Modified BT shunt: A not-so-simple palliative operation

Objective: Analysis of 35 consecutive modified BT shunt palliations performed in infancy since 2004.

Methods: Sternotomy was the only approach used. Median age and weight were 11(Range 1–111)days and 2.9(1.9–4.4)kg respectively. Shunt palliation was performed for TOF/Pulmonary Atresia(20), dTGA/VSD/PS(3) and single ventricle(12). HLHS were excluded. 5 procedures were performed using CPB. 15 shunts in Era I(2004–07) versus 20 shunts from Era II(2008–11) were compared. Other demographics being equal, adjunctive pulmonary artery unifocalization/TAPVC repair were performed in 3(20%) patients in Era I versus 0(0%) in Era II [p=0.04]. Median shunt size/body weight ratio were 1.25(0.91–1.69) and 1.16(0.89–1.58)mm/kg [p=0.1] and absolute shunt size were 4(3.5–4.5) and 3.5(3–3.5)mm [p<0.001] respectively. Shunt size reduction was needed in 5(33%) and 2(10%) patients [p=0.09] respectively.

Results: 4 patients died after 9(1–62) days due to cardio respiratory decompensation (all in Era I)[p=0.02]. Acute shunt thrombosis was observed in 3(all in Era II)[p=0.12], none leading to death. Need for decongestive therapy (more than diuretics) was in 8(67%) and 4(20%) patients respectively [p=0.02]. Mechanical ventilation duration was 2(1–15) and 1.5(0–9)days respectively. 26 patients have undergone successful shunt take down at 5.5(0.5–11.9)months.

Conclusion: Palliation with a modified BT shunt continues to be indicated despite increased thrust for primary corrective surgery. Though seemingly simple, it is associated with a significant mortality and morbidity. Bigger shunt size seems to be associated with lower thrombosis, but may be responsible for haemodynamic decompensation. Various intricate factors such as indication for shunt (univentricular/biventricular heart), adjunctive procedure and pulmonary perfusion, early anticoagulation regimen and learning curve may influence outcome, and need to be prospectively studied.