[High-flow fistula: a problem not easy to handle].

High-output cardiac failure is a well-known phenomenon of high-flow fistula in hemodialysis patients. The definition of "high flow" is varied and almost always connected to proximal arteriovenous fistulas (AVF). High flow access is a condition in which hemodynamics is affected by a greater rate of blood flow required for hemodialysis and this can compromise circulatory dynamics, particularly in the elderly in the context of pre-existing heart disease. High access flow is associated with complications like high output heart failure, pulmonary hypertension, massively dilated fistula, central vein stenosis, dialysis associated steal syndrome or distal hypoperfusion ischemic syndrome. Although there is no single agreement about the values of AVF flow volume, nor about the definition of high-flow AVF, there is no doubt that AVF flow should be considered too high if signs of cardiac failure develop. The exact threshold for defining high flow access has not been validated or universally accepted by the guidelines, although a vascular access flow rate of 1 to 1.5 l/min has been suggested. Moreover, even lower values may be indicative of relatively excessive blood flow, depending on the patient's condition. The pathophysiology contributing to this disease process is the shunting of blood from the high-resistance arterial system into the lower resistance venous system, increasing the venous return up to cardiac failure. Accurate and well-timed diagnosis of high flow arteriovenous hemodynamics by monitoring of blood flow of fistula and cardiac function is required in order to stop this process prior to cardiac failure. We present two cases of patients with high flow arteriovenous fistula with a review of the literature.

[Cephalic arch stenosis. Case report and literary review].

Dysfunctional AVF represents one of the leading causes of morbidity in the hemodialysis population, with venous stenosis-related dysfunction being the most common underlying problem. Cephalic arch is a well-known site for the development of stenosis, especially in patients with brachiocephalic fistulas. The pathophysiology of cephalic arch stenosis (CAS) is still being investigated and various contributing factors have been suggested. The treatment options for CAS are many and include angioplasty, endovascular stent insertion, access flow reduction and surgical interventions, but none of the current modalities are ideal. Therefore, the treatment of CAS is difficult, as the stenosis in this area tends to recur leading to the need for repeat angioplasty, stents or surgical revision. A 57-year-old woman undergoing hemodialysis (HD) through a right brachiocephalic arteriovenous fistula was found to have high venous pressure during HD and prolonged bleeding after HD. Clinical examination revealed a hyperpulsatile fistula suggestive of outflow obstruction. Doppler ultrasound examination showed cephalic vein thrombosis, severe outflow stenosis and juxta-anastomotic area. A 10 x 40 mm stent (Cordis Smart stent) was positioned appropriately in the cephalic arch and deployed, the stenotic lesion in juxta-anastomotic area was dilated with angioplasty balloon with improvement in flow. After 14 months, the fistula is still working perfectly with adequate flow.

[CEUS, a world to discover. Three clinical cases and literature review].

Currently, CEUS (Contrast-Enhanced UltraSound) is used in the evaluation of different organs and systems. It offers valuable information about vascular disease, both on a macro- and a micro-vascular level, and has a series of well-established applications in the monitoring of adult patients; official guidelines and recommendations are also available. Its use in a nephrological setting is constantly growing thanks to the lack of nephrotoxicity of the contrast agent, the absence of ionizing radiation and the possibility of characterizing focal pathologies, for diagnosis and in clinical practice. We describe here 3 clinical cases relating to renal diseases and we review the relevant literature with a specific focus on the use of CEUS in a nephro-urological setting.

[Evaluation via ecocolordoppler before creating a vascular access for hemodyalisis: a monocentric experience].

The use of a preoperative echocolordoppler improves the clinical evaluation because provides anatomical and hemodynamic information that make it an important tool in planning vascular access strategy. The preoperative ultrasound study of the vessels can significantly reduce the failure rate and the incidence of complications of vascular access. We describe the experience of our center, lasting 10-year, where the ultrasound assessment was performed in all patients before the creation of vascular access. Indeed, ultrasound reduces the rate of fistula failure and increases the utilization of fistula, allowing proper selection of vessels. In addition, the presence of the vascular access team has allowed us to achieve quite satisfactory results.

