移植肾舒张期反向血流动态观察的临床意义

目的 探讨移植肾舒张期反向血流动态观察的临床意义.方法 回顾性分析17例移植肾舒张期反向血流频谱形态的变化及其与临床结局的关系.将17例移植肾舒张期反向血流频谱形态分为2型:Ⅰ型,即全舒张期反向血流无变化或从非全舒张期反向血流变化为全舒张期反向血流.全舒张期反向血流变化型6例,病因:肾静脉血栓2例,肾动脉血栓1例,急性和慢性排斥反应各1例,肾小管坏死1例.Ⅱ型,即非全舒张期反向血流无变化或全舒张期反向血流变化为非全舒张期反向血流或反向血流消失.非全舒张期反向血流变化型11例,病因:急性排斥7例,肾小管坏死3例,感染1例.结果Ⅰ型6例中5例行移植肾切除术,1例保肾成功;Ⅱ型11例中10例保肾成功,1例行移植肾切除术.Ⅰ型频谱变化中保肾成功率低于Ⅱ型(Fisher确切概率法,P=0.005).结论移植肾出现舒张期反向血流时对血流频谱的变化进行动态观察有助于判断预后,Ⅰ型血流频谱形态变化患者预后不良.     

彩色多普勒超声在肾移植后排斥反应诊断中的应用

目的 探讨彩色多普勒超声在移植肾排斥反应监测中的应用价值。方法 对68例肾移植患者采用彩色多普勒超声进行监测，观察移植肾的结构及体积、肾皮质厚度、肾动脉内径、血流灌注情况、血流动力学参数。结果术后随访最长者达4年，45例移植肾功能正常，未发生排斥反应者，其移植肾在彩色多普勒超声下表现为边界清晰，肾内结构清楚，皮、髓质界限分明，血流丰富。13例发生急性排斥反应者，彩色多普勒超声下可见移植肾明显肿大，肾实质血流信号稀少，叶间动脉呈断续闪烁状，弓形动脉几乎无血流信号。10例发生慢性排斥反应者，彩色多普勒超声下可见移植肾体积缩小，皮质变薄，肾皮质与肾髓质界限不清，肾内血管分枝稀疏，血管树不连续，弓形动脉及小叶间动脉往往不显示，为低速高阻血流。血流动力学参数显示，发生急性排斥反应者的肾动脉阻力指数及搏动指数明显增高，舒张期峰值流速减低；发生慢性排斥反应者的肾动脉内径明显缩小，收缩期峰值流速及舒张期峰值流速明显减低，血流灌注量明显减少，阻力指数及搏动指数明显升高，与肾功能正常者比较，差异均有统计学意义。结论对于肾移植患者的术后监测，彩色多普勒超声具有独特的优点，无创、便捷，其所测得的移植肾形态学数据和血流动力学参数对排斥反应的判断具有重要参考价值，可作为肾移植术后的常规峪测手段。     

彩色多普勒超声诊断早期移植肾急性排斥

目的探讨彩色多普勒超声图像数据分析在诊断早期移植肾急性排斥中的作用及临床价值.方法总结203例肾移植术后6～30d内行彩色多普勒超声检查,结合临床症状、生化检查并参照病理诊断,对二维灰阶图像、彩色血流图、血流频谱及阻力指数(RI)、搏动指数(PI)、收缩期与舒张期血流速度比(S/D)等参数进行回顾性分析.结果以彩色多普勒RI>0.78、PI>1.82、S/D>4.1为标准,结合彩色血流图及血流频谱形态,早期移植肾急性排斥正确诊断率可达85.7%.结论应用彩色多普勒超声诊断移植肾早期急性排斥并监测其功能恢复,具有快速、准确、无创等优点,可提早发现病情变化并指导治疗,提高移植肾存活率.     

肝硬化病人肾血流变化的临床研究

目的 研究肝硬化患者肾脏血液动力学的变化。方法 对49例肝硬化病人采用彩色多普勒超声测定肾叶间动脉及弓形动脉搏动指数(PI)、阻力指数(RI)及收缩期最高峰值／舒张期最低峰值(PS／PD)等指数，并同时监测患者的血内皮素情况。结果 肝功能越差，搏动指数和阻力指数越高，尤以RI为著；随腹水量的增加，肝硬化病人的PI、RI等亦有明显增高。肝硬化血内皮素(ET)的增高与PI及RI增高密切相关。结论 通过多普勒超声发现肝硬化患者肾血流与肝功能有直接相关性，肝硬化腹水和肾血流亦有相关性，而顽固性腹水PI、RI的演变可能有助于早期发现肝肾综合征(HRS)；血内皮素水平在肝硬化病人中明显增高。且与肾血管阻力的增加呈正相关，因而内皮素可能是参与肝硬化病人肾血管收缩的重要活性因子。     

