Israel Medical Association Journal

Background: Hemodialysis requires reliable, recurrent access to the circulatory system. Central venous tunneled dialysis catheters (TDC) are frequently used for patients receiving hemodialysis as a bridge to permanent vascular access or as a final option. TDC are prone to complications such as infection and dysfunction.

Objective: To assess the prevalence and predictors of TDC dysfunction in a cohort of chronic hemodialysis patients.

Methods: This single-center, retrospective study was based on data from an electronic database of chronic hemodialysis patients during 5 years of follow-up.

Results: A total of 625 TDC were inserted in 361 patients, of which 234 (37.4%) were replaced due to dysfunction. The main insertion site was the right internal jugular vein. Diabetes mellitus was an important predictor of TDC dysfunction and was significantly correlated with TDC extraction. Chronic anticoagulation and antiplatelet treatment did not affect the rate of TDC dysfunction or replacement.

Conclusions: TDC use for chronic dialysis patients is increasing and dysfunction is a major problem. In our study, we highlighted the high prevalence of TDC dysfunction and the need for further research to improve hemodialysis access as well as TDC patency and function.

Higher potency bisphosphonates, typically intravenous formulations, are given at lower doses for postmenopausal women. The treatment has improved compliance compared to daily oral therapy. Since bisphosphonates are exclusively excreted via the kidneys, intravenous formulation has been associated with deterioration of renal function, specifically in the setting of preexisting renal disease or concomitant use of nephrotoxic agents [1].

Background: Reliable vascular access is a fundamental tool for providing effective hemodialysis. Vascular access dysfunction is associated with increased morbidity and mortality among hemodialysis patients. Current vascular access guidelines strongly recommend creating an arteriovenous fistula (AVF) as the first option; however, a substantial proportion of new AVFs may not be usable.

Objectives: To assess possible predictors of primary and secondary failure of vascular access.

Methods: This retrospective cohort study included all vascular access sites created at Meir Medical Center from 2006 through 2012. Vascular access site, primary and secondary failure rates, and relevant demographic and clinical data were recorded during 60 months of follow-up.

Results: A total of 612 vascular accesses were created and followed for a median of 32 ± 29.4 months. Of these, 490 (80%) were suitable for initiating hemodialysis. Vascular access site was the most important predictor of primary failure but did not predict secondary failure. Co-morbidities such as diabetes mellitus and congestive heart failure, as well as the use of antiplatelet agents did not predict primary or secondary failure. Preoperative vascular mapping using Doppler ultrasonography was performed in 36.4% of cases and was not associated with lower rates of primary or secondary failure.

Conclusions: Vascular access site is an important predictor of primary failure. We did not find a benefit of pre-operative vessel mapping or chronic antiplatelet therapy in terms of decreasing primary and secondary failure rates. Physicians should carefully consider the characteristics of the patient and blood vessels before creating vascular access in patients requiring chronic hemodialysis.

Background: The reduced immune response of maintenance hemodialysis patients to coronavirus disease 2019 (COVID-19) vaccines is a major concern.

Objectives: To analyze the late (6 months after full vaccination) antibody response and compare it to early post-vaccination titer.

Methods: We conducted a multicenter prospective study of 13 hemodialysis units in Israel.

Results: We demonstrated that the low titers observed among ESRD patients 2–3 months after vaccination with the Comirnaty vaccine (median 63.8 AU/ml) declined to critically lower values 6 months after full vaccination. (Mediananti S antibodies, 31 AU/ml). Seropositivity significantly declined among hemodialysis patients from 89% to 74% (P < 0.0001), although it did not significantly change among controls.

Conclusions: We recommend all patients on hemodialysis receive a booster COVID-19 vaccine 6 months after the second dose.

Background: Among dialysis patients, occlusive mesenteric vascular disease has rarely been reported.

Objectives: To report on the experience of one center with regard to diagnosing and treating this complication.

Methods: The retrospective case-series involved six patients (3 females, 3 males; age 52–88 years; 5/6 were smokers) on chronic hemodialysis at a single center. All patients with symptoms suggestive of occlusive mesenteric disease and a subsequent angiographic intervention were included. Demographic, clinical, and laboratory data were collected from patient charts for the period before and after angioplasty and stenting of the mesenteric vessels. A Wilcoxon signed-rank test was used to compare the relevant data before and after the intervention.

