INTRODUCTION: Often, studies on aortic prosthetic valves analyze their performance not at the primitive position, but using tricuspid and mitral ones or inserting it in the descending aortic area. Taking that into account, it would be relevant to observe results in those studies in which the conclusions are based on their original implantation. MATERIAL AND METHODS: Thirty young sheep, 28 males and 2 females, were operated on. Ages ranged 4.4 to 6.3 months and weights 25 to 37 Kg. Extra corporeal circulation (ECC) was applied to all the animals, always guided by the conventional criteria, that is to say, the arterial cannula was inserted in the thoracic aorta just past the arterious ducts and the venous cannulae, a single one, was placed in the right atrium. The operation was performed according to the principle of moderately low body temperature- 29ºC- and cold cristalloid cardioplegia, in the aortic root, to induce; but otherwise was utilized blood to the maintenance. Following with the technique proposed, the aortic valve of the animal heart was completely excised and finally implanted the valved tube stentless, not forgetting the refixation of the coronary main. The sheep were kept in clinical and laboratorial observation during thirty days in what was included a echocardiogram in the end. RESULTS: The results demonstrated 8 intraoperatory deaths (26.6%), and 6 during the following (27.7%). The mean time of ECC was 98 minutes. The dimension of the majority prothetics valves were 21 and 23. Only two valves evoluted with mild insufficiency, none denoted evidences of the endocarditis neither of leaflets perfuration, the mean fraction of ejection was 74%, the left ventricle had its wall preserved in all cases. CONCLUSION: This experimental model can certainly reproduce nearly the reality, confirming good parameters of prothetics stentless evaluation in the aortic position. And the sheep declared itself to be pleasant, which helps us its control during the whole study.
Aortic valve; Blood vessel prosthesis, implantation; Bioprosthesis