彩色多普勒在移植肾排异反应中的应用

彩色多普勒血流显像 (CDFI)具有直观、简易、无创伤等特点 ,现已成为判断移植肾排异反应的重要手段之一。我院自 1995年 1月～ 2 0 0 3年 4月做移植肾手术 6 2例 ,超声检查 2 34例次 ,脉冲多普勒检测了主肾动脉、段动脉血流、叶间动脉的血流参数 ,内容 :收缩期峰速度 (Vs) ,舒张期速度 (Vd) ,阻力指数 (RI) ,脉动脂数 (PI) ,并同 38例正常人(76只肾 )进行对比分析 ,现报告如下。资料与方法1　临床资料1.1　对照组　 38例健康者作为对照组 ,其中男 2 3例 ,女 15例 ;年龄 2 0岁～ 5 6岁 ,平均年龄 32岁 ,肾功能及其他肾脏检查均正常。1.2…     

行标准通道经皮肾镜碎石清石术患者肾内血流动力学变化的临床观察

目的 探讨标准通道经皮肾镜碎石清石术(PCNL)对患者肾血流动力学的近远期影响.方法 选取行标准通道经皮肾镜碎石清石术的43例患者,采用彩色多普勒超声对其各级肾动脉的血流参数进行评估,并于术后1d、1周、1个月进行复查,统计分析其手术前后的血流动力学变化规律.结果 术后1d,患者肾主动脉、段间动脉、叶间动脉及小叶间动脉的收缩期最高流速(PSV)、舒张期最低流速(EDV)及平均血流速度(Vm)较术前显著降低(P＜0.05);阻力指数(RI)较术前显著升高(P＜0.05).术后1周,患者各级肾动脉的PSV、EDV及Vm有所回升,RI有所下降,基本恢复至术前水平(P＞0.05);术后1个月,患者各级肾动脉的PSV、EDV及Vm显著高于术前水平(P＜0.05),RI显著低于术前水平(P＜0.05).结论 基于微创标准通道PCNL术对肾脏血流灌注有短暂的抑制效应;然而,随着术后时间的延长和血运障碍的缓解,患者各项血流动力学参数均可得到有效改善.     

移植肾动脉舒张期反向血流的临床意义

目的:评价移植肾动脉彩色多普勒超声检查中出现的舒张期反向血流(RDF)的临床意义。方法:对我院自2011年以来进行肾移植手术患者的临床资料进行回顾性研究,统计了所有出现RDF的病例,追踪记录其预后,并按照RDF发生时间和频谱形态进行分组。结果:42例移植肾患者出现了RDF,其原因包括排斥反应(24例)、急性肾小管坏死(7例)、肾静脉血栓(9例)、肾静脉受压(2例)。最终失肾率高达60%,仅3例患者肾功能恢复。结论:移植肾动脉出现RDF表明移植肾状态差,提示预后不良。但其发生时间及频谱形态与移植肾预后及病因无明显关联。     

标准通道PCNL对肾脏血流动力学的影响

目的：探讨标准通道经皮肾镜碎石清石术（PCNI。）对肾内血流动力学影响。方法：应用彩色多普勒血流显像测量100例采用标准通道经皮肾镜碎石清石术患者术前、术后即时、术后1周、术后3个月肾脏主动脉、段间动脉、叶间动脉收缩期峰值流速（Vmax）及收缩期峰值（s）与舒张期末流速（D）的比值（S／D）和阻力指数（resistantin—dex,RI）。结果：术后即时的。肾主动脉、段间动脉、叶问动脉的Vmax、S／D、RI值与术前比较,均P〈0．05,差异有统计学意义;但术后1周的。肾主动脉、段问动脉、叶间动脉的Vmax、S／D、RI值与术前比较,均P〈O．05;并且术后3个月的。肾主动脉、段间动脉、叶间动脉的RI值与术前比较,均P％0．05。结论：标准通道经皮肾镜碎石清石术对肾脏血流灌注有短暂影响,但术后1周左右可以恢复,术后3个月肾脏血流灌注有所改善。     

