Associations between calf, thigh, and arm circumference and cardiovascular and all-cause mortality in NHANES 1999-2004.

BACKGROUND AND AIMS: Prior studies have described an association between calf circumference and cardiovascular disorders. We evaluated the associations between calf, thigh, and arm circumference and cardiovascular and all-cause mortality. METHODS AND RESULTS: We performed a retrospective cohort study of 11,871 patients in the 1999-2004 National Health and Nutrition Examination Survey (NHANES) to determine the association between calf circumference and cardiovascular and all-cause mortality using univariate and multivariate Cox proportional hazards. We additionally examined the association between thigh and arm circumference and mortality. In the multivariable Cox regression for the female stratum, each centimeter increase in calf circumference was associated with a hazard ratio of 0.88 (95% CI 0.84-0.92), and a hazard ratio of 0.90 (95% CI 0.85-0.95) for cardiovascular death. In the model with males, the hazard ratio for higher calf circumference was 0.92 (95% CI 0.88-0.96) for all-cause mortality and 0.94 (95% CI 0.89-0.99) for cardiovascular death. There was a statistically significant association between higher thigh circumference and lower risk of all-cause and cardiovascular mortality. Arm circumference was not similarly associated with mortality in the multivariate model. CONCLUSION: Calf and thigh circumference may provide important prognostic information regarding cardiovascular and all-cause mortality. Future prospective studies should examine the role of extremity circumference and cardiovascular events.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update.

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Bowel Perforation During Peritoneal Dialysis Catheter Placement.

Interventional nephrologists and radiologists place peritoneal dialysis catheters using the percutaneous fluoroscopic technique in both the inpatient and outpatient setting. Nephrologists caring for such patients may have to diagnose and manage the complications resulting from these procedures. Abdominal pain can occur following peritoneal dialysis catheter placement when the local and systemic analgesia wears off. However, abdominal pain with hypotension is suggestive of a serious complication. Bleeding into the abdomen and perforation of the colon or bladder should be considered in the differential diagnosis. In the case reported here, the peritoneogram showed contrast in the bowel, and correct interpretation by the interventionist would have prevented this complication. The characteristic pattern of peritoneogram images in this case will guide interventionists to avoid this complication, and the discussion of the differential diagnosis and management will assist nephrologists in taking care of such patients.

Hyponatremia: A Review.

Hyponatremia is the most frequently occurring electrolyte abnormality and can lead to life-threatening complications. This disorder may be present on admission to the intensive care setting or develop during hospitalization as a result of treatment or multiple comorbidities. Patients with acute hyponatremia or symptomatic chronic hyponatremia will likely require treatment in the intensive care unit (ICU). Immediate treatment with hypertonic saline is needed to reduce the risk of permanent neurologic injury. Chronic hyponatremia should be corrected at a rate sufficient to reduce symptoms but not at an excessive rate that would create a risk of osmotic injury. Determination of the etiology of chronic hyponatremia requires analysis of serum osmolality, volume status, and urine osmolality and sodium level. Correct diagnosis points to the appropriate treatment and helps identify risk factors for accelerated correction of the serum sodium level. Management in the ICU facilitates frequent laboratory draws and allows close monitoring of the patient's mentation as well as quantification of urine output. Overly aggressive correction of serum sodium levels can result in neurological injury caused by osmotic demyelination. Therapeutic measures to lower the serum sodium level should be undertaken if the rate increases too rapidly.

A diagnostic dilemma: lupus nephritis or renal polyarteritis nodosa?

Lupus nephritis and renal polyarteritis nodosa (PAN) are two distinct disorders that rarely overlap. Herein, we describe a patient who was initially diagnosed with lupus nephritis based on her clinical presentation, proteinuria, hematuria, positive anti-nuclear antibody, and a kidney biopsy. A month later, the patient presented with left flank pain and weakness. A CT scan of the abdomen and pelvis showed a perinephric hematoma and the renal arteriogram revealed numerous microaneurysms within the kidney consistent with renal PAN. This case elucidates the diagnostic and management dilemmas that confront physicians taking care of patients with overlapping features of lupus nephritis and renal PAN and also points to the possible role of lupus nephritis in pathogenesis of renal PAN.

