经皮球囊二尖瓣成形术治疗风湿性二尖瓣狭窄的体会

目的：初步探讨经皮球囊二尖瓣成形术（PBMV）技术操作中的几个问题及处理对策。方法：采用国产单球囊导管对4例风湿性心脏病二尖瓣狭窄患进行PBMV。结果：4例患均获成功,血流动力学均明显好转。结论：PBMV技术操作中有关几个问题的处理对策是提高手术效果有效可行的方法。     

Ionic and haemodynamic changes influence the release of the excitatory amino acid glutamate in the posterior hypothalamus

The push-pull technique was used to investigate the release of the excitatory amino acid glutamate in the posterior hypothalamic area of the conscious rat. The hypothalamus was superfused through the pushpull cannula with artificial cerebrospinal fluid (CSF), and the superfusate was collected in time periods of 10 min when ionic conditions in the CSF were changed, or in short periods of 3 min when blood pressure changes were evoked. The mean glutamate release rate was 2.8 + 0.7 pmol/min. Depolarization by hypothalamic superfusion with CSF containing 50 mM K⁺ enhanced the release of glutamate in the presence of Ca²⁺. The K⁺-induced release was attenuated by 40% when the hypothalamus was superfused with Ca²⁺-free CSF. Replacement of Ca²⁺ by Mg²⁺ abolished the K⁺-induced release of glutamate. Hypovolaemia elicited by haemorrhage enhanced the release rate of glutamate. Similarly, a hypotension elicited by i.v. injection of chlorisondamine (3 mg/kg) led to a pronounced and permanent enhancement in glutamate release. The effects of hypovolaemia and chlorisondamine on glutamate release were abolished in aortic denervated rats, indicating that this response is due to a decrease of impulse generation in baroreceptors. A hypovolaemia elicited by blood infusion did not affect the release of glutamate. Similarly, a pronounced pressor response to phenylephrine (15 /kg per minute) infused intravenously for 9 min was ineffective.The results show that the K⁺-induced release of glutamate in the hypothalamus is dependent on the presence of Ca²⁺. The increase in glutamate release rate by hypovolaemia or chlorisondamine suggests that the glutamatergic neurons in the posterior hypothalamic area respond to unloading of aortic baroreceptors and possess a counteracting, hypertensive function.     

Finite Element Model Determination of Correction Factors Used for Measurement of Aortic Diameter via Conductance

Traditional methods for estimating the slope and offset volume V _P for determining real-time chamber volume by the conductance catheter technique are not suited to measurements made in the aorta due to the relatively low resistivity of the aortic wall. We developed three distinct three-dimensional finite element models of the conductance catheter and surrounding tissues in order to predict and V _P and to examine the nature of the electric field near the aortic wall. A heterogeneous isotropic model of the catheter, aorta and surrounding tissues accurately predicted the values of and V _P . A homogeneous anisotropic model was developed to examine the effects of anisotropy of blood and the layers of the aortic wall on measured values of resistance, and V _P . This model demonstrated that anisotropy of blood and aortic wall tissue can increase the values of both and V _P . Finally, a three-dimensional homogeneous isotropic rectangular model allowed examination of the effects of catheter position. This model showed small effects of catheter position on measured resistance (9.7% increase) and larger effects on (21.2% decrease) and V _P (41.9% increase). We conclude the following: the FEA models may lead to accurate estimate values of and V _P in vivo. The unique anisotropic conductive properties of the layers of the aortic wall contribute to the high observed values of and V _P in the aorta. Finally, catheter position has a proportionately greater effect on and V _P than on measured resistance. The results of this study should assist in the determination of aortic mechanical properties using conductance catheter measurements of vessel dimension. © 1999 Biomedical Engineering Society. PAC99: 8719Nn, 8719Rr, 8719Uv, 0270Dh, 8717Aa     

经皮球囊二尖瓣成形术10年临床经验

目的：旨在研究本院４００ 例经皮球囊二尖瓣成形术１０ 年的临床经验。　方法：采用改良的Ｉｎｏｕｅ 方法。　结果：经皮球囊二尖瓣成形术即刻成功率９８．３％ （３４４／３５０）,术后二尖瓣面积明显增加,达（１．１１±０．２９）～（２．１９±０．４０）ｃｍ ２。１０５ 例随访９个月～８ 年６ 个月,二尖瓣再狭窄率为１１．４％ （１２／１０５）,死亡率为２．９％ （３／１０５）,二尖瓣置换术为３．８％ （４／１０５）。　结论：经皮球囊二尖瓣成形术近、远期疗效均很好     

