Reconstituição da valva pulmonar e via de saída do ventrículo direito, com prótese bivalvular e prótese tubular valvada de tronco pulmonar de porco: estudo experimental e aplicação clínica

Maluf, Miguel Angel; Verde, José L; Leal, João Carlos Ferreira; Catani, Roberto; Garcia, H; Thevenard, Rubens S.; Carvalho, Antônio Carlos Camargo; Andrade, José L.; Andrade, José Carlos S; Braile, Domingo Marcolino; Leão, Luiz Eduardo Villaça; Buffolo, Ênio

doi:10.1590/s0102-76381993000100003

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…The gradient increase in sheep with lyophilized valves suggests that there are changes resulting in lyophilized valve replacement, as seen in the results of in vitro tests. There are references that RV-PA from 10 to 15 mm Hg are acceptable, resulting in satisfactory performance of the pulmonary valve (15,16). Comparing the gradients immediately after implantation of the lyophilized prosthesis presents similar gradient to the nonlyophilized prosthesis after 3 months of implantation when they exhibited stiff and deformed leaflets due to calcification ( Fig.…”

Section: Discussion Of In Vivo Resultsmentioning

confidence: 90%

In Vitro and In Vivo Evaluation of Lyophilized Bioprosthetic Valve

et al. 2011

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Freeze-drying of biological tissues allows for dry storage and gamma ray sterilization, which may improve their use as a medical prosthesis. The objective of this study was to evaluate the rehydration characteristics and hydrodynamic performance of prosthetic valves before and after lyophilization. Two size 23 bovine pericardium aortic valve prostheses from different manufacturers were evaluated in a Shelhigh (Union, NJ, USA) pulse duplicator (80 ppm, 5 L/min) before and after lyophilization. Flow and transvalvular pressure gradient were registered in vitro and in vivo, and images of opening and closing of the prosthesis were obtained in the pulse duplicator in a digital camera. Rehydration was evaluated by comparison of dry valve weight with valve weight after 15 min, and 1, 24, 48, and 72 h in saline solution, inside the pulse duplicator. In vivo performance was assessed by surgical implantation in Santa Inês young male sheep in the pulmonary position after 30 min rehydration with 0.9% saline. Transvalvular pressure gradient and flow measurements were obtained immediately after implantation and 3 months after surgery when valves were explanted. Captured images showed a change in the profile opening and closing of valve prosthesis after lyophilization. The gradient measured (in vitro) in two valves was 17.08 ± 0.57 and 18.76 ± 0.70 mm Hg before lyophilization, and 34.24 ± 0.59 and 30.40 ± 0.97 mm Hg after lyophilization. Rehydration of both lyophilized valves was approximately 82%. Drying changed the profile of the opening and closing of valve prostheses, and increased on average by 83% the gradient in vitro tests. The result of the in vivo tests suggests maintaining pressure levels of the animal with the lyophilized prostheses within acceptable levels.

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Section: Discussion Of In Vivo Resultsmentioning

confidence: 90%

In Vitro and In Vivo Evaluation of Lyophilized Bioprosthetic Valve

et al. 2011

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“…This suggests that 30 min of rehydration were not sufficient for complete hydration of the BP valves, causing increased rigidity in their leaflets during the initial phase, resulting in a significant difference between the two groups (P < 0.05) and possibly causing other changes in the lyophilized valvular prostheses as seen in the results of in vitro assays (20). There are, however, references that report RV/AP gradients of 10-15 mm Hg with acceptable and satisfactory performance of the pulmonary valve (21,22). After 3 months, when the valve prostheses had suffered structural damage and were stiff due to calcification, the gradients of the two groups were equivalent (P > 0.05), suggesting that the hydration process in lyophilized valves continues hours after implantation.…”

