Acardia: Predictive risk factors for the co‐twin's survival

Abstract

This study aimed to find factors in acardiac pregnancies that could be used to predict survival rates of the pump fetus. Five cases of acardia at Monash Medical Centre were found, and all case reports available in the literature from 1960 to 1991 (184 cases) were collected and analyzed. Acardia is more common in nulliparous women and in monoamniotic monochorionic pregnancy. The acardiac fetus usually has a two-vessel umbilical cord and is most likely to develop structures supplied by the lower aortic branches. Delivery is more often preterm (mean gestation = 31.1 weeks) than normal twins. The overall perinatal mortality for the pump fetus is 35% in twins and 45% in triplets. Factors associated with a statistically significant increase in perinatal mortality for the pump fetus include delivery before 32 weeks gestation, acardiacus anceps form of acardia, and the presence of arms, ears, larynx, trachea, pancreas, kidney, or small intestine in the acardiac fetus. Active intervention in these pregnancies is reasonable.

A case report of twin reversed arterial perfusion sequence with expectant management

“…Chromosomal abnormalities have been detected in one third of the acardiac cases. 2 The conservative approach can be considered if the acardiac fetus is small, its growth is rather slower and the pump fetus has no complications. 8,9 Yet expectant management can yield to perinatal mortality due to the development of heart failure or preterm delivery as shown in a case series of Pagani et al 10 It's controversial whether conservative management or therapeutic treatment is better in TRAP-sequence.…”

“…2 The nonviable twin is perfused with retrograde blood flow from the other twin that flows through arterioarterial anastomoses; the blood returns to the normal twin by venovenous anastomoses that bypass the placenta. Because these vessels carry less oxygenated blood and the flow is asymmetrical, the result is malformations mostly seen in the cranium and upper extremities.…”

Conservative management in a case of uncomplicated trap sequence: a case report and brief literature review

“…A primary defect in embryogenesis in one twin leads first to failure of cardiac formation, followed by secondary development of anastomosis between umbilical vessels allowing survival of affected twin (12). A range of structural anomalies have been reported in the acardiac twin, presumably due to the abnormal perfusion, from relatively normal body forms with well-differentiated organ structures through to apparent amorphous structures with no recognizable normal anatomy (13). The heart may be completely absent (holoacardius), represented by a rudimentary cardiac structure (pseudoacardius) or less than 20% have identifiable cardiac tissue.…”

A rare complication of monochorionic twin pregnancy: Twin-reversed arterial perfusion (TRAP) sequence

“…The natural history of TRAP is poorly documented due to the rarity of the disorder. Reported perinatal mortality rates for the pump twin vary between 35% and 50% 4,5 The goal of in utero treatment of acardiac twinning is interruption of aberrant vascular communication between the twins. Of these methods, 90-percent survival rate was found with radiofrequency ablation, which cauterizes umbilical vessels in the malformed recipient twin so as to terminate blood flow from the donor.…”