颈动脉切除术的体会

目的:探讨颈动脉切除术的安全检测指标,确保手术成功和患者生命安全.方法:19例行颈动脉切除的肿瘤患者采用术前体外或体内颈动脉压迫训练法,阻断颈动脉血流,通过经颅多普勒(TCD)和数字减影(DSA)检测了解脑侧支循环建立及交通动脉开放情况.术中夹闭颈总动脉,TCD检测患侧大脑前动脉(ACA)和大脑中动脉(MCA)代偿情况.结果:体外压迫训练18～45 d,体内压迫训练7～9 d达到合格标准.18例肿瘤全切,1例肿瘤包绕椎动脉入颅处行部分切除.无死亡病例和术后脑缺血及偏瘫等严重并发症.16例随访1～5 a无复发.结论:缓慢渐进的颈动脉压迫训练是促进脑侧支循环建立和患侧脑血流代偿的有效方法.TCD和DSA检测对手术成功和保障患者生命安全起决定性作用.     

颈动脉肿瘤术前大脑Willis环状况判定的临床研究

目的:探讨颈动脉瘤和颈动脉体瘤手术治疗前大脑Willis动脉环侧支循环状况判定的方法和标准,评价DSA全脑血管造影方法判定一侧颈动脉(颈内动脉)术中永久性阻断的安全性.方法:本组颈动脉瘤和颈动脉体瘤患者共14例,均行CT平扫、CT增强扫描和CTA血管成像三维重建,9例行DSA全脑血管造影检查.8例行手术治疗,3例保留颈总动脉和颈内动脉剥除肿瘤、5例颈总动脉(颈内动脉)连同肿瘤一并切除;4例术中同步行脑电图监测.分析术前颈动脉压迫训练后DSA全脑血管造影、术中脑电图监测等方法评价大脑侧支循环的可行性和可靠性.结果:8例手术患者中,无死亡病例,切口均一期愈合.术后均获随访3月～5 a,肿瘤相关症状消失,无肿瘤复发,其中1例术后出现偏瘫、失语,半年后康复.结论:DSA全脑血管造影检查是颈动脉肿瘤术前判断大脑Willis环侧支循环状况的重要方法,但不能作为判定一侧颈动脉结扎、切除安全性的"金标准".     

脑电图空间对称指数与单侧大脑中动脉狭窄后侧支循环状态的相关性

目的：探讨脑电图空间对称指数（spatial hemispheric brain symmetry index, sBSI）与大脑中动脉（McA）狭窄后患者侧支循环代偿之间的关系。方法：对25例单侧MCA重度狭窄或闭塞的患者（病例组）和15例健康者（对照组）进行16导联脑电图常规检查,计算出脑电图sBSI。病例均为经脑血管造影术（DsA）证实为MCA狭窄或闭塞。再将病例组分为有明显侧支循环代偿组和无明显代偿组两组,观察脑电图sBSI与MCA狭窄或闭塞后有无侧支代偿的关系。结果：lO例MCA闭塞病变患者中8例有明显侧支代偿。15例MCA重度狭窄患者中5例具有明显侧支代偿。病例组sBSI（0．078±0．025）明显大于正常对照组sBSI（0．058±0．010）,P=0．004;有侧支代偿病例组的脑电图sBSI（0．068±0．009）明显小于无侧支的病例组sBSI（0．092±0．032）,P=0．011。结论：脑电图检查作为一项无创的检查方法,其sBSI在评估MCA狭窄或闭塞后侧支代偿状态有一定的可行性。     

TCD对不同类型分水岭脑梗死的颅内血管评价研究

目的 通过研究经颅多普勒（TCD）对皮质和皮质下（内交界区）分水岭脑梗死狭窄或闭塞血管和侧枝循环的检出率,推测不同亚型分水岭脑梗死的发病机制,以指导临床采用相应的治疗策略。方法 对我院神经内科2015年1月~2018年10月住院的经MRI确诊的45例分水岭脑梗死患者行TCD检查,分析TCD对皮质分水岭（CBZ）脑梗死和皮质下分水岭（IBZ）脑梗死的血管狭窄检出率和侧枝代偿情况。结果 CBZ脑梗死24例,共211条血管纳入分析;IBZ脑梗死21例,共193条血管纳入分析。IBZ脑梗死颅内血管狭窄或闭塞的检出率及侧支循环代偿检出率高于CBZ脑梗死,差异有统计学意义（P＜0.05）。结论 IBZ脑梗死患者与血管狭窄和侧枝循环代偿关系更密切。     

