Sonographic detection of kidney infarctions using ultrasound contrast media

Contrast-enhanced CT is currently the gold standard for the diagnosis of kidney infarction. Particularly in patients with renal insufficiency, however, the use of iodine contrast media is limited. Sonographic examination using ultrasound contrast media may be an alternative for these patients. CASE REPORTS: We examined three patients with suspected ischaemic kidney infarction with ultrasound contrast media. Scanning was performed with low mechanical index, and SonoVue was used as by contrast-enhancing agent. In all three patients, kidney infarctions were clearly shown. In two patients, the lesions were confirmed by contrast-enhanced CT, in one no CT was performed because of impaired renal function. CONCLUSION: Kidney infarctions can reliably be detected by contrast-enhanced ultrasound using SonoVue as contrast agent. This is particularly valuable in patients with renal impaired renal function and other contraindications against iodine contrast media.     

Utilisation des produits de contraste au cours des examens radiologiques réalisés en urgence : risques et précautions à prendre

Use of contrast media in emergency investigations: risks and guidelines for their prevention. Diagnostic and interventional radiology of emergency patients is nowadays crucial and more and more requires the infusion of contrast media. These techniques may trigger deleterious side-effects, mainly iodinated contrast media-related allergies and acute renal failure. Patients at high risk to develop such adverse events have to be detected on the basis of their risk factors (previous allergies, renal failure, diabetes, etc.) in order to prevent or limit serious outcome. In case allergy is suspected, tests are mandatory because premedication may fail to prevent death. Allergy to non-iodinated contrast media is rarer and therefore offers an alternative to iodinated contrast media. Even if a benefit can be expected by the association of N-acetyl-cysteine and hydratation in preventing contrast media related nephropathy in non-emergency patients given iodinated media, in emergency situations a doubt still persists.     

Gadolinium-induced nephrotoxicity

Because of the well-documented risk of acute renal failure with the iodinated contrast media in patients with underlying chronic renal insufficiency, the use of intravenous gadolinium-based contrast media in magnetic resonance imaging for diagnostic and interventional radiology procedures has become a well-established clinical practice in the recent years. Although originally thought to be safe and lack the nephrotoxic effects of iodinated contrast media, gadolinium-based contrast media have recently been reported to induce a usually reversible decrease of glomerular filtration rate in a high-risk population group, especially in patients with altered baseline renal function. Here we present the current experimental and clinical evidence on this new challenge for the nephrologist, gadolinium-induced nephrotoxicity in patients with chronic kidney disease.     

Radiocontrast-induced acute kidney injury

Many radiographic studies and procedures use iodinated contrast media and consequently pose the risk of contrast-induced acute kidney injury (AKI). This is an important complication, which accounts for a significant number of cases of hospital-acquired renal failure associated increased hospital length of stay and increased mortality. Sustained reductions in renal blood flow, hypoxic injury, direct cellular toxicity by the contrast media, and superimposed organ injury are all believed to play a role in this form of AKI. Avoidance of dehydration and multimodality prevention measures may reduce rates of this problem in patients at risk. Contrast-induced AKI is likely to remain a significant challenge for specialists in the future since the patient population is aging, chronic kidney disease and diabetes are coming more common, and use of iodinated contrast is growing.     

Contrast media induced nephropathy: A literature review of the available evidence and recommendations for practice

BackgroundContrast media induced nephropathy (CIN) is a sudden compromise of renal function 24–48 h after administering contrast medium during a CT scan or angiography. CIN accounts for 10% of hospital acquired renal failure and is ranked the third cause of acquiring this condition. Identifying patients at risk through proper screening can reduce the occurrence of this condition.PurposeThis review paper aims to critique current evidence, provide a better understanding of CIN, inform nursing practice and make recommendations for bedside nurses and future research.MethodAn integrative review of the literature was made using the key terms: “contrast media”, “nephritis”, “nephropathy”, “contrast media induced nephropathy scores”, “acute kidney failure”, “acute renal failure” and “acute kidney injury”. MeSH key terms used in some databases were: “prevention and control”, “acute kidney failure” and “treatment”. Databases searched included Medline, CINAHL and Academic Search Complete, and references of relevant articles were also assessed. The search included all articles between the years 2000 and 2013.ResultsSixty-seven articles were obtained as a result of the search, including RCTs, systematic reviews, and retrospective studies.ConclusionContrast media induced nephropathy is an iatrogenic complication occurring secondary to diagnostic or therapeutic procedures. At times it is unavoidable but a systematic method of risk assessment should be adopted to identify high risk patients for tailored and targeted approaches to management interventions.Clinical implicationsAs the use of contrast media is increasing for diagnostic purposes, it is important that nurses be aware of the risk factors for CIN, identify and monitor high risk patients to prevent deterioration in renal function when possible.     

