Acardiac Twin: The Overlooked Diagnosis. A Recent Case Report and Review of Literature

Abstract

Objectives: Acardiac twinning is an uncommon, unique and complex vascular complication seen in multifetal pregnancies sharing a placenta. Alternatively referred as Twin Reverse Arterial Perfusion sequence (TRAPS), it comprises, an often normal donor twin pumping deoxygenated arterial blood, in retrograde manner, through an often acardiac dysmorphic counterpart. Method: Recently, a much higher incidence of 2.6% in monochorionic twin pregnancies has been cited for this rather severe form of fetal-fetal transfusion anomaly. Furthermore, mortality in those affected exceeds 50% for the donor twin, commonly from heart failure and complications of prematurity. To the best of our knowledge no cases of acardiac twin pregnancy with a surviving donor twin have been described and published in East and central African literature. Results: As such, we describe the case of a 28 year old para 0+1 gravida 2 presenting in the second late trimester with an acardiac twin pregnancy complicated by polyhydramnios of the normal donor twin, inadvertently diagnosed as twin gestation with a single fetal demise of a grossly malformed twin. The case was expectantly managed, resulting in eventual spontaneous preterm delivery in early third trimester and survival of the donor twin. In addition, we review current literature on the pathogenesis, diagnosis, management options and prognosis of monochorionic twin pregnancies complicated by this sequence. Conclusions: Although a rare condition, acardiac twin is perhaps more common than generally stated and thus necessitates a thorough clinical and sonographic evaluation as well as high index of suspicion in monochorionic multifetal pregnancies as highlighted in this case.