Twin Reversed Arterial Perfusion Syndrome (TRAP or Acardiac twin)- A Case Report

Abstract

Twin reversed arterial perfusion (TRAP) syndrome is a rare condition (0.3:10,000 births) that occurs in monochorionic twin pregnancies, resulting in coexistence of a normal "pump" twin and an acardiac twin. The acardiac twin is dependent upon the normal twin to provide circulation by means of vascular anastomosis. Many of the bizarre defects are felt to be caused by low oxygen tension and this causes dramatic alteration in the twin fetal physiology and high prenatal mortality. The acardiac twin is a parasite, putting the pump fetus at risk of high output cardiac failure. Overall only 50% of pump twins survive. We present a case in a twenty year female, gravida two, para one, living one, full term normal pregnancy, ultrasound showed twin pregnancy. Following delivery, the first fetus survived only for one day and the second fetus showed features of TRAP syndrome.

Ultrasound Doppler findings of a Twin Reversed Arterial Perfusion Sequence (TRAP)

“…In TRAP syndrome, the twin’s pregnancy includes a normal-developed (pump) fetus and an abnormal (acardiac) fetus who depends on the pump foetus to provide blood circulation by vascular anastomosis thus putting the pump fetus at risk of high cardiac output heart failure and congenital anomalies with approximately 50% reported mortality rate for the pump fetus. 1 - 3 …”

“…The abnormal acardiac twin is a parasite dependent upon the pump twin that provide blood circulation by vascular anastomosis and puts the pump fetus at risk of high cardiac output failure. 1 , 2 The acardiac twin is a rare complication of monozygotic twin pregnancy that occurs in one of every 35,000 twin pregnancies and in 1% of monochromatic twin pregnancies. The majority of pump twins are normal but cardiogenic defects, gastroschisis, and musculoskeletal anomalies may observe with approximately 50% reported mortality rate.…”