Laparoscopic peritoneal dialysis catheter placement is associated with decreased deep organ infection and reoperation.

INTRODUCTION: The optimal method for placement of peritoneal dialysis catheters (PDC) is unclear. The objective of this study was to compare the outcomes of laparoscopic and open surgical placement of PDC. MATERIALS AND METHODS: Patients who underwent laparoscopic (LPD) and open (OPD) surgical placement of PDC between 2007 and 2011 were identified from the American College of Surgeons National Surgical Quality Initiative Project (NSQIP) dataset using current procedural terminology (CPT) and international classification of diseases 9th revision (ICD-9) codes. Perioperative outcomes were compared using Fisher's exact test for categorical variables, Student's t-test and Gamma regression were used for continuous variables. Catheter function was not reported in the dataset. RESULTS: There were 1,560 PDC procedures in our study and most were performed laparoscopically (89%). 83% of these procedures were performed by general surgeons, mostly, with the patients under general anesthesia (95%). OPD was associated with a higher rate of perioperative deep organ infection (3.5% vs. 1.1%, p = 0.02) and need for reoperation (10.4% vs. 5.0%, p = 0.007). Operative time was, however, significantly longer with LPD (53.3 vs. 45.5 minutes, p < 0.001). In multivariate analysis, OPD was independently associated with increased risk of perioperative deep organ infection (odds ratio (OR) 3.7,95%, Confidence Interval (CI) 1.3 - 10.2, p = 0.01) and reoperation (OR 2.3, 95% CI 1.3 - 4.1, p = 0.005). CONCLUSIONS: Laparoscopic PDC placement is more commonly performed and is associated with a lower risk of perioperative deep organ infection and reoperation than the open surgical approach. When possible, laparoscopic PDC placement might be preferable over open surgical placement.

The structure and function of endovascular stents: a primer for the interventional nephrologist.

The use of stents has become common practice in various interventional fields. The purpose of this article is to provide the interventionalist with an understanding of the basic structure stent. We describe the etymology, the classification and describe various terms used by engineers as they strive to develop that "ideal" stent. We also describe the fabrication process briefly and finally elaborate on the characteristic "build and cut" of some commonly used stents.

Stent strut protrusion--an uncommon complication of stent placement in a fistula.

Stent strut protrusion through the skin is a rare and a potentially dangerous complication from the cannulation of stents placed within arterio-venous fistulas and grafts. Such cases are usually managed surgically. We present a case wherein strut penetration of an arterio-venous fistula was noted at the distal (uncovered) end of a Fluency Plus(®) tracheo bronchial stent graft. After analyzing the various reasons why this may have happened, a nonsurgical approach was taken to preserve the access and manage strut protrusion.

Polymer embolization from minimally invasive interventions.

Many of the tools used in interventional nephrology, such as glidewires and sheaths, are coated with a hydrophilic polymer to increase their lubricity; however, this polymer can shear off, which causes polymer embolization. We describe 3 cases in which polymer emboli were found on histopathologic examination in an arteriovenous graft, a transplanted kidney, and the myocardium. A review of the literature shows that although most of these phenomena are benign, in some patients, it may present with significant morbidity.

Graftula: a composite access consisting of a graft used to repair a dysfunctional hemodialysis fistula.

Nonmaturing or dysfunctional hemodialysis fistulas are often repaired with interposition grafts placed either within the fistula (fistula-to-fistula configuration), or connected to another vein (fistula-to-vein configuration). The goal of this study was to compare the survival and usefulness of the composite accesses thus created, which we call "graftulas," with upperarm grafts. This was a retrospective study wherein we determined the survival and thrombosis rates of graftulas (n=24) and upper arm grafts (n=31) placed 1/1/07 through 12/31/09 and followed through 11/30/10. Graftulas resembled grafts as most (96%) were successfully cannulated in 65 ± 43 days. Survival of graftulas was also similar to grafts (58%, 47%, and 32% vs. 56%, 47%, and 39% at 1, 2, and 3 years respectively, p=0.60). However, graftulas had a lower thrombosis rate than grafts (0.5 vs. 1.2 per patient year, p=0.04), and in the fistula-to-fistula configuration, a 2-year thrombosis-free survival of 78%. Total survival of the access site (fistula+graftula) was 92%, 73%, and 42% at 1, 3, and 5 years, respectively. Graftulas possess certain beneficial properties of fistulas and grafts that allows for continued use of the original access site.

