Sara Samoni

Peritoneal Dialysis in Patients with Refractory Congestive Heart Failure: A Systematic Review

Background: Refractory congestive heart failure (RCHF) is associated with a high mortality rate and is a major contributor to hospital admissions. Peritoneal dialysis (PD) is an option to control volume overload and perhaps improve outcomes in this challenging patient population. The aim of this systematic review is to describe the relative risk-benefit ratio based on data reported regarding the use of PD in RCHF. This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. An electronic search of PubMed, Embase, and the Cochrane Library was performed to identify relevant studies published from January 1951 to February 2014. Eligible studies selected were prospective or retrospective adult population studies on PD in the setting of RCHF. The following clinical outcomes were used to assess PD therapy: (1) hospitalization rates; (2) heart function; (3) renal function; (4) fluid overload, and (5) adverse clinical outcomes. Summary: Of 864 citations, we excluded 843 citations and included 21 studies (n = 673 patients). After PD, hospitalization days declined significantly (p = 0.0001), and heart function improved significantly (left ventricular ejection fraction: p = 0.0013; New York Heart Association classification: p = 0.0000). There were no statistically significant differences in glomerular filtration rate after PD treatment in non-chronic kidney disease stage 5D patients (p = 0.1065). Among patients treated with PD, body weight decreased significantly (p = 0.0006). The yearly average peritonitis rate was 14.5%, and the average yearly mortality was 20.3%. Key Messages: This systematic review suggests that PD may be an effective and safe therapeutic tool for patients with RCHF.

Nomenclature for renal replacement therapy and blood purification techniques in critically ill patients: practical applications

This article reports the conclusions of the second part of a consensus expert conference on the nomenclature of renal replacement therapy (RRT) techniques currently utilized to manage acute kidney injury and other organ dysfunction syndromes in critically ill patients. A multidisciplinary approach was taken to achieve harmonization of definitions, components, techniques, and operations of the extracorporeal therapies. The article describes the RRT techniques in detail with the relevant technology, procedures, and phases of treatment and key aspects of volume management/fluid balance in critically ill patients. In addition, the article describes recent developments in other extracorporeal therapies, including therapeutic plasma exchange, multiple organ support therapy, liver support, lung support, and blood purification in sepsis. This is a consensus report on nomenclature harmonization in extracorporeal blood purification therapies, such as hemofiltration, plasma exchange, multiple organ support therapies, and blood purification in sepsis.

Nephrolithiasis and hypertension: possible links and clinical implications

A definite epidemiological association exists between kidney stone disease and arterial hypertension, but the pathophysiological mechanisms are still not fully understood. Hypercalciuria or inflammation and oxidative stress have been proposed as possible links. However, there is more convincing evidence that the association between nephrolithiasis and hypertension may be considered as a part of the association between kidney stone disease, metabolic syndrome and atherosclerosis. From a clinical point of view, this association represents a crucial aspect of the clinical management of patients affected by kidney stone disease. In order to implement early prevention and treatment of cardiovascular and/or renal damage physicians should be encouraged to assess individual cardiovascular risk factors in any adult with kidney stones. Consequently, patients with kidney stones need a comprehensive approach rather than an intervention limited to the urinary tract and focused on stone resolution and recurrence prevention. It is time to view kidney stone disease as a systemic disorder, associated to or predictive of hypertension, chronic kidney disease, bone and cardiovascular damage. All these conditions negatively affect patient prognosis. This multi-systemic approach could increase the clinical impact of the kidney stone clinic.

