Eric J. Costanzo

The Complications of Vascular Access in Hemodialysis

&NA; Complications related to hemodialysis vascular access continue to have a major impact on morbidity and mortality. Vascular access dysfunction is the single most important factor that determines the quality of dialysis treatment. Vascular access stenosis is a common complication that develops in a great majority of patients with an arteriovenous access and leads to access dysfunction. By restricting luminal diameter, this complication leads to a reduction in blood flow and places the access at risk for thrombosis. Similarly, the development of catheter‐related fibroepithelial sheath also causes catheter dysfunction with its detrimental effects on blood flow. In this article, we discuss the most common complications associated with dialysis access and provide therapeutic options to manage these problems.

Management of hypertension in patients during percutaneous dialysis access interventions

Not infrequently, interventionalists are faced with a patient with increased blood pressure who is about to undergo a dialysis access intervention such as tunneled hemodialysis catheter, percutaneous balloon angioplasty, or declotting procedure for a clotted arteriovenous access. This can frequently create a dilemma as functional dialysis access is needed to provide dialysis therapy and delaying treatment could result in a life-threatening situation, particularly in the presence of hyperkalemia. This article investigates hypertension in patients undergoing percutaneous dialysis access interventions and provides guidance to their management.

A Simplified Approach to the Management of Hypercalcemia

Department of Internal Medicine, Jersey Shore University Medical Center, Neptune, New Jersey, USA Department of Endocrinology, Jersey Shore University Medical Center, Neptune, New Jersey, USA Division of Nephrology and Hypertension, Jersey Shore University Medical Center, Neptune, New Jersey, USA Division of Nephrology, Salisbury VA Health Care System, Salisbury, NC and Department of Nephrology, University of North Carolina, Chapel Hill, NC, USA

Contrast-induced nephropathy: Pathophysiology, risk factors, and prevention

Contrast-induced acute kidney injury is a common iatrogenic complication associated with increased health resource utilization and adverse outcomes, including short- and long-term mortality and accelerated progression of preexisting renal insufficiency. The incidence of contrast-induced nephropathy (CIN) has been reported to range from 0% to 24%. This wide range reported by the studies is due to differences in definition, background risk factors, type and dose of contrast medium used, and the frequency of other coexisting potential causes of acute renal failure. CIN is usually transient, with serum creatinine levels peaking at 2-3 days after administration of contrast medium and returning to baseline within 7-10 days after administration. Multiple studies have been conducted using variety of therapeutic interventions in an attempt to prevent CIN. Of these, careful selection of patients, using newer radiocontrast agents, maintenance of hydration status, and avoiding nephrotoxic agents pre- and post-procedure are the most effective interventions to protect against CIN. This review focuses on the basic concepts of CIN and summarizes our recent understanding of its pathophysiology. In addition, this article provides practical recommendations with respect to CIN prevention and management.

Atypical hemolytic uremic syndrome: Laboratory characteristics, complement-amplifying conditions, renal biopsy, and genetic mutations

Atypical hemolytic uremic syndrome (aHUS) is characterized by microangiopathic hemolytic anemia, consumptive thrombocytopenia, and widespread damage to multiple organs including the kidney. The syndrome has a high mortality necessitating the need for an early diagnosis to limit target organ damage. Because thrombotic microangiopathies present with similar clinical picture, accurate diagnosis of aHUS continues to pose a diagnostic challenge. This article focuses on the role of four distinct aspects of aHUS that assist clinicians in making an accurate diagnosis of aHUS. First, because of the lack of a single specific laboratory test for aHUS, other forms of thrombotic microangiopathies such as thrombotic thrombocytopenic purpura and Shiga toxin-associated HUS must be excluded to successfully establish the diagnosis of aHUS. Second, application of the knowledge of complement-amplifying conditions is critically important in making an accurate diagnosis. Third, when available, a renal biopsy can reveal changes consistent with thrombotic microangiopathy. Fourth, genetic mutations are increasingly clarifying the underlying complement dysfunction and gaining importance in the diagnosis and management of patients with aHUS. This review concentrates on the four aspects of aHUS and calls for heightened awareness in making an accurate diagnosis of aHUS.

Prevalence of chronic kidney disease among patients undergoing transradial percutaneous coronary interventions

Background: While transradial approach to conduct percutaneous coronary interventions offers multiple advantages, the procedure can cause radial artery damage and occlusion. Because radial artery is the preferred site for the creation of an arteriovenous fistula to provide dialysis, patients with chronic kidney disease are particularly dependent on radial artery for their long-term survival. Methods: In this retrospective study, we investigated the prevalence of chronic kidney disease in patients undergoing coronary interventions via radial artery. Stage of chronic kidney disease was based on estimated glomerular filtration rate and National Kidney Foundation - Kidney Disease Outcomes Quality Initiative guidelines. Results: A total of 497 patients undergoing transradial percutaneous coronary interventions were included. Over 70.4% (350/497) of the patients had chronic kidney disease. Stage II chronic kidney disease was observed in 243 (69%) patients (estimated glomerular filtration rate = 76.0 ± 8.4 mL/min). Stage III was observed in 93 (27%) patients (estimated glomerular filtration rate = 49 ± 7.5 mL/min). Stage IV chronic kidney disease was observed in 5 (1%) patients (estimated glomerular filtration rate = 25.6 ± 4.3 mL/min) and Stage V chronic kidney disease was observed in 9 (3%) patients (estimated glomerular filtration rate = 9.3 ± 3.5 mL/min). Overall, 107 of 350 patients (30%) had advanced chronic kidney disease, that is, stage III–V chronic kidney disease. Importantly, 14 of the 107 (13%) patients had either stage IV or V chronic kidney disease. Conclusion: This study finds that nearly one-third of the patients undergoing transradial percutaneous coronary interventions have advanced chronic kidney disease. Because many of these patients may require dialysis, the use of radial artery to conduct percutaneous coronary interventions must be carefully considered in chronic kidney disease population.

