Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied thes...Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied these improvements： in-stent restenosis （ISR） arising from neointimal hyperplasia. ISR after coronary angioplasty is currently one of the main limitations of this method, leading to the recurrence of exertional angina pectoris or acute coronary syndromes. The clinical incidence of ISR after bare-metal stent （BMS） implantation is approximately 20%35%. The use of drug-eluting stents （DES） has led to a further decrease in the occurrence of ISR to 5%-10%. Evidence resulting from controlled clinical studies suggests that DES and drug-eluting balloon catheters （DEB） provide the best clinical and angiographic results in the treatment of ISR. We undertook a systematic review of the pathophysiology, diagnostics and treatment options for BMS- and DES-ISR. We discuss recent randomised studies, comparing different DES or DEB used for BMS or DES-ISR treatment, as well as the use of new biovascular scafolds and the topic of scafold restenosis.展开更多
Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon...Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water waves.The numerical results are compared with experimental data available in the literature.The comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the resonant frequency reasonably well.However the conventional potential flow model(without artificial damping term) significantly over-predicts the wave height in narrow gaps around the resonant frequency.In order to calibrate the appropriate damping coefficient used for the potential model and make it work as well as the viscous fluid model in predicting the resonant wave height in narrow gaps but with little computational efforts,the dependence of damping coefficient μ on the body geometric dimensions is examined considering the parameters of gap width Bg,body draft D,body breadth ratio Br and body number n(n = 2,3),where Br = BB/BA for the case of two bodies(Body A and Body B) with different breadths of BA and BB,respectively.It was confirmed that the damping coefficient used for the potential flow model is not sensitive to the geometric dimensions and spatial arrangement.It was found that μ∈ [0.4,0.5] may guarantee the variation of Hg/H0 with kh to be generally in good agreement with the experimental data and the results of viscous fluid model,where Hg is the excited wave height in narrow gaps under various dimensionless incident wave frequencies kh,H0 is the incident wave height,k = 2π/L is the wave number and h is the water depth.展开更多
目的:探讨胃肠道狭窄或梗阻内支架置入术后常见并发症及其处理办法。对象与方法:60例胃肠道狭窄或梗阻病人,其中食管狭窄或梗阻39便,胃十二指肠梗阻或狭窄21例。在 X 光线监视下共放置支架66只(3例同一部位放置两只支架,3例不同部位放置...目的:探讨胃肠道狭窄或梗阻内支架置入术后常见并发症及其处理办法。对象与方法:60例胃肠道狭窄或梗阻病人,其中食管狭窄或梗阻39便,胃十二指肠梗阻或狭窄21例。在 X 光线监视下共放置支架66只(3例同一部位放置两只支架,3例不同部位放置2只支架),其中带膜27只,不带膜39只。结果:60例病人中,所有支架安放1～3次成功。疼痛12例(20%),其中轻微胀痛10例(17%),中度胀痛1例(1.7%).重度疼痛1例(1.75)。对轻中度胀痛给予止痛片等对症处理;重度疼痛,药物控制无效者,给予硬膜外麻醉止痛。胃肠道再狭窄9例(15%),其中肿瘤过度生长6例(10%),肉芽组织增生3例(5%)。肿瘤过度生长放置第二只支架2例,胃镜下热极烧灼4例;肉芽组织增生放置第二只支架1例,胃镜下热极烧灼2例。胃食管反流5例(8%),连续给予止酸剂(洛赛克)胃粘膜保护剂(舒可捷)胃肠动力药(吗叮啉)等一个月,症状消失。发生内支架移位3例(5%)。其中2例胃镜下取出,1例胃镜下复位。出血3例(5%),2例给予安络血后消失,1例反复渗血致缺铁性贫血,给予补铁,止酸.止血后好转。食物嵌顿2例(3%),采用探条和胃镜给予疏通。结论:胃肠道狭窄或梗阻内支架置入后常见并发症状为疼痛(20%),胃肠道再狭窄(15%),胃食管反流(8%),支架移位(5%).出血(5%)和食物嵌顿(3%)。并发症的处理应以内支架、胃镜和药物相结合的办法来进行。展开更多
文摘Coronary stem implantation has significantly improved percutaneous coronary intervention and enabled the management of early complications of plain balloon angioplasty. However, a new complication has accompanied these improvements： in-stent restenosis （ISR） arising from neointimal hyperplasia. ISR after coronary angioplasty is currently one of the main limitations of this method, leading to the recurrence of exertional angina pectoris or acute coronary syndromes. The clinical incidence of ISR after bare-metal stent （BMS） implantation is approximately 20%35%. The use of drug-eluting stents （DES） has led to a further decrease in the occurrence of ISR to 5%-10%. Evidence resulting from controlled clinical studies suggests that DES and drug-eluting balloon catheters （DEB） provide the best clinical and angiographic results in the treatment of ISR. We undertook a systematic review of the pathophysiology, diagnostics and treatment options for BMS- and DES-ISR. We discuss recent randomised studies, comparing different DES or DEB used for BMS or DES-ISR treatment, as well as the use of new biovascular scafolds and the topic of scafold restenosis.