超声二次谐波声面声学造影评价冠脉的微血管血流灌注

目的：本文获取冠状动脉血流变化所致的心肌灌注类型,以了解冠脉的微血管血流灌注变化。方法：36人先后完成冠状动脉影,静脉注射声学造影剂利声显（Levovist),通过超声二次谐波技术获取心肌灌注图像,按心肌灌注积分指数将病人分为三组。结果：三组病人的冠状动脉狭窄程度、心肌灌注积分指数明显差异（P＜0．001）,冠状动脉狭窄波＜75％者,病人心肌灌注多为正常,随着冠状动脉狭窄程度加重,出现不同程度的心肌灌注异常。8例完全阻塞的冠状动脉有不同的冠状动脉侧支循环表现为不同的心肌灌注类型。结论：静脉心肌声学造影是反映心肌灌注的有效方法,能够反应冠状动脉血流的改变及微循环结构的完整性变化,从而弥补冠状动脉造影仅能显示心外膜下的冠状动脉而无法观察毛细血管水平的心肌灌注之缺限。当心肌灌注不良时,MCE能提示冠状动脉病变的存在,及其严重性,但要注意侧支循环对心肌灌注之影响,可影响对冠脉病变程度判断的精确性。冠状动脉造影确定某支冠脉病变时,MCE心机灌注有助于评价侧支循环状态。     

Hemodynamic Effect of Cerebral Vasospasm in Humans: A Modeling Study

A mathematical model of cerebral hemodynamics during vasospasm is presented. The model divides arterial hemodynamics into two cerebral territories: with and without spasm. It also includes collateral circulation between the two territories, cerebral venous hemodynamics, cerebrospinal fluid circulation, intracranial pressure (ICP) and the craniospinal storage capacity. Moreover, the pial artery circulation in both territories is affected by cerebral blood flow (CBF) autoregulation mechanisms. In this work, a numerical value to model parameters was given assuming that vasospasm affects only a single middle cerebral artery (MCA). In a first stage, the model is used to simulate some clinical results reported in the literature, concerning the patterns of MCA velocity, CBF and pressure losses during vasospasm. The agreement with clinical data turns out fairly good. In a second stage, a sensitivity analysis on some model parameters is performed (severity of caliber reduction, longitudinal extension of the spasm, autoregulation gain, ICP, resistance of the collateral circulation, and mean systemic arterial pressure) to clarify their influence on hemodynamics in the spastic territory. The results suggest that the clinical impact of vasospasm depends on several concomitant factors, which should be simultaneously taken into account to reach a proper diagnosis. In particular, while a negative correlation between MCA velocity and cross sectional area can be found until CBF is well preserved, a positive correlation may occur when CBF starts to decrease significantly. This might induce false-negative results if vasospasm is assessed merely through velocity measurements performed by the transcranial Doppler technique. © 1999 Biomedical Engineering Society. PAC99: 8719Uv, 8719La, 8710+e     

冠心病患者冠状动脉侧支循环的形成与PDGF mRNA水平的关系

目的:探讨冠心病患者单核细胞血小板源性生长因子(PDGF)与冠状动脉侧支循环的关系。方法:依据选择性冠状动脉造影结果将64例患者分为对照组(非冠心病患者,n=15)、冠心病不伴侧支循环组(n=31)、冠心病伴侧支循环组(n=18),采用RT-PCR技术检测3组患者主动脉根部血液及股动脉血液中单核细胞PDGFmRNA水平。结果:(1)冠心病患者有、无侧支循环组之间的冠状脉动病变程度、不稳定心绞痛及心肌梗死发生率无显著差异(P>0.05);但无侧支循环患者心功能不全、室壁瘤的发生率显著增加(P<0.01);(2)与对照组相比,冠心病患者主动脉根部血液单核细胞PDGFmRNA水平增加(P<0.01);有侧支循环患者增加更为显著(P<0.01);而冠心病患者股动脉血液中单核细胞PDGFmRNA水平显著增加(P<0.01),有无侧支循环者之间无显著差别(P>0.05)。结论:冠状动脉侧支循环的建立可显著降低心肌梗死后心功能不全、室壁瘤的发生;PDGFmRNA水平增加与冠状动脉侧支循环形成密切相关;侧支循环形成与否可能主要取决于病变冠状动脉局部单核细胞PDGF基因水平;单核细胞PDGF基因水平可作为评价冠心病患者预后好坏的指标之一。     

