针对EVaR(Expectile-based Value at Risk)风险度量提出了基于GARCH类和SV波动率模型的EVaR风险度量计算方法,即EVaR计算的参数模型方法.并基于模拟学生t分布时间序列数据,给出EVaR样本外预测的失败率检验方法:Kupiec失败率检验和动态...针对EVaR(Expectile-based Value at Risk)风险度量提出了基于GARCH类和SV波动率模型的EVaR风险度量计算方法,即EVaR计算的参数模型方法.并基于模拟学生t分布时间序列数据,给出EVaR样本外预测的失败率检验方法:Kupiec失败率检验和动态分位数(DQ)检验法.与采用CARE(Conditional Autoregressive Expectile)模型的EVaR计算方法进行了对比研究,结果表明基于GARCH类模型和SV模型相对于基于CARE模型有更优的EVaR预测效果.选取2004年1月5日到2009年12月30日的国内外五个股票市场指数数据,针对日对数收益率进行了EVaR风险度量的实证研究,得出在金融危机期间,基于参数模型的EVaR预测要比基于CARE模型的EVaR预测更接近市场实际风险.展开更多
Objectives: This study aimed to determine whether errors in vascular measurements would affect device selection in endovascular aortic repair (EVAR) by comparing measurements obtained using non-contrast computed tomog...Objectives: This study aimed to determine whether errors in vascular measurements would affect device selection in endovascular aortic repair (EVAR) by comparing measurements obtained using non-contrast computed tomography (NCT) with those obtained using contrast-enhanced CT (CECT). Materials and Methods: This single-center, retrospective study included 25 patients who underwent EVAR for abdominal aortic aneurysm at our institution. A 1-mm horizontal cross-sectional slice of NCT and CECT from each patient was retrospectively reviewed. The area from the abdominal aorta to the common iliac artery was divided into four zones. A centerline was created using the NCT by manually plotting the center points. Subsequently, the centerlines were automatically extracted and manually corrected during the arterial phase of CECT. The diameter and length of each zone were measured for each modality. The mean diameters and lengths of the target vessels were compared between NCT and CECT. Results: The measurements obtained using both methods were reproducible and demonstrated good agreement. The mean differences in vessel length and diameter measurements for each segment between NCT and CECT were not statistically significant, indicating good consistency. Conclusion: NCT may be useful for preoperative EVAR evaluation in patients with renal dysfunction or allergies to contrast agents.展开更多
目的探讨综合应用多排螺旋CT血管成像(MSCTA)多种重建方法对腹主动脉瘤(AAA)进行术前影像学评估的临床应用价值。方法回顾分析2009年6月至2010年5月共75例AAA患者的MSCTA资料,并对比分析其中61例成功实施血管腔内修复(EVAR)术患者的MSCT...目的探讨综合应用多排螺旋CT血管成像(MSCTA)多种重建方法对腹主动脉瘤(AAA)进行术前影像学评估的临床应用价值。方法回顾分析2009年6月至2010年5月共75例AAA患者的MSCTA资料,并对比分析其中61例成功实施血管腔内修复(EVAR)术患者的MSCTA及术中DSA资料。应用容积再现(VRT)、多平面重建(MPR)、最大密度投影(MIP)和曲面重建(CPR)分别测量EVAR术相关各解剖学数据,并对照DSA测量数据,比较各测量值之间的差异。结果①12例(12/75,16.0%)行外科腹主动脉人工血管置换术,2例(2/75,2.7%)临床定期随诊,未行手术治疗,61例(61/75,81.3%)行EVAR术治疗。②行EVAR术治疗的61例患者中,Ⅰ型仅2例(3.2%,2/61);Ⅱ型44例(72.3%,44/61),其中Ⅱa型27例、Ⅱb型11例、Ⅱc型6例;Ⅲ型15例(24.5%,15/61)。③对比61例行EVAR术病例的术中DSA数据和MSCTA数据,近端瘤颈长度、内径,瘤体长度,远端瘤颈长度、内径,髂总动脉长度、内径等各测量值差异分析显示差异无统计学意义(F=0.006～0.427,P=0.653～0.999),以DSA测量值为参考标准,应用Bland And Altman方法计算3种重建方法测量数值的偏倚在0.00～1.70。结论采用VRT重建图像观察AAA与腹主动脉及其分支的解剖关系,MPR重建图像测量血管内径,MIP重建图像测量血管长度和血管走行角度,CPR重建图像观察血管及分支管腔内及管壁情况,合理应用MSCTA多种重建方法可以准确、直观显示AAA的形态学变异、腔内精确结构及分支血管关系,精确测量AAA与治疗相关的主要径线,为临床治疗方法的选择提供有力依据,具有显著的临床应用价值。展开更多