Results: All participants had variable co-morbidities and postprandial abdominal pain, food aversion, and weight loss. CT angiography was limited due to heavy vascular calcifications. All underwent angioplasty with stenting of the superior mesenteric artery (4 patients) or the celiac artery (2 patients). All procedures were successful in resolving abdominal pain, malnutrition, and inflammation. Weight loss before was 15 ± 2 kg and weight gain after was 6 ± 2 kg. C-reactive protein decreased from 13.4 ± 5.2 mg/dl to 2.2 ± 0.4 mg/dl (P < 0.05). Serum albumin increased from 3.0 ± 0.2 g/dl to 3.9 ± 0.1 g/dl (P < 0.05). Two patients underwent a repeat procedure (4 years, 5 months, respectively). Follow-up ranged from 0.5–7 years.

Conclusions: Occlusive mesenteric ischemia occurs among dialysis patients. The diagnosis requires a high degree of suspicion, and it is manageable by angiography and stenting of the most involved mesenteric artery.

Background: Dialysate purity contributes to the inflammatory response that afflicts hemodialysis patients.

Objectives: To compare the clinical and laboratory effects of using ultrapure water produced by a water treatment system including two reverse osmosis (RO) units in series, with a system that also includes an ultrapure filter (UPF).

Methods: We performed a retrospective study in 193 hemodialysis patients during two periods: period A (no UPF, 6 months) and period B (same patients, with addition of UPF, 18 months), and a historical cohort of patients treated in the same dialysis unit 2 years earlier, which served as a control group.

Results: Mean C-reactive protein, serum albumin and systolic blood pressure worsened in period B compared to period A and in the controls.

Conclusions: A double RO system to produce ultrapure water is not inferior to the use of ultrapure filters.

Background: Anemia management strategies among chronic hemodialysis patients with high ferritin levels remains challenging for nephrologists.

Objectives: To compare anemia management in stable hemodialysis patients with high (≥ 500 ng/ml) vs. low (< 500 ng/ml) ferritin levels

Methods: In a single center, record review, cohort study of stable hemodialysis patients who were followed for 24 months, an anemia management policy was amended to discontinue intravenous (IV) iron therapy for stable hemodialysis patients with hemoglobin > 10 g/dl and ferritin ≥ 500 ng/ml. Erythropoiesis-stimulating-agents (ESA), IV iron doses, and laboratory parameters were compared among patients with high vs. low baseline ferritin levels before and after IV iron cessation.

Results: Among 87 patients, 73.6% had baseline ferritin ≥ 500 ng/ml. Weekly ESA dose was greater among patients with high vs. low ferritin (6788.8 ± 4727.8 IU/week vs. 3305.0 ± 2953.9 IU/week, P = 0.001); whereas, cumulative and monthly IV iron doses were significantly lower (1628.2 ± 1491.1 mg vs. 2557.4 ± 1398.9 mg, P = 0.011, and 82.9 ± 85 vs. 140.7 ± 63.9 mg, P = 0.004). Among patients with high ferritin, IV iron was discontinued for more than 3 months in 41 patients (64%) and completely avoided in 6 (9.5%).ESA dose and hemoglobin levels did not change significantly during this period.

Conclusions: Iron cessation in chronic hemodialysis patients with high ferritin levels did not affect hemoglobin level or ESA dose and can be considered as a safe policy for attenuating the risk of chronic iron overload.

Background: The Epstein-Barr virus (EBV) is one of the most common viruses found in humans, causing lifelong infection in up to 95% of the world population.

Objectives: To analyze the seroprevalence of EBV infection in different population groups in Croatia.

Methods: During a 2 year period (2015–2016), a total of 2022 consecutive serum samples collected from Croatian residents were tested for the presence of EBV-specific viral capsid antigen (VCA) immunoglobulin M (IgM) and IgG antibodies using an enzyme-linked immunoassay. IgM/IgG-positive samples were further tested for IgG avidity.

Results: The overall prevalence of EBV IgG antibodies was 91.4%. Females had significantly higher IgG seroprevalence than males (93.1% vs. 89.9%, P = 0.008). According to age, IgG seropositivity increased progressively from 59.6% in children age < 9 years to 98.3% in 30–39 year olds, and remained stable thereafter (P < 0.001). The IgG seroprevalence differed significantly among groups: 68.1% in children/adolescents and 95.9% in adults; multiple sclerosis (100%), hemodialysis patients (97.7%), heart transplant recipients (93.8%), hematological malignancies (91.2%), and Crohn’s disease (88.5%), P < 0.001. IgM antibodies were detected in 9% of participants. Using IgG avidity, recent primary EBV infection was documented in 83.8% of IgM-positive subjects < 9 years old, 69.2% age 10–19, 33.3% age 20–29, and 3.6–4.2% > 40. All IgM positive participants > 40 years showed high IgG avidity. Logistic regression showed that age is associated with EBV IgG seropositivity.

Conclusions: EBV is widespread in the Croatian population. Older age appears to be the main risk factor for EBV seropositivity.

