Abstract:Since 1978 the definition of prosthesis-patient mismatch（PPM） was first introduced by Rahimtoola, it has attracted the attention of foreign researchers. The PPM phenomenon is concerned to be an important factor which will affect patients＇ survival rate and quality of life. Till now, a lot of effort should still be put on this problem. But unfortunately, this problem is still being neglected in our country. This paper is a review of PPM from it＇s many aspects, such as definition, current research status, prevention, and it＇s research prospect. We hope this paper will intensify the clinicians＇ knowledge on PPM.
Technical advances both in cardiac surgery and relating to anesthesia,cardiopulmonary bypass and myocardial protection have significantly improved the prognosis for patients combined with coronary heart disease and heart valve disease. In addition to technology, variable factors that affect operative survival following combined operation include the severity of valvular disease, the number of coronary vessels affected, impairment of left ventricular function and both age and gender differences. In this article, we review the outcome of surgical intervention for heart valve disease combined with coronary heart disease and discuss future prospects in this field.
Objective To observe the expression of integrin αVβ3 in vascular endothelium cultured in vitro at different time points under different level of shear stress. Methods（1）We established a vascular culture system in vitro which could provide steady flow with different level of shear stress, and tested the flow stability when loading different level of shear stress. （2） A total of 50 rabbits were randomly divided into low shear stress group （5 dyn/cm2, n=25）and normal shear stress group（20 dyn/cm2, n=25）. Rabbits in each group were further randomly divided into five different time points as 2 h, 4 h, 8 h, 16 h and 24 h（n=5 at each time point）. The descending aorta of rabbits were harvested and cultured in the vascular culture system in vitro under different level of shear stress. The expression sites and intensity of αVβ3-Integrin in vascular endothelium were examined at 5 different time points in both groups by immunohistochemical staining. Results The vascular culture system in vitro was stable in providing laminar flow with different level of shear stress required for the experiment. Vascular endothelium expressions of αVβ3-Integrin in the low shear stress group were in high level at all the 5 time points and reached its summit at 16 h, when the mean optical density（MOD）value was （1.995±0.194）×10-2. In the normal shear stress group, the MOD value decreased time-dependently at the 5 time points. The MOD values at 2 h （0.059±0.005）×10-2 and 4 h（0. 049±0.002）×10-2 were significantly higher than those at other time points （P＜ 0.05）. The αVβ3-Integrin MOD values of the low shear stress group were significantly higher than those of the normal shear stress group at all the 5 respective time points （P=0.000）. Conclusion Low shear stress can significantly promote the expression of αVβ3-Integrin while normal shear stress decreases the expression of αVβ3-Integrin in vascular endothelium cultured in vitro.
Objective To investigate the expression of transcription factors including nuclear factor-κB （NF-κB） and activator protein-1 （AP-1） in vascular endothelial cells （ECs） in different flow fields， and provide experimental evidence for mechanical signal effects on gene regulation pattern of ECs. Methods Cultured human umbilical vein ECs were loaded into steady flow chambers of laminar flow or turbulent flow and observed at 6 time points （0.5 h， 1 h， 2 h， 3 h， 4 h and 5 h） based on different load time. Spacial and temporal characteristics of NF-κB and AP-1 expression in ECs in different flow chambers were detected at a protein level by laser confocal microscope. Results In laminar flow， NF-κB expression rose to peak at 1 hour （26.49±1.63， P＜0.05）and then declined. In turbulent flow， NF-κB expression rose to peak at 3 hours （34.41±6.43， P＜0.05）. In laminar flow， c-Jun/AP-1 expression was transiently elevated， reached its peak at 0.5 hour （18.95±5.38，P＜0.05）and then fell to its baseline level. In turbulent flow， c-Jun/AP-1 expression rose slowly but steady to peak（P＜0.05） . Conclusion The effects of turbulent flow on NF-κB and AP-1 expression in ECs are different from those of laminar flow. Up-regulation and activation of NF-κB and AP-1 expression in ECs induced by turbulent flow may cause pathological changes in morphological structure and functional behavior of ECs.