Complement activation in atypical hemolytic uremic syndrome andscleroderma renal crisis: a critical analysis of pathophysiology

ABSTRACT Scleroderma is an autoimmune disease that affects multiple systems. While pathophysiologic mechanisms governing the development of scleroderma are relatively poorly understood, advances in our understanding of the complement system are clarifying the role of complement pathways in the development of atypical hemolytic uremic syndrome and scleroderma renal crisis. The abundant similarities in their presentation as well as the clinical course are raising the possibility of a common underlying pathogenesis. Recent reports are emphasizing that complement pathways appear to be the unifying link. This article reviews the role of complement system in the development of atypical hemolytic uremic syndrome and scleroderma renal crisis, and calls for heightened awareness to the development of thrombotic angiopathy in patients with scleroderma.

Subcutaneous defibrillators for dialysis patients

Defibrillation can be successfully provided by the subcutaneous implantable cardioverter defibrillator (ICD) without the leads. In contrast, traditional ICDs require leads that can cause central venous stenosis, lead‐induced endocarditis, and carry the risk of tricuspid regurgitation by valve adhesion, perforation, coaptation interference, or entanglement. Central venous stenosis, infection, and tricuspid regurgitation are all critically important considerations in hemodialysis patients. Recent reports are supporting the use of subcutaneous ICDs in renal patients maintained on long‐term hemodialysis. This article provides the risks associated with leads of traditional defibrillators and raises awareness of the subcutaneous ICD and their benefits for hemodialysis patients.

Ischemic monomelic neuropathy: A long-term follow-up of two cases

Introduction Ischemic monomelic neuropathy (IMN) is the most dreaded complication of an arteriovenous access creation. While uncommon, it can lead to pain, paresthesia or/and hand weakness. Creation of an arteriovenous connection causing a sudden diversion of blood away from the nerves can lead to ischemic injury to the neural tissue and cause IMN. Immediate surgical ligation has been traditionally recommended to limit ongoing neural tissue injury. Case description We present two diabetic patients who developed IMN after the creation of a left upper extremity brachial-cephalic fistula and refused to undergo surgical ligation. The clinical examination revealed paresthesia localized to the volar aspect of the left forearm with mild weakness of the thumb, index and middle finger. Rehabilitation therapy was initiated in both and revealed a significant improvement in weakness but paresthesia persisted. Fistula maturation was achieved in both patients with an access flow of 1100-1200 cc/min. At 4 months, fistula was used successfully for dialysis in both patients. At a follow-up of 11 months, hand weakness did not progress and paresthesia disappeared. Conclusions These cases demonstrate sensory-motor improvement with time and rehabilitation therapy and challenge the traditional approach of fistula ligation. The approach presented in this paper also results in the preservation of the lifeline of a patient. Future investigations should focus on identifying candidates who could benefit from physical therapy and rehabilitation.

Atypical Presentation of Gordon Syndrome and Its Management: A Report of Three Patients

Gordon syndrome (GS) usually presents in children with hyperkalemia, hypertension and hyperchloremic metabolic acidosis. However, it has been reported in adults, where diagnosis can be missed in the absence of vigilance for electrolytes and acid base abnormalities. GS is traditionally managed with hydrochlorothiazide and restricted sodium diet. We report adult patients with GS, who were successfully treated with a potassium-restricted diet. Three female patients (aged 70, 61, and 79 years) presented to the clinic with untreated isolated hyperkalemia for several years. Patients did not complain of headache, palpitation, chest pain, polyuria or hematuria. Upon examination, two patients were normotensive and one patient had hypertension (150/90 mm Hg). Laboratory analysis revealed hyperkalemia (6.2, 6.1 and 6.2 mEq/L), serum bicarbonate level of 30, 27 and 28 mEq/L, hyperchloremia (108, 107 and 94 mEq/L) and serum normal creatinine (0.90, 0.8 and 0.78 mg/dL), based upon normal reference lab values. Plasma aldosterone and renin were normal. Based on patients’ history, physical examination, laboratory findings and absence of other causes of hyperkalemia such as the history of the use of NSAID, ACE inhibitors (angiotensin receptor blockers, aldosterone receptor blockers, and beta-blockers), and the absence of diabetes mellitus and other causes of hyporeninemic hypoaldosteronism, a diagnosis of GS was made. All three patients were treated with a restricted potassium diet contrary to a low sodium diet and hydrochlorothiazide. A 4-week follow-up showed normal serum potassium levels (4.2, 4.6 and 4.9 mEq/L) in all three patients. While GS has been reported previously in adults and can present with normal blood pressure, its management by a restricted potassium diet has not been reported, to the best of our knowledge. GS should be included in the differential diagnosis of adult patients presenting with unexplained hyperkalemia. J Med Cases. 2017;8(8):252-255 doi: https://doi.org/10.14740/jmc2874w