Complete atrioventricular septal defect, Down syndrome, and surgical outcome: risk factors.

BACKGROUND: This study was conducted to evaluate surgical outcome and to identify risk factors for hospital mortality and reoperation after repair of complete atrioventricular septal defect.
METHODS: A total of 147 consecutive children underwent repair between January 1986 and December 1998. Of those, 106 had Down syndrome, 37% had normal chromosomes, and 4 had other syndromes; 108 underwent primary repair, 19 had prior pulmonary artery banding, and 20 had additional tetralogy of Fallot. The median weight at primary repair was 4.5 kg. A two-patch technique was used in 88%.
RESULTS: The 30-day mortality was 15% (70% confidence interval [CI] 12% to 19%). A double orifice atrioventricular valve was found to be a significant risk factor (p = 0.002), with 6 of 11 patients dying. If double orifice atrioventricular valve patients are excluded, the mortality rate falls to 12% (70% CI 9% to 15%). No difference in mortality was found between Down syndrome and chromosomally normal children but the latter more commonly required reoperation. Chromosomally normal children frequently have a dysplastic common atrioventricular valve (24% versus 3% in Down children, p < 0.001). In a multivariate Cox model including both variables, the presence of a dysplastic atrioventricular valve was a significant risk factor for reoperation. After controlling for the presence of a dysplastic atrioventricular valve, Down syndrome retained a significant protective effect but the upper limit of the confidence interval was close to 1.
CONCLUSIONS: The presence of a double orifice atrioventricular valve emerged as an unforeseen risk factor for death.