Portuguese Journal of Nephrology & Hypertension

Predialysis vascular access creation: To whom and when

Aims: The optimal timing of predialysis vascular access surgery remains uncertain. This study goal was to evaluate the influence of kidney function and clinical characteristics at predialysis vascular access surgery on the likelihood of initiating hemodialysis during follow-up. Methods: Our study retrospectively identified all patients undergoing predialysis arteriovenous fistula creation between 2012-2015. We assessed 3 outcomes: frequency of hemodialysis initiation, death before hemodialysis initiation, and dialysis-free survival after vascular access creation. Multiple variable logistic regression analyzed which factors predicted initiation of dialysis. Results: The study involved 202 patients. Using multiple variable logistic regression, 5 factors were associated with hemodialysis initiation: estimated glomerular filtration rate <10 mL/min/1,73m2 at vascular access placement [OR 4.7, CI: 1.98-8,60, p=0.005], diabetes [OR 2.14, CI: 1.07-4,30, p=0.033], proteinuria>1gr/24 hours [OR 1.88, CI: 0.95-3.71, p=0.049], higher phosphorus levels [OR 6.25, CI: 1.39-13.05, p=0.017] and glomerular filtration rate drop ³3mL/min/1.73m2 in the year preceding vascular surgery [OR 1.67, CI: 0.81-3.45, p=0.016]. Cancer and congestive heart failure were associated with dead before starting dialysis [OR 5.9, CI: 1.15-9.78, p=0.038 and OR 2.4, CI: 1.3-3.9, p=0.021, respectively] and higher hemoglobin (>10g/dL) without erythropoietin stimulating agent levels with survival without needing dialysis [OR 2.34, CI: 1.09-4,58, p=0.028]. Conclusions: Optimizing the timing of vascular access creation in predialysis patients requires consideration not only of the kidney function but also comorbidities such as diabetes, estimated glomerular filtration rate decline in the preceding year and degree of proteinuria

Echocardiography and cardiovascular risk: The relationship in the renal transplant recipient

Introduction: ardiovascular disease (CVD) is the major cause of death among renal transplant recipients (RTR). It is not known whether echocardiographic abnormalities are useful to identify RTR at high risk of CVD. Methods: Retrospective review of RTR with functioning and stable graft and an echocardiography performed in the last year. Risk of major adverse cardiac events (MACE) and death using a risk calculator specific for RTR. Results: Among 107 patients (57.9% males, 50.4±13.9 years), 7-year risk of MACE was >10% in 30.9% of patients and 7-year risk of death >10% in 56.1%. Left ventricular hypertrophy (LVH) was found in 55.1%, diastolic dysfunction in 39.3%, dilated left atrium (LA) in 53.3%, high pulmonary artery systolic pressure (PASP) in 29.0%, valvular calcifications in 22.4% and moderate to severe mitral regurgitation (MR) in 3.7%. Mean Ejection fraction was 68.36±6.87%. Univariate analysis showed an increased risk of MACE and death in patients with LVH, diastolic dysfunction, dilated LA, high PASP, valvular calcifications and MR. Multivariate analysis identified an independent association between the risk of MACE >10% and valvular calcifications and high PASP. Risk of death>10% in multivariate analysis had an independent association with diastolic dysfunction and elevated PASP. Conclusion: Echocardiographic abnormalities identify RTR at increased risk of MACE and death. Valvular calcifications and high PASP are predictors of MACE whereas diastolic dysfunction and high PASP predict death.

