Left ventricular mass regression following aortic valve replacement with mechanical valves

Objective The degree of Left Ventricular Mass Index (LVMI) regression following aortic valve replacement correlates with long-term survival. This study aims to assess the extent of LVMI regression at 3 months following aortic valve replacement (AVR) with different types and sizes of mechanical valves in rheumatic aortic valve disease. Methods The LVMI regression was studied in 34 consecutive patients, undergoing elective AVR for rheumatic aortic stenosis and/or regurgitation. They were grouped in A and B, matched in age, body surface area and pre-operative LVMI, receiving respectively a tilting disc and a bileaflet mechanical valve. The LVMI was calculated by M-mode echocardiography using the Devereux' formula pre-operatively and three months post-operatively. The trend of LVMI reduction was compared between the two groups and amongst the patients with stenotic, regurgitant and mixed aortic valve, pathologies; and receiving different sizes of valves. Results The mean preoperative LVMI was 199g±79.5 g/m². At three months post aortic valve replacement, the mean LVMI was 130g±49.0 g/m². There was a significant reduction of LVMI post-operatively (p=0.001) at three months follow-up. The extent of LVMI regression following surgery amongst the groups A and B did not vary significantly (p=0.92). The extent of LVMI regression did not vary significantly in patients with different aortic valve pathology nor with different sizes of the valves implanted. Conclusions There is a significant early LVMI regression following aortic valve replacement in rheumatic aortic valve disease. The type and the size of the mechanical prosthesis or the rheumatic pathology do not appear to influence this regression.     

Congenital quadricuspid aortic valve with tetralogy of Fallot and pulmonary atresia

We report the case of a 4-year-old girl who had quadricuspid aortic valve regurgitation with tetralogy of Fallot and pulmonary atresia. This combination is very uncommon. Aortic valve replacement was performed successfully due to aortic regurgitation which had progressed one year after the total repair. The dilated aortic annulus plus quadricuspid aortic valve may result in progressive aortic regurgitation for a short period.     

有关医院空调水系统若干问题的探讨

主要阐述空调水系统利用平衡阀调节系统阻力,保持系统水力稳定;利用软启动器实施水泵的平滑软启动;压差旁通阀的作用及选型安装;系统管道热膨胀等问题。     

Pediatric valve replacement, 15 years experience in Oman

Background Despite improving surgical techniques, treatment of heart valve disease in children remains controversial. Somatic growth and adequate anticoagulation are of concern when children undergo valve replacement. We conducted this study to evaluate the performance of valves in this age group. Methods 42 children under the age of 13 years who underwent valve replacement were included in this study. Totally, 50 valves were implanted in 42 patients: 48 were mechanical prostheses, two were bioprosthetic both in pulmonary position. 37 (74%) valves were implanted in mitral position, 10 (20%) in aortic position, 1 (2%) in tricuspid position and 2 (4%) in pulmonary position. Preoperatively, 14 (33,3%) patients were in New York Heart Association (NYHA) class IV, while 27 (64.2%) were in NYHA class III. Results There were 2 (4.7%) hospital deaths and 2 (4.7%) late deaths while 2 (4.7%) patients were lost to follow up. The mean follow up period was 9.4 yrs. 35 (83.3%) patients are in NYHA Class I and free of all medications except warfarin. 3 (7.1%) patients have undergone 5 successful pregnancies. The median INR was 2.23. Major thrombo-embolic episode occurred in 1 (2.3%) patient. Conclusions In view of the problems of sizing, anticoagulation and need for re-operation at an early age, there is a reluctance to replace valves in children. This study shows that despite these problems, valve replacement can be undertaken safely and successfully in children, when repair has failed or not technically feasible.     

Comparison of diagnostic usefulness of predictive models in preliminary differentiation of adnexal masses

The purpose of this study was to compare prognostic models evaluating the probability of an ovarian cancer occurrence based on a number of clinical and ultrasonographic data in women with adnexal masses. A total of 686 women with adnexal masses underwent the examinations between 1994 and 2002. The recorded parameters included: age, menopausal status, body mass index, the grayscale and Doppler ultrasonographic examination, and selected markers concentration levels. In order to find the best combination of features, which significantly influences the probability of malignancy, stepwise logistic regression analysis, as well as artificial neural network, was used. The diagnostic efficiency of received models was estimated and compared using receiver-operating characteristics (ROC) curve. The results indicate that 431 and 255 patients had a benign and malignant ovarian tumor, respectively. Application of stepwise logistic regression analysis revealed statistically significant importance of eight features. The sensitivity and specificity for the received model were 65.71% and 77.59%, respectively. Three-layer perceptron network shows 13 features as significant predictors of malignancy. The network gave a sensitivity of 85.7% and specificity of 93.1%. Comparison of area under ROC curve for received models was 0.9679 vs 0.9716. Prognostic values of the analyzed neural model are not optimal but seem to surpass logistic regression model in terms of the predictive possibilities.     

