What is the treatment for transposition of the great vessels?

Arterial switch. Before surgery the PDA is kept open with IV prostaglandin. The basic procedure is to switch the transposed vessels, to establish normal blood circulation. The coronary vessels are switched as well. In many cases there is also a vsd that will be closed at the same time.
Surgery. Initially at birth, medications are provided to prevent closure of the connections between the pulmonary and systemic circulations that are present in fetal life. This allows for some mixing of the oxygenated and un-oxygenated blood and buys time. The ultimate treatment is surgical correction of the defect.