The Spectrum Of Congenital Heart Diseases In Conjoined Twins: Current Evidence And Clinical Challenges

Abstract

Conjoined twins represent one of the rarest and most complex congenital conditions encountered in perinatal medicine. Among the many challenges they present, congenital heart disease (CHD) stands out as the most critical determinant of survival, surgical feasibility, and long-term outcome. Compared with singletons and other multiple gestations, conjoined twins show a markedly higher prevalence of cardiac malformations, particularly in ventrally fused types such as thoracopagus twins. Cardiac involvement ranges from relatively simple defects, including septal or valvular abnormalities, to severe and often irreparable conditions such as shared atrial or ventricular chambers or a single functional heart.

This literature review synthesizes current evidence on the epidemiology, anatomical spectrum, diagnostic approaches, clinical management, surgical outcomes, and ethical considerations associated with CHD in conjoined twins. Published case series, pooled analyses, and contemporary reviews were examined to highlight patterns of cardiac anatomy, advances in prenatal and postnatal imaging, and factors influencing prognosis.

Available evidence consistently demonstrates that survival following attempted separation is closely linked to the degree of cardiac sharing. Twins with separate hearts or a shared pericardium have significantly better outcomes than those with complex intracardiac fusion. Advances in prenatal diagnosis, particularly fetal echocardiography and fetal magnetic resonance imaging, have improved early detection, anatomical characterization, parental counseling, and perinatal planning, although interpretation remains challenging due to altered hemodynamics and shared circulation. Elective separation undertaken after comprehensive multidisciplinary planning is associated with higher survival than emergency procedures, while non-operative and palliative approaches remain appropriate in cases incompatible with surgical correction.

CHD remains the primary prognostic factor in conjoined twins. Accurate cardiac assessment, individualized multidisciplinary care, and thoughtful ethical decision-making are essential to optimizing outcomes in this exceptionally vulnerable population.