The Doppler guide wire: clinical applications in neuroendovascular treatment

The application of Doppler-tipped guide wires to measure blood flow velocity in coronary and peripheral arteries has been described previously as a valuable means of functional assessment in interventional cardiological procedures. In animal studies intravascular Doppler has been used in the cerebrovascular system, and this appears to be an important field of application for this new technique. We used intravascular haemodynamic monitoring by the Doppler guide wire during neuroendovascular procedures in patients with different cerebrovascular diseases and evaluated the clinical feasibility of the method. We found it a safe technique which complements morphological angiographic information with valuable functional data. Further studies may be expected to demonstrate the relation of flow parameters to clinical outcome. Received: 16 January 1996 Accepted: 30 January 1996     

Effects of molsidomine and dopamine infusion on the size of canine experimental myocardial infarct

Summary The effects of i.v. molsidomine and dopamine infusion on mean haemodynamic changes, myocardial oxygen consumption (pressure-rate-product), and ultimate infarct size were studied in pentobarbital-anaesthetized, open-chest dogs and compared to those occurring in dogs receiving saline infusion. Either agent was administered in a separate setting. Haemodynamic variables and oxygen consumption were determined during a 6-h period after ligation of the left anterior descending coronary artery and collected at 1-h intervals. Infarct size was determined by post-mortem nitroblue tetrazolium stain of intracellular lactic dehydrogenase enzymes. Coronary artery ligation during saline infusion (n=8) resulted in decreased blood pressure and cardiac output, whereas heart rate, systemic peripheral resistance, end-diastolic filling pressure and myocardial oxygen consumption increased. Infarct size amounted to 24.2±3.2% (i. e., 23.8±3.1 g) of left ventricular mass. Infusion of 1.4 g/kg/min molsidomine (n=8) produced significant fall of blood pressure, cardiac output, filling pressure and oxygen consumption while heart rate and peripheral resistance were unaffected. The infarct volume was reduced to 49% (P<0.01) of that observed in saline controls. The administration of 3 g/kg/min dopamine (n=8) elevated blood pressure and cardiac output initially with a subsequent reduction of either parameter. Arteriolar vascular resistance and oxygen consumption increased but filling pressure remained unchanged. Infarct size was not different from saline controls. Infusion of 6 g/kg/min dopamine, however, significantly increased blood pressure, heart rate, and peripheral resistance. Cardiac output and filling pressure fell and myocardial oxygen consumption rose. The histochemically measured final infarct was reduced to 13.5±1.8% of left ventricle (i. e., 16.2±2.2 g, P<0.05 vs saline control), but the hearts were edematous and haemorrhagic. Therapy with molsidomine appears promising in the treatment of clinical myocardial infarction with haemodynamic sequellae. The safe use of therapy with higher dopamine doses in patients with acute myocardial infarction, however, awaits further investigation.Part of the dopamine experiments were done at Bayer AG, Institut für Pharmakologie     

Haemodynamic frailty – A risk factor for acute kidney injury in the elderly

Clinical frailty in the elderly is defined by a composite measure of functional psychomotor decline. Herein, we develop the concept of haemodynamic frailty (HDF), a state of increased predisposition to disease prevalent in the elderly and characterised by impairment of the network of compensatory responses governing the defence of circulatory volume and adaptive haemodynamic function. We review the factors predisposing the elderly to HDF, with a focus on the impaired capacity to sustain total body water balance. As a component of HDF, dehydration generates vulnerability to diseases caused by tissue hypoperfusion, including acute kidney injury. We provide a detailed mechanistic explanation of how dehydration and depletion of the intravascular volume impacts on renal blood flow to become an important element of the heightened risk of acute kidney injury (AKI) in the elderly. We bring these mechanistic considerations into the clinical context with reference to examples of how pre-renal (haemodynamic) and intrinsic (involving renal parenchymal damage) AKI risk is elevated in the setting of dehydration. Finally, we present HDF as a state of opportunity to prevent disease, for which diagnostic and interventional standards need to be refined. Further prospective studies are warranted to help clarify the clinical utility of assessing and managing HDF with regard to the mitigation of AKI risk in the elderly.     

