Explain Bidirectional Superior vena cavo pulmonary shunt bidirectional glenn

"This is a palliative produce where blood from superior vena cava is diverted to the pulmonary artery. As the pulmonary artery bifurcation is preserved, the superior vena caval blood will flow to right and left pulmonary arteries. In the original Glenn shunt, the superior vena cava, and pulmonary arteries were divided and then end-to-end anastomosis done. The entire superior vena caval blood was diverted to the light pulmonary artery. Bidirectional Glenn (BDG) is a superior operation because the SVC blood flows into both pulmonary arteries.