肾窦内肾盂加肾后下部切开取石术对肾血流动力学的影响

目的探讨肾窦内肾盂加肾后下部切开取石术对肾内血流动力学的影响. 方法应用彩色多普勒血流显像连续观察98例复杂性肾结石患者术前及术后1、3、6个月肾内及切口区域血流动力学变化,对比分析肾内主肾动脉、段间动脉、叶间动脉收缩期峰值流速(S)与舒张期末流速(D)的比值(S/D)和阻力指数(RI),并将区域血流信号分为Ⅰ～Ⅳ级观察. 结果肾内血流动力学变化与肾积水程度相关(P<0.05,r=0.82),手术对肾内血流动力学指标影响不明显(P>0.05),但对切口区域则造成短期局限性血流障碍,多表现为Ⅲ～Ⅳ级血流信号,一般3～6个月后逐渐恢复,恢复时间长短与结石合并肾积水程度相关. 结论肾窦内肾盂加肾后下部切开取石术是治疗复杂性肾结石的一种安全有效的方法.     

糖尿病早期肾损害的彩色多普勒超声研究

目的：探讨彩色多普勒超声肾血流测定对诊断糖尿病早期肾损害的价值。方法：以尿白蛋白排泄率（UAER）作为早期肾损害指标,对60例糖尿病患在26例正常人行彩色多普勒超声肾血流检查,结果：小叶间动脉收缩期峰值流速（Vs),弓状动脉及小叶间动脉舒张末期流速（Vd)的减慢是糖尿病患最早出现的肾内血流动力学改变;有肾脏早期损害的糖尿病患肾血流频谱参数特点是肾内弓状动脉,小叶间动脉的Vs和肾内各分支动脉的Vd明显减低,肾内各分支动脉的阻力指数（RI）明显增高,RI与糖尿病患肾功能损害程度相关。结论：彩色多普勒超声肾血流检测是早期诊断糖悄病肾损害的简便,可靠的方法。     

The value of pulsed Doppler for the follow-up of the transplanted kidney in the first 3 months of transplantation

This prospective study was conducted in 34 consecutive renal transplant patients. Pulsed doppler was used to evaluate the peripheral resistance (PR) in the transplant vessels. Under normal conditions, the PR of the graft is low, resulting in a continuous diastolic blood flow. The intensity of this blood flow was evaluated by means of a resistance index (RI), Pourcelot's index, calculated as follows: RI = systolic peak - end-diastolic peak/systolic peak This study demonstrated values for RI of 0.71 +/- 0.087 in 14 totally asymptomatic patients. In 10 cases of acute rejection, the RI increased to 0.91 +/- 0.12. The 7 patients with acute tubular necrosis had an RI equal to 1. In patients with cytomegalovirus infection of suffering from cyclosporin overdose, the RI was not modified in relation to asymptomatic subjects. This study demonstrates the existence of a rise in the PR in cases of acute rejection and acute tubular necrosis with a sensitivity of 90% and 100% respectively for these two diagnoses. However, this method cannot be used to distinguish between acute rejection and acute tubular necrosis.     

High resolution ultrasound characterization of early allograft hemodynamics in pediatric living related renal transplantation

PURPOSE: Allograft vascular thrombosis occurs in 5% to 10% of pediatric renal transplants. The hemodynamics of renal allograft immediately after implantation is unclear. High resolution Doppler ultrasound of the renal allograft performed in the operating room after incision closure is an effective and objective method to advance our understanding of baseline renal allograft hemodynamics, and identify unsuspected vascular complications early enough to ensure prompt surgical repair. MATERIALS AND METHODS: Between September 1998 and July 2000 high resolution, color power Doppler ultrasound was prospectively performed on 21 living related renal transplants in the operating room immediately after incision closure. Each ultrasound described allograft anastomotic blood flow, direction of diastolic flow, parenchymal perfusion and resistive indexes. RESULTS: There were 20 (95%) allografts with good power Doppler perfusion that had satisfactory immediate function with no vascular complications at 9 to 26-month followup. Initially, anastomotic turbulence was described in 15 (71%) allografts, and resistive indexes were abnormal in 8 (38%). Turbulence and abnormal resistive index normalized in all allografts by 1-month followup. Ultrasound of 1 allograft identified unsuspected poor perfusion and reversal of diastolic flow in the operating room after incision closure. In another allograft in which a 4-hour post-transplant ultrasound was compared with the baseline study in the operating room an unsuspected thrombosis of the right common iliac vein was confirmed. CONCLUSIONS: Good parenchymal perfusion and forward diastolic flow after renal reperfusion correlated well with immediate graft function. Initial turbulence and abnormal resistive index in the presence of favorable perfusion are misleading and not independent predictors of graft function. Ultrasound performed in the operating room identified 2 unsuspected major vascular complications facilitating prompt surgical correction.     

