Low-molecular-weight dextran for optical coherence tomography may not be protective against kidney injury in patients with renal insufficiency

BACKGROUND

Low-molecular-weight dextran (LMWD) is considered a safe alternative to contrast media for blood displacement during optical coherence tomography (OCT) imaging.

AIM

To investigate whether the use of LMWD for OCT is protective against kidney injury in patients with advanced renal insufficiency.

METHODS

In this retrospective cohort study, we identified 421 patients with advanced renal insufficiency (estimated glomerular filtration rate < 45 mL/min/1.73 m²) who underwent coronary angiography or percutaneous coronary intervention; 79 patients who used additional LMWD for OCT imaging (LMWD group) and 342 patients who used contrast medium exclusively (control group). We evaluated the differences between these two groups and performed a propensity score-matched subgroup comparison.

RESULTS

The median total volume of contrast medium was 133.0 mL in the control group vs 140.0 mL in the LMWD group. Although baseline renal function was not statistically different between these two groups, the LMWD group demonstrated a strong trend toward the progression of renal insufficiency as indicated by the greater change in serum creatinine level during the 1-year follow-up compared with the control group. Patients in the LMWD group experienced worsening renal function more frequently than patients in the control group. Propensity score matching adjusted for total contrast media volume consistently indicated a trend toward worsening renal function in the LMWD group at the 1-year follow-up. Delta serum creatinine at 1-year follow-up was significantly greater in the LMWD group than that in the control group [0.06 (-0.06, 0.29) vs -0.04 (-0.23, 0.08) mg/dL, P = 0.001], despite using similar contrast volume.

CONCLUSION

OCT using LMWD may not be protective against worsening renal function in patients with advanced renal insufficiency.

Emperor's syndrome in the COVID-19 era: Time for patient-centered nephrology?

The coronavirus disease-19 (COVID-19) pandemic has been a wake-up call in which has forced us to react worldwide. Health policies and practices have attracted particular attention in terms of human and financial cost. Before COVID-19, chronic kidney disease was already considered a risk multiplier in patients with diabetes and hypertension, the two now being the major risk factors for COVID-19 infection and adverse outcome. In contrast to the urgent need for action, the nephrology field is considered to be in a state of stagnation regarding the management of chronic kidney disease patients who still experience unacceptably high morbidity and mortality. Ironically and paradoxically in a field lacking robust clinical trials, clinical practice is driven by guidelines-based medicine on weak evidence. The Emperor's syndrome, referring to Hans Christian Andersen's fairy tale, has been described in medicine as voluntary blindness to an obvious truth, being a weak evidence-based therapeutic intervention or weak health care. A promising positive example of improving heart and kidney outcomes is the emerging treatment with sodium-glucose cotransporter 2 inhibitors. COVID-19 could boost actions for patient-centered care as a positive shift in nephrology care.

Restructuring nephrology services to combat COVID-19 pandemic: Report from a Middle Eastern country

Coronavirus disease 2019 has spread across the world and has been classified as a pandemic. It has overwhelmed the healthcare systems. Specifically, it has overstretched the intensive care units and renal replacement therapy services in many countries. In this paper, we discuss the reconfiguration of nephrology services in the State of Qatar during the current pandemic. We highlight the key strategies that have been implemented to ensure that renal replacement therapy capacity is not constrained in either the intensive care or ambulatory setting. Some innovative approaches for the safe delivery of ambulatory care to dialysis and kidney transplant patients are also discussed.

Kidney injury in COVID-19

Coronavirus disease 2019 (COVID-19) continues to affect millions of people around the globe. As data emerge, it is becoming more evident that extrapulmonary organ involvement, particularly the kidneys, highly influence mortality. The incidence of acute kidney injury has been estimated to be 30% in COVID-19 non-survivors. Current evidence suggests four broad mechanisms of renal injury: Hypovolaemia, acute respiratory distress syndrome related, cytokine storm and direct viral invasion as seen on renal autopsy findings. We look to critically assess the epidemiology, pathophysiology and management of kidney injury in COVID-19.

