The Underrated Role of Ultrasound in Peritoneal Dialysis.

Ultrasound is very effective in performing procedures and assessment of complications in peritoneal dialysis. The ultrasound examination can be applied for preoperative assessment, during the peritoneal catheter placement, for the detection and monitoring of infection, as well as for the evaluation of the catheter malfunction. Despite being not only a cost- and time-saving technique but also a bedside procedure, ultrasonography remains an underrated clinical tool in the field of peritoneal dialysis. This publication wants to explain and reinforce the clinical utility of US in PD and to expand the diagnostic equipment for the clinician.

The dark side of the kidney in cardio-renal syndrome: renal venous hypertension and congestive kidney failure.

Renal involvement in some forms of acute or chronic diseases, such as heart failure or sepsis, presents with a complex pathophysiological basis that is not always clearly distinguishable. In these clinical settings, kidney failure is traditionally and almost exclusively attributed to renal hypoperfusion and it is commonly accepted that causal elements are pre-renal, such as a reduction in the ejection fraction or absolute or relative hypovolemia acting directly on oxygen transport mechanisms and renal autoregulation systems, causing a reduction of glomerular filtration rate. Nevertheless, the concept emerging from accumulating clinical and experimental evidence is that in complex clinical pictures, kidney failure is strongly linked to the hemodynamic alterations occurring in the renal venous micro and macrocirculation. Accordingly, the transmission of the increased venous pressure to the renal venous compartment and the consequent increasing renal afterload has a pivotal role in determining and sustaining the kidney damage. The aim of this review was to clarify the physiopathological aspects of the link between worsening renal function and renal venous hypertension, analyzing the prognostic and therapeutic implications of the so-called congestive kidney failure in cardio-renal syndrome and in other clinical contexts of its possible onset.

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.

Renal Resistive Index: not only kidney.

From growing data from the literature emerges that so-called ecoDoppler "Renal" Resistive Indexes (RRI) are not only specific markers of kidney damage and indicators of renal functional prognosis but they always express more clearly a strong link with the systemic circulation. In fact, some cardiovascular parameters such as aortic pulse pressure, aortic stiffness, abdominal aortic calcifications and clinical settings for instance heart failure progression have shown a great association with RRI. Relationships between renal and inflammatory indexes in hypertensive patients have been found and data from the literature on kidney transplants underline the capability of the graft RRI to change according to host hemodynamic features. The purpose of this article is to explain the emerging pathophysiological aspects of this relationship between renal microcirculation and cardiovascular system by emphasizing the importance for the ultrasonographer and for the nephrologist of not overlooking a global vision of the patient before interpreting the RRI.

Lung Ultrasound in Hemodialysis: A Card to be Played?

The end-stage renal disease is characterized by a profound impairment in the regulation of body fluid distribution, and volume assessment in hemodialysis is one of the challenging goals for the nephrologist. To determine a state of euvolemia, different validated techniques have been employed and among them lung ultrasonography (LUS) has recently attracted growing attention on account of its capacity to estimate accurately extra vascular lung water and to detect lung edema even in its early asymptomatic stage, that is, hidden lung congestion.With its noninvasiveness, freedom from radiation, the ease of use, acceptable intra/inter-operator reproducibility and availability of portable ultrasound devices, LUS can be considered one of the most interesting "cards to play" for the volume assessment in patients on hemodialysis.

Case 230: Congenital Inguinal Herniation of the Left Ureter (Extraperitoneal Form).

History A 52-year-old man with a history of urinary tract infections and a previous clinical diagnosis of left inguinal hernia presented to the nephrologist with recent onset of dysuria and increasing swelling in the left inguinoscrotal region in the absence of fever or scrotal trauma. There was no relevant surgical or family history. The general physical examination findings were unremarkable, with a normal abdomen at both visual inspection and palpation; urogenital examination revealed a small left-sided palpable mass of the testis, compatible with an inguinal hernia or hydrocele. At first, gray-scale and color Doppler ultrasonographic (US) images of the testes and the inguinoscrotal region were obtained. Contrast material-enhanced computed tomographic (CT) images of the lower abdomen and pelvis were then obtained to further evaluate the urinary tract.

Inferior Vena Cava Ultrasonography for Volume Status Evaluation: An Intriguing Promise Never Fulfilled.