Section: Lyophilized Groupmentioning

confidence: 99%

Behavior of Lyophilized Biological Valves in a Chronic Animal Model

et al. 2013

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Glutaraldehyde is used in order to improve the mechanical and immunogenic properties of biological tissues, such as bovine pericardium membranes, used to manufacture heart valve bioprostheses. Lyophilization, also known as freeze-drying, preserves biological material without damage by freezing the water content and removing ice by sublimation. Through this process, dehydrated products of high quality may be obtained; also, the material may be easily handled. The lyophilization process reduces aldehyde residues in biological tissue previously treated with glutaraldehyde, thus promoting reduction of cytotoxicity, increasing resistance to inflammation, and possibly decreasing the potential for tissue calcification. The objective of this study was to chronically evaluate the calcification of bovine pericardium heart valve prostheses, previously lyophilized or not, in an animal model. Six-month-old sheep received implants of lyophilized and unlyophilized heart valve prostheses in the pulmonary position with right bypass. The study followed 16 animals for a period of 90 days. Right ventricle-pulmonary artery (RV/PA) transvalvular pressure gradient was evaluated before and immediately after implantation and before explantation, as were tissue calcium, inflammation intensity, and thrombosis and pannus formation. The t-test was used for statistical analysis. Twelve animals survived to the end of the experiment, but one of the animals in the control group had endocarditis and was excluded from the data. Four animals died early. The mean RV/PA gradient on implantation was 2.0 ± 1.6 mm Hg in the control group and 6.2 ± 4.1 mm Hg in the lyophilized group (P = 0.064). This mean gradient increased at explantation to 7.7 ± 3.9 mm Hg and 8.6 ± 5.8 mm Hg, respectively (P = 0.777). The average calcium content in the tissue leaflets after 3 months was 21.6 ± 39.1 mg Ca(2+)/g dry weight in the control group, compared with an average content of 41.2 ± 46.9 mg Ca(2+)/g dry weight in the lyophilized group (P = 0.478). In this experimental study there was no reduction of calcification after lyophilization. However, histological analysis showed less inflammation over the lyophilized tissue when compared with the control.

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“…Thus, swine have been widely used as a comparative model in recent years due to the anatomical and physiological similarities, both in normal and pathological conditions and in studies on acute heart failure (Santos et al 2012), atherosclerosis (Artinger et al 2009), valvular problems (Maluf et al 1993, Grehan et al 2000 and ventricular function (Hendry 1994).…”

Section: Introductionmentioning

confidence: 99%

Patterns of arterial vascularization in swine hearts

et al. 2016

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This study aimed to characterize the patterns of arterial vascularization in swine hearts. Ninety swine hearts were submitted to the Spalteholz diaphanization technique in order to dissect the coronary arteries. Three types of arterial vascularization patterns were characterized through the behaviorof the rami circumflexus and interventricularis, namely: balanced, right and left types. The balanced pattern was the most frequently (42.2%); in this case, the rami circumflexus and interventricularis occupied their respective sulci. The right type (40%) was further categorized into three vascularization subtypes. In the first, ramus circumflexus dexter branched from the ramus interventricularis subsinuosus. In the second, the arteria coronaria dextra branched from ramus interventricularis subsinuosus and ramus circumflexus. In the third model, arteria coronaria sinister branched from ramus interventricularis paraconalis. The left type (17.7%) exhibited two subtypes. In the first, ramus interventricularis paraconalis ran through the entire corresponding sulcus and the ventral third of sulcus interventricularis subsinuosus, and ramus interventricularis subsinuosus occupied the dorsal and middle third of its respective sulcus. In the second, ramus interventricularis subsinuosus branched from arteria coronaria dextra and ran through the dorsal and medium thirds of its respective sulcus, and the ventral third was occupied by the collateral branch of ramus circumflexus sinister. Our results reinforce the thesis that the blood distribution system through the coronary artery in swine is similar to human, not only in qualitative but also by a quantitative comparison.INDEX TERMS: Heart, cardiovascular system, coronary circulation, swine, animal models.

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Reconstituição da valva pulmonar e via de saída do ventrículo direito, com prótese bivalvular e prótese tubular valvada de tronco pulmonar de porco: estudo experimental e aplicação clínica

Cited by 4 publications

References 17 publications

In Vitro and In Vivo Evaluation of Lyophilized Bioprosthetic Valve

In Vitro and In Vivo Evaluation of Lyophilized Bioprosthetic Valve

Behavior of Lyophilized Biological Valves in a Chronic Animal Model

Patterns of arterial vascularization in swine hearts

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