多层螺旋CT对肝硬化患者肾脏血流灌注扫描的研究

目的用多层螺旋CT灌注成像技术观察肝硬化患者肾脏血流灌注参数的变化。方法对20例正常对照组和47例肝硬化病例组,其中代偿期肝硬化(compensatedcirrhosis,CC)18例,失代偿期肝硬化(decompensatedcirrhosis,DCC)29例,行16层螺旋CT肾脏灌注检查。通过专用灌注软件得出兴趣区相应的灌注参数值,包括血流量(bloodflow,BF),血容量(blowvolume,BV),对比剂平均通过时间(meantransittime,MTT)和表面渗透积乘积(permeabilitysurfaceareaproduct,PS)。统计分析这些参数。结果DCC较CC和正常对照组BF值明显减低,MTT值明显延长[皮质BF:对照组(513.95±106.69)ml/(100g.min),CC组(501.56±120.23)ml/(100g.min),DCC组(390.62±113.15)ml/(100g.min);P<0.01。MTT:对照组(2.73±0.72)s,CC组(2.56±0.77)s,DCC组(4.00±2.15)s;P<0.01。髓质BF:对照组(133.16±38.30)ml/(100g.min),CC组(137.96±62.86)ml/(100g.min),DCC组(90.37±60.33)ml/(100g.min);P<0.01。MTT:对照组(5.72±1.95)s,CC组(6.01±3.63)s,DCC组(9.55±5.82)s;P<0.01];DCC较CC和正常对照组皮质的PS值明显减低[对照组(61.57±18.87)ml/(100g.min),CC组(62.09±13.06)ml/(100g.min),DCC组(50.82±15.69)ml/(100g.min);P<0.05];CC与正常对照组BF值、MTT值、PS值差别无统计学意义(P>0.05)。3组间的BV值和髓质PS值差别无统计学意义(P>0.05)。结论失代偿期肝硬化患者肾脏BF值和皮质PS值明显减低,MTT值明显延长,而BV值和髓质PS值无明显变化。     

壁冠状动脉血流动力学体外模拟

目的 研究心肌桥压迫对壁冠状动脉内血流、正压力、周向应力、切应力的影响。方法 对原有的壁冠状动脉模拟装置进行较大改进,使其测量的血流动力学参数从单一应力（正应力）扩展到多种应力,以便更全面准确地模拟在正压力、周向应力、切应力共同作用下的真实血流动力学环境,从而综合考虑在多种应力共同作用下血流动力学规律与壁冠状动脉粥样硬化之间的关联。结果 壁冠状动脉模拟装置实验结果表明,应力的异常主要位于壁冠状动脉近端,随着心肌桥压迫程度加剧,近端的应力平均值与波动值明显增大,正应力平均值升高27.8%,波动值升高139%。结论 心肌桥压迫造成壁冠状动脉近端血流动力学发生异常,对认识冠脉粥样硬化发病的血流动力学机理具有重要意义,对于心肌桥的病理影响及治疗具有潜在的临床价值。     

低分子肝素钙并单硝酸异山梨酯治疗肺心病心衰疗效分析

慢性肺源性心脏病(肺心病)是临床常见危重症之一,往往可进一步发展为肺心病心力衰竭。肺心病患者由于慢性缺氧引起代偿性红细胞增多,使血液粘滞度明显增加,从而造成肺动脉压力的增高及通气/血流比例的严重失调,进一步加重缺氧,导致严重的右心衰竭或全心衰竭,此为慢性肺源性心脏     