[Peripheral hypoperfusion syndrome and monomielic syndrome: from diagnosis to treatment. Case report with review of the literature].

Arteriovenous access ischemic steal is a fairly uncommon complication associated with the creation of a vascular access for hemodialysis, which can sometimes cause potentially devastating complications, with permanent disability. Several old names for this syndrome have now been replaced by two new denominations: Hemodialysis Access-Induced Distal Ischemia (HAIDI) and Distal Hypoperfusion Ischemic Syndrome (DHIS). Clinically, we distinguish between the Peripheral Hypoperfusion Syndrome, which can cause gangrene of the fingers, and the Monomelic Syndrome, characterized by low incidence and by the presence of neurological dysfunctions. Risk factors include diabetes mellitus, atherosclerotic vascular disease, old age, female gender, tobacco use and hypertension. We report the case of a patient with HAIDI in order to increase awareness on this syndrome's early diagnosis and proper management. After describing the case, we also include a literature review.

[Retroperitoneal renal hemorrhage: experience of our dialysis center].

The aging of the uremic population, the increasingly common use of anticoagulants, antiplatelet agents e heparin, during hemodialysis, can expose our patients to a greatest risk of bleeding. Spontaneous retroperitoneal hematomas are a fairly rare and potentially fatal condition. We describe 5 clinical cases of retroperitoneal hemorrhage that we observed during 10 years in our department, focusing on modalities of symptom onset, clinical-laboratory picture and treatment modalities.

[Management of the incidental renal masses].

The diagnosis of renal masses has increased in the last decades owing to the widespread use of imaging (ultrasound, computed tomography and magnetic resonance). Majority of the renal masses are detected incidentally on routine ultrasound examination. Solid masses detected on ultrasound require further imaging evaluation with CT and/or MRI for suitable characterization. US-guided renal biopsy is a safe, effective and accurate method for evaluating the small renal masses with ambiguous radiologic findings. Navigation technology and multimodality image fusion represent an important development in interventional radiology, especially for performing difficult percutaneous biopsies and ablations of small renal masses. Multidisciplinary approach is required which results from experience and knowledge and in hard cases the use of serial imaging can be helpful.

[Acute kidney injury and rhabdomyolysis after cocaine overdose: case report and literature review].

Cocaine, a natural alkaloid derived from the coca plant, is one of the most commonly used illicit drugs. Cocaine abuse causes systemic adverse effects like stroke, myocardic infarction, arterial dissection, vascular thrombosis and rhabdomyolysis. Cocaine use is, also, associated with renal complications such as acute kidney injury, vasculitis, acute interstitial nephritis, chronic kidney disease, malignant hypertension with thrombotic microangiopathy. Acute kidney injury may or may be not associated to rhabdomyolysis. Rhabdomyolysis caused by cocaine abuse is multifactorial, involving tissue ischemia secondary to vasoconstriction and cellular damage caused by the drug. We report a 50-year-old man with history of chronic hepatitis C and substance abuse admitted to our unit with severe rhabdomyolysis and acute kidney failure after nasal insufflation of cocaine overdose. Renal function recovered after several treatments of dialysis. We conclude that cocaine adversely impacts kidney function ; in addition cocaine and rhabdomyolysis are the double danger for acute kidney injury. Medical management of cocaine toxicity requires a multisystem approach, with close monitoring cardiac, neurological and renal function.

Crossed fused renal ectopia: case report and review of the literature.

Crossed fused renal ectopia is a rare congenital anomaly, and is mostly detected incidentally. A 45-year-old man, during investigation for recurrent abdominal pain, was found to have an empty left renal fossa and right crossed renal ectopia with fusion on ultrasonography. In the present case, there were no abnormalities and/or alteration of the renal function. Abdominal tomography scan with contrast medium confirmed the diagnosis. Ectopic kidney is often associated with other abnormal situations such as agenesis, vascular malformation, incontinence, a palpable abdominal mass, urinary tract infection, high incidence of stone formation, and genital anomalies. Through this case report, we emphasize the importance of adequate imaging.

[Neprilysin inhibition and chronic kidney disease]. / Gli inibitori della Neprilisina nei pazienti affetti da Malattia Renale Cronica e Sindrome Cardio:Renale.

