PURPOSE: To evaluate, by digital morphometry, the intimal thickening after the placement of two different kinds of stents: polyester covered stainless steel stents (Dacron) and non-covered stents implanted in young pigs' infrarenal aortas. METHODS: The experiment was carried out on two separate groups of pigs. Eight polyester-covered stainless steel stents (Dacron) and eight stainless steel stents (30-mm long, 8-mm diameter) were deployed through extraperitoneal approach in the normal infrarenal aorta of 16 normolipemic pigs. To allow the passage of the delivery system, a small arteriotomy was performed (phase I). After four weeks, the aorta with the stent was removed en bloc. (phase II). The values of the hematimetric and lipid analysis did not show any changes that could influence the study. Tissue samples of the fixing sites (proximal and distal) of the stents were taken. Microscope slices were prepared and submitted to Verhoeff's hematoxilin and eosin techniques and sent to morphometric analysis. RESULTS: The intima immediately proximal to the device was thicker in the group of covered stents with marginal significance (p=0.054). The distal intimal layer (p=0.185), proximal medial layer of the proximal portion (p=0.141) and distal portion (p=0.375) did not present statistical difference between the two groups. CONCLUSIONS: Patency was 100% in both groups of these normolipemic pigs. After four weeks the intimal layer immediately proximal to the covered stents was ticker when compared to uncovered stents, but this had a borderline significance. The intimal layer distal to covered stents and the media proximal or distal to the devices had similar morphometric features when covered and uncovered stents where compared.

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Background Diagnosis of the etiologic agent of endoprosthesis infections is essential to enable treatment, since these infections constitute important complications of endovascular procedures. Sonication of explanted tissue and materials is a technique that can be used to facilitate detection of biofilm-producing bacteria. Objectives To evaluate infection of pigs' aortas after implantation of nitinol stents coated with polytetrafluoroethylene (ePTFE) or Dacron, previously infected with biofilm-producing Staphylococcus epidermidis. Intimal thickening and the inflammatory response in the aortic wall were also evaluated. Methods 11 ePTFE-coated nitinol stents and 10 Dacron stents infected with S. epidermidis strains were implanted in the infrarenal aorta of 21 8-week-old pigs. After 2 weeks, the aorta containing the stents was removed. A vortex mixer and ultrasound were used to homogenize the samples and remove the biofilm. Subsequently, the number of colony-forming units was counted. Results There were no significant differences between the two groups in terms of the number of colony-forming units or of inflammation in the arterial wall. With the exception of one specimen from the Dacron group, all aortic stent cultures were positive for S. epidermidis. Conclusions There were no significant differences in the inflammatory response or infection rate between ePTFE and Dacron-coated stents actively infected with biofilm-producing S. epidermidis. Intimal thickening and the inflammatory response to infection of endoprostheses were similar. These results suggest that the two most widely used stent lining materials have a similar infection rate.

SUMMARY OBJECTIVE To investigate the association between low serum vitamin D levels and peripheral arterial disease (PAD). METHODS A cross-sectional study with a consecutive sample of 133 individuals from Caxias do Sul, Brasil. We considered PAD patients those with an ankle-brachial index (ABI) ≤ 0.90 or with arterial revascularization. Vitamin D serum level was categorized as sufficient (≥30 ng/mL), insufficient (>20 to 29 ng/mL), and deficient (<20 ng/mL). Prevalence ratios (RP) were calculated through Poisson regression. RESULTS The prevalence of PAD was 50.7% (95% CI 42-59). After adjustment for potential PAD risk factors, RP were 1.08 (95% CI 0.66-1.76) for insufficient serum level and 1.57 (95% CI 0.96-2.57) for deficient vitamin D serum level; (p for trend = 0.020). CONCLUSION Vitamin D serum levels showed an inverse and significant dose-response relationship with PAD.

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