小剂量瑞芬太尼降低心脏手术血流动力学反应的研究

目的:探索国产瑞芬太尼用于心脏手术的较低的有效剂量。方法:选择68例首次接受择期心脏直视手术患者,ASA≤Ⅲ级,根据4个不同剂量的瑞芬太尼0.1,0.2,0.3或0.4μg/(kg.min),随机分为四组(即R1,R2,R3或R4组)。以脑电双频指数(BIS)监测指导和调控依托咪酯的恒速输注,分别复合不同剂量的瑞芬太尼持续泵注的全凭静脉麻醉,研究心脏手术转流前各种伤害性刺激(气管插管、切皮、锯胸骨3个事件点)对血流动力学的影响,并分别记录各事件点前后的平均动脉压(MAP)、心率(HR)、心脏指数(CI)、每搏指数(SI)、外周血管阻力指数(SVRI)、加速度指数(ACI)以及BIS值。MAP、HR或二者同时增加超过基础值的20%,视为有临床意义,表明这些患者对伤害性刺激有反应。结果:四组间及各事件点前后的CI、SI、SVRI、ACI和BIS值无统计学意义。R3和R4组的剂量能较好地预防MAP和HR的增加(P(0.05)。结论:瑞芬太尼0.3或0.4μg/(kg.min)复合依托咪酯恒速输注在体外循环转流前可以减轻应激刺激的血流动力学反应,并可等同于来自相关文献的更高剂量瑞芬太尼而不影响心脏泵的功能。     

肝脏流入道血流动力学变化与酒精性肝病的相关性研究

目的应用彩色多普勒技术探讨酒精性肝病患者肝脏流入道血流动力学变化与酒精性肝损害不同病理改变的相关性及其临床意义。方法经超声检查、临床资料及实验室各项生化指征证实符合酒精性肝病诊断条件,临床除外其它肝病及显性心脏病者为研究对象。设A、B两组,A组为病变组,依据病变程度将其分为酒精性脂肪肝、酒精性肝炎和酒精性肝硬化。B组为正常对照组。应用彩色多普勒技术分别检测病变组肝动脉、门静脉最大血流速度(Vmax)、平均流速(Vmea)、血流量、阻力指数(RI)、搏动指数(PI),并与正常组对照。综合分析肝脏流入道血流动力学变化与酒精性肝病病变程度的关系。结果A、B两组入肝血管血流参数测值差异有统计学意义(P<0.05),病变组间亦差异有统计学意义(P<0.05),肝动脉、门静脉血流速度与病变程度呈负相关,RI、PI与之呈正相关。结论酒精性肝病患者肝脏血流动力学变化与酒精性肝损害程度密切相关,动态检测肝脏流入道血流参数变化对本病的早期诊断、预防和治疗具有重要意义。     

Association of tumour necrosis factor and haemodynamic shock in a newborn undergoing surgery for sacrococcygeal teratoma

A newborn who was operated upon for a benign sacrococcygeal teratoma at the age of 2 weeks developed haemodynamic instability with a shock episode at the time of operation. The serum level of tumour necrosis factor alpha (TNF-Alpha) during this event rose to 158 pg/ml (normal <15 pg/ml). Preoperatively TNF-Alpha was undetectable, while post-operatively the level was 23 pg/ml. Serum levels of the cytokine interleukin-1 beta (IL-1 beta) were undetectable throughout the study. The baby was treated successfully by fluid challenge and dopamine. This case represents a temporal association between haemodynamic instability during surgical intervention and a high serum level of TNF-Alpha, which is an important mediator in the pathogenesis of septic shock.     

Arterial haemodynamic parameters derived from noninvasively recorded pulsewaves,using parameter estimation

A parameter-estimation technique has been developed to derive haemodynamic parameters from pulsewaves, at a number of positions along a peripheral artery. The technique is entirely noninvasive, and uses pulsewaves recorded simultaneously from the brachial and radial arteries, which are fed into an analogue-computer model of the arm arteries. As the pulsewave amplitudes are uncalibrated, a novel technique was developed for comparing the model pulses with the pulsations of the actual artery. A least-squares error criterion was used in preference to an absolute-value criterion. As pressure but no flow waveforms were used, the impedance level, and thus the arterial cross-sections, in the model are, at first sight, undetermined. Linking the Poiseuille resistance of each segment of artery to its blood-mass parameter via the length of the arterial segment nevertheless gives unique per-segment values for radius. Parameters estimated with an acceptable result include the arterial internal radius, arterial compliance and the magnitude of the amplification effect of the pulsewave. Values for peripheral resistance are consistently understimated, owing to the use of an arterial model lacking viscous wall damping. Although the model parameter values are not exact, for various reasons explained in the text, they may still be useful for comparison between normal and abnormal conditions.