Patients with chronic kidney disease (CKD) have a higher incidence of cardiovascular (acute and chronic) events, which in turn have an increased risk of progression to end-stage renal disease (ESRD) Inhibition of neprilysin, in addition to offering a new therapeutic target in patients with heart failure, could represent a potential improvement strategy in cardiovascular and renal outcome of patients with CKD. Inhibition of neprilysin by inhibiting the breakdown of natriuretic peptides, increases their bioavailability resulting in an increase in diuresis and sodium excretion and, in addition to exerting an inhibition of the renin-angiotensin-aldosterone (RAAS) system. Inhibition of RAAS, in turn, generates a series of counter-regulations that can balance the adverse effects present in CKD and heart failure (HF). The idea of blocking neprilysin is not very recent, but the first drugs used as inhibitors had an inadmissible incidence of angioedema. Among the latest generation molecules that can perform a specific inhibitory action on the neprilysin receptor and, at the same time, on the angiotensin II receptor thanks to the association with valsartan there is the LCZ696 (sacubitril / valsartan). This drug has shown promising benefits both in the treatment arterial hypertension and heart failure. It is hoped that equally positive effects may occur in CKD patients, particularly those with macroproteinuria.

Buttonhole Cannulation of the AV Fistula: A Critical Analysis of the Technique.

As a consequence of the central role of the arteriovenous fistula for dialysis (AVF) in the clinical management of the dialysis patient the necessity to limit the puncture-related complications to extend as much as possible the life of the vascular access. Accordingly, the AVF needling technique has gained growing attention. Alongside the traditional rope ladder (RL) puncture method, the buttonhole technique (BH) is increasingly popular; this technique employs the same cannulation sites of AVF in every dialysis associated with the use of dull needles to minimize vessels damage. The BH technique, utilized only for native AVF, is considered an appropriate alternative to the RL and is now recommended by several scientific societies for its reported benefits such as: AVF greater ease of cannulation, less pain, faster hemostasis and less tendency to the creation of aneurysms and hematomas. The use of BH is especially recommended in cases in which the RL is problematic with short or winding venous sections and in home dialysis in which the patient performs the needling. However recent evidence in literature, countering these theoretical advantages, indicates that the BH technique appears to be closely related to an increased risk of local and systemic infections. Furthermore, the purported benefits of BH have not held up under closer examination.

Echo color Doppler ultrasound: a valuable diagnostic tool in the assessment of arteriovenous fistula in hemodialysis patients.

A functioning vascular access is a critical requirement to improve the quality of life in hemodialysis patients, so monitoring and surveillance of vascular access play key roles in identifying all dysfunctions and reducing the huge economic cost as well as adequacy of dialysis.In our five-year experience, a study protocol has been used and improved with the help of ultrasonography.Doppler ultrasound is an excellent and sensitive modality for hemodialysis access evaluation, one of techniques employed for arteriovenous fistulae (AVF) study, not only as a preoperative tool, but also in post-operative monitoring of AVF maturation. In addition, the current guidelines recommend AVF surveillance by access blood flow measurement and the correction of hemodynamic stenosis in order to prolong access survival. Doppler ultrasound is readily available, directly used by nephrologists, non-invasive, safe, inexpensive, reproducible, although it requires more clinical skill and time to perform and proper equipment. Ultrasonography imaging can substantially reduce the number of subsequent invasive angiographic procedures. In our opinion, Doppler ultrasound should have a crucial place in the interdisciplinary cooperation in AVF monitoring and it should be included as part of an integrated vascular access management program.

[Clinical, ultrasound and treatment of aneurysms and pseudoaneurysms in hemodialysis vascular access]. / Clinica, ecografia e trattamento degli aneurismi e pseudoaneurismi nell'accesso vascolare dell'emodializzato.