The correct determination of volume status is a fundamental component of clinical evaluation as both hypovolaemia (with hypoperfusion) and hypervolaemia (with fluid overload) increase morbidity and mortality in critically ill patients. As inferior vena cava (IVC) accounts for two-thirds of systemic venous return, it has been proposed as a marker of volaemic status by indirect assessment of central venous pressure or fluid responsiveness. Although ultrasonographic evaluation of IVC is relatively easy to perform, correct interpretation of the results may not be that simple and multiple pitfalls hamper its wider application in the clinical setting. In the present review, the basic elements of the pathophysiology of IVC behaviour, potential applications and limitations of its evaluation are discussed.

Electrocardiographic Time-Intervals Waveforms as Potential Predictors for Severe Acute Kidney Injury in Critically Ill Patients.

Background: Acute kidney injury (AKI) is common in critically ill patients admitted to intensive care units (ICU) and is frequently associated with poorer outcomes. Hence, if an indicator is available for predicting severe AKI within the first few hours of admission, management strategies can be put into place to improve outcomes. Materials and methods: This was a prospective, observational study, involving 63 critically ill patients, that aimed to explore the diagnostic accuracy of different Doppler parameters in predicting AKI in critically ill patients from a mixed ICU. Participants were enrolled at ICU admission. All underwent ultrasonographic examinations and hemodynamic assessment. Renal Doppler resistive index (RDRI), venous impedance index (VII), arterial systolic time intervals (a-STI), and venous systolic time intervals (v-STI) were measured within 2 h from ICU admission. Results: Cox proportional hazards models, including a-STI, v-STI, VII, and RDRI as independent variables, returned a-STI as the only putative predictor for the development of AKI or severe AKI. An overall statistically significant difference (p < 0.001) was observed in the Kaplan−Meier plots for cumulative AKI events between patients with a-STI higher or equal than 0.37 and for cumulative severe AKI-3 between patients with a-STI higher or equal than 0.63. As assessed by the area under the receiver operating curves (ROC) curves, a-STI performed best in diagnosing any AKI and/or severe AKI-3. Positive correlations were found between a-STI and the N-terminal brain natriuretic peptide precursor (NT-pro BNP) (ρ = 0.442, p < 0.001), the sequential organ failure assessment (SOFA) score (ρ: 0.361, p = 0.004), and baseline serum creatinine (ρ: 0.529, p < 0.001). Conclusions: Critically ill patients who developed AKI had statistically significant different a-STI (on admission to ICU), v-STI, and VII than those who did not. Moreover, a-STI was associated with the development of AKI at day 5 and provided the best diagnostic accuracy for the diagnosis of any AKI or severe AKI compared with RDRI, VII, and v-STI.

Perioperative Renal Ultrasonography of Arterio-to-Venous Coupling Predicts Postoperative Complications after Major Laparoscopic Urologic Surgery.

Point-of-care ultrasonography (POCUS) with concomitant venous and arterial Doppler assessment enables clinicians to assess organ-specific blood supply. To date, no studies have investigated the usefulness of including a comprehensive perioperative POCUS assessment of patients undergoing major laparoscopic surgery. The primary aim of the present study was to evaluate whether the combined venous and arterial renal flow evaluation, measured at different time points of perioperative period, may represent a clinically useful non-invasive method to predict postoperative acute kidney injury (AKI) after major laparoscopic urologic surgery. The secondary outcome was represented by the development of any postoperative complication at day 7. We included 173 patients, subsequently divided for analysis depending on whether they did (n = 55) or did not (n = 118) develop postoperative AKI or any complications within the first 7 days. The main results of the present study were that: (1) the combination of arterial hypoperfusion and moderate-to-severe venous congestion inferred by POCUS were associated with worst outcomes (respectively, HR: 2.993, 95% CI: 1.522-5.884 and HR: 8.124, 95% CI: 3.542-18, p < 0.001); (2) high intra-operative abdominal pressure represents the only independent determinant of postoperative severe venous congestion (OR: 1.354, 95% CI: 1.017-1.804, p = 0.038); (3) the overall number of complications relies on the balance between arterial inflow and venous outflow in order to ensure the adequacy of peripheral perfusion; and (4) the overall reliability of splanchnic perfusion assessment by Doppler is high with a strong inter-rater reliability (ICC: 0.844, 95% CI: 0.792-0.844). The concomitant assessment of arterial and venous Doppler patterns predicts postoperative complications after major laparoscopic urologic surgery and may be considered a useful ultrasonographic biomarker to stratify vulnerable patients at risk for development of postoperative complications.

Feasibility of routine ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula dysfunction.

