Biomedical subjects
L A de Sousa
Publications and source records attributed to L A de Sousa.
Cost problems in an African country.
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Technology in Portugal, the European community, and developing countries.
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Microangiographic aspects of the ureter.
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Vascularization of the parietal pleura. Experimental study.
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Vasa vasorum changes following stent placement in experimental arterial stenoses.
PURPOSE: Experimental stenoses were created in canine aortae to compare the effects of stent placement and balloon angioplasty on the vasa vasorum. MATERIALS AND METHODS: A balloon-expandable Palmaz stent was placed in the proximal stenosis, and angioplasty was performed in the distal stenosis in each of eight dogs. Two dogs were killed at 4, 8, 12, and 18 months, respectively. Specimens were studied by means of microangiography, histology, scanning electronic microscopy, and Spalteholz technique. RESULTS: At up to 12 months, there was proliferation of the vasa vasorum and a rich plexus formed in each of the animals at each treated site. More vasa vasorum were seen after stent placement than after angioplasty. The new vessels were mainly venules located in the media. At 18 months, there was regression of the venules and the vasa vasorum distribution returned to baseline. CONCLUSION: The authors conclude that the effects of stents on the vasa vasorum are temporary.
Changes in the vasa vasorum following percutaneous transluminal angioplasty in a canine model of aortic stenosis.
PURPOSE: To investigate the effects of percutaneous transluminal angioplasty on the vasa vasorum in dogs with experimentally created abdominal aortic stenoses. MATERIALS AND METHODS: Two stenoses were created in the abdominal aorta in each of 21 dogs. After 6 weeks, the more cephalic stenosis was dilated; the other stenosis served as an untreated control. Groups of three dogs were killed at 24 hours, 3 and 6 weeks, and 4, 8, 12, and 18 months after angioplasty. The aortae were studied by means of histologic examination, microangiography, scanning electron microscopy, and the Spalteholz technique. RESULTS: At nondilated stenoses, the vasa vasorum was interrupted in the outer adventitia and unchanged in the outer media. At dilated stenoses, the number of precapillary arterioles in the outer media progressively increased up to 8 months; thereafter, the number of precapillary arterioles began to decrease. At 18 months, the number was normal. CONCLUSION: Angioplasty brings about changes in the number of precapillary arterioles in the outer media of the aorta in our canine model of focal abdominal aortic stenosis.