Radiologic contrast-induced renal failure

RCIRF is a complex syndrome resulting in acute renal dysfunction following exposure to radiologic contrast media. It accounts for 10 per cent of all cases of acute renal failure. The pathogenesis appears multifactorial but most probably involves contrast-mediated renal ischemia and direct tubular toxicity. Significant risk factors include preexisting renal insufficiency, diabetes mellitus, advanced age, volume depletion, and presence of multiple myeloma. The diagnosis should be suspected with acute renal dysfunction temporally related to radiologic contrast administration. The prognosis for recovery is good in most cases. Key preventive measures include identification of high-risk patients, ensuring adequate hydration prior to contrast agent administration, avoiding excessive and repeated contrast exposure, and instituting prophylactic therapy in selected cases.     

Néphropathie induite par les produits de contraste iodés en réanimation

A growing number of imaging procedures requiring intravenous administration of iodinated contrast media are performed in the intensive care unit (ICU). Renal toxicity of contrast media added to the multiple renal injuries suffered by the critically ill patients may influence the outcome. The incidence of contrast-induced nephropathy (CIN) in the ICU is difficult to determine because of so many definitions used. Applying the definition of the Acute Kidney Injury Network, about 10?C20% of ICU patients receiving iodinated contrast media will develop CIN. In addition to patient??s severity assessed by the Sequential Organ Failure Assessment score, few other ICU-specific risk factors have been identified. The independent effect of contrast media on the kidney function of patients with multiple factors of renal injury is difficult to evaluate and, in the context of emergency imaging, the scarce comparative studies of patients who are either undergoing or not undergoing iodinated contrast-media infusion did not report any difference in the incidence of acute kidney insufficiency. Nevertheless, the independent effect of contrast media, even if minimal, is likely to influence critically ill patients?? outcome, given the poor prognosis of acute kidney insufficiency in this population. Thus, strategies based on the risk/benefit ratio assessment and including hypovolemia correction and preventive drug administration are considered in the light of recent international guidelines.     

Recent advances in the prevention of radiocontrast-induced nephropathy

PURPOSE OF REVIEW: Radiocontrast nephropathy is a serious clinical problem associated with increased morbidity and mortality, particularly in patients with chronic renal failure. The optimal strategy to prevent radiocontrast nephropathy has not been established. This article reviews recent clinical researches concerning new developments in the prevention of radiocontrast nephropathy and analyzes unresolved issues. RECENT FINDINGS: Among all prophylactic measures that have been proposed, periprocedural hydration with isotonic saline has demonstrated effectiveness in the prevention of radiocontrast nephropathy. Thus, it remains the most frequently applied measure in clinical practice. Recently, additional benefit has been shown to derive from the infusion of isotonic alkalizing (sodium bicarbonate), instead of isotonic (sodium chloride) solutions. The use of nonionic low-osmolar and, more recently, nonionic iso-osmolar contrast agents has been demonstrated to significantly reduce the risk of radiocontrast nephropathy in patients with renal impairment, in comparison with hyperosmolar contrast media. Recently, periprocedural hemofiltration has emerged as a safe and very effective strategy to prevent radiocontrast nephropathy and to reduce its associated poor outcome in patients with severe chronic renal failure. In the past few years, several trials with acetylcysteine have shown conflicting results. Nevertheless, most of them indicated that acetylcysteine, particularly when associated with adequate hydration, might be useful in preventing radiocontrast nephropathy in patients with renal impairment. A possible dose-dependent protective effect has been suggested by more recent trials that included patients undergoing coronary interventional procedures requiring large contrast volume. SUMMARY: Adequate prophylaxis is needed to reduce the high morbidity and mortality associated with radiocontrast nephropathy in high-risk patients. By reviewing the available evidence from clinical trials, this article provides an overview of current strategies and unresolved issues concerning the prevention of radiocontrast nephropathy.     

