Occlusive plug

Sharafuddin M, Gu X, Umess M et al (1999) The Niti-nol vascular occlusion plug preliminary experimental evaluation in peripheral veins. J Vase Intervent Radiol 10 23-27... 

A variety of Amplatzer devices are applicable for LAA occlusion including the atrial and ventricular septal defect devices, the patent foramen ovale devices, the patent ductus arteriosus devices, and other arteriovenous fistulae devices. A special fabric-free LAA plug is currently under investigation (Rg. 2). 

Other materials are also available for patients deemed suitable for more permanent occlusion. Form Fit intracanalicular plugs (OASIS) are made of hydrogel material that once inserted into the vertical canaliculus and exposed to tears expands to form a gelatinous plug. The SmartPLUG (Medennium) also expands into a gelatinous plug after insertion into the canaliculus. Instead of hydration, body temperature conforms the thermodynamic acrylic polymer to the puncta. 

Lacrimal occlusion can benefit patients who have symptoms of dryness or other ocular abnormalities that topical therapy alone does not resolve. The procedures are indicated in moderately severe to severe dry eye patients to prevent drainage and thereby conserve natural tears as well as instilled tear substitutes, reducing the frequency of application. Lacrimal occlusion also can improve contact lens tolerance in mild dry eye cases. Various studies have demonstrated that plugs may increase the aqueous tear component of the tear film, decrease corneal and conjunctival staining, and improve patient symptoms. Tear osmolarity decreases, probably due to increased tear volume. 

Although rare, punctal occlusion can lead to epiphora, rupture of the punctal ring, pruritus, or canaUcuUtis. Pyogenic granulomas, in response to the presence of silicone plugs, have also been reported in a few patients. 

Balaram M, Schaumberg DA, Dana MR. Efficacy and tolerability outcomes after punctual occlusion with silicone plugs in dry eye syndrome.AmJ Ophthalmol 2001 131 30-36. 

Tear Preservation. Occlusion of the lacrimal puncta, either temporarily or permanently, is one method of preserving tears that are available. Lacrimal plugs are available in diagnostic (dissolvable collagen) or reversible... 

Darsun D, Ertan A, Bhezikei B, et al. Ocular surface changes in keratoconjunctivitis sicca with shicone punctum plug occlusion. Curr Eye Res 2003 26 263-269. 

Occlusive vascular disease is a major cause of morbidity and mortality.There is now better understanding of the mechanisms by which the haemostatic system ensures blood remains fluid within vessels, yet forms a solid plug when a vessel is breached, and of the ways in which haemostasis may be altered by drugs to prevent or reverse (lyse) pathological thrombosis. 

Formation of a hemostatic plug or a red thrombosis (fibrin and entrapped red blood cells) at a site at which there is no injury produces occlusion. Death to the surrounding tissues can occur (infarction), or pieces of the thrombus may be tom away and moved to the lungs, producing pulmonary embolism. Such dysfunction of the hemostatic system is generally not attributable to a single cause. For example, heterozygous individuals with half of the normal amount of protein C do not necessarily present with... 

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