超声引导下动静脉内瘘球囊扩张术疗效及通畅率影响因素分析

摘要 目的：观察超声引导下动静脉内瘘球囊扩张术疗效及通畅率的影响因素。方法：选择2018年6月-2020年12月在安徽医科大学第二附属医院行超声引导下自体动静脉内瘘球囊扩张患者230例作为研究对象,根据患者术前血镁水平将患者为低镁血症组87例、正常及高镁血症组143例。分析患者一般人口学资料、术前实验室检查及超声记录指标,随访预后疗效。结果：手术技术成功率98.12 %,平均随访443±100天。两组术后3个月的血管内径与透析血流量高于术前,正常及高镁血症组高于低镁血症组（P<0.05）。术后3个月正常及高镁血症组的总有效率高于低镁血症组（P<0.05）。正常及高镁血症组术后3个月、6个月与1年的血管通畅率分别为90.9 %、77.62 %、67.83 %,明显高于低镁血症组的80.46 %、64.37 %、51.72 %（P<0.05）。COX多因素分析影响随访血管1年通畅率的因素主要为镁、血管内径、肱动脉血流量、年龄等（P<0.05）。结论：超声引导下动静脉内瘘球囊扩张术对自体动静脉内瘘狭窄或血栓具有很好的效果,低镁血症、血管内径、肱动脉血流量是影响血管通畅率的重要因素。     

彩色多普勒超声在血液透析动静脉内瘘功能评估及病变检测中的应用探究

目的:探讨彩色多普勒超声在血液透析动静脉内瘘功能评估及病变检测中的应用价值。方法:选取2013年3月至2016年3月于我院接受血液透析的终末期肾病患者62例作为研究对象,采用二维超声观察动静脉内瘘的一般情况,采用彩色多普勒观察血流方向、速度以及充盈情况,对检测结果进行比较。结果:自体动静脉内瘘成形术后桡动脉管径(RAD)、桡动脉血流量(RVF)、头静脉管径(CVD)均较术前有所提高,各项指标随时间延长而逐渐增高,差异有统计学意义(P0.05)。62例血液透析患者中,共有41例(66.13%)患者动静脉内瘘通畅,21例(33.87%)患者出现动静脉内瘘并发症,其中血栓形成9例(14.52%)、动静脉瘘狭窄7例(11.29%)以及静脉瘤状扩张5例(4.84%)。血栓形成组头静脉血管内径(D)、吻合口D、最大峰值流速(PSV)及血流阻力指数(RI)、桡动脉D、PSV及RI均较正常组有显著差异。血栓形成、动静脉瘘狭窄患者上述参数及血流量与正常组比较有显著差异(P0.05)。结论:彩色多普勒超声可有效监测血液透析患者动静脉内瘘病变发生情况,对其结构功能进行直接观察的同时还可明确诊断动静脉内瘘并发症。     

Ulceration of the hand secondary to a radial arteriovenous fistula: a model for varicose ulceration.

A patient in whom a radial arteriovenous fistula was constructed in preparation for haemodialysis subsequently developed ulceration on the dorsum of the hand. The lesion failed to heal despite antibiotic treatment, and so the fistula was closed. The lesion healed within three weeks. Subsequent construction of a fistula at the right wrist was followed 12 months later by the development of similar ulceration of the right hand. This complication of arteriovenous fistulas is similar to varicose ulceration of the leg and provides a unique opportunity to study the effects of sustained venous hypertension on the skin.     

Systemic arteriovenous fistula leads to pulmonary artery remodeling and abnormal vasoreactivity in the fetal lamb

Several cases of systemic arteriovenous fistula diagnosed in the human fetus have been associated with the postnatal development of persistent pulmonary hypertension. The aim of this study was to determine the effects of a prenatally created systemic arteriovenous fistula on the structure and reactivity of the pulmonary circulation in the fetal lamb. A fistula between the jugular vein and carotid artery was created in fetal lambs at 119-124 days of gestation. At delivery (134-139 days), left pulmonary artery (LPA) pressure was increased in the fistula group (n = 12) compared with controls (n = 11, P < 0.01). The pulmonary vascular resistance was significantly higher in the fistula group (P < 0.05), whereas mean LPA blood flow was not statistically different between the two groups. Morphometric analysis of the pulmonary vascular bed revealed an increase in the number of peripheral muscular arteries, together with an increase in pulmonary arterial medial thickness in the fistula group. There was no difference in the relative number or size of intraacinar arteries. In vitro organ bath studies on pulmonary arterial rings showed impaired endothelium-dependent relaxation in the fistula group compared with controls. However, endothelial nitric oxide synthase protein expression was similar in both groups, whereas endothelium-independent relaxation to sodium nitroprusside was greater in the fistula group compared with controls. A systemic arteriovenous fistula leads to both structural and functional alteration of the pulmonary vasculature, which might lead to the development of persistent pulmonary hypertension after birth.     