Role of adenosine in contrast media-induced acute renal failure in diabetes mellitus

Increased release of renal adenosine and stimulation of renal adenosine receptors have been proposed to be major mechanisms in the development of contrast media-induced acute renal failure (CM-ARF). Patients with diabetes mellitus or preexisting renal disease who have reduced renal function have a markedly increased risk to develop CM-ARF. This increased risk to develop CM-ARF in patients with diabetes mellitus is linked to a higher sensitivity of the renal vasculature to adenosine, since experimental studies have shown increased adenosine-induced vasoconstriction in the kidneys of diabetic animals. Furthermore, recent evidence suggests that administration of adenosine receptor antagonists reduces the risk of development of CM-ARF in both diabetic and nondiabetic patients. The purpose of this review is to discuss the role of adenosine in the development of CM-ARF, particularly in the kidneys of diabetic patients, and to evaluate the therapeutic potential of adenosine receptor antagonists in the prevention of CM-ARF. Selective adenosine A1 receptor antagonists may provide a therapeutic tool to prevent CM-ARF in patients with diabetes mellitus and reduced renal function.     

Time-course of iodine elimination by hemodialysis in patients with renal failure after angiography.

The study was designed to examine the time-course of iodine elimination by hemodialysis to determine a desirable duration for dialysis after angiography to prevent contrast media nephropathy (CMN) in patients with renal failure. Reduction rates of iodine by hemodialysis (DRR) of 1 to 3 h and the renal elimination of iodine (RER) for 20 h after hemodialysis were prospectively examined in 8 chronic renal failure (CRF) patients. The mean DRR was 46.6% at 1 h, 65.2% at 2 h, and 75.1% at 3 h, and the mean RER was 49.4% in the CRF patients. Renal function significantly deteriorated in 2 CRF patients after angiography. Plasma iodine was eliminated by more than 80% after 2 h of hemodialysis following angiography, and the subsequent renal elimination in patients with mild-to-moderate renal failure was also examined. There is no need of prophylactic hemodialysis to prevent CMN for these patients when they have no additional risk factors such as a high dose of contrast medium, diabetes mellitus, or severe heart failure. However, 2 h of hemodialysis is desirable immediately after angiography for patients with moderate renal failure and one additional risk factor, and three hours or more of hemodialysis is also desirable for patients with severe renal failure, and for those with moderate renal failure having two or more additional risk factors.     

Nephrotoxicity of contrast media following cardiac angiography: pathogenesis, clinical course, and preventive measures, including the role of low-osmolality contrast media.

OBJECTIVE: To review the incidence, definition, clinical course, risk factors, pathogenesis and prevention of contrast-associated nephropathy (CAN) following cardiac angiography with emphasis on differences between high-osmolality contrast media (HOCM) and low-osmolality contrast media (LOCM). DATA SOURCES: Investigations in animal models and in patients following cardiac angiography. DATA EXTRACTION: Animal models of the pathogenesis of CAN are presented. Human studies describing the incidence, clinical course, risk factors, and prevention of CAN are reviewed. Comparative clinical trials of HOCM (diatrizoate, metrizoate) and LOCM (iohexol, iopamidol, ioxaglate) nephrotoxicity following cardiac angiography are critically evaluated. DATA SYNTHESIS: All clinical studies comparing CAN of HOCM versus LOCM following cardiac angiography have some methodologic limitations (e.g., small sample size, lack of control for other factors) that may affect renal function, lack of stratification for other reported risk factors, and variable or short follow-up periods. CONCLUSIONS: Whether the incidence of CAN following cardiac angiography is reduced with LOCM remains controversial. The incidence of CAN in patients with normal renal function does not appear to differ in patients treated with LOCM versus HOCM because few patients in each group develop renal failure. Additional controlled clinical trials comparing CAN of LOCM and HOCM in patients with renal dysfunction are needed. Because of greater product cost and scarcity of documented benefit compared with HOCM, selection of LOCM based on the presence of renal dysfunction cannot be recommended at this time.     

实时超声造影对肾脏恶性肿瘤的应用探讨

目的探讨不同病理类型肾脏恶性肿瘤的造影特点,评价超声造影诊断肾脏恶性肿瘤的应用价值.方法对30例超声诊断为肾脏占位病变或可疑肾脏占位病变的患者,应用新型声学造影剂声诺维进行超声造影检查,结果与病理对比.结果25例肾脏恶性肿瘤造影剂灌注显像无一定规律;3例肾柱肥大造影后与正常肾组织造影剂显像一致;2例肾囊肿内无造影剂显示.结论超声造影对肾脏肿瘤的诊断和鉴别诊断具有一定的实用价值.     

Nephrogenic systemic fibrosis and gadolinium-based contrast media

Nephrogenic systemic fibrosis (NSF) is a recently characterized systemic fibrosing disorder occurring in patients with underlying renal disease. This condition principally leads to skin thickening and hardening and may induce joint immobility and inability to walk. In 2006, clusters of NSF were associated to an exposure to gadolinium containing contrast agents during magnetic resonance imaging. Gadolinium has been detected in skin tissue of patients with NSF. Gadodiamide, a linear gadolinium chelate appears to be particularly at risk. During renal failure, gadodiamide accumulation may explain the development of NSF. Regulatory decisions have been taken to contraindicate gadodiamide in patients with severe renal impairment.     