Findings on intraprocedural non-contrast computed tomographic imaging following hepatic artery embolization are associated with development of contrast-induced nephropathy

BACKGROUND

Contrast-induced nephropathy (CIN) is a reversible form of acute kidney injury that occurs within 48-72 h of exposure to intravascular contrast material. CIN is the third leading cause of hospital-acquired acute kidney injury and accounts for 12% of such cases. Risk factors for CIN development can be divided into patient- and procedure-related. The former includes pre-existing chronic renal insufficiency and diabetes mellitus. The latter includes high contrast volume and repeated exposure over 72 h. The incidence of CIN is relatively low (up to 5%) in patients with intact renal function. However, in patients with known chronic renal insufficiency, the incidence can reach up to 27%.

AIM

To examine the association between renal enhancement pattern on non-contrast enhanced computed tomographic (CT) images obtained immediately following hepatic artery embolization with development of CIN.

METHODS

Retrospective review of all patients who underwent hepatic artery embolization between 01/2010 and 01/2011 (n = 162) was performed. Patients without intraprocedural CT imaging (n = 51), combined embolization/ablation (n = 6) and those with chronic kidney disease (n = 21) were excluded. The study group comprised of 84 patients with 106 procedures. CIN was defined as 25% increase above baseline serum creatinine or absolute increase ≥ 0.5 mg/dL within 72 h post-embolization. Post-embolization CT was reviewed for renal enhancement patterns and presence of renal artery calcifications. The association between non-contrast CT findings and CIN development was examined by Fisher’s Exact Test.

RESULTS

CIN occurred in 11/106 (10.3%) procedures (Group A, n = 10). The renal enhancement pattern in patients who did not experience CIN (Group B, n = 74 with 95/106 procedures) was late excretory in 93/95 (98%) and early excretory (EE) in 2/95 (2%). However, in Group A, there was a significantly higher rate of EE pattern (6/11, 55%) compared to late excretory pattern (5/11) (P < 0.001). A significantly higher percentage of patients that developed CIN had renal artery calcifications (6/11 vs 20/95, 55% vs 21%, P = 0.02).

CONCLUSION

A hyperdense renal parenchyma relative to surrounding skeletal muscle (EE pattern) and presence of renal artery calcifications on immediate post-HAE non-contrast CT images in patients with low risk for CIN are independently associated with CIN development.

Renal transplant recipient seizure practical management

Seizures are not uncommon in renal transplant patients. The common aetiologies are metabolic disturbance associated with renal failure, immunosuppression and associated complications and infections. Their management can be challenging because of altered pharmacokinetics of antiepileptic drugs (AEDs) and their removal by dialysis. A practical approach to the management of seizure in renal transplant patients is discussed. This review highlights the guidelines for use of various AEDs in renal transplants.

Broad spectrum of interferon-related nephropathies-glomerulonephritis, systemic lupus erythematosus-like syndrome and thrombotic microangiopathy: A case report and review of literature

BACKGROUND

Interferons (IFNs) are characterized by a wide range of biological effects, which justifies their potential therapeutic use in several pathologies, but also elicit a wide array of adverse effects in almost every organ system. Among them, renal involvement is probably one of the most complex to identify.

CASE SUMMARY

We describe four cases of kidney damage caused by different IFN formulations: IFN-β-related thrombotic microangiopathy, IFN-β-induced systemic lupus erythematosus, and two cases of membranous nephropathy secondary to pegylated-IFN-α 2B. In each case, we carefully excluded any other possible cause of renal involvement. Once suspected as the casual relationship between drug and kidney damage, IFN treatment was immediately discontinued. In three cases, we observed a complete and persistent remission of clinical and laboratory abnormalities after IFN withdrawal, while the patient who developed thrombotic microangiopathy, despite IFN withdrawal and complement-inhibitor therapy with eculizumab, showed persistent severe renal failure requiring dialysis.

CONCLUSION

This case series highlights the causal relationship between IFN treatment and different types of renal involvement and enables us to delineate several peculiarities of this association.