Mycotic or infected aneurysms are focal vascular dilatations from inflammation or infection that results in weakening of the blood vessel wall. It poses a high risk of complications such as aneurysm rupture, uncontrol...Mycotic or infected aneurysms are focal vascular dilatations from inflammation or infection that results in weakening of the blood vessel wall. It poses a high risk of complications such as aneurysm rupture, uncontrolled sepsis and extensive periaortic infection. Symptoms are frequently minimal during the early stages and a high index of suspicion is essential to make the diagnosis. They are more likely to expand rapidly and rupture without surgical intervention. We report a case of a middle-aged man presented with 3-week history of fever, abdominal pain and low back pain. Initially presented as acute pyelonephritis with subsequent findings of liver abscess, right epididymoorchitis and left infrarenal mycotic aneurysm, which rapidly increased in size and underwent successful endovascular surgery.展开更多
Purpose: To determine if there were differences in quality of life (QOL) within the first year following EVAR for patients undergoing internal iliac embolization depending on the type of device used. Methods: Patients...Purpose: To determine if there were differences in quality of life (QOL) within the first year following EVAR for patients undergoing internal iliac embolization depending on the type of device used. Methods: Patients who underwent endovascular AAA repair were identified using a Vascular surgery database at a tertiary care center from 2002-2008. The Radiology Information System and Image Viewer were then used to identify patients who underwent preprocedural embolization prior to endovascular aneurysm repair. Nine patients had embolization with nester coils, 9 had embolization with the amplatzer vascular plug, a type of nitinol based self expanding device. Another group of 8 patients who did not undergo preprocedural embolization was used as a comparator group. These patients were contacted via telephone and answered questions regarding QOL post procedure. The Australian Vascular QOL was the tool used to measure QOL. Differences in QOL were tabulated between the groups of patients. Results: Of the 9 patients who underwent embolization with amplatzer plug, the median QOL score was 60 (p value 0.575), the median QOL for the nester coil group was 52.5 and the comparator group was 58. Separate analysis was done dividing patients into two groups, with and without comorbidities without statistical significance. Conclusion: Patients who underwent preprocedural embolization using amplatzer plugs compared to coils had higher overall QOL scores although the difference was not significant.展开更多
Objectives: Endovascular abdominal aortic aneurysm repair (EVAR) is a common procedure for abdominal aortic aneurysm (AAA), based on minimal invasiveness compared with open surgical repair (OSR). However, general anes...Objectives: Endovascular abdominal aortic aneurysm repair (EVAR) is a common procedure for abdominal aortic aneurysm (AAA), based on minimal invasiveness compared with open surgical repair (OSR). However, general anesthesia can cause considerable perturbations in patients with AAA undergoing operative repair. The aim of this study was to compare the incidence of myocardial ischemic events in association with hemodynamic changes during EVAR and OSR under general anesthesia. Methods: We retrospectively reviewed the anesthetic and medical records of patients who underwent elective abdominal aortic aneurysm repair. ST segment changes on electrocardiography and hemodynamic changes were reviewed by the attending physicians. Results: Among 120 patients, EVAR and OSR were performed in 81 and 39 patients, respectively. There were no significant differences in preoperative morbidity between the two groups. The amount of estimated blood loss was significantly lower in EVAR than OSR. The incidence of ST?segment changes