Resistive index and chronic allograft nephropathy evaluated in protocol biopsies as predictors of graft outcome.

INTRODUCTION: The presence of chronic allograft nephropathy (CAN) in protocol biopsies is negatively associated with graft survival. Although recent studies have indicated that the resistive index (RI) is a predictor of graft failure, it does not correlate with CAN in stable grafts. We therefore studied the relationship between RI and CAN and examined the predictive value of both parameters on graft outcome. METHODS: Included were patients transplanted between 1997 and 2002 and who had protocol biopsies and RI determinations. Renal lesions were blindly evaluated according to Banff 97 criteria. Mean glomerular volume, cortical interstitial volume fraction and intimal arterial volume fraction were estimated using a point counting technique. RI was determined before biopsy in at least two different renal locations. The outcome variable was defined as graft failure or a 30% serum creatinine increase between protocol biopsy and last follow-up. RESULTS: Eighty-seven patients were included. RI correlated with recipient age (R = 0.52, P < 0.0001), diastolic blood pressure (R = -0.36, P = 0.0006), pulse pressure index (R = 0.27, P = 0.009) and g-score for histological glomerulitis (rho = 0.30, P = 0.0054), but there were no correlations between RI and chronic Banff scores or any morphometric parameter. The presence of CAN (relative risk, 3.5; 95% confidence interval 1.2-10.2; P = 0.02) but not RI was associated with the outcome variable. CONCLUSION: RI was associated with surrogate measures of vascular compliance such as recipient age and pulse pressure index but not with chronic allograft damage, even when it was evaluated by histomorphometry. Our results indicate that histology may be superior to RI in predicting graft function deterioration, at least in patients with stable renal function.     

Intraoperative evaluation of coronary anastomosis by transit-time ultrasonic flow measurement

BACKGROUND: Intraoperative assessment of the anastomosis is important during coronary bypass on a beating heart. The purpose of this study is to predict the quality of anastomosis using transit-time flow measurement and to find out the most accurate indicator. METHODS: Eight swine underwent internal thoracic-anterior descending coronary artery bypass grafting on a beating heart. Flow measurement and angiography were performed at various degrees of stenosis created on the graft. As flow parameters, total flow, systolic flow, diastolic flow, diastolic/total flow ratio, systolic peak flow, diastolic peak flow, systolic/diastolic peak flow index, and pulsatility index were used. Mixed procedure and probability test (negative means successful anastomosis) were used to analyze the diagnostic ability. RESULTS: Diastolic flow, diastolic/total flow ratio, diastolic peak flow, systolic/diastolic peak flow index, and pulsatility index showed significant variance with increased stenosis. Among these measures, diastolic/total flow ratio showed the highest value of area under the curve (0.91) and the highest specificity (82%) at 90% sensitivity with actual value of 42%. CONCLUSIONS: Diastolic/total flow ratio was the most reliable indicator to predict critical stenosis in coronary artery bypass grafting.     

Role of duplex Doppler sonography in diagnosis of acute allograft dysfunction—time to stop measuring the resistive index?

Measurement of vascular resistive index (RI) by duplex Doppler sonography (DDS) has been proposed as a non-invasive technique to detect the presence of acute rejection in renal allograft recipients. Our aim was to evaluate the clinical utility of this technique. From 107 patients we reviewed 159 biopsies that were performed from 1993 to 2001 for the investigation of acute allograft dysfunction. Histological findings were correlated with RI measurements by contemporaneously performed DDS. The majority of biopsies were carried out within the first 3 months post-transplantation (111/159). Sixty-eight biopsies showed acute rejection, 91 biopsies had findings other than rejection (acute tubular necrosis, CyA toxicity, recurrent GN). Using a threshold mean RI value of 0.9, the test had a specificity for acute rejection of 89%, but a sensitivity of just 6%. If the threshold was lowered the sensitivity rose, but specificity declined sharply. Average RI in the rejection group was not higher than in controls (0.73+/-0.11 vs 0.74+/-0.11, respectively). We conclude that measurement of RI by DDS does not contribute to the diagnosis of acute allograft dysfunction.     