Clinical application of the M-numbers of aortic cannulas during hypothermic cardiopulmonary bypass in pediatric patients

A standardized system to describe the pressure-flow characteristics of a given cannula has recently been proposed and has been termed the M-number system. Using 3 different sizes of aortic cannulas in 50 pediatric cardiac patients on hypothermic cardiopulmonary bypass, we analyzed the correlation between experimentally and clinically derived M-numbers and found it to be positive. Clinical M-numbers were typically 0.35 to 0.55 greater than experimental M-numbers and correlated inversely with a patient's temperature change; this was most probably due to increased blood viscosity arising from hypothermia. This inverse relationship was more marked in higher M-number cannulas. The clinical data obtained in this study suggest that the experimentally derived M-number correlates strongly with the clinical performance of the cannula and that the influence of temperature is significant.     

Prevalence of cardiac and aortic enlargement in rheumatoid arthritis and its relationship to some characteristics of the patients

Summary The chest radiographs of 309 patients with rheumatoid arthritis (RA) were compared with those of 309 controls matched for sex and age. Cardiac enlargement was more frequent in RA females than in controls (P<0.05) and the frequency of aortic shadow enlargement was higher in RA patients aged 60 years than in controls (P<0.05). Both cardiac and aortic enlargement was significantly related to several parameters of the severity and the activity of RA, corticosteroid therapy, and elevated blood pressure. A high mortality was present in patients with aortic enlargement and in patients with ECG signs of myocardial ischaemia.     

Intraoperative color Doppler assessment in valve repair surgery

Intraoperative color Doppler recordings, obtained either from the epicardial or transesophageal approach, offer real-time information about the presence and severity of mitral regurgitation at the time of surgery. The technique allows instantaneous evaluation of mitral and tricuspid repair and may offer important information about the postoperative outcome.     

胃粘膜瓣成型预防食管胃吻合术后反流的观察

目的:介绍胃粘膜瓣成型预防食管胃吻合术后反流的临床应用.方法:食管、贲门癌50例,行部分食管部分胃切除,用吻合器作食管胃吻合后行胃粘膜瓣成型.结果:成型组术后无反流症状,上消化道造影及放射性核素显像表明该手术方法抗反流作用明显.食管镜检查示胃粘膜瓣成型组吻合口粘膜充血、水肿、糜烂、溃疡较常规手术组明显减轻.结论:胃粘膜瓣成型术可有效预防食管胃吻合术后胃食管反流.     

Changes in patterns of left ventricular hypertrophy after aortic valve replacement for aortic stenosis and regurgitation with St. Jude Medical cardiac valves

In this study, we analyzed the extent and pattern of regression of left ventricular (LV) hypertrophy after aortic valve replacement in patients with aortic stenosis (AS) and compared the results with those of another group of patients with aortic regurgitation (AR). Seventy patients who underwent isolated aortic valve replacement were divided into 2 groups. Group 1 was comprised of 29 patients who underwent aortic valve replacement for aortic stenosis, and Group 2 of 41 patients who underwent aortic valve replacement for aortic regurgitation. A third group of 10 healthy subjects served as a healthy control group. Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up, a significant reduction in the left ventricular mass was found in both groups, but it remained significantly greater than in the healthy control group. The ratio of LV wall thickness to radius (th/r) in Group 1 decreased significantly, and at follow-up it was within the normal value. In Group 2, the th/r ratio increased, and at follow-up it was within the normal value. After aortic valve replacement, the wall thickness remained significantly greater than normal for patients with AS, and the chamber radius remained significantly greater than normal for patients with AR. For these reasons, LV hypertrophy still existed in both groups at postoperative follow-up. The actuarial survival rate was 85.3% at 16 years for Group 1 and 83.4% at 18 years for Group 2. There was no significant difference in the long-term survival rates between the 2 groups. Actuarial freedom from valve-related events was 91.9% at 16 years for Group 1 and 82% at 18 years for Group 2. There was no significant difference in the valve-related event free curves between groups. After 5 years of follow-up, th/r reached normal for both groups, indicating remodeling of the LV geometry after aortic valve replacement.