RESUMO
The development of the prosthetic heart valve has led to the evolution of cardiac intensive care units, a better understanding of cardiac function and biocompatible materials, and new surgical procedures. Initial efforts with formaldehyde-fixed valves did not have long-term success. They led to the development of the stabilized glutaraldehyde process (SGP) valve and the flexible stent. The safety and efficacy of a heart valve bioprosthesis has been demonstrated through laboratory and animal experiments. Data on long-term clinical implants are needed to validate the results of these experiments.
Assuntos
Próteses Valvulares Cardíacas/métodos , Valvas Cardíacas/transplante , Animais , Glutaral , Humanos , Suínos , Preservação de Tecido , Transplante HeterólogoRESUMO
The low mortality of isolated mitral valve (MV) replacement permits attention to be focused on those valve-related factors which affect the quality of life after operation. Comparison of a number of MV prostheses indicates that all perform satisfactorily from the hemodynamic standpoint. An asset of the "stabilized glutaraldehyde process" (SGP) Hancock bioprosthesis (H-B) is the significantly lower incidence of thromboembolism encountered in patients who have not been permanently anticoagulated. While additional time is required before meaningful durability comparisons can be made, the absence of valve failure and the low incidence of tissue dysfunction in H-B over 6 1/2 years is encouraging. Although the ideal device for replacing the MV is not yet available, the Hancock SGP bioprostheses represent the best compromise of available choices.
Assuntos
Aldeídos , Glutaral , Próteses Valvulares Cardíacas , Insuficiência da Valva Mitral/cirurgia , Estenose da Valva Mitral/cirurgia , Valva Mitral/cirurgia , Coagulação Sanguínea , Pressão Sanguínea , Estudos de Avaliação como Assunto , Frequência Cardíaca , Próteses Valvulares Cardíacas/efeitos adversos , Humanos , Valva Mitral/citologia , Tromboembolia/etiologia , Fatores de TempoRESUMO
From March 1971 through April 1975, one hundred twenty patients underwent mitral valve replacement with a Hancock "stabilized glutaraldehyde process" porcine aortic xenograft. A simultaneous canine experimental series was also carried out. In the clinical series, the early mortality was 8.3%. Actuarial analyses of all patients predicts survival at two years of 81.0% and at four years of 70.0%. The predicted survival for patients without coronary disease or prior prosthetic valve replacement is 87.5% at two years and 77.5% at four years. There were four thromboembolic episodes, a rate of 2.4% per patient-year. None were fatal. No valve failure were noted. Histologic examination and shrink temperature analysis of recovered valves show excellent tissue preservation at 40 months. The data indicate that the Hancock valve is durable, enjoys a low incidence of thromboembolism, and may be the valve of choice for mitral valve replacement.
Assuntos
Aldeídos , Valva Aórtica/transplante , Glutaral , Valva Mitral/cirurgia , Transplante Heterólogo , Adulto , Idoso , Animais , Encefalopatias/induzido quimicamente , Procedimentos Cirúrgicos Cardíacos/mortalidade , Doença das Coronárias/complicações , Cães , Endocardite Bacteriana/etiologia , Estudos de Avaliação como Assunto , Feminino , Hemorragia Gastrointestinal/induzido quimicamente , Hematoma/induzido quimicamente , Humanos , Masculino , Métodos , Pessoa de Meia-Idade , Insuficiência da Valva Mitral/cirurgia , Estenose da Valva Mitral/cirurgia , Complicações Pós-Operatórias , Suínos , Tromboembolia/etiologia , Tromboflebite/prevenção & controle , Varfarina/efeitos adversos , Varfarina/uso terapêuticoRESUMO
Collagen from the cardiovascular system is extremely resistant to proteolytic digestion, in contrast with the proteoglycans of these connective tissues. In particular this is true for the heart valves, which contain the largest proportion of collagen. The tensile strength of aortic tissue incubated at 37 degrees C declines rapidly unless fixed with aldehydes. Stabilized glutaraldehyde gives rise to the most stable form of cross-link and renders the tissue structurally intact after more than 4 years of incubation at 37 degrees C in physiological solution. Formaldehyde, on the other hand, gives rise to transcient cross-links.