老年危重病人人工气道气囊压力监测及护理

[目的 ]探讨人工气道气囊压力监测在老年危重病人气管导管护理中的应用价值。 [方法 ]将 60例建立人工气道的老年危重病人随机分成两组 ,实验组应用PORTEX专用气囊压力监测表注气测压 ,对照组采用传统的手指捏感法注气 ;用呼吸机检查漏气情况 ,并比较两组病人的气囊注气容积、气囊压力及并发症发生率。 [结果 ]实验组气囊压力为 2 .45 2kPa±0 .490kPa时 ,气囊容积为 10 .0mL± 4.7mL ,呼吸机检查不漏气 ;对照组气囊压力为 3 .92 3kPa± 0 .73 6kPa时 ,气囊容积为 15 .0mL± 5 .1mL ,呼吸机检查不漏气。两组病人气管黏膜损伤、气囊破裂发生率比较有统计学意义 (P <0 .0 5 ) ;两组病人误吸、食管气管瘘发生率比较无统计学意义 (P >0 .0 5 )。 [结论 ]建立人工气道的老年危重病人气囊压力维持在1.961kPa～ 2 .942kPa ,能有效避免误吸的发生和气管黏膜的损伤。     

Ventricular septal fistula formation due to infectious endocarditis in a hemodialysis patient with aortic valve replacement

We report a case of infectious endocarditis in a 77-year-old woman who was undergoing maintenance hemodialysis therapy, and who was also having a prosthetic aortic valve replacement. The disease resulted from a local skin infection at the needle puncture site of the arteriovenous fistula. Ampicillin-resistant Staphylococcus aureus was the causal organism. Surgical treatment could not be performed because of associated intracranial hemorrhage due to septic embolism. In spite of intensive treatment with several antibiotics, a ventricular septal abscess just beneath the prosthetic aortic valve progressed to form a ventricular septal fistula. The resultant intracardiac left-to-right shunt led to refractory congestive heart failure. The patient finally died of heart failure. The formation of a ventricular septal fistula is considered to be a rare and extraordinary complication of infectious endocarditis in a hemodialysis patient with aortic valve replacement. Received: July 25, 2001 / Accepted: November 3, 2001     

医用钛合金在三种不同生理电解液中的耐腐蚀行为研究

利用电化学方法研究医用钛合金在0.9%NaCl生理盐水，模拟人工唾液，模拟人工体液中的腐蚀情况，分析腐蚀电位和腐蚀电流密度，扫面电镜观察腐蚀表面形貌，CA-A型接触角测试仪测试钛合金表面被腐蚀后接触角的变化。实验表明：钛合金在三种生理电解液中的腐蚀情况依次是：模拟人工唾液〉模拟人工体液〉0.9%NaCl生理盐水。扫面电镜观察表明，医用钛合金在0.9% NaCl生理盐水腐蚀后，表面出现了许多腐蚀孔，经模拟人体体液腐蚀后，表面变得粗糙不平整，腐蚀孔数目变化不大，钛合金经人工唾液腐蚀后，腐蚀孔数目增多，部分腐蚀孔孔径明显增大。经三种生理电解液腐蚀后，钛合金表面接触角都减小。结论：医用钛合金在人工唾液中的腐蚀最严重，在临床应用中应给予相应的防范措施。     

螺旋CT及CAD技术在人工关节定制设计中的应用研究

随着生物医用材料研制和医学的迅速发展，以及生活水平、医疗保健、康复水平的提高，人们对自身组织、器官及骨骼缺损的修复和置换方面的要求日益提高，尤其对人造骨骼和人工关节的需求越来越广泛。由于计算机断层成像技术CT（computed tomography）已经成为显示和研究人体内部结构非常有用的手段，将计算机辅助设计技术CAD（Computer aided design）和计算机辅助工程CAE（Computer aided Engineering）等相关技术应用于人造骨骼和内置假体的设计，不仅可以提高产品的设计质量，同时，结合CT和计算机三维重建方法，     

Entrapment of pacemaker lead by a large netlike Eustachian valve within the right atrium

Summary During pacemaker implantation in a patient with permanent atrial fibrillation, it remained impossible to advance a passive fixation lead with fins through the right atrium. However, a lead with a retractable screw easily passed the right atrium and was positioned in the right ventricle. Transesophageal echocardiography revealed an extensive net–like perforated Eustachian valve within the right atrium that had caused entrapment of the anchor fins during lead implantation. Remnants of embryonal structures within the right atrium should be considered a rare possible barrier during pacemaker implantation.