基金supports from the Natural National Science Foundation of China (Grant Nos.50909016,50921001 and 10802014)support of ARC Discovery Project Program (Grant No. DP0557060)supported by the Open Fund from the State Key Laboratory of Structural Analysis for Industrial Equipment (Grant No. GZ0909)
文摘Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water waves.The numerical results are compared with experimental data available in the literature.The comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the resonant frequency reasonably well.However the conventional potential flow model(without artificial damping term) significantly over-predicts the wave height in narrow gaps around the resonant frequency.In order to calibrate the appropriate damping coefficient used for the potential model and make it work as well as the viscous fluid model in predicting the resonant wave height in narrow gaps but with little computational efforts,the dependence of damping coefficient μ on the body geometric dimensions is examined considering the parameters of gap width Bg,body draft D,body breadth ratio Br and body number n(n = 2,3),where Br = BB/BA for the case of two bodies(Body A and Body B) with different breadths of BA and BB,respectively.It was confirmed that the damping coefficient used for the potential flow model is not sensitive to the geometric dimensions and spatial arrangement.It was found that μ∈ [0.4,0.5] may guarantee the variation of Hg/H0 with kh to be generally in good agreement with the experimental data and the results of viscous fluid model,where Hg is the excited wave height in narrow gaps under various dimensionless incident wave frequencies kh,H0 is the incident wave height,k = 2π/L is the wave number and h is the water depth.
文摘目的:探讨胃肠道狭窄或梗阻内支架置入术后常见并发症及其处理办法。对象与方法:60例胃肠道狭窄或梗阻病人,其中食管狭窄或梗阻39便,胃十二指肠梗阻或狭窄21例。在 X 光线监视下共放置支架66只(3例同一部位放置两只支架,3例不同部位放置2只支架),其中带膜27只,不带膜39只。结果:60例病人中,所有支架安放1～3次成功。疼痛12例(20%),其中轻微胀痛10例(17%),中度胀痛1例(1.7%).重度疼痛1例(1.75)。对轻中度胀痛给予止痛片等对症处理;重度疼痛,药物控制无效者,给予硬膜外麻醉止痛。胃肠道再狭窄9例(15%),其中肿瘤过度生长6例(10%),肉芽组织增生3例(5%)。肿瘤过度生长放置第二只支架2例,胃镜下热极烧灼4例;肉芽组织增生放置第二只支架1例,胃镜下热极烧灼2例。胃食管反流5例(8%),连续给予止酸剂(洛赛克)胃粘膜保护剂(舒可捷)胃肠动力药(吗叮啉)等一个月,症状消失。发生内支架移位3例(5%)。其中2例胃镜下取出,1例胃镜下复位。出血3例(5%),2例给予安络血后消失,1例反复渗血致缺铁性贫血,给予补铁,止酸.止血后好转。食物嵌顿2例(3%),采用探条和胃镜给予疏通。结论:胃肠道狭窄或梗阻内支架置入后常见并发症状为疼痛(20%),胃肠道再狭窄(15%),胃食管反流(8%),支架移位(5%).出血(5%)和食物嵌顿(3%)。并发症的处理应以内支架、胃镜和药物相结合的办法来进行。
