As closing a patent arterial duct is relatively simple, safe, and successful, most children with a patent arterial duct have it closed soon after diagnosis. The larger ducts are closed to prevent congestive heart failure, pulmonary vascular disease, or aneurysmal dilatation of the ductus, and smaller ducts are closed to prevent infective endocarditis. Consequently, there is no opportunity to determine whether spontaneous closure or diminution in size of the patent arterial duct is common.
If the duct does become smaller, flow through it may be so low that no murmur is produced – the silent ductus. The frequency and best management of the silent patent arterial duct are unknown, and we do not know whether these tiny ducts are the last stage before spontaneous closure.