Diagnosis and treatment of haemodialysis vascular access problems without iodinated contrast: a single-centre experience

Introduction: The use of iodinated contrast angiography in the diagnostic and therapeutic approach to arteriovenous access (AVA) problems is limited by nephrotoxicity and allergic reactions. The use of alternatives such as CO2 or ultrasound guidance has increased over the last few decades. Purpose: To evaluate the results and complications of the diagnostic and therapeutic procedures of AVA performed at our centre without the use of iodinated contrast. Methods: We evaluated retrospectively all patients submitted to endovascular diagnostic and/or therapeutic procedures using CO2 or ultrasound at our hospital between January 2013 and December 2016. Results: 30 procedures were performed in 22 patients: 15 ultrasound-guided angioplasties and 15 CO2 procedures (14 angioplasties and 1 diagnostic angiography). The mean age of patients was 74±10 years (41--94). Most procedures (90%) were performed on proximal arteriovenous fistulas (AVFs) and 3 were performed on distal AVFs. Iodinated contrast was not used because of its potential nephrotoxicity. Ultrasound-guided angioplasty was performed to treat outflow stenoses in the majority (73%) of the cases. The result was favourable in all procedures. One was complicated by venous rupture. Regarding angioplasties with CO2, outflow stenoses were the most treated (38%). The result was favourable in all procedures. Diagnostic angiography with CO2 was performed in a patient with signs of limb venous hypertension and was inconclusive. There were two complications in CO2 procedures: formation of pseudoaneurysm at the place of insertion of the introducer (n=1) and transient headache and nausea (n=1). Three of the patients who underwent angioplasty with CO2 and one patient who underwent ultrasound-guided procedure were submitted to balloon-assisted maturation. Conclusion: In our experience, the use of alternative methods with no iodinated contrast (CO2/ultrasound) in the evaluation and treatment of vascular access problems in patients with renal dysfunction is effective and safe

Dialysis catheter malfunction

Vascular access is a crucial factor in the treatment of hemodialysis patients. Dialysis catheters are associated with higher mortality than fistulas, meaning they should be the last choice for most patients. Although they have many drawbacks, catheters play an important role in providing a reliable vascular access in some patients. Dialysis catheter dysfunction is a major cause of morbidity. Early dysfunction usually occurs as a result of mechanical issues while late dysfunction is most commonly due to thrombosis. The causes of dysfunction and their management are distinct, and understanding of them is essential to preserve catheter patency and improve dialysis patient outcomes

Symptom control in End Stage Renal Disease

Chronic kidney disease (CKD) patients experience a high burden of symptoms that are not always recognized or relieved by standard measures. Principles of palliative care may be helpful both in dialysis or conservative treatment. This article intends to review some of the most common and distressing symptoms affecting ESRD patients in daily life, focusing on pathogenesis, pharmacological and non-pharmacological management. It will not include end of life care

Glucosylceramides and kidney disease

Glucosylceramides are part of the wider family of glycosylceramides. Glucosylceramide synthase catalyzes the incorporation of a single glucose residue into ceramide to yield glucosylceramide. Glucosylceramide is known as a precursor for globotriaosylceramide (Gb3). In the cell membrane, Gb3 acts a receptor for verotoxin and plays a key role in allowing verotoxin entry into endothelial cells. Verotoxin causes endothelial cell injury leading to microangiopathy in hemolytic uremic syndrome. Additionally, Gb3 accumulates mainly in lysosomes in Fabry disease, caused by an X-linked deficiency in alfa-galactosidase A. Accumulated Gb3 is metabolized to lyso-Gb3, a circulating water soluble molecule that elicits a stress response in podocytes similar to the response elicited by high glucose levels. The activation of Notch 1, CD74 expression and autocrine secretion of TGF-β1 induced by lyso-Gb3 and high glucose levels may underlie the characteristic fibrosis observed in both diabetic nephropathy and Fabry nephropathy. While current therapy for Fabry disease consists mainly of enzyme replacement therapy, glucosylceramide synthase inhibitors, such as lucerastat and venglustat, are undergoing clinical trials as substrate reduction therapy, aiming at decreasing Gb3 synthesis. Additionally, eliglustat is already in clinical use to treat Gaucher disease. Preclinical evidence has shown an excess accumulation of glycosylceramides in acute kidney injury and polycystic kidney disease. Furthermore, glucosylceramide synthase inhibitors are protective in polycystic kidney disease, suggesting a wider role of glucosylceramide or derivatives in kidney injury. However, inhibition of glucosylceramide synthase increases the severity of preclinical acute kidney injury, probably through increase ceramide accumulation, although direct toxicity of a specific drug could not be ruled out. This adds a note of caution for clinical studies, at least for some glucosylceramide synthase inhibitors

