Classic Blalock Taussig shunt (BT shunt) is done on opposite side of aortic arch so that brachiocephalic trunk prevents kinking of the subclavian artery.
Catch 22 syndrome or 22q11 deletion is likely if there are dysmorphic features and arterial anomalies in TOF like right aortic arch and PA branch stenosis.
Reynolds number: Re = (V x d x rho) / eta. When Reynolds number is above 2000, flow becomes turbulent. When viscosity increases, Reynolds number decreases.