RESUMEN
OBJECTIVES: Analyze the demographic and clinical characteristics of complete atrioventricular septal defect (AVSD), its association with Down's syndrome, with other cardiac and extra-cardiac anomalies, and finally the impact of consanguineous marriages on the incidence of AVSD. PATIENTS & METHODS: The sample consisted of 2195 consecutive patients with congenital heart defect, entered in the National Register of Paediatric and Congenital Heart Disease, Lebanese Society of Cardiology, Beirut, between Jan 1999 and Dec 2007. 120 patients with AVSD were analyzed. The gathered data included age, sex, type of AVSD, mother's age, 1st and 2nd degree cousins, and other associated cardiac or extra-cardiac anomalies. RESULTS: AVSD was diagnosed in 5.5% of all patients with congenital heart disease, with 81.7% (n = 98) being complete AVSD. Male sex was predominant (58%). More than half (57.5%) were also diagnosed with Down's syndrome. The mean maternal age was 30.4 years (+/- 4.7 years) and consanguinity found in 16.7% of the cases. Cardiac and extra-cardiac anomalies (all in the esophagus and intestine) were associated in 15% and 6.7% respectively. Complete AVSD was significantly associated with Down's syndrome: 94% of patients with Down's syndrome had a complete AVSD. Digestive anomalies were also significantly more frequent with Down's syndrome (10% versus 2%, p = 0.02). Other cardiac anomalies, however, were less frequent with Down's syndrome (33% versus 7.7%, p = 0.02). CONCLUSION: Down's syndrome is more frequently associated with isolated and complete AVSD. Other anomalies may complicate the management of these patients. The cause of this probable genetic anomaly is still debated.