in the two groups (EVAR: 16%, OSR: 23%) was not statistically different. ST segment changes occurred mainly postoperatively at resolution of anesthesia in EVAR, compared with intraoperatively in OSR. ST segment changes were mostly accompanied by tachycardia in EVAR patients, whereas they were associated with hypotension in OSR. Conclusion: Our results demonstrated a comparable incidence of perioperative ST segment changes under general anesthesia in EVAR and OSR. Patients who undergo EVAR and develop tachycardia are at risk of myocardial ischemia at resolution of anesthesia.展开更多
文摘针对EVaR(Expectile-based Value at Risk)风险度量提出了基于GARCH类和SV波动率模型的EVaR风险度量计算方法,即EVaR计算的参数模型方法.并基于模拟学生t分布时间序列数据,给出EVaR样本外预测的失败率检验方法:Kupiec失败率检验和动态分位数(DQ)检验法.与采用CARE(Conditional Autoregressive Expectile)模型的EVaR计算方法进行了对比研究,结果表明基于GARCH类模型和SV模型相对于基于CARE模型有更优的EVaR预测效果.选取2004年1月5日到2009年12月30日的国内外五个股票市场指数数据,针对日对数收益率进行了EVaR风险度量的实证研究,得出在金融危机期间,基于参数模型的EVaR预测要比基于CARE模型的EVaR预测更接近市场实际风险.
文摘Objectives: This study aimed to determine whether errors in vascular measurements would affect device selection in endovascular aortic repair (EVAR) by comparing measurements obtained using non-contrast computed tomography (NCT) with those obtained using contrast-enhanced CT (CECT). Materials and Methods: This single-center, retrospective study included 25 patients who underwent EVAR for abdominal aortic aneurysm at our institution. A 1-mm horizontal cross-sectional slice of NCT and CECT from each patient was retrospectively reviewed. The area from the abdominal aorta to the common iliac artery was divided into four zones. A centerline was created using the NCT by manually plotting the center points. Subsequently, the centerlines were automatically extracted and manually corrected during the arterial phase of CECT. The diameter and length of each zone were measured for each modality. The mean diameters and lengths of the target vessels were compared between NCT and CECT. Results: The measurements obtained using both methods were reproducible and demonstrated good agreement. The mean differences in vessel length and diameter measurements for each segment between NCT and CECT were not statistically significant, indicating good consistency. Conclusion: NCT may be useful for preoperative EVAR evaluation in patients with renal dysfunction or allergies to contrast agents.
文摘目的探讨综合应用多排螺旋CT血管成像(MSCTA)多种重建方法对腹主动脉瘤(AAA)进行术前影像学评估的临床应用价值。方法回顾分析2009年6月至2010年5月共75例AAA患者的MSCTA资料,并对比分析其中61例成功实施血管腔内修复(EVAR)术患者的MSCTA及术中DSA资料。应用容积再现(VRT)、多平面重建(MPR)、最大密度投影(MIP)和曲面重建(CPR)分别测量EVAR术相关各解剖学数据,并对照DSA测量数据,比较各测量值之间的差异。结果①12例(12/75,16.0%)行外科腹主动脉人工血管置换术,2例(2/75,2.7%)临床定期随诊,未行手术治疗,61例(61/75,81.3%)行EVAR术治疗。②行EVAR术治疗的61例患者中,Ⅰ型仅2例(3.2%,2/61);Ⅱ型44例(72.3%,44/61),其中Ⅱa型27例、Ⅱb型11例、Ⅱc型6例;Ⅲ型15例(24.5%,15/61)。③对比61例行EVAR术病例的术中DSA数据和MSCTA数据,近端瘤颈长度、内径,瘤体长度,远端瘤颈长度、内径,髂总动脉长度、内径等各测量值差异分析显示差异无统计学意义(F=0.006～0.427,P=0.653～0.999),以DSA测量值为参考标准,应用Bland And Altman方法计算3种重建方法测量数值的偏倚在0.00～1.70。结论采用VRT重建图像观察AAA与腹主动脉及其分支的解剖关系,MPR重建图像测量血管内径,MIP重建图像测量血管长度和血管走行角度,CPR重建图像观察血管及分支管腔内及管壁情况,合理应用MSCTA多种重建方法可以准确、直观显示AAA的形态学变异、腔内精确结构及分支血管关系,精确测量AAA与治疗相关的主要径线,为临床治疗方法的选择提供有力依据,具有显著的临床应用价值。
