chapter  21
7 Pages

Occlusion of the patent arterial duct

WithRalf J Holzer, John P Cheatham

Transcatheter closure of the patent ductus arteriosus (PDA) was first introduced by Porstmann and colleagues in 1968.1 While the device was cumbersome to use and required a large arterial cannulation, it set the stage for subsequent device developments, such as the Rashkind device in the late 1970s.2-4 At present, the only device approved specifically for the closure of the patent arterial duct is the Amplatzer® Duct Occluder (ADO), which was introduced in 1997.5

The device is mushroom-shaped and made of 0.005 inch Nitinol wire mesh, with Dacron fabric incorporated into the retention disc as well as the skirt of the device (Figure 21.1). Prior to the introduction of the ADO, detachable as

well as controlled-release coils were used to occlude the majority of PDAs, irrespective of size or shape. However, at the present time, coil occlusion is virtually exclusively reserved for the occlusion of very small PDAs. The Nit-Occlud PDA Occlusion System (pfm AG, Cologne, Germany) (Figure 21.2), which was introduced in 2001, is a suitable alternative to the ADO for medium sized PDAs, and is presently undergoing clinical evaluation in the US. A variety of additional devices have been used for PDA occlusion, such as the Amplatzer Muscular VSD Occluder,6 the Amplatzer Septal Occluder,7 the buttoned device,8

the Amplatzer Vascular Plug,9 and the GianturcoGrifka Vascular Occlusion Device (GGVOD).10-12

The techniques referred to in this chapter are focused mainly on the ADO as well as the detachable Flipper coil (Cook, Bloomington, IN). PDA occlusion can be performed under deep seda-

tion or general endotracheal anesthesia, depending on patient age and preference of patient and/or parents. The transcatheter evaluation should include a basic left-and right-heart catheterization. Care should be taken to avoid inadvertently entering the PDA before angiographic evaluation can be completed, as this may trigger ductal spasm, thereby rendering any obtained angiographic measurements inaccurate. An aortogram is the most important evaluation of the PDA, and is obtained by placing an angiographic catheter (such as a pigtail catheter) just underneath the ductal ampulla, using biplane imaging with standard lateral projection as well as 30° right anterior oblique (RAO) projection. The imaging planes may have to be altered slightly in

each individual patient to best profile the PDA. Measurements should be obtained at the pulmonary arterial end and the aortic end, as well as for the total length of the PDA. The type of device or coil that is chosen for any specific PDA occlusion does not only depend on the size of the PDA, but also its shape. The majority of PDAs are classically cone-shaped (type A), while rarer varieties include PDAs that are short with a narrow aortic end (type B), tubular (type C), having multiple constrictions (type D), or elongated conical with a distant constriction (type E).13