Ischemia from extrinsic compression of the brachial artery by a stent in the venous outflow of a brachio-basilic arterio-venous graft.

Distal artery embolization is a well-known complication after mechanical thrombectomy, manifesting as limb ischemia. We describe a case of ischemia that developed after mechanical thrombectomy and stent placement in the venous anastomosis of a brachio- basilic arterio-venous graft. Subsequent investigations revealed that the stent had extrinsically compressed the adjacent brachial artery. Although balloon angioplasty of the artery initially restored flow, the patient needed surgical removal of the graft and stent to prevent persistent ischemia.

Serial SARS-CoV-2 Antibody Titers in Vaccinated Dialysis Patients: Prevalence of Unrecognized Infection and Duration of Seroresponse.

Rationale & Objective: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are likely underdiagnosed, but the degree of underdiagnosis among patients receiving maintenance dialysis is unknown. The durability of the immune response after the third vaccine dose in this population also remains uncertain. This descriptive study tracked antibody levels to (1) assess the rate of undiagnosed infections and (2) characterize seroresponse durability after the third dose. Study Design: Retrospective observational study. Setting & Participants: SARS-CoV-2-vaccinated patients receiving maintenance dialysis through a national dialysis provider. Immunoglobulin G spike antibodies [anti-spike immunoglobulin (Ig) G] titers were assessed monthly after vaccination. Exposures: Two and 3 doses of SARS-CoV-2 vaccine. Outcomes: Undiagnosed and diagnosed SARS-CoV-2 infections; anti-spike IgG titers over time. Analytical Approach: Undiagnosed SARS-CoV-2 infections were identified as an increase in anti-spike IgG titer of ≥100 BAU/mL, not associated with receipt of vaccine or diagnosed SARS-CoV-2 infection (by polymerase chain reaction test or antigen test). In descriptive analyses, anti-spike IgG titers were followed over time. Results: Among 2,703 patients without previous coronavirus disease 2019 (COVID-19) who received an initial 2-dose vaccine series, 271 had diagnosed SARS-CoV-2 infections (3.4 per 10,000 patient-days) and 129 had undiagnosed SARS-CoV-2 infections (1.6 per 10,000 patient-days). Among 1,894 patients without previous COVID-19 who received a third vaccine dose, 316 had diagnosed SARS-CoV-2 infections (7.0 per 10,000 patient-days) and 173 had undiagnosed SARS-CoV-2 infections (3.8 per 10,000 patient-days). In both cohorts, anti-spike IgG levels declined over time. Of the initial 2-dose cohort, 66% had a titer of ≥500 BAU/mL in the first month, with 24% maintaining a titer of ≥500 BAU/mL at 6 months. Of the third dose cohort, 95% had a titer of ≥500 BAU/mL in the first month after the third dose, with 77% maintaining a titer of ≥500 BAU/mL at 6 months. Limitations: The assays used had upper limits. Conclusions: Among patients receiving maintenance dialysis, about 1 in every 3 SARS-CoV-2 infections was undiagnosed. Given this population's vulnerability to COVID-19, ongoing infection control measures are needed. A 3-dose primary mRNA vaccine series optimizes seroresponse rate and durability. Plain-Language Summary: Patients receiving maintenance dialysis have been particularly vulnerable to COVID-19. Using serially measured antibodies, we found that a substantial proportion (about one-third) of SARS-CoV-2 infections among this population had been missed, both among those who had completed a 2-dose vaccine series and among those who had received a third vaccine dose. Such missed infections likely had only mild or minimal symptoms, but this failure to recognize all infections is concerning. Furthermore, vaccines have been effective among patients receiving dialysis, but our study additionally shows that the immune response wanes over time, even after a third dose. There is therefore a role for ongoing vigilance against this highly transmissible infection.

Serial SARS-CoV-2 antibody titers in vaccinated dialysis patients: prevalence of unrecognized infection and duration of seroresponse.

