Utilização do pericárdio de avestruz na aortoplastia em coelhos: avalição dopplerfluxométrica e estrutural

Abstract

The use of biological membranes in vascular surgery has been used on a large scale in veterinary and human medicine. The objectives of this study were to evaluate the hemodynamic, morphometric and ultrastructural patterns of the abdominal aorta region of rabbits, where the pericardium of ostrich was implanted. The replacement of tissues or organs in animals or in humans is a great challenge to be overcome by the current surgery. This replacement is indicated when loss of anatomical structure occurs. Many materials have been tested and are used for this purpose, whether synthetic or biological. The bovine pericardium is the most researched and employed material in implants and to make prosthesis due to its features: easy acquisition, low cost and by possessing a thick resistant layer of collagen and elastic fibers that intersect at various angles. In this project, fragments of ostrich pericardium, treated and preserved in a 0.5% glutaraldehyde solution will be used and implanted in the abdominal portion of rabbits’ aorta. Two groups will be established: Group I (control), group II (ostrich pericardium). The rabbits of Group II will be submitted to standard anesthetic Protocol and celiotomy to aorta where an incision of about 1 cm and aortoplasty using ostrich pericardium fragment with adhesive or surgical suture thread will be made. The animals was also be evaluated by Doppler for characterization of morphometric and arterial hemodynamic parameters. We used a Sonosite Titan, with linear multifrequency transducer.After completing the different healing times (7, 14 and 21 days) the animals from Group I and II was submitted to assisted death through overdose of intravenous thiopental sodium and necropsied to collect fragments of aorta (in Group II, where the implants were made). The fragments was cleaved across and fixed in a 10% buffered formaldehyde solution. All incisions will be processed to be included into paraffin following the histological technique routine, stained by histological and histochemical techniques and. The aorta of animals submitted to the implant with the pericardium of ostrich had a strong inflammatory reaction in the portion facing the vessel lumen on the 7th day, as well as a disorganization of inner and median layers. In addition, the pericardium remained healthy without blood extravasation. On the 14th day, the reorganization of inner and median layer was observed and there were still regions with inflammatory cells. The pericardium has remained healthy. On the 21st day, the aorta had its layers already consolidated. In the abdominal aortic artery was seen a laminar flow profile. The diameter of the aorta varied between 0.31 and 0.54 centimeters. The mean 0.431 ± 0.030 in group I, 0.404 ± 0.100 in group II, 0.408 ± 0.008 in group III, in group IV was 0.431 ± 0.006 (p = 0.2095). The thickness of the aorta varied between 0,10 and 0,29 centimeters The mean and standard deviation were the 0.107 ± 0.011 in group I, 0.105 ± 0.007 in group II, 0.108 ± 0.008 in group III and 0.121 ± 0.006 in group IV (p <0.0105). The velocity of the systolic peak varied between 32.5 and 71.4 centimeters per second. The mean and standard deviation 49.44 ± 2.260 in group I, 67.49 ± 3.128 in group II, 35.07 ± 0.657 in group III and 31.50 ± 1.190 group IV (p <0.0001). The velocity of the diastolic peak ranged from 7.21 to 17.3 centimeters per second, mean and standard deviation 8.264 ± 0.292 in group I, 16.07 ± 0.680 in group II , 7.090 ± 0.1712 in group III and 10.37 ± 0.427 group IV (p <0.0001). The systole diastole ratio varied between 2.0 and 4.90 the mean and the standard deviation 4.263 ± 1.042 in group I, 2.854 ± 1.153 in group II, 3.890 ± 1.017 in group III and 3,201 ± 0,171 group IV (p = 0.0376). The resistivity index ranged from 0.43 to 0.80 the mean and the standard deviation 0.742 ± 0.061 in group I, 0.612 ± 0.131 in group II, 0.620 ± 0.100 in group III and 0.635 ± 0.033 in group IV (p = 0.0416). The pulsatility index ranged from 1.15 to 1.32 and the mean and standard deviation 1.289 ± 0.159 in group I, 1.159 ± 0.029 in group II 1.311 ± 0.026 in , group III and 1.333 ± 0.014in group IV (p = 0.0025). Aortoplasty using ostrich pericardium with fixation by surgical glue was totally feasible and safe. The ostrich pericardium graft with surgical glue promoted optimal fixation of the pericardium implant, did not present deformation of its structure, not resulting in aneurysmal dilatation, nor hemorrhage at the site of the graft.