Risk factors to acute shunt occlusion in infants aged less than three months with congenital cyanotic heart disease after modified Blalock-Taussig shunt operation at King Chulalongkorn Memorial Hospital

Abstract

Background : Acute shunt occlusion in children after modified Blalock-Taussig shunt  (MBTS) operation results in sudden reduction of pulmonary vascular perfusion causing oxygen saturation drop and cyanosis that may lead to
death.

Objective : To identify potential risk factors to acute shunt occlusion that could be prevented and reduce morbidity and mortality in patients.

Methods : Data of congenital cyanotic heart disease patients aged 0 - 3 months that underwent MBTS operation at King Chulalongkorn Memorial Hospital from January 2002 to December 2010 were collected; clinical data, pre-, peri-, and post-operative data. Then data were analyzed to find potential risk factors to acute shunt occlusion.

Results : In total, 123 children that underwent MBTS operation with mean age of 28 days and mean body weight of 3.17 kg. The shunt sizes varied from 2.5 to 5.0 mm. Acute shunt occlusion was found in 22 of 123 patients (17.9%). The significant risk factors to shunt occlusion were low body weight, subclavian artery diameter, shunt size and prolonged use of Prostaglandin E1 (PGE1) (P value = 0.007, 0.00, 0.042 and 0.001, respectively.) The mean oxygen saturation at 4 hr after surgery was significantly lower in children whose shunt was occluded (P value = 0.012). Cardiac catheterization with intervention was performed in 13 cases of acute shunt occlusion with successful result. The other 7 cases that underwent surgery as well as the other 2 died, however, none of these was associated with shunt occlusion.

Conclusion : In this study, acute shunt occlusion mostly occurred within the first 24 hr after the operation. The risk factors to shunt occlusion were, namely: low body weight, subclavian artery diameter, shunt size and prolonged use of PGE1. Percutaneous cardiac catheterization with intervention was the effective method to recanalize the occluded shunt and might constitute the alternative to surgical treatment, especially in patients with                      life-threatening conditions.