1.Improving Hemocompatibility Of Left Ventricle Assistant Devices By Surface Modification 2.A Observational Study For Improving Clinic Outcomes Of Female Patients After Coronary Artery Bypass Graft Surgery

Long-term and short-term support with a left ventricular assist device resulted in substantial improvement in survival in patients with severe heart failure.Despite the substantial survival benefit,the morbidity and mortality associated with the use of the left ventricular assist device were considerable.The adverse events such as infection,bleeding, thromboembolic events,stroke,mechanical failure,etc.remain major challenges for left ventricular assist device that are used in contact with blood.In particular,bleeding and thromboembolic events were major factors in the early survival rate of patients.The rate of thromboembolic events was more than 30%percent in the early reports.Therefore,there is still a great need for improving hemocompatibility of left ventricular assist device.Surface modification is a very effective way to improve blood compatibility of a material as well as maintain its required bulk properties. The surface modification for improving blood compatibility is the direction of the present research.The aim of the present investigation was to evaluate whether ZrN films show sufficient hemocompatibility,and to find out which kind of material is the most effective surface mofidication among Titanium oxide films(TiO),diamond-like carbon(DLC) and 2-Methacryloyloxyethyl phosphorylcholine(MPC).Because of their biocompatibility and extremely wear resistant,zirconium nitride(ZrN) films are usually used for industrial products and dental implants.Previous in vitro studies have shown that Ti implant surfaces coated with TiN or ZrN reduce bacterial colonization compared with other clinically used implant surfaces.All above characters of ZrN films indicate their suitability as materials for implants and biomedical devices with direct blood contact,such as blood pumps.The morphology,chemical compound of composition and crystal structure were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS).Surface energy and interface tension were calculated by contact angle measurements.Comprehensive evaluation of the hemocompatibility of ZrN films included clotting time,platelet adhesion and activation,protein adsorption,and in vivo experiment.The adsorption of fibrinogen to the surface was assessed using Iodo-Gen method labeling with ¹²⁵I,whereas,platelet attachment was studied by SEM and quantified using stereological techniques.Titanium nitride(TiN) coating on the same substrates was adopted as reference material for comparison.In vitro and in vivo experiments proved that ZrN films have excellent hemocompatibility. Interface tension of ZrN with blood and plasma proteins was significantly lower than that of TiN.DLC,Tio and MPC are very effective surface modification to improve blood compatibility of a material.However,no imformation could be obtained about their comparative study.The aim of the present investigation was to find out which kind of material is the most effective surface mofidication among TiO,DLC and MPC.Comparative evaluation of the hemocompatibility of three kinds of film included clotting time,platelet adhesion and activation, protein adsorption,and in vivo experiment.In vitro and in vivo experiments proved that MPC films have excellent hemocompatibility,and DLC,TiO film show sufficient hemocompatibility,too.Conclusion:ZrN,DLC,TiO,MPC all show sufficient hemocompatibility.It is suggested that the significantly lower interface tension between ZrN films and plasma proteins give them their improved hemocompatibility.Among the three kinds of films,MPC film offer hemocompatibility significantly superior to that of DLC and TiO films.The results of the present study provide the basic imfromation for the future' s use of surface modification for improving hemocompatibility of left ventricle assist device. Background:Off-pump coronary artery bypass graft surgery(OPCAB) is associated with lower early mortality and benefits women disproportionately. The objective of this study was to assess the impact of off-pump techniques on sex differences in late outcomes.Methods:We reviewed a clinical database of consecutive patients who underwent isolated coronary artery bypass graft surgery(CABG) at FuWai Hospital from 1999 to 2005.Logistic regression analysis and proportional hazards modeling were used to investigate whether sex or surgery type were associated with early mortality and late outcomes(mortality,major cardiac and cerebral event).Results:Female sex was associated with higher rates of early death (adjusted odds ratio,2.285;p=0.0037),and OPCAB benefited women disproportionately for early mortality.Odds ratio of death for women versus men was 2.572(p=0.0110) in the conventional CABG on cardiopulmonary bypass group;odds ratio of death for women versus men was 1.914(p=0.1562) in the OPCAB group.Analysis of late outcomes indicated that OPCAB and cardiopulmonary bypass resulted in similar survival,regardless of sex.The women versus men hazard ratio of late mortality after CABG on cardiopulmonary bypass and OPCAB for women was 0.823(p=0.4239) and 0.642(p=0.1876), respectively.Women treated with OPCAB were less likely to be free from major cardiac and cerebral events than men treated with OPCAB.The women versus men hazard ratio of major cardiac and cerebral events after CABG on cardiopulmonary bypass and OPCAB for women was 1.085(p=0.4569) and 1.297 (p=0.0364),respectively.Conclusions:Compared with men,women are a highrisk group and benefit from off-pump operation in terms of early mortality after CABG.Conversely, during follow-up,women have high adjusted risks of major cardiac and cerebral events after OPCAB.