Rationale & Objective: SARS-CoV-2 infections are likely underdiagnosed, but the degree of underdiagnosis among maintenance dialysis patients is unknown. Durability of the immune response after third vaccine doses in this population also remains uncertain. This study tracked antibody levels to 1) assess the rate of undiagnosed infections and 2) characterize seroresponse durability after third doses. Study Design: Retrospective observational study. Setting & Participants: SARS-CoV-2 vaccinated patients receiving maintenance dialysis through a national dialysis provider. Immunoglobulin G spike antibodies (anti-spike IgG) titers were assessed monthly following vaccination. Exposures: Two and three doses of SARS-CoV-2 vaccine. Outcomes: Undiagnosed and diagnosed SARS-CoV-2 infections; anti-spike IgG titers over time. Analytical Approach: "Undiagnosed" SARS-CoV-2 infections were identified as an increase in anti-spike IgG titer of ≥ 100 BAU/mL, not associated with receipt of vaccine or "diagnosed" SARS-CoV-2 infection (by PCR or antigen test). In descriptive analyses, anti-spike IgG titers were followed over time. Results: Among 2660 patients without prior COVID-19 who received an initial two-dose vaccine series, 371 (76%) SARS-CoV-2 infections were diagnosed and 115 (24%) were undiagnosed. Among 1717 patients without prior COVID-19 who received a third vaccine dose, 155 (80%) SARS-CoV-2 infections were diagnosed and 39 (20%) were undiagnosed. In both cohorts, anti-spike IgG levels declined over time. Of the initial two-dose cohort, 66% had a titer ≥ 500 BAU/mL in the first month, with 23% maintaining a titer ≥ 500 BAU/mL at six months. Of the third dose cohort, 95% had a titer ≥ 500 BAU/mL in the first month after the third dose, with 76% maintaining a titer ≥ 500 BAU/mL at six months. Limitations: Assays used had upper limits. Conclusions: Among maintenance dialysis patients, 20-24% of SARS-CoV-2 infections were undiagnosed. Given this population's vulnerability to COVID-19, ongoing infection control measures are needed. A three-dose primary mRNA vaccine series optimizes seroresponse rate and durability.

Angioplasty and stenting of a jugular-carotid fistula resulting from the inadvertent placement of a hemodialysis catheter: case report and review of literature.

Hemodialysis catheterization through the right internal jugular vein (IJV) is widely used for mid- to long-term hemodialysis for patients with renal failure. The purpose of this report is to address a serious complication in conjunction with this procedure. This is a case report of an iatrogenic jugular-carotid fistula (JCF) and a method for rectifying such a vascular conundrum, using endovascular techniques. We describe the technique used to achieve closure of the fistula as well a review of the literature. An 82-year-old woman with history of congestive heart failure, chronic renal failure, and diabetes mellitus developed an iatrogenic arteriovenous fistula, following an attempt of canalizing the right IJV. The patient was treated using three different stents, which achieved closure of the fistula. Venous catheter misplacement into an artery is a serious complication. Early endovascular treatment should be considered for a JCF.

Catheter-directed thrombolytic infusion for thrombosed arteriovenous fistulas with a large clot burden: A case series.

Arteriovenous fistula (AVF) thrombosis occurs less often when compared to arteriovenous grafts. Since the number of AVFs has increased in the United States, AVF thrombosis is seen more frequently today. AVF thrombectomy can be tedious, requires physician ingenuity, and many times results in failure. Substantial clot burden in megafistulas and aneurysms is considered a relative contraindication to endovascular thrombectomy. Usually, it results in surgical referral for open thrombectomy or, at times, abandonment of the fistula altogether. Herein, we describe the technique, results, and cautions of combining a continuous infusion of recombinant tissue plasminogen (rTPA) followed by angioplasty of the culprit stenotic lesion that was successful in opening five of six AVFs with a substantial clot burden.

Seroresponse to SARS-CoV-2 Vaccines among Maintenance Dialysis Patients over 6 Months.