Renovascular disease: Doppler ultrasound

Color Doppler ultrasound (CDUS) seems to be an effective imaging technique for the diagnosis of renal vascular diseases. It is already the modality of choice for the detection of acute renal vein thrombosis and nonocclusive intrarenal vascular disorders including iatrogenic arteriovenous fistula and false aneurysm, particularly in patients with impaired renal function that precludes the use of iodinated contrast agents. Although proximal Doppler interrogation remains an important step in diagnosing renal artery (RA) stenosis, useful hemodynamic information can be obtained from the distal arterial bed. When CDUS fails in identifying proximal RAs, normal waveform velocity and morphology obtained from intrarenal arteries enable one to rule out RA occlusion and most of the severe stenoses (≥80%). Such information, which is not subject to a significant risk of technical failure, seems to be particularly useful in studying patients with acute renal failure of suspected vascular origin. Despite the extreme variability in reported performance between studies, CDUS has seemed to be a valuable tool compared with other noninvasive modalities in the diagnosis of RA stenosis. Whereas a CDUS-based strategy is already accepted in numerous specialized centers, a thorough evaluation of diagnostic criteria and extensive training of operators will allow CDUS to be widely accepted for the screening of patients at high risk for renovascular hypertension.     

Risk factors for acute renal failure: inherent and modifiable risks

PURPOSE OF REVIEW: Our purpose is to discuss established risk factors in the development of acute renal failure and briefly overview clinical markers and preventive measures. RECENT FINDINGS: Findings from the literature support the role of older age, diabetes, underlying renal insufficiency, and heart failure as predisposing factors for acute renal failure. Diabetics with baseline renal insufficiency represent the highest risk subgroup. An association between sepsis, hypovolemia, and acute renal failure is clear. Liver failure, rhabdomyolysis, and open-heart surgery (especially valve replacement) are clinical conditions potentially leading to acute renal failure. Increasing evidence shows that intraabdominal hypertension may contribute to the development of acute renal failure. Radiocontrast and antimicrobial agents are the most common causes of nephrotoxic acute renal failure. In terms of prevention, avoiding nephrotoxins when possible is certainly desirable; fluid therapy is an effective prevention measure in certain clinical circumstances. Supporting cardiac output, mean arterial pressure, and renal perfusion pressure are indicated to reduce the risk for acute renal failure. Nonionic, isoosmolar intravenous contrast should be used in high-risk patients. Although urine output and serum creatinine lack sensitivity and specificity in acute renal failure, they remain the most used parameters in clinical practice. SUMMARY: There are identified risk factors of acute renal failure. Because acute renal failure is associated with a worsening outcome, particularly if occurring in critical illness and if severe enough to require renal replacement therapy, preventive measures should be part of appropriate management.     

Role for intrarenal adenosine in the renal hemodynamic response to contrast media

The intrarenal injection of contrast media results in a transient fall in renal blood flow (RBF) and a decrease in glomerular filtration rate (GFR). These effects are enhanced by dietary sodium restriction and attenuated by sodium loading. A similar sodium-dependent response of RBF and GFR occurs with the intrarenal injection of adenosine. In view of these similarities, we sought to determine whether endogenous adenosine is involved in the renal hemodynamic response to contrast media. The intrarenal injection of contrast media (meglumine-Na diatrizoate, 76%) in six sodium-depleted, anesthetized dogs resulted in a 17% +/- 4% decrease in RBF and a 31% +/- 5% decrease in GFR. The infusion of the adenosine receptor antagonist, theophylline (5 mumol/min), reduced the decrease in RBF to 6% +/- 2% and in GFR to 12% +/- 3% of control values. During the intrarenal infusion of dipyridamole (24 micrograms/kg/min), a potentiator of adenosine through its action to inhibit the cellular uptake of nucleosides, the hemodynamic response to contrast media was greater; RBF fell 25% +/- 4% and GFR fell 44% +/- 7%. In addition, the urinary excretion of endogenous adenosine increased after the injection of contrast media (388 +/- 79 vs. 830 +/- 231 nmol/min). In summary, the contrast media-induced fall in RBF and GFR was attenuated by theophylline and augmented by dipyridamole, and the administration of contrast media resulted in an increase in the excretion of endogenous adenosine. These results support the hypothesis that endogenous adenosine is involved in the renal hemodynamic response to contrast media.     