Aneurysms (AN) and pseudoaneurysms are among the complications of vascular access. AN is a focal area of expansion, concentric or eccentric, with the wall consistency the same as all elements of the vessel wall (intima, media and adventitia). Pseudoaneurysm, or false aneurysm, is a blood harvesting without vascular wall, it is characterized by a reactive capsule of connective tissue that delimits it. The K/DOQI guidelines recommend a regular program of monitoring and surveillance of the vascular access. Color-Doppler ultrasound is considered a valuable tool in the preoperative evaluation and in the follow-up. The echo-color-Doppler surveillance plays an important role in diagnosis of aneurysm. It allows monitoring the evolution of the aneurysm, studying vessels walls, thickened because of intimal hyperplasia and to identify the presence of thrombotic material and/or calcification of the wall. Early identification of complications and the adoption of corrective measures will extend the life of the vascular access, with benefit for the patient. Moreover, it will reduce health care costs.

[Takotsubo cardiomyopathy recurrence in patient with chronic kidney disease: case report and literature review]. / Recidiva di cardiomiopatia Takotsubo in paziente con insufficienza renale cronica: analisi di un caso clinico e revisione della letteratura.

Takotsubo cardiomyopathy (CT) is a syndrome characterized by an acute and transient left ventricular dysfunction, electrocardiographic abnormalities suggestive of acute coronary syndrome, chest pain and/or dyspnea, left ventricular mid-apical segments akinesia and normal coronary angiography. It is mainly observed in postmenopausal women after an intense physical or mental stress. The course is usually favourable but sometimes severe complications occur. The recurrence rate is 2-10%. We present the case of a recurrence of CT in a female, 79 years old, with hypertension, diabetes, chronic kidney disease (CKD) stage 3 who was admitted to the emergency room for dyspnea and vomiting. The electrocardiogram (ECG) showed a sinusal rhythm and T wave inversion in the pre-cordial leads and the echocardiogram a typical feature of CT with depressed left ventricular systolic function (FE). The ECG ranged quickly with atrial fibrillation rhythm, followed by a major hypokinetic arrhythmia with advanced atrio-ventricular block which indicated the need for a temporary pacemaker placement. The patient was oligouric, with severe renal failure, hyponatremia, hyperkalemia and metabolic acidosis. A continuous renal replacement therapy (CRRT) was started. On the seventh day improvement in urine output, electrolyte and acid base imbalance and FE normalization occurred. The renal function improved gradually, but after 36 months, persisted CKD stage 4. The case report describes the development of a cardiorenal syndrome type 1 induced by CT recurrence and effectiveness of CRRT in the management of acute heart failure. It also suggests a potential role played by CKD as a risk factor in the onset and recurrence of CT.

[Lactic acidosis, acute renal failure and heart failure during treatment with metformin: what do we know?]. / Acidosi lattica, insufficienza renale acuta e insufficienza cardiaca in corso di terapia con metformina: cosa sappiamo?

Metformin is a common medication used for the treatment of type 2 diabetes, especially in obese subjects. Clinical studies show that, in addition to the lowering effect of blood glucose, metformin reduces cardiovascular risk, does not induce weight gain and additionally, provides a unique safety strategy and efficacy in patients with diabetes and heart disease. However, this treatment is not without risks. The most feared metabolic complication is lactic acidosis that often occurs with complex and severe clinical symptoms and is associated with a high mortality risk. We detail our experience, during one year, regarding four patients with diabetes treated with metformin who developed such acute renal failure and lactic acidosis as to require hemodialysis treatment. The patients selected had previous normal renal function but a history of serious cardiovascular disease (hypertensive cardiomiopathy, ischemic revascularized and/or dilated, chronic obstructive arterial disease). We observed in all four of our patients an onset of non-related symptoms (fever, fatigue, vomiting and gastrointestinal disorders), a rapid deterioration in renal function, anuria and very high levels of lactic acid. In two patients we found acute pancreatitis. In addition to rehydration therapy, hemodialysis was started instantly with progressive rebalancing of the biohumoral status, effective recovery of spontaneous diuresis and improvement of the clinical status in three patients. Unfortunately, we had a failure during the initial hours of ward admittance, with an important clinical situation complicated by acute cardiac ischemia, abnormal heart rhythm, ending in death. Our experience provides us with elements to reflect on. Lactic acidosis is a serious metabolic disorder because it is associated with a high mortality risk. So a rapid diagnosis and a complete recognition of all the fundamental elements are important for its management. Starting hemodialysis early and prolonged treatment can solve complicated clinical status, correct acidosis and restore kidney function in patients with serious comorbidity.

