Acardiac twin is a rare event with high perinatal mortality rate and the management strategies remain controversial. The authors report 4 cases of twin pregnancies associated with one acardiac twin diagnosed at King Chulalongkorn Memorial Hospital during the period 1993 to 2002. Two cases were expectantly managed and intrauterine interventions were performed in order to occlude umbilical artery of the acardiac twin in 2 cases, by using Guglielmi detachable coil (GDC) embolization and absolute alcohol injection. Overall, the perinatal mortality rate for the pump twin was 50% and the survival rate of expectant management in the present series was 100%. GDC embolization was judged to be technically successful since it completely occluded the circulation to the acardiac twin. However, the pump twin was dead which might have resulted from the compromised state due to cardiac failure. At present, it seems that conservative management with close antenatal surveillance is the treatment of choice when the twin-weight ratios are substantially less than 70%. Invasive techniques should be considered when there is ultrasound evidence of hydramnios or congestive heart failure of the pump twin at a previable gestational age.

Keywords: Acardiac twin, TRAP sequence