两种水化护理方法对行冠状动脉介入术后患者肾功能的影响

目的探讨两种水化护理方法对行冠状动脉介入术后患者肾功能的影响。方法选择2006年9月，2008年4月在本院心内科住院的肾功能轻度受损行冠状动脉造影术的患者56例，将患者随机分为常规水化组29例与强化水化组27例，分别观察两组患者造影前、造影后第3d及造影后第7d血浆肌酐水平及尿β2-微球蛋白水平。结果两组患者造影前血浆肌酐及尿β2-微球蛋白水平比较，均P〉0．05，差异无统计学意义；但两组在造影后第3d及第7d比较，均P〈0．05，差异具有统计学意义，常规水化组高于强化水化组。结论强化水化护理法较常规水化护理法能明显减少患者行冠状动脉介入术后造影剂引起的肾功能损害，值得临床推广应用。     

优化对比剂注射技术在CT血管造影中对肾段动脉图像质量的影响

目的探讨优化对比剂注射技术在256排螺旋CT血管造影(CTA)中对主肾动脉及肾段动脉图像质量的影响。方法选取行肾动脉CTA检查的98例体质量相近的患者,将其随机分为A组和B组,应用的对比剂为碘普罗胺(370mg/ml)。A组50例:根据患者体质量选择对比剂用量(1.0ml/kg);B组48例:对比剂用量在A组用量基础上减去10ml。以CT原始横断位图像为基础,结合容积再现(VR)、最大密度投影(MIP)等重建图像对两组各级肾动脉图像质量及对比剂用量进行统计学分析。结果 A组50例患者:共显示肾动脉100条;B组48例患者:共显示肾动脉96条。两组主肾动脉及各肾段分支显示清晰,两者比较差异无统计学意义(P0.05)。两组图像质量评分分别为(4.937±0.177)分和(4.565±0.189)分,两者比较差异无统计学意义(P0.05)。对比剂用量分别为(68.76±8.17)ml和(58.27±6.48)ml,差异有统计学意义(P0.05)。结论 256排螺旋CT血管造影在肾动脉造影中,与依据患者体质量选择对比剂用量比较,在此基础上再减少10ml的优化对比剂注射技术亦能清晰显示肾段动脉,获得满足诊断要求的图像,从而为临床诊断肾段动脉狭窄和了解肾肿瘤分支血供提供了重要的信息。     

Duplex-assisted internal carotid artery balloon angioplasty and stent placement

Carotid artery balloon angioplasty and stenting (CBAS) is gaining popularity as an adequate alternative to carotid endarterectomy (CEA) in selected patients. Unfortunately, the substantial amount of contrast media used for CBAS, traditionally performed under fluoroscopic guidance, may impair renal function in patients with diabetes or ones with elevated serum creatinine. We attempted to apply duplex assistance to limit or eliminate the use of contrast during CBAS. Fluoroscopy was utilized to assist manipulation of the guidewire into the aorta and the common carotid artery, and positioning of the distal cerebral protection device. Selective catheterization of the internal and external carotid arteries was performed under ultrasound guidance. Balloons and stent were successfully deployed with ultrasound guidance alone in all cases. Appropriate stent apposition and arterial patency were confirmed by duplex in all cases. One ipsilateral stroke (2.9%) occurred intraoperatively with almost complete clinical recovery in 4 months. On-table biplanar cerebral arteriogram performed in this patient was normal. No early (30-day) mortalities were in the series. Duplex-assisted CBAS is feasible and may reduce the need for contrast media in selected patients with high risk for renal failure. Additional advantages include guidance of the femoral puncture, precise position of the balloon and stent and B-mode and hemodynamic confirmation of the adequacy of the technique.     

糖尿病患者发生造影剂肾病临床观察108例

目的：观察糖尿病患者使用造影剂后发生造影剂肾病的临床情况。方法：108例肾功能正常的患者根据血糖水平被分为3组,分别接受X线造影,观察3组发生造影剂肾病情况。结果：血糖正常组血清肌酐造影前后无明显变化,糖尿病早期组造影后血肌酐升高,与造影前相比有统计学意义（P〈0.05）,糖尿病组造影后肌酐升高明显,与造影前相比具有显著统计学意义（P〈0.01）,且血肌酐恢复较慢,造影后第5天仍处于较高水平,与造影前相比有统计学意义（P〈0.05）。结论：糖尿病早期及糖尿病患者即使肾功能正常,使用造影剂后也容易发生造影剂肾病,对这类高危人群应尽量避免使用造影剂。