Complement activation and long-term graft function in ABO-incompatible kidney transplantation

BACKGROUND

ABO-incompatible and ABO-compatible kidney transplantation are equivalent in terms of short-term graft and patient survival. This is thought to be the result of ABO-incompatible graft accommodation, which occurs when anti-blood group antibodies re-occur after transplantation but somehow do not yield their detrimental effect. The underlying mechanism is unclear, but one of the hypotheses is that this is the result of complement inhibition. Since virtually all ABO-incompatible graft biopsies are C4d positive, this complement inhibition must occur somewhere in the complement cascade after the formation of C4d has already taken place, but where exactly is unclear. It is also unclear whether complement inhibition is complete. Incomplete accommodation could explain why recent studies have shown that long-term graft function in ABO-incompatible transplantation is somewhat inferior to ABO-compatible kidney transplantation.

AIM

To unravel the relationship between pre-transplant anti-ABO antibodies, complement activation, and long-term graft function.

METHODS

We included all 27 ABO-incompatible transplantations that were performed between 2008 and 2013 at the Academic Medical Center Amsterdam and the University Medical Center Groningen. For each ABO-incompatible transplantation, we included four ABO-compatible controls matched by age, sex, and transplantation date.

RESULTS

Graft and patient survival were not significantly different. The slope of kidney function during five-year follow-up was also not significantly different, but ABO-incompatible recipients did have a lower kidney function at three months (creatinine clearance 58 vs 69 mL/min, P = 0.02, Modification of Diet in Renal Disease 46 vs 52 mL/min/1.73 m², P = 0.08), due to a high rate of early rejection (33% vs 15%, P = 0.03), mostly T-cell mediated. Pre-transplant anti-ABO IgG titers were positively correlated with C5b-9 staining, which itself was positively correlated with the occurrence of T-cell mediated rejection. This may be the result of concurrent C5a formation, which could function as a costimulatory signal for T-cell activation.

CONCLUSION

Co-stimulation of T-cell activation by ongoing complement activation by anti-ABO antibodies may be responsible for an impaired long-term graft function in ABO-incompatible kidney transplantation.

WNT/β-catenin signaling in urothelial carcinoma of bladder

Urothelial carcinoma of bladder is the second most prevalent genitourinary disease. It is a highly heterogeneous disease as it represents a spectrum of neoplasms, including non-muscle invasive bladder cancer (NMIBC), muscle invasive bladder cancer (MIBC) and metastatic lesions. Genome-wide approaches and candidate gene analysis suggest that malignant transformation of the bladder is multifactorial and a multitude of genes are involved in the development of MIBC or NMIBC phenotypes. Wnt signaling is being examined to control and maintain balance between stemness and differentiation in adult stem cell niches. Owing to its participation in urothelial development and maintenance of adult urothelial tissue homeostasis, the components of Wnt signaling are reported as an important diagnostic and prognostic markers as well as novel therapeutic targets. Mutations/epigenetic alterations in the key molecules of Wnt/β-catenin canonical pathway have been linked with tumorigenesis, development of drug resistance and enhanced survival. Present review extends our understanding on the functions of key regulatory molecules of canonical Wnt/β-catenin pathway in urothelial tumorigenesis by inducing cancer stem cell phenotype (UCSCs). UCSCs may be responsible for tumor heterogeneity, high recurrence rates and complex biological behavior of bladder cancer. Therefore, understanding the role of UCSCs and the regulatory mechanisms that are responsible for high relapse rates and metastasis could help to develop pathway inhibitors and augment current therapies. Potential implications in the treatment of urothelial carcinoma of bladder by targeting this pathway primarily in UCSCs as well as in bulk tumor population that are responsible for high relapse rates and metastasis may facilitate potential therapeutic avenues and better prognosis.