Operating management of central venous hypertension complicating upper extremity dialysis access

Aim: To evaluate the importance of surgical bypass between the terminal part of functional arteriovenous shunt (av) for hemodialysis on upper extremity and inner jugular vein in axillosubclavian venous segment obstruction associated with central venous hypertension. Method: Retrospective assessment of surgical bypass between central segments of av fistula and ipsilateral/contralateral inner jugular vein using ePTFE graft in 17 patients over a 20 year period (1987-2006). Results: The surgical procedure was not associated with intra- or post-operative complications. Primary cumulative bypass and av fistula function persisted for 26 months on average. Conclusion: An accurate bypass to salvage the functional dialysis access associated with central venous hypertension requires careful decision based on clinical and radiological examination. The bypass procedure is beneficial where endovascular treatment is not indicated. Clinical and radiological bypass monitoring is crucial.     

高频彩色多普勒超声监测维持性血透内瘘功能的临床应用现状

该文综述了应用高频彩色多普勒超声在血透患者动静脉内瘘（ AVF）术前进行目标血管的选择,检查、筛选与定位,术后可用于监测动静脉内瘘（ AVF）功能、流量、流速与各种并发症,以利于提高血透患者的生活质量与生存率。     

Effects of wall distensibility in hemodynamic simulations of an arteriovenous fistula

Arteriovenous fistulae are created surgically to provide adequate access for dialysis patients suffering from end-stage renal disease. It has long been hypothesized that the rapid blood vessel remodeling occurring after fistula creation is in part a process to restore the mechanical stresses to some preferred level, i.e., mechanical homeostasis. The current study presents fluid–structure interaction (FSI) simulations of a patient-specific model of a mature arteriovenous fistula reconstructed from 3D ultrasound scans. The FSI results are compared with previously published data of the same model but with rigid walls. Ultrasound-derived wall motion measurements are also used to validate the FSI simulations of the wall motion. Very large time-averaged shear stresses, 10–15 Pa, are calculated at the fistula anastomosis in the FSI simulations, values which are much larger than what is typically thought to be the normal homeostatic shear stress in the peripheral vasculature. Although this result is systematically lower by as much as 50 % compared to the analogous rigid-walled simulations, the inclusion of distensible vessel walls in hemodynamic simulations does not reduce the high anastomotic shear stresses to “normal” values. Therefore, rigid-walled analyses may be acceptable for identifying high shear regions of arteriovenous fistulae.     

Recovery after surgery of the spinal N24 SEP in dural arteriovenous malformation of the dorsal cord

We studied somatosensory evoked potentials (SEPs) to tibial nerve stimulation in two patients suffering from dorsal dural arteriovenous malformation (AVM). We found in both patients abnormalities in the lumbar N24 potential and in the cortical P40 response. After surgical removal of the AVM, the N24 recovered in both patients. Cord lesions probably occur in patients with dural AVM because of a theft of blood through the fistula; N24 recovery may therefore be associated with a restoration of blood supply after surgery. The N24 recovery in our patients with dural AVM suggests that the abnormality of this potential does not necessarily reflect irreversible damage to the Jumbo-sacral cord and that the N24 recording can be useful in post-surgical monitoring.     

Computational model for simulation of vascular adaptation following vascular access surgery in haemodialysis patients

An important number of surgical procedures for creation of vascular access (VA) in haemodialysis patients still results in non-adequate increase in blood flow (non-maturation). The rise in blood flow in arteriovenous shunts depends on vascular remodelling. Computational tools to predict the outcome of VA surgery would be important in this clinical context. The aim of our investigation was then to develop a 0D/1D computational model of arm vasculature able to simulate vessel wall remodelling and related changes in blood flow. We assumed that blood vessel remodelling is driven by peak wall shear stress. The model was calibrated with previously reported values of radial artery diameter and blood flow after end-to-end distal fistula creation. Good agreement was obtained between predicted changes in VA flow and in arterial diameter after surgery and corresponding measured values. The use of this computational model may allow accurate vascular surgery planning and ameliorate VA surgery outcomes.     

