion syndrome (TTTS) is a rare condition that occurs in approximately 9% to 15% of monochorionic diamniotic twin pregnancies. The Quintero staging system was established to categorize the severity of this disease. Published outcomes for selective laser photocoagulation of communicating vessels demonstrate a significant difference in dual survival outcomes among the different stages of TTTS. Per Quintero staging, Stage I TTTS includes those with donor twin umbilical artery (UA) intermittent, absent, or reversed end diastolic velocity (AREDV), whereas patients with persistent donor twin UA-AREDV are classified as Stage III. This distinction between intermittent and persistent UA-AREDV appears to have been variably interpreted since the original publication.

Our objective was to compare laser-treatment outcomes in Stage I patients with intermittent UA-AREDV vs Stage I patients with a normal UA waveform; Stage III patients with persistent donor twin UA-AREDV were used for comparison. Because arterio-arterial communications (AA) have been associated with postoperative donor demise, the rate of such vascular communications was also assessed within the 3 groups.

Three groups of monochorionic diamniotic twins with TTTS that was treated with laser surgery (2006-2023) were analyzed for the primary outcome of donor twin intrauterine fetal demise (IUFD): Stage I with preoperative normal donor UA flow (Stage-I Normal); Stage I with preoperative intermittent donor UA-AREDV (Stage-I Intermittent); and Stage III with preoperative persistent donor UA-AREDV (Stage-III).

Of 349 study patients, 101 were classified as Stage-I Normal, 36 were Stage-I Intermittent, and 212 were Stage-III. The rate of donor IUFD was lowest in Stage-I Normal vs Stage-I Intermittent and Stage-III groups: 3.0% vs 25.0% vs 29.2%, P<.0001. At least one survival did not differ among the 3 groups; dual survival was highest for Stage-1-Normal (97.0% vs 75.0% vs 66.0%, P<.0001) and differed from both Stage-I Intermittent and Stage-III groups in pairwise comparisons. AA communications were most common in the Stage-I Intermittent group: 27.7% vs 69.4% vs 42.5%, P<.0001. In a multiple logistic regression model, Stage-I Intermittent patients were 7 times more likely to have donor twin IUFD (Odds ratio [OR] 7.23 [1.69-30.82], P=.0075), as were Stage-III patients (OR 7.24 [2.06-25.47], P=.0020), compared to Stage-I Normal patients. In this same model, independently, patients with AA were 3.6 times more likely to have donor IUFD (OR 3.59 [1.95-6.61]; P<.0001).

TTTS Stage I patients with intermittent UA-AREDV were at increased risk of donor IUFD after laser surgery.