Objective: This study aimed to explore the incidence of acute shunt occlusion in neonates and infants within 24 hours after undergoing MBTS surgery and to determine the potential predisposing factors of acute shunt occlusion.
Material and Method: The electronic database of patients was reviewed retrospectively. The occurrence of acute shunt occlusion and the potential risk factors in neonates and infants who had undergone MBTS surgery between January 2009 and December 2015 were collected.
Results: One hundred and two patients were enrolled. The incidence of acute shunt occlusion was 13.7% (14 patients). Using a univariate analysis, a 3-mm shunt size (OR 11.88, 95% CI 2.24 to 63.11, p<0.01), a pulmonary artery size less than 4 mm (OR 4.82, 95% CI 1.32 to 17.54, p = 0.02), no concomitant ligation of ductus arteriosus (OR 14.50, 95% CI 1.22 to 172.31, p = 0.03) and the surgeon with low case volume (<6 cases per year) (OR 5.96, 95% CI 1.71 to 10.74, p<0.01) were significantly associated with acute MBTS occlusion postoperatively. The multiple logistic regression analysis revealed the surgeon with low case volume (<6 cases per year) (OR 8.90, 95% CI 1.74 to 45.66, p<0.01) and non-ligated patent ductus arteriosus (PDA) (OR 36.58, 95% CI 2.02 to 661.26, p = 0.02) were the significant risk factors contributing to acute shunt blockage.
Conclusion: A small volume of MBTS cases operated per year and non-ligated PDA are significant risk factors for acute shunt occlusion within 24 hours postoperatively.

Keywords: Blalock-Taussig procedure, Incidence, Infant, Risk factors, Thrombosis