Intra-Parenchymal Renal Resistive Index Variation (IRRIV) Describes Renal Functional Reserve (RFR): Pilot Study in Healthy Volunteers

An increase of glomerular filtration rate after protein load represents renal functional reserve (RFR) and is due to afferent arteriolar vasodilation. Lack of RFR may be a risk factor for acute kidney injury (AKI), but is cumbersome to measure. We sought to develop a non-invasive, bedside method that would indirectly measure RFR. Mechanical abdominal pressure, through compression of renal vessels, decreases blood flow and activates the auto-regulatory mechanism which can be measured by a fall in renal resistive index (RRI). The study aims at elucidating the relationship between intra-parenchymal renal resistive index variation (IRRIV) during abdominal pressure and RFR. In healthy volunteers, pressure was applied by a weight on the abdomen (fluid-bag 10% of subjects body weight) while RFR was measured through a protein loading test. We recorded RRI in an interlobular artery after application of pressure using ultrasound. The maximum percentage reduction of RRI from baseline was compared in the same subject to RFR. We enrolled 14 male and 16 female subjects (mean age 38 ± 14 years). Mean creatinine clearance was 106.2 ± 16.4 ml/min/1.73 m2. RFR ranged between −1.9 and 59.7 with a mean value of 28.9 ± 13.1 ml/min/1.73 m2. Mean baseline RRI was 0.61 ± 0.05, compared to 0.49 ± 0.06 during abdominal pressure; IRRIV was 19.6 ± 6.7%, ranging between 3.1% and 29.2%. Pearsons coefficient between RFR and IRRIV was 74.16% (p < 0.001). Our data show the correlation between IRRIV and RFR. Our results can lead to the development of a “stress test” for a rapid screen of RFR to establish renal susceptibility to different exposures and the consequent risk for AKI.

Creatinine-Based Definitions: From Baseline Creatinine to Serum Creatinine Adjustment in Intensive Care

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

Prospective, randomized, multicenter, controlled trial (TRIATHRON 1) on a new antithrombogenic hydrophilic dialysis membrane

Introduction Hemodialysis treatment requires anticoagulation to prevent thrombosis of the dialyzer. The Hydrolink® (NV series; Toray) has been designed to reduce thrombotic complications by increasing membrane hydrophilic properties. Previous studies have confirmed reduced platelet activation, improved removal of β2-microglobulin and excellent small-solute removal. Methods We designed a prospective, multi-centered, randomized clinical study to compare the antithrombogenic effects (platelet count) of NV dialyzers versus conventional treatment. To compare the possibility of performing heparin-free dialysis, we carried out progressive heparin reduction tests. Patients with an average platelet count lower than 170,000 cells/mm3 using standard high flux membranes in the 6 months prior to the study were enrolled and randomized. Patients were either dialyzed for 6 months without changing the previous membrane (control group) or treated with the Hydrolink® membrane (NV group). After the third week, the heparin reduction test was conducted for 5 weeks in order to assess the minimum amount of anticoagulant needed to safely perform a 4-hour dialysis treatment. Performance and safety were evaluated measuring platelet count and activation, middle-molecule removal rate and nutritional status. Results We found no significant difference in platelet count, platelet activation factors β-thromboglobulin and platelet factor 4 (PF-4), between the groups. More patients in the study group reached heparin-free dialysis without clotting events during the heparin reduction test. The NV dialyzers displayed anti-thrombogenic effects as compared to conventional dialyzers. Conclusions The NV dialyzer series is safe with no adverse events reported. Further studies are required to understand the mechanisms of anti-thrombogenic effects.

Imaging in Chronic Kidney Disease.