BACKGROUND: Stenosis is the main cause of arteriovenous fistula failure and is due to neointimal hyperplasia. Percutaneous transluminal angioplasty is the gold standard for patients with vascular access stenosis. The aim of the study was to evaluate the efficacy and safety of ultrasound-guided percutaneous transluminal angioplasty in the treatment of native arteriovenous fistula venous stenosis. METHODS: The need for intervention was determined by physical examination and duplex ultrasound in 162 patients. All patients with failing or not maturing arteriovenous fistula were treated in the outpatient setting under ultrasound guidance. Procedural success was assessed with repeated post-procedural ultrasound examinations. All procedures were performed under local anesthesia by a single nephrologist and were performed in a single vascular laboratory, while follow-up ultrasound was performed in the dialysis unit of destination. RESULTS: Early technical success was obtained in 95.6% of cases (154 of 162). Complications occurred in 22 patients (13.5%) with no major complication requiring surgical or fluoroscopic endovascular intervention. Primary patency at 6 and 12 months was 84% and 69.8%, respectively. Risk factors for arteriovenous fistula failure/secondary percutaneous transluminal angioplasty were vascular access low blood flow rate and vintage, as well as the need for thrombolysis during the first percutaneous transluminal angioplasty. CONCLUSION: Ultrasound-guided percutaneous transluminal angioplasty is a valuable tool to treat vascular access stenosis.

[Management of hemodialysis patient subject to medical-nuclear investigation].

In recent years imaging techniques that use radionuclides have become more and more clinically relevant as they can provide functional information for specific anatomical districts. This has also involved nephrology, where radionuclides are used to study patients with different degrees of renal function failure up to terminal uremia. Although chronic kidney disease, and dialysis in particular, may affect the distribution and the elimination of radiopharmaceuticals, to date there are no consistent data on the risks associated with their use in this clinical context. In addition to the lack of data on the safety of radio-exposure in dialysis patients, there is also a shortage of information concerning the risk for healthcare staff involved in conducting the dialysis sessions performed after a nuclear test. This study, performed on 29 uremic patients who underwent hemodialysis immediately after a scintigraphic examination, assessed the extent of radio-contamination of the staff and of hemodialysis devices such as monitor, kits and dialysate. The data collected has been used to quantify the radiological risk in dialysis after the exposure to the most common radionuclides.

Renal intraparenchymal resistive index: the ultrasonographic answer to many clinical questions.

The use of renal resistive indices (RRIs) for the study of renal microcirculation has in the past been proposed for the identification of renal organ damage or even to specifically identify injury to some areas of the renal parenchyma. Nevertheless, according to the most recent evidences from literature this organ-based conception of RRIs has been proven to be partial and unable to explain the RRIs variations in clinical settings of sepsis or combined organ failure of primitively extrarenal origin or, more generally, the deep connection between RRIs and hemodynamic factors such as compliance and pulsatility of the large vessels. The aim of this review is to explain the physiopathological basis of RRIs determination and the most common interpretative errors in their analysis. Moreover, through a comprehensive vision of these Doppler indices, the traditional and emerging clinical application fields for RRIs are discussed.

[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.

Anatomical variations of the left anonymous trunk are associated with central venous catheter dysfunction.

BACKGROUND: Internal jugular vein cannulation has become increasingly widespread. Compared to the left internal jugular vein (LIJV), the right internal jugular vein (RIJV) is the preferred choice for the placement of central venous catheter (CVC) for hemodialysis, mostly due to the major technical difficulties and higher rate of complications of the LIJV approach. We aimed to investigate whether variability in the direction of the LIJV/brachiocephalic vein (BV) axis on the frontal plane could be a decisive factor in determining CVC dysfunctions. METHODS: Retrospective cohort study. From our Register, a total of 1489 consecutive patients (age 69 ± 9 years, males 60%) in whom a CVC for hemodialysis was placed from January 2012 to June 2014 were selected. RESULTS: LIJV cannulation, compared with RIJV, was associated with a higher rate of catheter dysfunction during an observational period of 2 weeks after catheter placement (16 vs.12%; p = 0.005). This complication was strongly correlated with the amplitude of the angle between the LIJV and the ipsilateral BV axis on the frontal plane; an angle ≤ 110° was associated with a higher rate of catheter dysfunction (78 vs.16%; p < 0.001). CONCLUSIONS: The anatomical clarification presented in our study provides useful data that could explain the dysfunction rate of CVC inserted in the LIJV. Clinicians who insert high-flow catheters (such as hemodialysis catheters) should be aware of LIJV/BV axis variability and of the possible risks of CVC dysfunction when the angle between the LIJV and ipsilateral BV is ≤ 110°.

[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.