The role of mycophenolate in the treatment of antineutrophil cytoplasmic antibody-associated vasculitis

Mycophenolic acid, the active metabolite for mycophenolate mofetil and mycophenolic sodium, is a strong, noncompetitive, reversible inhibitor of inosine monophosphate dehydrogenase, the key enzyme in de novo synthesis of guanosine nucleotides leading to selective inhibition of lymphocyte proliferation. Mycophenolic acid has been evaluated as induction and remission maintenance agent in the treatment of antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Since the course of disease of AAV usually requires long term immunosuppression, mycophenolate has been explored as a less toxic agent compared to cyclophosphamide and azathioprine. Mycophenolate is a potent immunosuppressive agent in the therapy of AAV, non-inferior to other available drugs with comparable side effect profile. Therefore, it could be a valuable alternative in cases of toxicity with life threatening side effects or intolerance to cyclophosphamide or azathioprine, in cases with high cumulative dose of cyclophosphamide, but also in cases with insufficient response. Several studies have shown a higher relapse rate following discontinuation of mycophenolate or in mycophenolate treated subjects that raises concerns about its usefulness in the treatment of AAV. This review describes the efficacy of mycophenolate in AAV as remission induction agent, as remission maintenance agent, and as therapeutic option in relapsing AAV disease, the relapse rate following discontinuation of mycophenolate, and the adverse events related to mycophenolate treatment.

A rare presentation of spontaneous atheroembolic renal disease: A case report

BACKGROUND

Atheroembolic renal disease (AERD) is caused by occlusion of the small renal arteries from embolized cholesterol crystals arising from ulcerated atherosclerotic plaques. This usually manifests as isolated renal disease or involvement from systemic atheroembolic disease. Here we report a case of AERD that responded well to steroid therapy.

CASE SUMMARY

A 62-year-old woman with a history of hypertension and stage IIIa chronic kidney disease was referred for rapidly worsening renal function over a 4-mo period. She complained of swollen legs, dyspnea on exertion, and two episodes of epistaxis about a month prior to admission. She reported no history of invasive vascular procedures, use of radio contrast agents, or treatment with anticoagulants or thrombolytic agents. Urinalysis showed a few red blood cells and granular casts. Serology was positive for cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA). Non-contrast-enhanced computed tomography of the chest, abdomen, and pelvis showed diffuse atherosclerotic changes in the aortic arch. Thus, c-ANCA-associated vasculitis was suspected, and the patient was started on pulse intravenous methylprednisolone. Her renal biopsy showed evidence of AERD. She was discharged with oral prednisone, and her renal function continued to improve during the initial follow-up.

CONCLUSION

In cases of non-vasculitis-associated ANCA, a high degree of clinical suspicion is required to pursue the diagnosis of spontaneous AERD in patients with clinical or radiological evidence of atherosclerotic burden. Although no specific treatment is available, the potential role of statins and steroids requires exploration.

Point of care renal ultrasonography for the busy nephrologist: A pictorial review

The application of bedside ultrasonography in routine clinical practice has dramatically evolved over the last few decades and will likely continue to grow as technological advances lead to enhanced portability and affordability of the equipment. Despite mounting interest, most nephrology fellowship training programs do not offer formal training in renal ultrasonography and there is inertia among practicing nephrologists to adopt this skill as a practice-changing advancement. Lack of familiarity with the topic is considered a key reason for this inertia. Understanding of basic ultrasound physics, instrumentation, principles of optimal image acquisition and interpretation is critical for enhanced efficiency and patient safety while using this tool. Herein, we provide a brief overview of the basic principles of diagnostic renal ultrasonography as well as introduction to common sonographic pathologies encountered in day-to-day nephrology practice with illustrative images.

Static pressures, intra-access blood flow and dynamic Kt/V profiles in the prediction of dialysis access function

BACKGROUND

Hemodialysis machine-generated circuit pressures and clearance profiles are potential predictors of quality assurances. In our practice, we previously we observed that elevated static access pressures were associated with abnormal Kt/V values, high access recirculation and deviation of the Kt/V profile (Abnormal Kt/V profile) from normally expected values (Normal Kt/V profile).

AIM

To hypothesize that static or derived access pressures would correlate with direct intra-access blood flow rates and that clearance (Kt/V) profiles would correlate with measured Kt/V values.