复制大鼠门脉高压食管静脉曲张模型的解剖基础

采用血管灌注技术,对４０例成年Ｗｉｓｔａｒ大鼠肝外门脉系统和侧副循环途径作了系统观察。结果表明：大鼠脾静脉多为２条,且具有由胃十二指肠静脉,胃冠状静脉与脾静脉合成的胃脾静脉干,肠系膜后静脉均汇入到肠系膜前静脉。除食管静脉与直肠下静脉外,左肾上腺静脉,精索内静脉或子宫静脉也是门脉高压时门腔侧副循环的重要通道。     

单侧颈内动脉闭塞后侧支循环开放及其临床表现

目的：探讨在清醒状态下颅内动脉狭窄支架置入术的可行性及临床意义.方法：2007年2月到2008年1月,在局麻下应用血管内支架置入术治疗颅内动脉狭窄患者12例,其中颈内动脉系狭窄7例,椎-基底动脉系狭窄5例.结果：本组12例均成功接受了血管内支架置入,术中患者清醒,配合良好,无不良反应.术后6个月复查DSA提示,颅内动脉狭窄程度由原来的67.5%±9.5%下降至9.5%±2.8%（P＜0.01）.随访12～23个月,12例患者症状均改善,无卒中发生.结论：局麻下行血管内支架置入术治疗颅内动脉狭窄,可将重要并发症的危险性降到最低;颅内动脉痛觉神经并不敏感,完全可以承受介入支架置入操作.     

The value of phase-contrast magnetic resonance angiography of the circle of Willis in predicting cerebral ischemia-hypoxia (shunt need) during carotid endarterectomy

Background: Cerebral perfusion during carotid cross-clamping depends on collateral function of the circle of Willis. The aim of this study was to determine the value of 3D Phase-Contrast (3D PC) MR angiography in predicting pre-operatively the need of shunting. Methods: 3D PC MR angiography were performed in 121 patients before carotid endarterectomy under locoregional anaesthesia. Based on the MR analysis, the risk of cerebral ischemia–hypoxia during clamping was classified as high, moderate and low. The analysis was then correlated with intraoperative neurological examination. Results: In patients with high risk of cerebral ischemia (n=9), immediate cerebral ischemia developed in all patients within one min of clamping (P<0.001). All nine underwent shunt placement. In six of the patients with moderate risk (n=46), cerebral ischemia occurred between 20 and 25 min after clamping; All occurred during intraoperative hypotension. Conclusion: 3D PC MR angiography can significantly determine the need of shunting in patients with important risk of immediate intraoperative cerebral ischemia. It also focuses on the intraoperative blood pressure stability in patients with moderate risk of ischemia.     

肝动脉闭塞后侧支循环DSA表现

目的探讨肝动脉闭塞后侧支循环数字化减影血管造影(DSA)表现。方法收集肝动脉闭塞7例患者,其中男性6例,女性1例;年龄36～60岁,平均年龄49.6岁(标准差11.0岁)。肝动脉闭塞原因:肝动脉插管所致6例,外科手术1例。对患者均进行腹腔动脉和肠系膜上动脉造影以显示肝动脉侧支循环。结果肝总动脉近端完全闭塞7例,均可见侧支循环形成,肝脏侧支循环动脉起源于肠系膜上动脉6例,起源于胃左动脉1例。结论肝动脉闭塞后侧支循环形成并供应肝脏;DSA能清晰显示肝动脉闭塞后侧支循环并为介入治疗提供途径。     

