Long-term survival and phenotypic spectrum in heterotaxy syndrome: a 25-year follow-up experience

Background: Heterotaxy syndrome (HS) is a group of congenital disorders characterized by abnormal arrangement of thoraco-abdominal organs across the left-right axis of the body, classified as right (RAI) and left atrial isomerism (LAI)·We investigated the long-term survival and phenotypic spectrum in our HS cohort. Results are compared to literature data. Methods: This is a single centre, observational, both retro and prospective study. Cardiac features, surgical management and abdominal ultrasound (US) of all HS patients were reviewed or investigated if missing. We evaluated all anatomical data and their clinical impact on survival, arrhythmias, infections, and heart transplant (HT). Results: 136 patients were classified as RAI (81) and LAI (55). Long-term survival and freedom from HT reached 69.8% and 87.8% at 40 years in RAI and LAI, respectively. Multivariate analysis showed that LAI is an independent predictor for pacemaker implantation (p = 0.019). Splenic status varied in both groups: in RAI, abdominal US showed asplenia, polysplenia and normal spleen in 48%, 4% and 32% of patients, respectively, whereas in LAI polysplenia, asplenia and normal spleen occurred in 64%, 4% and 16% of cases, respectively. Conclusions: Mortality was significantly lower (9%) compared to literature (50%). Although patients with RAI experienced a higher mortality, no independent predictors were found. We demonstrated that the obsolete cardiac definition of “asplenia” and “polysplenia” instead of RAI and LAI is misleading, because of the high variability of the splenic phenotype among patients of both groups.