Self-Expandable Nitinol Stent Placement in Homocysteinemic Porcine Aorta

Abstract

França LHG, Pereira AH, Perini SC. Self-expandable nitinol stent placement in homocysteinemic porcine aorta. Clinics. 2008;63:229-36. PURPOSE:To compare aortic intimal thickening of normal and hyperhomocysteinemic pigs (induced with a methionine-rich diet) following placement of a self-expanding nitinol stent. METHODS: Eighteen Macau pigs were used. They were older than eight weeks in age and had an average weight of 30 kg. Pigs were randomly divided into two groups. The first, Group C (control), was fed a regular diet, and the second group, Group M, was fed a methionine-rich diet for 30 days to induce hyperhomocysteinemia. The self-expandable nitinol stents were 25mm in length and 8 mm in diameter after expansion. Blood samples were collected to measure total cholesterol, triglycerides, HDL and homocysteine concentrations. All animals were subjected to angiography. Thirty days after the procedure, the animals were sacrificed, and the abdominal aorta was removed for histological and digital morphometry analysis. RESULTS: Under microscopic evaluation, the intima was significantly thicker in Group C than in Group M. When groups were compared by digital morphometric analysis, intimal thickening of the vessel wall was higher in Group C than in Group M. There was no significant change in total cholesterol, triglycerides or HDL concentrations in either group. In group C the levels of plasma homocysteine ranged from 14,40 to 16,73µmol/l; in Group M, plasma homocysteine levels ranged from 17.47 to 59.80 µmol/l after 30 days of a methionine-rich diet. CONCLUSION: Compared to normal pigs, less intimal hyperplasia was observed in the abdominal aortas of hyperhomocysteinemic pigs thirty days after the insertion of a self-expandable nitinol stent.

Histological analysis of cobalt–chromium stents with and without Camouflage® polymer coating: experimental porcine carotid artery model

“…Extrapolation of results to human beings is limited, as there were no stenotic lesions or pre-existing occlusions associated with the presence of atherosclerotic plaques. At the same time, as observed by França et al , 37 intimal hyperplasia in pigs developed after stent implantation whether their diet was normal or atherogenic. 37 It is well defined that the peak of intimal hyperplasia varies with the species: for example, 28 days in pigs and 6–12 months in humans.…”

“…At the same time, as observed by França et al , 37 intimal hyperplasia in pigs developed after stent implantation whether their diet was normal or atherogenic. 37 It is well defined that the peak of intimal hyperplasia varies with the species: for example, 28 days in pigs and 6–12 months in humans. 38 As the objective of this study was to assess vascular wall response to two stents whose only difference was the presence or not of a polymer coating, the animal model was chosen.…”

Análise morfométrica da carótida de suínos submetidos a angioplastia com ou sem implante de stent de cromo-cobalto

“…Dietary lipid supplementation of laboratory animals induces the formation of vulnerable atherosclerotic plaques, 18 but subsequent intimal hyperplasia and restenosis are similar to those occurring in animals fed a normal diet. 19 The use of an atherogenic diet thus appears to provide no advantage in porcine animal models of restenosis.…”

Effect of cilostazol on neointimal hyperplasia in iliac arteries of pigs after transluminal angioplasty

“…Extrapolation of the data is limited, since in the clinical setting the treated arteries present with atherosclerotic stenoses or occlusions. The adoption of an atherogenic diet does not appear to enhance neointimal hyperplasia in response to vascular wall injury in the porcine model 26 . The cilostazol dose of 50mg twice daily used in this study is similar to the maximum dose used in adults, and there were no adverse effects or change in behavioral pattern in treated pigs.…”