Increased Inlet Blood Flow Velocity Predicts Low Wall Shear Stress in the Cephalic Arch of Patients with Brachiocephalic Fistula Access

BackgroundAn autogenous arteriovenous fistula is the optimal vascular access for hemodialysis. In the case of brachiocephalic fistula, cephalic arch stenosis commonly develops leading to access failure. We have hypothesized that a contribution to fistula failure is low wall shear stress resulting from post-fistula creation hemodynamic changes that occur in the cephalic arch.MethodsTwenty-two subjects with advanced renal failure had brachiocephalic fistulae placed. The following procedures were performed at mapping (pre-operative) and at fistula maturation (8–32 weeks post-operative): venogram, Doppler to measure venous blood flow velocity, and whole blood viscosity. Geometric and computational modeling was performed to determine wall shear stress and other geometric parameters. The relationship between hemodynamic parameters and clinical findings was examined using univariate analysis and linear regression.ResultsThe percent low wall shear stress was linearly related to the increase in blood flow velocity (p < 0.01). This relationship was more significant in non-diabetic patients (p < 0.01) than diabetic patients. The change in global measures of arch curvature and asymmetry also evolve with time to maturation (p < 0.05).ConclusionsThe curvature and hemodynamic changes during fistula maturation increase the percentage of low wall shear stress regions within the cephalic arch. Low wall shear stress may contribute to subsequent neointimal hyperplasia and resultant cephalic arch stenosis. If this hypothesis remains tenable with further studies, ways of protecting the arch through control of blood flow velocity may need to be developed.     

Gender differences in vascular access in hemodialysis patients in the United States: Developing strategies for improving access outcome

Background: Patients undergoing chronic hemodialysis (HD) require placement of permanent vascular access with the creation of an arteriovenous fistula (AVF), an arteriovenous prosthetic graft (AVG), or a tunneled central venous catheter. AVFs provide greater long-term patency, fewer complications, and lower infection rates than do either AVGs or catheters. Despite these advantages, women continue to be underrepresented among AVF patients, possibly because of concerns about smaller vascular diameters and higher rates of early primary fistula failure in female HD patients. The numerous clinical benefits of AVF suggest that a greater effort should be made to promote AVF placement in women.Objective: This review analyzes risk factors for AVF failure in women and describes clinical strategies to improve AVF utilization and success for female HD patients.Methods: English-language publications were identified through a MEDLINE database search from January 1997 to March 2007, using the search terms arteriovenous fistula, vascular access, hemodialysis, female, and gender. Reference lists of identified articles were also reviewed.Results: There are significant benefits to using AVFs instead of AVGs or catheters in HD patients: greater long-term fistula patency, superior flow rates, and fewer complications. Vascular anatomical differences between the sexes contribute to the underutilization of AVF in women. AVF placement rates can be improved if patients and staff are adequately educated and provided with the tools to facilitate AVF placement. Noninvasive preoperative screening is important to identify superior access sites in women. Intraoperative monitoring of blood flow is a reliable predictor of early radiocephalic AVF patency. Routine postoperative vascular monitoring may improve overall success with AVF, and exercise may improve vascular diameter and may be even more beneficial for women, who may have smaller preoperative veins.Conclusions: Concerns about smaller vascular diameters and reports of higher failure rates in women may prevent nephrologists and surgeons from considering AVF for female HD patients. The numerous advantages associated with AVF suggest that a greater effort should be made to increase its utilization in women. With appropriate motivation, care, and diligence by treating clinicians, the success of AVFs in women can approach the good results typically expected in men.     

Radial artery wall shear stress evaluation in patients with arteriovenous fistula for hemodialysis access

It has been extensively documented that changes in blood flow induce vascular remodeling and this phenomenon seems to be correlated to the shear forces imposed on the vessel wall by motion of blood. Wall shear stress, the tractive force that acts on the endothelium, has been shown to influence endothelial cell function. To study changes in wall shear stress that develop on the vessel wall upon changes of blood flow, we set up a technique that allows estimation of shear stress in the radial artery of patients on chronic hemodialysis therapy. The technique is based on color-flow Doppler examination of the radial artery before and after surgical creation of radiocephalic fistula for hemodialysis. Calculation of time function wall shear stress and blood flow rate in the radial artery is performed on the basis of arterial diameter, center-line velocity waveform and blood viscosity, using a numerical method developed according to Womersley's theory for pulsatile flow in tubes. The results presented confirm that the model developed is suitable for calculation of the wall shear stress that develops in the radial artery of patients before and after surgical creation of an arteriovenous fistula for hemodialysis. This methodology was developed for characterization of wall shear stress in the radial artery but may be well applied to other vessels that can be examined by echo-Doppler technique.     

