ObjectiveTo investigate the role of ischemic postconditioning on lung ischemic/reperfusion injury induced by cardiopulmonary bypass (CPB) in combined mitral and aortic valve replacement,and evaluate the effects of different protocol of ischemic postconditioning,and analyze its possible mechanisms.Methods24 patients diagnosed as rheumatic mitral and aortic valve disease with or without tricuspid valve disease were randomly divided into 3 groups (8 in each):Control group( group A),patients undergoing routine cardiac surgery; Postconditioning group Ⅰ (group B ),patients undergoing routine cardiac surgery and ischemic postconditioning by occlusion of the pulmonary artery of five cycles of 15 s ischemia and 15 s repeffusion before the pulmonary artery totally restoring peffusion; Postconditioning group Ⅱ (group C),patients undergoing routine cardiac surgery and ischemic postconditioning by occlusion of the pulmonary artery of five cycles of 30 s ischemia and 30 s repeffusion before the pulmonary artery totally restoring perfusion.The Oxygenation Index (OI) was measured at pre -operation and 1 h,2 h,3 h,6 h and 12 h after terminating CPB.The plasma contents of MDA were detected by Enzyme-linked Immunosorbent Assay at pre -operation,1 h,3 h,6 h and 12 h after terminating CPB.ResultsCompared with group A and C,OI in group B significantly increased at 1 h,2 h,3 h,6 h after terminating CPB (283.25 ±56.47 vs 384.76 ±29.17 vs 310.50 ±65.71,265.75 ±58.78 vs 381.75 ±29.67 vs 310.50 ±48.17,283.75 ±73.15 vs389.74±39.34 vs 317.87 ±78.41,310.37 ±52.00 vs 401.62 ±4 2.89 vs 337.25 ± 64.06,all P ＜0.05),and the plasma contents of MDA in group B reduced at 1 h,3 h,6 h,12 h after terminating CPB (4.64±0.63 vs 3.88 ±0.20 vs 4.38 ±0.41,5.75±0.49 vs 4.44 ±0.34 vs 5.28 ±0.76,4.42±0.31vs 3.77 ± 0.40 vs 4.35 ± 0.54,3.74 ± 0.31 vs 3.19 ± 0.17 vs 3.64 ± 0.24,all P ＜ 0.05 ), However,there were no significant differences in OI and MDA between group C and A (all P ＞0.05 ).Conclusions Ischemic postconditioning by occlusion of the pulmonary artery of 5 cycles of 15 s ischemia and 15 s reperfusion attenuates lung oxygenation function injury induced by CPB in double valves replacement,and it is possibly mediated by reducing MDA produced by lipid peroxidation.However,ischemic postconditioning by occlusion of the pulmonary artery of 5 cycles of 30 s ischemia and 30 s repeffusion may not have significant protective effect for lung oxygenation function injury induced by CPB in double valves replacement.

Objective To analyze the current status and hotspots of surgical transmural ablation of atrial fibrillation using CiteSpace and VOSviewer. Methods The Web of Science Core Collection database was used as the data source. The CiteSpace 5.8.R3 and VOSviewer software were used to analyze the related studies on surgical transmural ablation of atrial fibrillation about the authors, countries/institutions, literature co-citation and keywords. Results A total of 109 articles were enrolled. Damiano RJ was the most prolific researcher, while Cox JL was the author with the highest number of citations. The United States was the leading country in this research field. The University of Washington was an important institution in the study of atrial fibrillation transmural ablation. The main hotpots were the effectiveness of surgical ablation, especially Cox-maze procedure, selection of the energy source of surgical ablation, combination of surgical and catheter ablations, and pulmonary vein isolation. Conclusion This study visualizes the current research status of surgical ablation of atrial fibrillation. How to improve the effectiveness and transmurality of surgical ablation is a hot research topic in the surgical treatment of atrial fibrillation. The combination of electrophysiology mapping and surgical ablation may be the development direction in the surgical treatment of atrial fibrillation.