Management and Outcomes of TRAP Sequence

Twin reverse arterial perfusion syndrome (TRAP) is a rare complication in twin pregnancies in which a structurally abnormal, acardiac twin that is not compatible with extra-uterine life grows at the expense of a healthy (“pump”) co-twin that supplies blood to the acardiac co-twin. This may cause high-output cardiac failure and hydrops in the normal twin, potentially leading to fetal death, and the risk seems to be proportion to the volume/size of the acardiac twin relative to that of the normal twin. When the a-cardiac twin is size is ≥ 50% of the normal twin or there are signs of fetal hydrops, intervention may be required, either using radio-frequency ablation or laser cord occlusion via fetoscopy, which also carry risks to the normal “pump” twin. Occasionally, when the a-cardiac twin is small or its blood flow ceases spontaneously, expectant management is preferred. In this project, we will aim to review all cases of TRAP sequence seen by the Victorian Fetal Therapy Service (VFTS) at Monash Health to characterise the management and the outcomes of TRAP sequence with intervention and expectant management, and to further investigate the association between a-cardiac twin size and outcomes for the healthy twin.