Abstract

OBJECTIVES: To assess the perinatal outcomes of fetuses affected by heterotaxy. METHODS: Medline, Embase and Cinhal were searched. Only studies reporting a prenatal diagnosis of isomerism were included. The outcomes observed were: associated cardiac and extra-cardiac anomalies, fetal arrhythmias, abnormal karyotype, type of surgical repair and perinatal mortality. The analysis was stratified according the type of heterotaxy syndrome (left, LAI, and right, RAI, atrial isomerism). Meta-analyses of proportions were used to combine data. RESULTS: 16 studies (647 fetuses) were included. Atrioventricular septal defect (AVSD) was the most common associated major cardiac anomaly found in fetuses with LAI (Pooled Proportion [PP] 59.3%, 95% CI 44.0-73.7), while obstructive lesions of the right outflow tract occurred in 35.5% (95% CI 21.4-51.0). Fetal arrhythmias occurred in 36.7% (95% CI 26.9-47.2) of the cases and were mainly represented by complete atrio-ventricular block (26.5%, 95% CI 15.0-40.0). Abnormal stomach and liver position were found in 59.4% (95% CI 38.1-79.0) and 32.5% (95% 11.9-57.6) of cases, while intestinal malrotation was detected in 14.2% (95% CI 2.5-33.1). Hydrops developed in 11.8% (95% CI 2.9-25.6) of these fetuses. Biventricular repair was accomplished in 78.2% (95% CI 64.3-89.4) of the cases while univentricular repair or palliation was needed for 17.0% (95% CI 9.7-25.9). Death during or after surgery occurred in 26.8% (95% CI 4.6-58.7) of cases. Almost all (99.0% 95% CI 97.5-99.9) cases with RAI had associated cardiac anomalies, with AVSD being the most common heart defect (PP 72.9%, 95% CI 60.4-83.7). Abnormal heart rhythm was not common with an incidence of 1.3% (95% CI 0.2-3.2). Abnormal stomach and liver position were found in 54.5% (95% CI 38.5-70.1) and 45.9% (95% CI 11.3-83.0) of cases, respectively, while intestinal malrotation was detected in 27.1% (95% CI 7.9-5.2). Most children with RAI had univentricular repair and 27.8% (95% CI 15.5-42.1) died during or after surgery. CONCLUSION: Fetal heterotaxy is affected by a high prevalence of cardiac and extra-cardiac anomalies. Approximately one quarter of these fetuses died during or after surgery. Abnormal heart rhythm, especially heart block is common in fetuses with LAI while is uncommon in RAI. Univentricular repair is common in RAI.