RESUMO
OBJECTIVES: The aim of this study was to explore the influence of the characteristics of Japanese patients on the long-term outcomes after aortic valve replacement with either mechanical or biological prostheses by means of a microsimulation. METHODS: A microsimulation model was used to simulate the lives of patients living in Japan and in the United States after aortic valve replacement. The background mortality data taken from the 21st complete life table of Japan and the bleeding hazard determined from a meta-analysis of long-term results in Japanese institutions were used to simulate Japanese patients. The life expectancy, event-free life expectancy, and lifetime risk of structural valve degeneration were calculated. A sensitivity analysis for various bleeding hazards was performed. RESULTS: Regarding the event-free life expectancy, the age crossover points between the two valve types were 64-65 and 57-58 years for Japanese and American patients, respectively. Regarding the life expectancy, the age crossover points were 88-89 and 64-65 years, respectively, for Japanese and American patients. The lifetime risk of structural valve degeneration was higher in Japanese patients than in American patients. The sensitivity analysis showed that the age crossover points were sensitive to the hazard of bleeding complications. CONCLUSIONS: The long-term clinical outcomes after aortic valve replacement were simulated with a microsimulation model. The results indicated that the age crossover points in the advantages and disadvantages between mechanical valves and bioprostheses may be higher in Japanese patients than in American subjects.
Assuntos
Bioprótese/efeitos adversos , Doenças das Valvas Cardíacas/cirurgia , Implante de Prótese de Valva Cardíaca/mortalidade , Próteses Valvulares Cardíacas/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Valva Aórtica/cirurgia , Simulação por Computador , Feminino , Doenças das Valvas Cardíacas/etnologia , Implante de Prótese de Valva Cardíaca/efeitos adversos , Humanos , Japão/etnologia , Expectativa de Vida/etnologia , Masculino , Pessoa de Meia-Idade , Método de Monte Carlo , Hemorragia Pós-Operatória/etnologia , Hemorragia Pós-Operatória/etiologia , Hemorragia Pós-Operatória/mortalidade , Reoperação/mortalidade , Resultado do Tratamento , Estados Unidos/etnologiaRESUMO
Skeletal muscle-derived stem cells (MDSCs) are able to differentiate into cardiomyocytes (CMs). However, it remains to be investigated whether differentiated CMs contract similar to native CMs. Here, we developed a three-dimensional collagen gel bioreactor (3DGB) that induces a working CM phenotype from MDSCs, and the contractile properties are directly measured as an engineered cardiac tissue. Neonate rat MDSCs were isolated from hind-leg muscles via the preplate technique. Isolated MDSCs were approximately 60% positive to Sca-1 and negative to CD34, CD45, or c-kit antigens. We sorted Sca-1(-) MDSCs and constructed MDSC-3DGBs by mixing MDSCs with acid soluble rat tail collagen type-I and matrix factors. MDSC-3DGB exhibited spontaneous cyclic contraction by culture day 7. MDSC-3DGB expressed cardiac-specific genes and proteins. Histological assessment revealed that cardiac-specific troponin-T and -I expressed in a typical striation pattern and connexin-43 was expressed similar to the native fetal ventricular papillary muscle. beta-Adrenergic stimulation increased MDSC-3DGB spontaneous beat frequency. MDSC-3DGB generated contractile force and intracellular calcium ion transients similar to engineered cardiac tissue from native cardiac cells. Results suggest that MDSC-3DGB induces a working CM phenotype in MDSCs and is a useful 3D culture system to directly assess the contractile properties of differentiated CMs in vitro.