Amyloidosis related to HIV - An unusual cause of nephrotic syndrome in HIV patients

Human immunodeficiency virus infection is a multisystemic disease which causes kidney disease in a variable proportion of infected patients. AA amyloidosis, in turn, is an unusual complication related to HIV infection and also an infrequent cause of kidney disease; in this setting AA amyloidosis usually results from chronic skin infections related to intravenous use of recreational drugs. We report the case of a 43-year-old woman, native of the Ivory Coast, with active HIV 1 infection diagnosed 11 years ago, currently in the Centers for Disease Control and Preventions stage C3, out of antiretroviral therapy for non-adherence and with persistent positive viral load, admitted to the nephrology department for nephrotic syndrome. The patient denied any other relevant clinical history, including chronic or recurrent inflammatory or infectious disease or use or abuse of recreational drugs. Urine sediment and renal function were both normal as was renal ultrasound. Other opportunistic infections were excluded. The renal biopsy revealed deposition of amorphous substance, Congo red positive, in the vascular walls and a positive immunofluorescence for serum amyloid A, confirming the diagnosis of renal amyloidosis. The patient was started on antiretroviral and symptomatic therapy, with clinical improvement. The clinical diagnosis of renal amyloidosis secondary to HIV can be challenging, as it requires the exclusion of other possible aetiologies, but should be considered in the differential diagnosis of renal disease in HIV patients. This case illustrates the importance of the renal biopsy in such cases in which the diagnosis can be improperly set up if based only on clinical data.

Rivaroxaban-related nephropathy

Novel oral anticoagulants (NOAC) are a group of drugs recently approved for the treatment of patients at high risk of arterial or venous thrombosis. Unlike vitamin K antagonists, NOAC have a faster onset of action, less drug interactions and do not need frequent monitoring, making their prescription more convenient for physicians and patients. However, both classes of drugs have the potential for nephrotoxicity. Anticoagulation-related nephropathy is a form of acute kidney injury caused by excessive anticoagulation, resulting in glomerular haemorrhage and tubular obstruction by red blood casts. It was first described with warfarin, but new cases have been reported with acenocumarol and dabigatran. We report a case of a 82-year-old woman suffering from atrial fibrillation under rivaroxaban treatment with previous normal renal function, admitted to our unit with gross haematuria and acute kidney injury. A renal biopsy revealed typical features of anticoagulant-related nephropathy superimposed on chronic interstitial nephritis and hypertensive nephroangiosclerosis. There was no recovery of renal function despite withdrawal of rivaroxaban and the patient started on chronic haemodialysis three months after initial episode. To the best of our knowledge, this is the first case of a patient with a biopsy-proven anticoagulant nephropathy related to rivaroxaban. As novel oral anticoagulants are increasingly being prescribed and available data on their safety concerning renal toxicity are scarce, this report highlights the importance of a cautious prescription of these drugs and regular clinical and laboratory evaluation to avoid poor clinical outcomes.

Atypical renal presentation of antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease which can occur as a primary disease or in association with other autoimmune diseases, the most frequent being Systemic Lupus Erythematosus (SLE). Although renal manifestations of SLE are well known, antiphospholipid syndrome renal manifestations such as antiphospholipid syndrome nephropathy and glomerulopathies have yet to be better characterized. The authors present the case of a 39-year-old Caucasian woman with antiphospholipid syndrome diagnosis and a previous history of deep venous thrombosis and intermittent polyarthralgia, who was referred to a nephrology consultation for proteinuria and microscopic haematuria with preserved renal function. The renal biopsy showed a pattern of membranous glomerulopathy and thrombotic microangiopathy in association with antiphospholipid syndrome nephropathy. This case report illustrates a complex clinical and anatomopathological case of a 39- year-old woman with a previous antiphospholipid syndrome diagnosis who presented with unspecific manifestations such as proteinuria and microscopic haematuria and preserved renal function. The histological findings alert us to the range of possible renal manifestations of APS and the need to better characterize these patients by preforming renal biopsy.