Clinical interest of digestive arterial trunk anastomoses

Arterial vascularization of the gastrointestinal tract is a three-level system composed of the coeliac trunk, and both superior and inferior mesenteric arteries. The three levels are joined together via arterial trunk anastomoses such as the so-called and well-known Riolan arcade or supramarginal arcade. The aim of this study was to review the embryology of the digestive arteries in order to understand the anatomic variations, the development of the arterial trunk anastomoses and the potential collateral circulation in the case of obstruction of one or several arterial trunks. The arch theory by Mac Kay and Tandler longitudinal arterial anastomosis account for the genesis of the arterial trunk anastomoses and the main anatomic variations. The coeliac trunk and the superior mesenteric artery are joined together via the pancreaticoduodenal arcades and the Bühler arcade. These anastomoses are divided during pancreatic resections but developed in the case of coeliac trunk stenosis. The mesenteric arteries are joined together by the Riolan, Villemin arcades and by the marginal artery of Drummond. This collateral circulation and the Riolan arcade in particular, is utilized during left colonic resection. In the case of this collateral circulation insufficiency, inferior mesenteric artery reimplantation is necessary during abdominal aortic aneurysmectomy. Arteriopathy, more and more frequent due to population ageing is responsible for frequent obliteration of one or several digestive arterial trunks with subsequent development of collateral circulation. For such reasons, a sound knowledge of digestive arterial anatomy is an absolute prerequisite for surgical practice.     

小型幼猪体外循环模型灌注流量对脑血流灌注的影响

目的建立幼猪体外循环(cardiopulmonary bypass,CPB)模型,观察CPB灌注流量发生改变期间,脑灌注流量和局部脑氧饱和度(regional cerebral oxygen saturation,rSO_2)的变化,从而探索CPB灌注流量对脑血流量自我调节的影响,以期为婴幼儿CPB合理的灌注管理、预防脑缺血提供理论依据。方法 12只幼猪按照随机表分为3组,对照组、高流量组(H组)、低流量组(L组)。建立单泵双管CPB灌注模型,用血流检测仪直接检测灌注管路流量反映不同流量下脑动脉内血液灌注的变化,并采用近红外分光广度检测技术(near infrared reflectance spectroscopy,NIRS)监测幼猪CPB模型中rSO_2的变化。在CPB开始前10 min、CPB开始后10 min、升主动脉阻断后30 min和升主动脉开放后10 min 4个时间点检测血清S100钙结合蛋白B(S100 B)浓度。分别进行苏木精-伊红(HE)染色、尼氏染色观察海马CA区组织学变化。结果在主动脉阻断期间,H组脑灌注流量[(30.8±9.9)mL/(kg·min)]较L组[(19.0±7.4)mL/(kg·min)]有增高趋势但无统计学差异(P=0.072),且该时间点H组rSO_2值(52.65%±3.1%)显著高于L组(47.3%±3.3%)(P0.05)。海马组织学变化及血清S100 B蛋白水平无组间差异。结论在小型猪体外循环灌注模型中,脑动脉内流量及局部脑氧饱和度监测提示脑血流压力/血流自我调节减弱,高流量组脑灌注效果优于低流量灌注。     

Brain microvessels: factors altering their patency after the occlusion of a middle cerebral artery (Wistar rat).

The progression from ischemic injury to pannecrosis that occurs in the rat brain several hours after occluding a large artery may be partly attributable to a worsening of the circulation through the microvessels. The objective of this study was to quantitate selected structural changes involving astrocytes and endothelial cells within an area of focal brain ischemia created by the occlusion of a middle cerebral artery. The magnitude of these structural changes was correlated with alterations in the patency to a circulating macromolecule through the microvessels (< or = 15 mu in diameter) located within the territory of the occluded artery. One hundred eighty-five adult male Wistar rats had the right middle cerebral artery occluded after threading a nylon monofilament through the external carotid artery. Experiments were terminated by either cardiovascular perfusion or decapitation and immersion fixation at intervals ranging between 30 minutes and 7 days after the arterial occlusion. Randomly selected animals from each experimental subgroup were injected intravenously with horseradish peroxidase (molecular weight 44 kd) approximately 20 minutes before death. The progressive decline in the area fraction comprised by the vessels filled with horseradish peroxidase was preceded at 30 to 60 minutes by an increase in the surface area occupied (on a cross-section of a microvessel) by endothelial cells (both nucleus and cytoplasm). This was followed by an increase of 23.7% in the mean diameter of astrocytes nuclei and a decrease of approximately 35% in lumenal surface of the microvessels. These observations suggest that the occlusion of a large cerebral artery causes prompt swelling of endothelial cells and astrocytes; both of these early biological responses may interfere with erythrocyte circulation and oxygen delivery, which (after the arterial occlusion) are entirely dependent on the circulation provided by the collateral arterial connections. Through its interference with microvascular patency and oxygen delivery, cell swelling may influence the rate at which neurons become necrotic. In this model of brain infarct the number of necrotic neurons peaks approximately 72 hours after middle cerebral artery occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)     