METHODS

Static access pressures, real-time adequacy of dialysis and intra-access blood flow were investigated in end stage renal disease patients undergoing hemodialysis. Wilcoxon-Mann-Whitney test, chi-square test or Fisher’s exact test was used to investigate differences between the groups; Spearman’s rank correlation test to investigate relationships between static pressures, direct intra-access pressures and Kt/V profiles; and multinomial logistic regression models to identify the independent effect of selected variables on Kt/V profiles. Odds ratio were calculated to measure the association between the variables and Kt/V profiles.

RESULTS

One hundred and seven patients were included for analysis. There were no significant differences between genders, and types of vascular access between the normal vs. abnormal clearance (Kt/V) profile groups. No significant correlation could be demonstrated between static access pressures and Kt/V profiles, static access pressures and intra-access blood flow, intra-access blood flow and Kt/V profiles, measured Kt/V and Kt/V profiles or recirculation and Kt/V profiles.

CONCLUSION

In this study utilizing measured versus estimated data, we could not validate that dialysis machine generated elevated static pressures predict intra-access blood flow disturbances or that abnormal Kt/V profiles predict access recirculation or inadequate dialysis. These parameters, though useful estimates, cannot be accepted as quality assurance for dialysis adequacy or access function without further evidences.

Associations of renal function with diabetic retinopathy and visual impairment in type 2 diabetes: A multicenter nationwide cross-sectional study

BACKGROUND

Diabetic retinopathy (DR) separately has been noted as a major public health problem worldwide as well. Currently, many studies have demonstrated an association between diabetic nephropathy and DR in type 1 diabetes mellitus (T1DM) patients, but this association is less strong in T2DM. The evidence for an association between renal function and DR and visual impairment among T2DM patients is limited, particularly in the Asian population.

AIM

To assess the association between glomerular filtration rate (GFR) and DR, severe DR, and severe visual impairment among T2DM patients in Thailand.

METHODS

We conducted a nationwide cross-sectional study based on the DM/HT study of the Medical Research Network of the Consortium of Thai Medical Schools. This study evaluated adult T2DM patients from 831 public hospitals in Thailand in the year 2013. GFR was categorized into ≥ 90, 60-89, 30-59 and < 30 mL/min/1.73 m². The association between GFR and DR, severe DR, and severe visual impairment were assessed using multivariate logistic regression.

RESULTS

A total of 13192 T2DM patients with available GFR were included in the analysis. The mean GFR was 66.9 ± 25.8 mL/min/1.73 m². The prevalence of DR, proliferative DR, diabetic macular edema, and severe visual impairment were 12.4%, 1.8%, 0.2%, and 2.1%, respectively. Patients with GFR of 60-89, 30-59 and < 30 mL/min/1.73 m² were significantly associated with increased DR and severe DR when compared with patients with GFR of ≥ 90 mL/min/1.73 m². In addition, increased severe visual impairment was associated with GFR 30-59 and < 30 mL/min/1.73 m².

CONCLUSION

Decreased GFR was independently associated with increased DR, severe DR, and severe visual impairment. GFR should be monitored in diabetic patients for DR awareness and prevention.

Insulin receptors in the kidneys in health and disease

Insulin is an important hormone that affects various metabolic processes, including kidney function. Impairment in insulin’s action leads to insulin resistance in the target tissue. Besides defects in post-receptor insulin signaling, impairment at the receptor level could significantly affect insulin sensitivity of the target tissue. The kidney is a known target of insulin; however, whether the kidney develops “insulin resistance” is debatable. Regulation of the insulin receptor (IR) expression and its function is very well studied in major metabolic tissues like liver, skeletal muscles, and adipose tissue. The physiological relevance of IRs in the kidney has recently begun to be clarified. The credit goes to studies that showed a wide distribution of IR throughout the nephron segments and their reduced expression in the insulin resistance state. Moreover, altered renal and systemic metabolism observed in mice with targeted deletion of the IR from various epithelial cells of the kidney has strengthened this proposition. In this review, we recapitulate the crucial findings from literature that have expanded our knowledge regarding the significance of the renal IR in normal- and insulin-resistance states.