Background: Late nephrology referral, before initiation of dialysis treatment, is associated with adverse outcome.

Objectives: To investigate the implications of late nephrology referral on mortality among dialysis patients in Israel.

Methods: We retrospectively analyzed 200 incident dialysis patients. Patients were defined as late referrals if they started dialysis less than 3 months after their first nephrology consultation. Survival rates and risk factors for mortality were analyzed

Results: The early referral (ER) group comprised 118 patients (59%) and the late referral (LR) group 82 patients (41%). The mortality rate was 44.5% (53 patients) in the ER and 68% (n=56) in the LR group. The 4 year survival rate was 41.1% in the ER and 18.7% in the LR group (P < 0.0001). The mortality rate increased with late nephrology referral (HR 1.873, 95%CI 1.133–3.094), with age (HR 1.043 for each year, 95%CI 1.018–1.068), with diabetes (HR 2.399, CI 1.369-4.202), and with serum albumin level (HR 0.359 for an increase of each 1 g/dl, 95%CI 0.242–0.533). The median survival time was higher for the ER group in women, in patients younger than 70, and in diabetic patients. A trend for longer survival time was found in non-diabetic patients. Survival time was not increased in early referred patients older than 70 and in male patients.

Conclusions: Late nephrology referral is associated with an overall higher mortality rate in dialysis patients. The survival advantage of early referral may have a different significance in specific subgroups. The timing of nephrology referral should be considered as a modifiable risk factor for mortality in patients with end-stage renal disease. 

Background: Acute renal failure (ARF) is a common complication in critically ill children. It is known as an important predictor of morbidity and mortality in this population. Data on the factors affecting the choice of renal replacement therapy (RRT) modality and its impact on mortality of children with ARF[1] are limited.

Objectives: We retrospectively studied 115 children with ARF necessitating RRT[2] during the period 1995–2005 to evaluate the effect of several prognostic factors as well as RRT type on their immediate outcome.

Methods: The data collected from charts included demographics, primary disease, accompanying medical conditions, use of vasopressor support, indications for dialysis, RRT modality, and complications of dialysis. Categorical variables were analyzed using chi-square or Fisher’s exact tests. Variables associated with mortality (P < 0.1) at the univariable level were studied by a multivariable logistic regression model.

Results: The most common cause of ARF was congenital heart disease (n=75). RRT modalities included peritoneal dialysis (PD) (n=81), hemodialfiltration (HDF) (n=31) and intermittent hemodialysis (IHD) (n=18). Median RRT duration was 4 days (range 1–63 days). Overall mortality was 52.2%. IHD[3] was associated with the best survival rate (P < 0.01 vs. PD[4] and HDF[5]), while children treated with HDF had the worse outcome. Hemodynamic instability and systemic infections were associated with greater mortality, but the rate of these complications did not differ between the study groups.

Conclusions: Our results suggest that IHD[6] when applied to the right patient in an appropriate setting may be a safe and efficient RRT modality in children with ARF. Randomized prospective trials are needed to further evaluate the impact of different RRT modalities on outcome in children with ARF.

Objectives: To investigate the effect of low calcium dialysis on post-dialysis hypertension in view of an evident link between serum calcium and blood pressure in both normal renal function and chronic renal failure patients.

Methods: We evaluated 19 chronic hemodialysis patients in whom both post-dialysis hypertension and PDHCa[1] were observed. We investigated changes in serum total calcium, ionized calcium, intact parathormone levels and arterial blood pressure in response to 4 weeks low calcium dialysis as a treatment for PDHCa.

Results: When PDHT[2] patients were treated with low calcium dialysis, post-dialysis blood pressure was significantly decreased compared to pre-dialysis values (155.3 ± 9.7/82.2 ± 7.9 mmHg pre-dialysis vs. 134.1 ± 20.8/80 ± 8.6 mmHg post-dialysis, P = 0.001). Additionally, post-dialysis blood pressure was significantly lower than post-dialysis blood pressure prior to the low calcium dialysis treatment (176.1 ± 15/86 ± 10.8 mmHg post-standard dialysis, 134.1 ± 20.8/80 ± 8.6 mmHg after low calcium dialysis, P = 0.001). A decline in post-dialysis serum calcium (2.34 ± 0.2 vs. 2.86 ± 0.12 mmol/L, P = 0.04) and ionized calcium (1.17 ± 0.12 vs. 1.3 ± 0.06 mmol/L, P = 0.03) compared to pre-dialysis levels was also achieved by this treatment, with no significant changes in iPTH[3] levels.

Conclusions: These data suggest a role for low calcium dialysis in treating acute serum calcium elevation and post-dialysis hypertension in patients receiving maintenance hemodialysis.