Clinical and anatomic features of acardiac twins

To report 6 cases of acardiac twins, and to investigate prognostic factors that would lead to survival of the normal twin.

During a 9-year period from 1993 to 2001, 6 cases of acardiac twins out of 109,000 deliveries at the Maternity Center, Tunis, Tunisia were studied. Detailed inspection, X-rays, ultrasound and autopsies were performed.

Prenatal diagnosis was made in only 1 case at 33 weeks of gestation. Rudimentary cardiac tissue was observed in 2 of the 6 perfused twins, and the cephalic pole was less developed than other parts of the body. Severe agenesis or hypoplasia of the thoracoabdominal organs was commonly observed. Many limb malformations were observed, with arms the most affected. One of the pump twins was stillborn, 3 died between days 1 and 3 from respiratory distress, and 2 developed cardiac failure after birth and were treated with diuretics and digoxin, which led to a favorable outcome in only 1. The ratio of the weight of the acardiac to pump twin (TWR) ranged from 50 to 142%.

The findings of this study indicate that acardia can be diagnosed by means of ultrasound in front of a monochorial twin pregnancy when one of the fetuses is deformed and has no cardiac activity. Heart failure and polyhydramnios, as well as a TWR greater than 50% are prognostic factors for the pump twin.