Dehydration and volume depletion: How to handle the misconceptions

Dehydration and volume depletion describe two distinct body fluid deficit disorders with differing pathophysiology, clinical manifestations and treatment approaches. However, the two are often confused or equated with each other. Here, we address a number of commonly encountered misconceptions about body-fluid deficit disorders, analyse their origins and propose approaches to overcome them.

Choice of dialysis modality prior to kidney transplantation: Does it matter?

The population of patients with end stage renal disease (ESRD) is increasing, lengthening waiting lists for kidney transplantation. Majority of the patients are not able to receive a kidney transplant in timely manner even though it is well established that patient survival and quality of life after kidney transplantation is far better when compared to being on dialysis. A large number of patients who desire a kidney transplant ultimately end up needing some form of dialysis therapy. Most of incident ESRD patients choose hemodialysis (HD) over peritoneal dialysis (PD) as the modality of choice in the United States, even though studies have favored PD as a better choice of pre-transplant dialysis modality than HD. PD is largely underutilized in the United States due to variety of reasons. As a part of the decision making process, patients are often educated how the choice regarding modality of dialysis would fit into their life but it is not clear and not usually discussed, how it can affect eventual kidney transplantation in the future. In this article we would like to discuss ESRD demographics and outcomes, modality of dialysis and kidney transplant related events. We have summarized the data comparing PD and HD as the modality of dialysis and its impact on allograft and recipient outcomes after kidney transplantation.

Clear cell papillary renal cell carcinoma: A case report and review of the literature

Clear cell papillary renal cell carcinoma (ccpRCC) was recently established as a distinct type of epithelial neoplasm by the International Society of Urological Pathology Vancouver Classification of Renal Neoplasia. Here, we report a case of partial nephrectomy for a ccpRCC detected during the routine follow-up of a previously treated liposarcoma in a 70-year-old male patient. The patient was referred to the urology department for a right-sided renal mass (size: 2 cm) detected during routine annual imaging follow-up for a malignant right inguinal fibrous histocytoma and liposarcoma that had been diagnosed 6 and 4 years earlier, respectively, and treated with surgery and adjuvant radiation therapy. Following partial nephrectomy, the renal mass was pathologically diagnosed as ccpRCC, and immunohistochemistry revealed carbonic anhydrase 9 (CA9) expression. No recurrences or metastases were detected on follow-up imaging for 6 months. This is the first report of partial nephrectomy for incidentally discovered CA9-positive ccpRCC.

Palliative care for acute kidney injury patients in the intensive care unit

Patients with acute kidney injury (AKI) in the intensive care unit (ICU) are often suitable for palliative care due to the high symptom burden. The role of palliative medicine in this patient population is not well defined and there is a lack of established guidelines to address this issue. Because of this, patients in the ICU with AKI deprived of the most comprehensive or appropriate care. The reasons for this are multifactorial including lack of palliative care training among nephrologists. However, palliative care in these patients can help alleviate symptoms, improve quality of life, and decrease suffering. Palliative care physicians can determine the appropriateness and model of palliative care. In addition to shared decision-making, advance directives should be established with patients early on, with specific instructions regarding dialysis, and those advance directives should be respected.

Confounding risk factors and preventative measures driving nephrolithiasis global makeup

Nephrolithiasis is increasing in developed and developing countries at an alarming rate. With the global spike in kidney stone diseases, it is crucial to determine what risk factors are influencing the current global landscape for kidney stones. Our aims for this review are: to identity and analyze the four categories of risk factors in contributing to the global scale of stone formation: lifestyle, genetics, diet, and environment; and discuss preventative measures for kidney stone formation. We also performed data search through the published scientific literature, i.e., PubMed^® and found that there is a significant link between lifestyle and obesity with cases of calcium stones. Food and Agriculture Organization of the United Nations and World Health Organization factor indicators for dietary intake and obesity, along with climate data were used to create the projected total risk world map model for nephrolithiasis risk. Complete global analyses of nephrolithiasis deplete of generalizations is nearly insurmountable due to limited sources of medical and demographic information, but we hope this review can provide further elucidation into confounding risk factors and preventative measures for global nephrolithiasis analysis.