OBJECTIVE:To discuss the preparation methods of polyaspartate derivatives as drug delivery systems. DATA SOURCES:An online search of Elselvier,ACS publications and Springerlink between January 1990 and January 2006 was undertaken by using the keywords of "polyaspart*,hydrogels,micelles,complexes" to identify the relevant articles published in English.Meanwhile,Chinese journals full-text database were scanned with computer to search relevant articles published from January 1995 to October 2005,and the keywords were"asparmide,complexes,hydrogels,release" with language limited to Chinese.STUDY SELECTION:All the related data were analyzed to select those were aimed directly at the criteria.As for the arti cles in the same field,those published recently or published in the authority journals were preferred. DATA EXTRACTION:A total of 56 articles about the preparation methods of polyaspartate derivatives as drug delivery systems were collected, and 29 of them were in accordance with the inclusion criteria. DATA SYNTHESIS:Polyaspartate derivatives are new biodegradable and biocompatible materials.Covalent complexes, hydrogels and micelles,three main drug delivery systems of polyaspartate derivatives,exhibit good biocompatibility and conspicuous effect of control-release.CONCLUSION:With the help of the short synthesis route,simple manipulation,high production rate, the excellent biocompatibility as well as the better hydrophile,the polyaspartate derivatives are prone to reacting with other compounds for the modification.It is noted that the controllability of the control-release systems will be well improved through the researches of the influence factors of the degrading velocity and the new modifying method,additionally,the polyaspartate derivatives will be applied in the drug delivery field widely.

Objective    To assess the feasibility and safety of percutaneous transcatheter closure of atrial septal defect (ASD) guided by transthoracic echocardiography (TTE) in outpatients. Methods    From December 2016 to June 2018, 50 simple ASD patients underwent TTE-guided transcatheter closure in the outpatient operating room of our hospital (a TTE group) including 22 males and 28 females at the age of 16-48 (27.40±6.95) years. Fifty patients with simple ASD treated with the guidance of conventional fluoroscopy during the same period were treated as a control group, including 22 males and 28 females at the age of 15-48 (28.58±6.96) years. Both groups were re-examined by TTE during follow-up at 1 month, 3 months, 6 months and 1 year. Results    The mean age, body weight, the size of ASD and occluder and success rate had no statistical difference between the two groups (P>0.05). Compared with the control group, the TTE group had significantly lower mean operation time (P<0.01) and less cost (P<0.01) since patients need not to be hospitalized. No related complications were found in the TTE group during follow-up. Conclusion    Percutaneous transcatheter closure of ASD guided by TTE appears safe and effective for outpatients, and can significantly reduce the cost.

Transcatheter intervention for congenital heart disease has been developed for 40 years in China, it has experienced the transition of learning to self-dependent innovation, and witnessed the intervention therapy system starting from scratch and gradually reaching the top level and gaining high achievements in the world scale. With the continuous development of interventional technology and devices, cutting-edge ideas and viewpoints are constantly discussed. This review summarized the development of intervention techniques and devices, hoping to provide some experience for the further development of transcatheter interventions for congenial heart disease.