BACKGROUND AND OBJECTIVES: Although most patients receiving maintenance dialysis exhibit initial seroresponse to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, concerns exist regarding the durability of this antibody response. This study evaluated seroresponse over time. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: This retrospective cohort study included patients on maintenance dialysis, from a midsize national dialysis provider, who received a complete SARS-CoV-2 vaccine series and had at least one antibody titer checked after full vaccination. IgG spike antibodies (anti-spike IgG) titers were assessed monthly with routine laboratory tests after vaccination; the semiquantitative assay reported a range between zero and ≥20 Index. Descriptive analyses compared trends over time by history of coronavirus disease 2019 (COVID-19) and vaccine type. Time-to-event analyses examined the outcome of loss of seroresponse (anti-spike IgG <1 Index or development of COVID-19). Cox regression adjusted for additional clinical characteristics. RESULTS: Among 1870 patients receiving maintenance dialysis, 1569 had no prior COVID-19. Patients without prior COVID-19 had declining titers over time. Among 443 recipients of BNT162b2 (Pfizer), median (interquartile range) anti-spike IgG titer declined from ≥20 (5.89 to ≥20) in month 1 after full vaccination to 1.96 (0.60-5.88) by month 6. Among 778 recipients of mRNA-1273 (Moderna), anti-spike IgG titer declined from ≥20 (interquartile range, ≥20 to ≥20) in month 1 to 7.99 (2.61 to ≥20) by month 6. The 348 recipients of Ad26.COV2.S (Janssen) had a lower titer response than recipients of an mRNA vaccine over all time periods. In time-to-event analyses, recipients of Ad26.COV2.S and mRNA-1273 had the shortest and longest time to loss of seroresponse, respectively. The maximum titer reached in the first 2 months after full vaccination was associated with durability of the anti-spike IgG seroresponse; patients with anti-spike IgG titer 1-19.99 had a shorter time to loss of seroresponse compared with patients with anti-spike IgG titer ≥20 (hazard ratio, 15.5; 95% confidence interval, 11.7 to 20.7). CONCLUSIONS: Among patients receiving maintenance dialysis, vaccine-induced seroresponse wanes over time across vaccine types. Early titers after full vaccination are associated with the durability of seroresponse.

Dialysis vascular access management by interventional nephrology programs at University Medical Centers in the United States.

The development of interventional nephrology has undoubtedly led to an improvement in patient care at many facilities across the United States. However, these services have traditionally been offered by interventional nephrologists in the private practice arena. While interventional nephrology was born in the private practice setting, several academic medical centers across the United States have now developed interventional nephrology programs. University Medical Centers (UMCs) that offer interventional nephrology face challenges, such as smaller dialysis populations, limited financial resources, and real or perceived political "turf" issues." Despite these hurdles, several UMCs have successfully established interventional nephrology as an intricate part of a larger nephrology program. This has largely been accomplished by consolidating available resources and collaborating with other specialties irrespective of the size of the dialysis population. The collaboration with other specialties also offers an opportunity to perform advanced procedures, such as application of excimer laser and endovascular ultrasound. As more UMCs establish interventional nephrology programs, opportunities for developing standardized training centers will improve, resulting in better quality and availability of nephrology-related procedures, and providing an impetus for research activities.

To ligate or not to ligate hemodialysis arteriovenous fistulas in kidney transplant patients.

There is significant disagreement about maintenance or ligation of arteriovenous fistulas (AVFs) in kidney transplant patients (KTPs). Potential harms from maintaining AVFs are their impact on cardiac function, cosmetic concerns and complications such as bleeding and rupture. High flow AVFs can place a strain on the heart and cause or exacerbate pre-existing cardiac dysfunction. There is an improvement in cardiac function after kidney transplantation independent of vascular access status. Studies comparing cardiac parameters in patients with and without AVFs after renal transplantation have shown conflicting results. Ligation of high flow AVFs in KTPs resulted in improvement in cardiac function and prevention of heart failure. In KTPs with deteriorating renal function and high flow AVFs, banding of the AVFs to reduce flow is an option. Patients who retain AVFs after renal transplant have the advantage of immediate, optimal access should the transplant fail and may have preserved kidney function. The patient's post-transplant kidney function, risk factors for transplant loss, AVF blood flow, and cardiac function play an important role when making the decision to ligate or preserve AVFs.