Microcirculatory bed of the heart during peripheral arteriovenous shunting

In the experiment performed on 108 test and 28 control dogs, by means of injection and histological methods, the effect of arteriovenous fistula on the cardiac microcirculatory bed has been studied. The arteriovenous blood shunting results in plethora and stasis in the cardiac microcirculatory bed, in dilatation of all its links, in aggregation and adhesion of the blood formed elements, in increased permeability of microvessels, in diapedesis of erythrocytes and in myocardial edema, in winding microvessels, in development of the venoarterial reaction, in hypertrophy of myocytes, recalibration and sclerosis of the microvascular walls.     

Endovascular embolization of arteriovenous lung fistulas (review of literature and own results)]

The authors analyze the literature data on and their own experience in endovascular closure of arteriovenous lung fistulas: 20 fistulas were closed in 12 patients, in whom transcutaneous catheterization of the pulmonary artery was performed. Large-frame angiopulmonography made it possible to reveal 10 common arteriovenous lung fistulas (7 single and 3 multiple ones). Afterwards the diagnostic procedure was turned into a therapeutic one. Several types of spirals, spongogel fragments, pieces of felt and pools with wool were used as embolizing materials. All these measures resulted in hermetic closure of the arteries and a complete stop of pathological right-left shunting of the blood at the lung level and positive dynamics of blood gaseous indices.     

桡动脉-头静脉瘘成熟障碍原因分析及治疗的研究进展

桡动脉-头静脉瘘因其通畅率高、并发症少而被认为是血液透析血管通路的第一选择,但高达50%的内瘘因各种原因不能成熟,这主要是由于持续性地低血流量或穿刺困难导致无法进行充分的血液透析。常见的原因有流入道或流出道狭窄、吻合口狭窄、静脉位置过深及分支静脉的分流。此外,血栓形成是造成狭窄的一个常见原因。术前通过体格检查和超声检查评估血管条件选择合适的血管对于内瘘的成熟有着重要的意义。应针对引起成熟障碍的病因选择合适的治疗方法:术后普遍应用阿司匹林预防血栓形成进而减少狭窄的发生;外科手术有绕过损伤区域的优点但却创造一个新的吻合;近年来血管腔内技术因其微创的特点在大多数时候是第一选择。本文将对内瘘成熟障碍的定义、病因、诊断及治疗进行综述。     

Direct effects of nitroprusside do not alter gas exchange in canine oleic acid edema

The authors investigated why intrapulmonary shunt (QS/QT) increases with sodium nitroprusside (SNP) in canine oleic acid pulmonary edema. To determine the effects of flow alone on QS/QT, a peripheral arteriovenous fistula with a variable resistor was employed to increase cardiac output (Q) 26 and 52% above base line in a stepwise fashion (P less than 0.01). To examine the direct effects of SNP, distinct from changes in flow, the drug was given to produce matched increments in Q in each dog (P less than 0.01). To control for time, base-line measurements were obtained before and after each intervention, the sequence of which was alternated. At each increment in Q, SNP and the arteriovenous fistula increased QS/QT a similar amount. The mixed venous O2 tension (P-vO2) followed Q similarly in each group. Pulmonary vascular resistance (PVR) fell more (P less than 0.01) with SNP than with the arteriovenous fistula at identical Q and P-vO2. The authors conclude that, in this model, a direct pharmacological effect of SNP does not contribute to the deterioration in QS/QT. In fact, SNP exerts a pulmonary vasoactive effect that does not adversely affect gas exchange.     

Liver Transplantation in Man—III,Studies of Liver Function,Histology, and Immunosuppressive Therapy

The experience gained from 13 hepatic transplant operations is described, with particular reference to the findings in nine patients who survived the immediate operative period. A major problem was found to be infection. Fulminant pneumonia caused death in two adults, at a time when liver function was virtually normal. Infection related to bile fistula and sepsis may be overcome by an improved method of biliary drainage by cholecyst-dochostomy, which was carried out in the last two patients. Jaundice in the second week due to rejection was observed in several patients. The striking histological change was centrilobular cholestasis. The jaundice, which was not prevented by administration of antilymphocyte globulin, was rapidly controlled by temporarily increasing die dose of prednisone. One patient who survived for four and a half months and who had a poor tissue match subsequently developed chronic rejection with progressive cholestatic jaundice. Five of the patients were able to go home and at time of publication two are alive and well 14 and 20 weeks after treatment.     