An unusual cause of lumbar pain after physical exercise: Caval vein duplicity and its detection by ultrasound.

This paper deals with two recent cases of Inferior Caval Vein (IVC) duplicity, congenital anomaly often but not always asymptomatic that should be considered in the differential diagnosis of flank pain when other more common disorders have been excluded. Here are described the clinical and surgical significance together with the typical sonographic findings useful for the diagnosis of IVC duplicity. Particular attention is given to a peculiar and easily repeatable sonographic aspect associated with IVC duplicity, not previously reported in Literature and that we called the "Neptune's sign".

Renal transplantation parenchymal complications: what Doppler ultrasound can and cannot do.

Kidney transplantation is the treatment of choice in end-stage renal disease, given the better quality of life of transplanted patients when compared with patients on maintenance dialysis. In spite of surgical improvements and new immunosuppressive regimens, parts of transplanted grafts still develop chronic dysfunction. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of vascular and surgical complications of the transplanted kidney, its role is not fully understood in case of parenchymal complications of the graft. The specificity of Doppler is low both in case of acute complications, such as acute tubular necrosis, drugs toxicity and acute rejection, and in case of chronic conditions, such as chronic allograft nephropathy. Single determinations of resistance indices present low diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques such as tissue pulsatility index, maximal fractional area and contrast-enhanced ultrasound increase ultrasonography diagnostic power in case of parenchymal complications of the transplanted kidney.

[Oral hypoglycemic drugs in chronic kidney disease: which limitations in the clinical setting]. / Ipoglicemizzanti orali nella malattia renale cronica: quali limiti nell'uso clinico.

A large amount of recent epidemiological studies have shown the worldwide growth on the incidence and prevalence of diabetes mellitus type II (DM2), especially in industrialized countries where DM2 is the most frequent cause of chronic kidney disease. Diabetic nephropathy progression to ESRD (End Stage Renal Disease) may be slowed down only with a tight glycemic control, since no hypoglycemic drugs have been shown to possess renoprotective effects. Treatment with oral hypoglycemic agents should be closely and regularly monitored in patients with diabetic nephropathy since the decline of renal function below 60 ml/min of glomerular filtration rate (GFR) could cause multiple pharmacokinetic alterations. It may expose the patient to serious side effects if cautious dose reduction or even withdrawal of these drugs is not considered. Pharmacological approaches to the treatment of diabetes type 2 include the traditional oral hypoglycemic drugs (insulin sensitizers, insulin secretagogues and drugs inhibiting the absorption of glucose), incretin system drugs (orally or intravenously administered) and insulin therapy, if these drugs are insufficient or are contraindicated. The objective of this review is to evaluate the evidence regarding the use of oral hypoglycemic agents (with particular attention to the DPP-4 inhibitors) in diabetes type 2 with chronic kidney disease stage III- IV and ESRD, while in case of eGFR > 60 ml / min no dosage adjustment is usually required.

Chronic kidney disease progression and outcome according to serum phosphorus in mild-to-moderate kidney dysfunction.

BACKGROUND AND OBJECTIVES: Several factors might alter serum phosphate homeostasis and induce hyperhosphatemia in patients with chronic kidney disease (CKD) not requiring dialysis. However, whether and to what extent hyperphosphatemia is associated with a poor prognosis in different CKD patient groups remain to be elucidated. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: We utilized the "Prevenzione Insufficienza Renale Progressiva" (PIRP) database, a large project sponsored by the Emilia-Romagna Health Institute. PIRP is a collaborative network of nephrologists and general practitioners located in the Emilia-Romagna region, Italy, aimed at increasing awareness of CKD complications and optimizing CKD patient care. We identified 1716 patients who underwent a GFR and serum phosphorous assessment between 2004 and 2007. We tested whether phosphate levels ≥4.3 mg/dl are associated with the risk of CKD progression or all causes of death. RESULTS: Older age and male sex were associated with lower phosphate levels. Instead, higher phosphate levels were noted in patients with diabetes. Patients with phosphate levels ≥4.3 mg/dl were at an increased risk of starting dialysis or dying (hazard ratio 2.04; 95% confidence interval [1.44, 2.90]). Notably, subgroup analyses revealed that the magnitude of the risk associated with hyperphosphatemia varied depending on age, sex, diabetes, and different stages of CKD. CONCLUSIONS: These analyses lend support to the hypothesis that phosphorous abnormalities might have a negative effect on the residual renal function and prognosis in different groups of CKD patients. However, the risk associated with hyperphosphatemia might vary in specific CKD patient subgroups.