Evaluation of intrarenal hemodynamics by Doppler ultrasonography for renoprotective effect of angiotensin receptor blockade

AIMS: It has been shown that both angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin II type 1 receptor blockers (ARB) have renoprotective effects via mechanisms that are independent of blood pressure reduction. The aim of this study was to evaluate the intrarenal hemodynamic change with ARB by renal Doppler ultrasonography (RDU) and to assess the mechanism of ARB in patients with hypertension. METHODS: Thirty hypertensive patients with renal insufficiency caused by glomerular diseases, diabetes and hypertensive nephrosclerosis were included in this study. RDU was performed before and one week after taking ARB. Resistance index (RI) (peak systolic velocity - end diastolic velocity/peak systolic velocity) in the intrarenal segmental artery were calculated, and the amounts of urinary protein or albumin were determined. RESULTS: We defined patients whose microalbuminuria or proteinuria was reduced by greater than 30% by ARB as responders (n = 22) and defined other patients as non-responders (n = 8). There were no significant differences between the responder and non-responder groups in baseline characteristics. RI was significantly improved by ARB in the responder group, but not in the non-responder group. The reduction of RI after ARB treatment was most prominent in patients with hypertensive nephrosclerosis. CONCLUSIONS: Improvement in intrarenal hemodynamics might play an important role in the mechanisms of the renoprotective effect of ARB in patients with hypertension.     

Correlation of invasive Doppler flow wire with renal duplex ultrasonography in the evaluation of renal artery stenosis: the Renal Artery Stenosis Invasive Doppler (RAIDER) study

OBJECTIVE: Determining renal resistive index (RI) in the setting of renal artery stenosis may predict which patients benefit from revascularization. Renal duplex ultrasonography (RDUS) is the traditional method of assessing RI, but it is not available in most invasive endovascular laboratories. Conversely, endovascular techniques to assess RI are available but not well validated. The primary goal was to determine if an invasive approach using an endovascular Doppler flow wire correlates with RI assessment using traditional noninvasive RDUS. METHODS: In a single-center prospective trial, patients were enrolled if they had known or suspected renovascular disease. A Doppler flow wire was placed in multiple segments of the renal artery, and peak (PSV) and end-diastolic velocities (EDV) were measured. RI was calculated using the formula: RI = [1 - (EDV/PSV)] x 100. Similarly, RI was also derived using standard RDUS. All patients underwent both RI techniques before any revascularization procedure. Secondary end points included assessing the correlation for pole-to-pole renal length assessment and PSV and EDV velocities using both invasive and noninvasive techniques. Pearson correlation coefficient calculations were used to determine degree of correlation. RESULTS: The study enrolled 20 patients, and 35 renal arteries were studied. Overall, Pearson correlation coefficient for invasive vs noninvasive RI assessment was 0.86 (95% confidence interval [CI], 0.73 to 0.93). The r values were 0.43 (95% CI, 0.11 to 0.67) for pole-to-pole renal length, 0.66 (95% CI, 0.54 to 0.76) for PSV, and 0.61 (95% CI, 0.48 to 0.72) for EDV determination. No major complications occurred during this study. Average time to perform invasive Doppler assessment was 10.4 +/- 7.4 minutes per artery. CONCLUSIONS: Invasive RI assessment using an endovascular flow wire technique correlates well with traditional noninvasive RDUS. A moderate statistical correlation also exists for pole-to-pole renal length, PSV, and EDV determinations. The procedure is safe and can be performed rapidly.     

Evaluation of renal allograft function by Doppler spectrum analysis

A decreased renal function is rather common after renal transplantation. The causes of this decreased function are diverse and difficult to differentiate. Yet, duplex examination, and especially quantitative Doppler spectrum analysis of the blood velocities in the renal artery, may be an effective method for differentiating between some of these causes. Forty-five renal transplant recipients were included in this preliminary study. Doppler spectra were recorded from the renal artery to the allograft. Parameters were derived from every Doppler spectrum in order to characterize each spectrum. Renal allograft function was evaluated on the basis of a number of clinical parameters. A significant correlation was found between the clinical parameters and the Doppler spectrum parameters indicative for changes in the peripheral resistance. Patients with a normal renal allograft function showed Doppler spectra with a high diastolic flow, typical of a vascular bed with a low peripheral resistance. Patients with a decreased renal allograft function caused by a stenosis in the renal artery could be distinguished by a low peak velocity and a low pulsatility index. A decreased allograft function caused by allograft rejection or cyclosporin nephrotoxicity also led to characteristic arterial flow disturbances. In these cases, the peripheral resistance was increased, and this was primarily reflected in a decrease in the diastolic blood velocity. We conclude that quantitative analysis of the blood velocities in the renal artery by Doppler spectrum analysis seems to be a useful, noninvasive diagnostic tool that discriminates between some of the causes of a decreased renal allograft function.