主动脉弓手术停循环与脑灌注期间脑区域氧饱和度监测

目的:明确深低温停循环(DHCA)与脑灌注相结合进行主动脉弓手术期间脑区域氧饱和度监测(rSO2)的价值.方法:28位病人的rSO2被监控,数据被统计分析.结果:DHCA的平均停循环时间是(59±17.1)min,外科手术的结果比较满意,住院期间死亡2例,死亡率(5.6%).虽然全部病人兼有脑灌注支持,rSO2在DHCA期间仍然逐渐下降,平均降到(47±9.7)%,在复温末期又恢复到它的最初水平.有2位病人rSO2降低最明显,在长达83和88min的DHCA之后rSO2分别从57%和56%下降到27%和29%,这2位病人最终发展永久的神经系统损害.我们同时考察了End-rSO2和△-rSO2两个参数,在DHCA期间,脑灌注的灌注流速和这两个参数都存在线性相关.结论:(1)尽管DHCA和一定方式脑灌注的结合能提供大脑更有效的保护,这种保护措施仍然有一个安全的时限;(2)NIRS能实时监控脑rSO2,可用于监测大脑保护是否充分,有利于DHCA下脑灌注参数的凋整.     

A pressure controller of selective cerebral perfusion with single centrifugal pump

We are developing an original nonroller extracorporeal circulation system (NRECC). However, this NRECC could not perform selective cerebral perfusion (SCP). Therefore, we added cerebral perfusion lines and an automatic pressure controller to the system. The purpose of this study was to evaluate the stability and response of the pressure controller for the SCP in simulated clinical circulation. The NRECC consists of a centrifugal pump, four isolated vacuum suction lines and a conventional module. The SCP line branches from the main perfusion tubing and divides into three lines. Cerebral perfusion is regulated by a pressure controller, which is composed of an actuator, a pressure transducer, and a personal computer. The mock circuit was primed with normal saline, and the actual SCP pressure and flow were measured when the target pressure settled at 60, 80, and 100 mm Hg. The main perfusion flow was maintained at 4 L/min and the main perfusion pressure was altered from 120 to 300 mm Hg. The pressure and flow data were recorded. The SCP pressure was maintained within +/-1.47 mm Hg when the set pressure was 80 mm Hg. Fluctuation of flow in the SCP line was within the range of +/-2.8%. The time needed to reach the steady state pressure was 8+/-1 seconds when the initial setting of the roller occluder was full-open, and it took only 3+/-1 seconds to reach the next initial set pressure. We have developed the NRECC-SCP system. The SCP pressure is stable and quickly reaches steady state via the pressure controller. This system is useful for extracorporeal circulation during aortic arch operation.     

Analog Electrical Model of the Coronary Circulation in Case of Multiple Revascularizations

In this work, we propose an analog electrical model of the coronary circulation for patients with obstructive disease undergoing revascularization. In this clinical situation, the collateral circulation to the occluded artery is difficult to ascertain via preoperative measurements and well-developed collaterals might induce long-term restenosis of the revascularized artery due to flow competition mechanisms. The proposed model allows an original biomechanical analysis of per-operative hemodynamic data in order to assess quantitative evaluation of pressures and flows inside the native stenosed arteries, the collateral network and the bypass grafts. Average cardiac cycle values are analysed. In the case of 3-vessel disease and chronic occlusion of the right coronary artery, the quantitative results confirm the protective effects of the collateral flows in the pathological situation, but also show that the revascularization of the occluded right artery is fully justified since the collateral flows remain low, even when the left territory is revascularized. The model thus provides a computational tool to evaluate therapeutic strategies for each patient.     

