Twin reversed arterial perfusion (TRAP) Sequence (Acardiac twin)

TRAP Sequence

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Figer-1

📄 Report Sample Line- Reversed arterial perfusion Acardiac twin
Twin pregnancy, monochorionic monoamniotic (confirmed by T-sign and absence of intertwin membrane).
Pump Twin (Twin A):
Live intrauterine fetus with active cardiac pulsations. Biometry corresponds to gestational age: [23w 2D]. No signs of hydrops fetalis. Normal fetal anatomy visualized. No structural anomalies detected.
Acardiac Twin (Twin B):
Amorphous soft tissue mass noted with ill-defined cephalic and truncal structures. No cardiac activity. No identifiable fetal heart, brain, or organized thoracoabdominal structures. Grossly malformed with absent cranial vault and rudimentary limbs. Color Doppler shows reversed arterial flow in the umbilical artery supplying the acardiac twin. Blood flow entering the acardiac twin from the pump twin confirms reversed perfusion.
Doppler Findings:

• Umbilical artery Doppler (Pump Twin): Normal resistance indices
• Middle cerebral artery (MCA) Doppler (Pump Twin): Normal
• Ductus venosus flow (Pump Twin): Normal
• Reversed flow in umbilical artery (Acardiac Twin): Present
• Cardiac activity in Acardiac Twin: Absent (No independent cardiac activity)

Conclussion: 📋

• TRAP Sequence / Acardiac Twin Identified
• Viable Pump Twin with Normal Doppler Parameters
• No current evidence of cardiac strain or hydrops in the pump twin

Recommendation: Serial ultrasound monitoring every 1–2 weeks to evaluate growth of acardiac twin and strain on pump twin.