A high red blood cell distribution width predicts failure of arteriovenous fistula

In hemodialysis patients, a native arteriovenous fistula (AVF) is the preferred form of permanent vascular access. Despite recent improvements, vascular access dysfunction remains an important cause of morbidity in these patients. In this prospective observational cohort study, we evaluated potential risk factors for native AVF dysfunction. We included 68 patients with chronic renal disease stage 5 eligible for AVF construction at the Department of General and Vascular Surgery, Central Clinical Hospital Ministry of Internal Affairs, Warsaw, Poland. Patient characteristics and biochemical parameters associated with increased risk for AVF failure were identified using Cox proportional hazards models. Vessel biopsies were analyzed for inflammatory cells and potential associations with biochemical parameters. In multivariable analysis, independent predictors of AVF dysfunction were the number of white blood cells (hazard ratio [HR] 1.67; 95% confidence interval [CI] 1.24 to 2.25; p<0.001), monocyte number (HR 0.02; 95% CI 0.00 to 0.21; p?=?0.001), and red blood cell distribution width (RDW) (HR 1.44; 95% CI 1.17 to 1.78; p<0.001). RDW was the only significant factor in receiver operating characteristic curve analysis (area under the curve 0.644; CI 0.51 to 0.76; p?=?0.046). RDW>16.2% was associated with a significantly reduced AVF patency frequency 24 months after surgery. Immunohistochemical analysis revealed CD45-positive cells in the artery/vein of 39% of patients and CD68-positive cells in 37%. Patients with CD68-positive cells in the vessels had significantly higher white blood cell count. We conclude that RDW, a readily available laboratory value, is a novel prognostic marker for AVF failure. Further studies are warranted to establish the mechanistic link between high RDW and AVF failure.     

Pyogenic Postpneumonectomy Empyema

The Clagett method of managing postpneumonectomy empyema was used on two patients and proved efficacious. After tube drainage (if a bronchopleural fistula is present), treatment is begun by creating a pleurostomy in a dependent site. The patient may then be cared for as an outpatient, and dressings may be changed at home. After a few months, when the pleura is clean, the pleurostomy is closed surgically and the space is filled with ¼% neomycin solution. If a fistula is present, this is closed at the same time. The treatment depends on the ability of the neomycin to sterilize any residual infection, after temporary drainage of the empyema. It makes unnecessary a major and mutilating thoracoplasty or even permanent tube drainage, which is usually difficult to manage on an outpatient basis.     

Ventilatory responses to increased blood flow and decreased lung volume in awake dogs

The effect of decreased lung volume on ventilatory responses to arteriovenous fistula-induced increased cardiac output was studied in four chronic awake dogs. Lung volume decreases were imposed by application of continuous negative-pressure breathing of -10 cmH2O to the trachea. The animals were surgically prepared with chronic tracheostomy, indwelling carotid artery catheter, and bilateral arteriovenous femoral shunts. Control arteriovenous blood flow was 0.5 l/min, and test flow level was 2.0 l/min. Arterial blood CO2 tension (PaCO2) was continuously monitored using an indwelling Teflon membrane mass spectrometer catheter, and inhaled CO2 was given to maintain isocapnia throughout. Increased fistula flow alone led to a mean 52% increase in cardiac output (CO), whereas mean systemic arterial blood pressure (Psa) fell 4% (P less than 0.01). Negative-pressure breathing alone raised Psa by 3% (P less than 0.005) without a significant change in CO. Expired minute ventilation (VE) increased by 27% (P less than 0.005) from control in both of these conditions separately. Combined increased flow and negative pressure led to a 50% increase in CO and 56% increase in VE (P less than 0.0025) without any significant change in Psa. Effects of decreased lung volume and increased CO appeared to be additive with respect to ventilation and to occur under conditions of constant PaCO2 and Psa. Because both decreased lung volume and increased CO occur during normal exercise, these results suggest that mechanisms other than chemical regulation may play an important role in the control of breathing and contribute new insights into the isocapnic exercise hyperpnea phenomenon.