Biological valves can lead to structural valve degeneration (SVD) over time and due to various factors, reducing their durability. SVD patients need to undergo valve replacement surgery again, while traditional open chest surgery can cause significant trauma and patients often give up treatment due to intolerance. Research has shown that as an alternative treatment option for reoperation of thoracic valve replacement surgery, redo-transcatheter aortic valve replacement for SVD is safe and effective, but still faces many challenges, including prosthesis-patient mismatch, high cross valve pressure difference, and coronary obstruction. This article aims to review the strategies, clinical research status and progress of redo-transcatheter aortic valve replacement in SVD patients.
Objective To analyze the international hotspots of study in age-related macular degeneration (AMD) in recent years. Methods Articles related to AMD that appeared during period January 2002-December 2010 from Pubmed database were quantitatively analyzed by software of BICOMS. PASW 18.0 statistical software used to cluster high frequency keywords of published articles. Clustering relationships of high frequency hot topics were identified. Results A total of 8529 AMD related articles were retrieved. The number of published articles in 2009 was 2.45 times greater than that of published articles in 2002. Six thousand five hundred and fourteen AMD related articles were published in the United States, England and Germany, which accounted for 76.37% of worldwide total. Fifty-two high frequency keywords were analyzed. They were clustered into 6 categories, which were identified as physiological/genetics, etiology and prevention and control, pathology and tomography and other diagnostic techniques, surgical therapy, drug therapy and photochemical therapy, and drug/laser therapy. Conclusions Recently, more attention has been paid to AMD, and the published AMD related articles has rapidly increased. The United States and European countries occupy the dominant position for the number of published AMD related articles. The international main research focus included 6 fields: basic research in AMD, etiology, pathology and diagnostic techniques, AMD prevention and control, surgery/drugs/laser and photochemical treatment of AMD.