Chronic kidney disease (CKD) diagnosis and staging are based on estimated or calculated glomerular filtration rate (GFR), urinalysis and kidney structure at renal imaging techniques. Ultrasound (US) has a key role in evaluating both morphological changes (by means of B-Mode) and patterns of vascularization (by means of color-Doppler and contrast-enhanced US), thus contributing to CKD diagnosis and to the follow-up of its progression. In CKD, conventional US allows measuring longitudinal diameter and cortical thickness and evaluating renal echogenicity and urinary tract status. Maximum renal length is usually considered a morphological marker of CKD, as it decreases contemporarily to GFR, and should be systematically recorded in US reports. More recently, it has been found to be a significant correlation of both renal longitudinal diameter and cortical thickness with renal function. Conventional US should be integrated by color Doppler, which shows parenchymal perfusion and patency of veins and arteries, and by spectral Doppler, which is crucial for the diagnosis of renal artery stenosis and provides important information about intrarenal microcirculation. Different values of renal resistive indexes (RIs) have been associated with different primary diseases, as they reflect vascular compliance. Since RIs significantly correlate with renal function, they have been proposed to be independent risk factors for CKD progression, besides proteinuria, low GFR and arterial hypertension. Despite several new applications, US and color Doppler contribute to a definite diagnosis in <50% of cases of CKD, because of the lack of specific US patterns, especially in cases of advanced CKD. However, US is useful to evaluate CKD progression and to screen patients at risk for CKD. The indications and the recommended frequency of color Doppler US could differ in each case and the follow-up should be tailored.

Routine Adoption of TIMP2 and IGFBP7 Biomarkers in Cardiac Surgery for Early Identification of Acute Kidney Injury

Background and purpose Acute Kidney Injury (AKI) is a severe complication affecting many hospitalized patients after cardiac surgery, with negative impacts on short- and long-term clinical outcomes and on healthcare costs. Recently, clinical interest has been aimed at defining and classifying AKI, identifying risk factors and developing diagnostic strategies to identify patients at risk early on. Achieving an early and accurate diagnosis of AKI is a crucial issue, because prevention and timely detection may help to prevent negative clinical outcomes and avoid AKI-associated costs. In this retrospective study, we evaluate the NephroCheck Test as a diagnostic tool for early detection of AKI in a high-risk population of patients undergoing cardiac surgery at the San Bortolo Hospital of Vicenza. Methods We assessed the ability of the NephroCheck Test to predict the probability of developing CSA-AKI (cardiac surgery-associated AKI) and evaluated its accuracy as a diagnostic test, by building a multivariate logistic regression model for CSA-AKI prediction. Results Based on our findings, when the results of the NephroCheck Test are included in a multivariate model its performance is substantially improved, as compared to the benchmark model, which only accounts for the other clinical factors. We also define a rule – in terms of a probability cut-off – for discriminating cases that are at higher risk of developing AKI of any stage versus those in which AKI is less likely. Conclusions Our study has implications in clinical practice: when a Nephrocheck Test result is >0.3 ng/dL, an automated electronic alert prompts the physician to intervene by following a checklist of preventive measures.

Clinical Scenarios in Chronic Kidney Disease: Vascular Chronic Diseases.

Vascular chronic diseases represent one of the leading causes of end-stage renal disease in incident dialysis patients. B-Mode ultrasound (US) and color Doppler (CD) have a high sensitivity and specificity in the diagnosis of vascular chronic diseases. US and CD should be used to identify subjects in the high risk population who are affected by main renal artery stenosis (RAS) and to identify and characterize patients without RAS who have chronic ischemic nephropathy caused by nephroangiosclerosis and/or atheroembolic disease. The most important CD parameters in the work-up of suspected RAS are increased peak systolic velocity and diastolic velocity, spectral broadening, high renal:aortic ratio and lateralization of renal resistive indexes (RIs). In the absence of direct or indirect signs of RAS, increases in intraparenchymal RIs, associated with systemic atherosclerotic disease, are indicative of microcirculation damage related to nephroangiosclerosis or atheroembolic disease.

Clinical Scenarios in Acute Kidney Injury: Post-Renal Acute Kidney Injury

The incidence of acute kidney injury related to urinary tract obstruction is low (1-10%). It occurs in bilateral renal or lower urinary tract obstruction or in ureter obstruction in patients with a single functioning kidney or with pre-existing chronic kidney disease. The etiology and the incidence of obstruction vary on the basis of age and gender. Conventional ultrasound has a high sensitivity (>95%), but low specificity (<70%) in the diagnosis of urinary tract obstruction. Nevertheless, color Doppler is used through the evaluation of renal resistive indexes, ureteral jet and twinkling artifact.