Cerebral circulation in different types of brain hypoxia

The paper describes differences of hypoxic and circulatory hypoxias (i.e. brain ischemia) which cause decreases not only in the supply of O2, but in the delivery of glucose and other oxidation substrates and in venous return, which is attended by the accumulation of metabolic products in the brain tissue. It also considers the mechanisms of primary and secondary brain ischemia occurring with decreased cerebral circulation due to breakdown of cerebral blood flow autoregulation at its lower and upper borders to develop cytotoxic or vasogeneous brain tissue edema with possible compression of the microcirculatory bed in the latter case. Emphasis is laid on the significance of autoimmune reactions occurring with the impaired blood-brain barrier due to different types of cerebral circulatory disorders, which gives an insight into the cause of progressive damage to the brain in some cases despite its single damage. The paper outlines current therapies for brain ischemia, including those that exert effects on metabolic disturbances and neurosurgical reparative operations. In conclusion, the paper considers a new nontraditional way of increasing collateral CBF by decreasing blood flow pseudoturbulence with special high molecular-weight linear polymer solutions by the Thoms-effect method (1948). The prospects for using this approach in patients with brain ischemia are substantiated by a number of the established facts: 1) the above patients have higher hemodynamic blood flow resistance which may be corrected by adding a polymer solution into the sample in in vitro tests; 2) there was an inverse relationship of the intrinsic plasma concentrations of high molecular-weight fragments of DNA and hemodynamic resistance to the changes in plasma DNA properties in stroke patients.     

Quantitative assessment of cerebral autoregulation from transcranial Doppler pulsatility: a computer simulation study

Transcranial Doppler (TCD) ultrasonography is largely used today to achieve non-invasive assessment of cerebral autoregulation and cerebrovascular reactivity in neurosurgical patients. Recent experimental and clinical studies suggest that not only the pattern of mean velocity, but also velocity pulse amplitude alterations during changes in cerebral perfusion pressure (CPP) contain information on autoregulation status. The aim of this work is to investigate the relationship between cerebral autoregulation and TCD pulsatility by means of a comprehensive mathematical model of intracranial dynamics and cerebrovascular regulation. Simulation results, performed using different values of the most important clinical parameters of the model (autoregulation strength, cerebrospinal fluid (CSF) outflow resistance and intracranial elastance coefficient) show that velocity pulse amplitude increases with a reduction in CPP in patients with intact autoregulation, whereas changes in velocity pulsatility are modest in patients with weak autoregulation. Finally, velocity pulse amplitude decreases during a CPP reduction in patients with impaired autoregulation. Moreover, the relationship between the velocity pulse amplitude changes and autoregulation strength is almost linear in a wide range of CPP values, and is scarcely affected by changes in CSF circulation and intracranial elasticity. Starting from these results, we suggest a new quantitative index to assess autoregulation strength, i.e. G(aut)% = (s-b)/a, where G(aut)% is autoregulation strength (100% means intact autoregulation, 0% means impaired autoregulation), a approximately -0.03; b approximately 1.5 and s is the slope of the relationship ' percentage changes of velocity pulse amplitude to arterial pressure pulse amplitude vs. CPP changes'.     

Measurement of hemodynamic changes with the axial flow blood pump installed in descending aorta

We have developed various axial flow blood pumps to realize the concept of the Valvo pump, and we have studied hemodynamic changes under cardiac assistance using an axial flow blood pump in series with the natural heart. In this study, we measured hemodynamic changes of not only systemic circulation but also cerebral circulation and coronary circulation under cardiac support using our latest axial flow blood pump placed in the descending aorta in an acute animal experiment. The axial flow blood pump was installed at the thoracic descending aorta through a left thoracotomy of a goat (43.8 kg, female). When the pump was on, the aortic pressure and aortic flow downstream of the pump increased with preservation of pulsatilities. The pressure drop upstream of the pump caused reduction of afterload pressure, and it may lead to reduction of left ventricular wall stress. However, cerebral blood flow and coronary blood flow were decreased when the pump was on. The axial flow blood pump enables more effective blood perfusion into systemic circulation, but it has the potential risk of blood perfusion disturbance into cerebral circulation and coronary circulation. The results indicate that the position before the coronary ostia might be suitable for implantation of the axial flow blood pump in series with the natural heart to avoid blood perfusion disturbances.