**Abstract**

Patent ductus arteriosus (PDA) is the most common cardiovascular condition afflicting premature neonates especially those born extremely low birth weight (ELBW). Despite five decades of scientific inquiry which has produced thousands of publications including over 65 randomized controlled trials, cardiologists, neonatologists, and surgeons still cannot answer simple questions such as if, when and how to close to the PDA in ELBW infants. This chapter will examine current evidence in order to answer these fundamental questions. The chapter will specifically focus on transcatheter PDA closure (TCPC), which albeit a new therapy, has displayed great potential to be the best therapeutic option in the future. It is about time that physicians from all sub-specialties come together and integrate the evidence to develop a management algorithm for ELBW infants with hemodynamically significant PDA.

**Keywords:** PDA, ELBW, hemodynamics, devicer, ligation
