A simple non-thrombogenic coating.
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Biomedical subjects
Publications and source records attributed to K Amplatz.
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A technique is described for potential use in the nonsurgical closure of patent ductus arteriosus. Occlusion is accomplished with an Ivalon umbrella, inserted via a catheter placed percutaneously into the femoral artery. The technique was tested in thirteen dogs with surgically created shunts closely simulating patent ductus arteriosus. In two cases, the Ivalon plug was undersize; and incomplete occlusion occurred, but without embolization of the plug. In one case, the umbrella emoblized due to improper positioning. Several dogs with successfully occluded ductus were observed from two weeks to six months postoperative. In all cases, the ductus remained closed. The technique has potential application in patients with a small and long patent ductus.
The reliable and safe production of myocardial infarction in closed-chest animals is of paramount research interest. To date, the injection of particulate matter and the introduction of occlusive solid plugs have been described. Because of the limited size of the catheter, only small branches could be occluded, which resulted in a high incidence of mortality. A new simple technique is described that allows occlusion of a major coronary artery at a preselected site. An Ivalon (polyvinyl alcohol) plug compressed around the tip of an introducing wire is advanced through a selectively placed catheter into the coronary artery. It is felt in place for 5 minutes and assumes its original size upon contact with blood. Once the plug is re-expanded, the wire is withdrawn. The new technique was carried out successfully on nine dogs with no immediate fatality and myocardial infarction as demonstrated by cine ventriculography and histopathologic examination.
Embolization of coils into the lungs has been reported following their use for the obliteration of large arteriovenous fistulas. So far, except for a recent report, they have not been used on the venous side of the circulation. Experimental studies at our institution demonstrated that the placement of coils on the venous side can result in embolization to the lungs, even when oversized coils are introduced. A simple, easy to perform modification of the standard stainless steel coils (Gianturco-Wallace-Chuang spring embolus and coilons) makes these devices safe embolic agents for used on the venous side of the circulation, as for example in the obliteration of spermatic veins.
Canine superficial extremity veins were examined grossly and microscopically in a double blind fashion for endothelial damage and phlebitis one hour and four days after the injection of ionic monomeric or dimeric, and non-ionic monomeric, 300 mg I/ml, contrast media. Superficial veins of all four extremities and the tail vein were injected with the same amounts of contrast medium after application of tourniquets for 20 minutes following the injections. Silver staining and prefixation of the veins were done in situ. The specimens were evaluated together with cross-sectioned, hematoxylin-eosin stained biopsies. On the basis of a randomized study of 77 dogs, endothelial damage or thrombosis caused by various contrast media as seen in man was not demonstrated. This may be due to species differences. It is postulated that canine endothelium may have a higher resistance to contrast medium injury than human endothelium.
The treatment of renal and ureteral stones has undergone rapid and major changes over the past ten years. Extracorporeal shockwave lithotripsy has become the most commonly used modality for the treatment of renal and upper ureteral stones. Lower ureteral stones are more commonly being approached by retrograde techniques. Percutaneous nephrolithotomy, medical therapy, and open surgical nephrolithotomy offer viable alternatives in given situations. Presented here is the current application of each of these techniques, both alone and in combination, for the treatment of urinary stones.
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The Amplatzer septal occluder is a new device intended for the percutaneous closure of secundum atrial septal defects that has distinctive characteristics and important advantages over other available devices. We present the first successful closure of an atrial septal defect with this device in Mexico in a 19 year old man with a 16 mm secundum type septal defect.