文摘Mycotic or infected aneurysms are focal vascular dilatations from inflammation or infection that results in weakening of the blood vessel wall. It poses a high risk of complications such as aneurysm rupture, uncontrolled sepsis and extensive periaortic infection. Symptoms are frequently minimal during the early stages and a high index of suspicion is essential to make the diagnosis. They are more likely to expand rapidly and rupture without surgical intervention. We report a case of a middle-aged man presented with 3-week history of fever, abdominal pain and low back pain. Initially presented as acute pyelonephritis with subsequent findings of liver abscess, right epididymoorchitis and left infrarenal mycotic aneurysm, which rapidly increased in size and underwent successful endovascular surgery.
文摘Purpose: To determine if there were differences in quality of life (QOL) within the first year following EVAR for patients undergoing internal iliac embolization depending on the type of device used. Methods: Patients who underwent endovascular AAA repair were identified using a Vascular surgery database at a tertiary care center from 2002-2008. The Radiology Information System and Image Viewer were then used to identify patients who underwent preprocedural embolization prior to endovascular aneurysm repair. Nine patients had embolization with nester coils, 9 had embolization with the amplatzer vascular plug, a type of nitinol based self expanding device. Another group of 8 patients who did not undergo preprocedural embolization was used as a comparator group. These patients were contacted via telephone and answered questions regarding QOL post procedure. The Australian Vascular QOL was the tool used to measure QOL. Differences in QOL were tabulated between the groups of patients. Results: Of the 9 patients who underwent embolization with amplatzer plug, the median QOL score was 60 (p value 0.575), the median QOL for the nester coil group was 52.5 and the comparator group was 58. Separate analysis was done dividing patients into two groups, with and without comorbidities without statistical significance. Conclusion: Patients who underwent preprocedural embolization using amplatzer plugs compared to coils had higher overall QOL scores although the difference was not significant.
文摘Objectives: Endovascular abdominal aortic aneurysm repair (EVAR) is a common procedure for abdominal aortic aneurysm (AAA), based on minimal invasiveness compared with open surgical repair (OSR). However, general anesthesia can cause considerable perturbations in patients with AAA undergoing operative repair. The aim of this study was to compare the incidence of myocardial ischemic events in association with hemodynamic changes during EVAR and OSR under general anesthesia. Methods: We retrospectively reviewed the anesthetic and medical records of patients who underwent elective abdominal aortic aneurysm repair. ST segment changes on electrocardiography and hemodynamic changes were reviewed by the attending physicians. Results: Among 120 patients, EVAR and OSR were performed in 81 and 39 patients, respectively. There were no significant differences in preoperative morbidity between the two groups. The amount of estimated blood loss was significantly lower in EVAR than OSR. The incidence of ST?segment changes in the two groups (EVAR: 16%, OSR: 23%) was not statistically different. ST segment changes occurred mainly postoperatively at resolution of anesthesia in EVAR, compared with intraoperatively in OSR. ST segment changes were mostly accompanied by tachycardia in EVAR patients, whereas they were associated with hypotension in OSR. Conclusion: Our results demonstrated a comparable incidence of perioperative ST segment changes under general anesthesia in EVAR and OSR. Patients who undergo EVAR and develop tachycardia are at risk of myocardial ischemia at resolution of anesthesia.