Aneurysms and pseudoaneurysms in dialysis access.

Aneurysms are a common and often difficult complication seen with arteriovenous vascular access for haemodialysis. The purpose of this narrative review is to define and describe the scale of the problem and suggested therapeutic strategies. A narrative review of the published literature illustrated by individual cases is presented with the aim of summarising the relevant literature. The definitions of aneurysm are inconsistent throughout the literature and therefore systematic review is impossible. They vary from qualitative descriptions to quantitative definitions using absolute size, relative size and also size plus characteristics. The incidence and aetiology are also ill defined but separation into true aneurysms and false, or pseudoaneurysms may be helpful in planning treatment, which may be conservative, surgical or radiological. The lack of useful definitions and classification along with the multitude of management strategies proposed make firm evidence based conclusions difficult to draw. Further robust well designed studies are required to define best practice for this common problem.

[Horseshoe kidney: not a simple fusion anomaly]. / Rene a ferro di cavallo: non è una semplice anomalia di fusione. Analisi di due casi clinici e revisione della letteratura.

The horseshoe kidney is a congenital anatomical defect of the kidney that occurs in 0,25% of the population and is generally characterized by the fusion of the lower poles of the two kidneys through an isthmus and to which may be associated with urogenital and renal vascular anomalies. Asymptomatic in 1/3 of the cases and, most of time, accidentally discovered during a radiological examination, promotes nephrolithiasis, ureteropelvic junction obstruction, hydronephrosis, vesicoureteral reflux and pyelonephritis. We report two cases of patients with kidney horseshoe, characterized by the abrupt onset of a septic state with oligo-anuric acute renal failure, electrolyte and acid-base abnormalities, rapid decay of the general conditions, with detection of nephrolithiasis, hydronephrosis and acute pyelonephritis and whose clinical management resulted in a significant and synergistic nefro-urology involvment. The kidney horseshoe not represent so only a simple fusion anomaly but rather an important anatomical condition that, once diagnosed, it would be worthy of a careful clinical, radiological and laboratory surveillance, in order to prevent the potential complications that may be also particularly severe.

Bladder neck disease and kidney damage.

Primary bladder neck obstruction (PBNO) was first described in men by Marion in 1933. The precise cause of PBNO has not been clearly elucidated. This paper review the theories on etiology, clinical presentation, diagnostic evaluation and treatments for PBNO. Also this paper focuses on management of patients with complications like acute urine retention, hydroureteronephrosis and severe renal failure. The treatment options for men and women with PBNO include careful clinical evaluation, pharmacotherapy with alpha-blockers and surgical intervention.

Role of ultrasound in management of long-term complications after to radical cystectomy and orthotopic neobladder construction: case report.

Radical cystectomy with urinary diversion is considered the gold standard treatment for bladder cancer. We report a case of 66-years-old male with long term complications, after radical cystectomy and an ileal neobladder according to Hautmann. He developed uroseptic episodes, stones, post-void residual, stenosis of the uretero-neobladder anastomosis, metabolic acidosis and progressive deterioration of renal function. Renal ultrasound helped us to identify the dilation of the urinary tract, the grade of hydronephrosis and the presence of stones. During the follow-up, it is very important the collaboration between urologist and nephrologist and the role of ultrasound for an early correction of the hydronephrosis and the elective replacement of the stents in order to preserve the renal function.

[A case of arteriovenous fistula stenosis treated with percutaneous transluminal angioplasty]. / Un caso di stenosi serrata post-anastomotica di fistola arterovenosa trattata con angioplastica percutanea trans-luminale.

Arteriovenous fistula (AVF) is considered the gold standard for vascular access in hemodialysis, even in elderly patients. Malfunction of AVF is the first cause of hospitalization in the HD population, with a correlated increase in costs. For the monitoring and surveillance of fistulas, the 2006 K/DOQI workgroup recommends physical examination, direct flow measurement, Doppler ultrasonography and recirculation (by a non-urea-based dilutional method). We report the case of a 67-year-old woman affected by AVF stenosis. Combined AVF surveillance with recirculation and Doppler ultrasonography permitted early diagnosis and treatment with percutaneous angioplasty.