Traditional Repair Methods

Electrochemical chloride extraction and electrochemical realkalisation have been proposed as an alternative to traditional repair methods for the rehabilitation of chloride-contaminated or carbonated structures. Due to increasing field experience... 

The traditional surgical repair method for ASD is a full sternotomy (open heart surgery), where the hole is either stitched closed or sealed using a synthetic patch or the patient s own pericardium, which forms the fluid-filled sac surrounding the heart. Typically, the synthetic patches are made of either polyester (polyethylene terephthalate) (Dacron ) or expanded poly-tetrafluoroethylene (ePTFE) (Goretex ) fabric. TTiis method is still used in severe cases of ASD. °... 

However, most internal repair methods are used for low operating pressure pipelines and only to restore leak tightness (Toutanji and Dempsey, 2001). Also, these internal repair systems are considered to cause reductions in the inside diameter of pipelines that may hinder the ability to clean and inspect them using traditional tools. Thus, the use of composite materials for internal repair of pipes presents a number of difficulties that have yet to be fully explored. 

Congenital heart disease (CHD) occurs in approximately 25 000 births per year in the United States. An atrial septal defect (ASD) is a spedfic form of CHD and is the third most common type of defect. Many people suffer from this disorder and in many cases it is only detected when the patient reaches middle age. Effective and efficient methods of repair are therefore needed to minimize the risks associated with traditional methods of ASD repair. In recent years, transcatheter closure methods for secundum type ASD have been developed. Currently the Amplatzer Septal Occluder, the Gore Helex Septal Occluder and the NMT Medical CardioSEAL-STARFiex Septal Occlusion systems have received FDA approval for ASD repair, the first of these only in 2001. This indicates that the use of these devices is still in its infancy. It can therefore be assumed that much more can be done to develop improved and more effective closure devices. It is the purpose of this chapter to describe ASDs and to outline the available technology with regard to transcatheter ASD repair devices. Hie discussion will centre around their construction and functioning, with special reference to their textile component. 

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