Diastolic cardiac pathology and clinical twin-twin transfusion syndrome in monochorionic/diamniotic twins

Objective: We sought to identify differences in echocardiographic profiles of monochorionic (MC)/diamniotic (DA) pregnancies with early or mild twin-twin transfusion syndrome (TTTS), compared to MC/DA twins affected only by discordant growth or discordant fluid. Study Design: This was a retrospective evaluation of sonograms and echocardiograms of twin pregnancies referred for suspected TTTS. Results: A total of 112 MC/DA pairs were studied. In all, 41 did not have/develop TTTS, and 61 had stage I/II TTTS. Ten developed TTTS after initially not meeting criteria. TTTS recipients had a higher rate of venous Doppler or tricuspid inflow abnormalities than purported recipients in non-TTTS pregnancies (86% vs 37%, P <.001). TTTS recipients had shorter tricuspid inflow duration/R-R intervals than non-TTTS fetuses (32 ± 6% vs 37 ± 4%, P <.001). Logistic regression and recursive partitioning identified shorter tricuspid inflow duration, longer isovolumic relaxation, and ductus venosus abnormality associated with TTTS. Conclusion: Diastolic pathology, specifically shorter tricuspid inflow duration, may be considered a hallmark of TTTS distinguishing these pregnancies from other MC/DA twin complications.