Vascular access for hemodialysis in Italy: What a national survey reveals

BACKGROUND

Since in Italy there are no official data on vascular access (VA) for hemodialysis the Vascular Access Project Group (VAPG) of the Italian Society of Nephrology (SIN) designed a national survey.

METHODS

A 35-question survey was designed and sent it to the Italian facilities through the SIN website. The basic questions were the prevalence, the location, and the surveillance of VA, the bedside use of ultrasound, the use of fluoroscopy for central venous catheter (CVC) placement, and of buttonhole technique, the role of nephrologist in the access creation.

RESULT

The questionnaire was completed in June 2022 by 161 facilities. The survey registered 15,499 patients, approximately one-third of the Italian dialysis population. The prevalence of arteriovenous fistula (AVF), arteriovenous Graft (AVG), and CVC were 61.8%, 3.7%, and 34.5% respectively. The AVF location was 50% in distal forearm, 20% in meanproximal forearm, 30% in upper arm. For AVF creation, nephrologists were involved in 72% of facilities while for CVC placement in 62%. As regards VA monitoring, 21% of the facilities did not have a surveillance protocol; 60% did not register AVF thrombosis and 53% did not register CVC infections. Most of facilities use the fluoroscope during CVC placement, 37% when needed, and 22% never. Ultrasound-guided puncture of complex AVFs was used by 80% of facilities. Buttonhole puncture was used in 5% of patients.

CONCLUSIONS

Some considerations emerge from the survey data: (1) The increasing CVC prevalence compared to DOPPS 5 study. (2) The low rate of AVG prevalence. (3) The nephrologist is the operator in many VA procedures. (4) The fluoroscopy for CVC placement and the US-guide puncture of the complex AVF are widely used in most facilities. (5) The practice of the buttonhole is not widespread. (6) When the operator is the nephrologist more distal fistulas are performed.

Nephrology Partnership for Advancing Technology in Healthcare (N-PATH) program: the teachers' perspective

The N-PATH (Nephrology Partnership for Advancing Technology in Healthcare) program concluded with the 60th European Renal Association 2023 Congress in Milan, Italy. This collaborative initiative aimed to provide advanced training in interventional nephrology to young European nephrologists. Funded by Erasmus+ Knowledge Alliance, N-PATH addressed the global burden of chronic kidney disease (CKD) and the shortage of nephrologists. CKD affects >850 million people worldwide, yet nephrology struggles to attract medical talent, leading to unfilled positions in residency programs. To address this, N-PATH focused on enhancing nephrology education through four specialized modules: renal expert in renal pathology (ReMAP), renal expert in vascular access (ReVAC), renal expert in medical ultrasound (ReMUS) and renal expert in peritoneal dialysis (RePED). ReMAP emphasized the importance of kidney biopsy in nephrology diagnosis and treatment, providing theoretical knowledge and hands-on training. ReVAC centred on vascular access in haemodialysis, teaching trainees about different access types, placement techniques and managing complications. ReMUS recognized the significance of ultrasound in nephrology, promoting interdisciplinary collaboration and preparing nephrologists for comprehensive patient care. RePED addressed chronic peritoneal dialysis, offering comprehensive training in patient selection, prescription, monitoring, complications and surgical techniques for catheter insertion. Overall, N-PATH's strategy involved collaborative networks, hands-on training, mentorship, an interdisciplinary approach and the integration of emerging technologies. By bridging the gap between theoretical knowledge and practical skills, N-PATH aimed to revitalize interest in nephrology and prepare proficient nephrologists to tackle the challenges of kidney diseases. In conclusion, the N-PATH program aimed to address the shortage of nephrologists and improve the quality of nephrology care in Europe. By providing specialized training, fostering collaboration and promoting patient-centred care, N-PATH aimed to inspire future nephrology professionals to meet the growing healthcare demands related to kidney diseases and elevate the specialty's status within the medical community.

Color Doppler ultrasound evaluation of arteriovenous grafts for hemodialysis

Although arteriovenous fistula (AVF) continues to be the vascular access of choice for the hemodialysis, arteriovenous graft (AVG) can be the best choice in certain categories of patients and could have several advantages over AVF in a "patient centered approach" to vascular access. In the clinical management of prosthetic fistulas, color Doppler ultrasound (CDU) is the imaging method of choice for identifying stenosis and other AVG complications. In this review, besides highlighting the pivotal role of CDU in the diagnosis of AVG complications, we will underline the key role that ultrasound can play in identifying those stenosis most likely to cause AVG thrombosis. Furthermore, we will emphasize the support that CDU can play in distinguishing the different types of grafts and prosthetic devices such as stent-grafts, in identifying AVG with lower survival, CDU utilities and limitations in the evaluation of freshly-implanted grafts, the different sites available for AVG volume flow measurement and their use based on the configuration of the prosthesis, the time interval elapsed from the surgical intervention and the integrity of the prosthetic walls.

Rethinking an effective AV fistula-graft screening program. An "A B C"

The goal of a vascular access screening program is to detect and preemptively correct hemodynamically significant stenosis, however, a practice pattern allowing to implement such a program still remains to be defined. Achieving balance between the increase in access-related procedures by adopting an aggressive screening program, and the risks associated with the absence of any screening program, i.e., failure or abandonment of the arterio-venous access with need for central venous catheter placement, can be extremely challenging. All major guidelines agree about the role of arterio-venous access monitoring, but the way surveillance should be managed is still a controversial issue. Preserving long-term vascular access function should be a goal for all hemodialysis teams, yet it ideally requires a multidisciplinary effort with a monitoring program, calling for a great deal of involvement by hemodialysis health professionals. In this context, the engagement of skilled nurses and the role of patient empowerment with collaborative decision-making may be the key to a successful vascular access screening program. Screening programs should be personalized, shared with the patients, and tailored according to vascular access type and site. In the near future, new devices and the use of artificial intelligence may allow to support interpretation of complex data and lead to the development of prediction models for vascular access failure.

Parathyroidectomy and survival in a cohort of Italian dialysis patients: results of a multicenter, observational, prospective study

BACKGROUND

Severe secondary hyperparathyroidism (SHPT) is associated with mortality in end stage kidney disease (ESKD). Parathyroidectomy (PTX) becomes necessary when medical therapy fails, thus highlighting the interest to compare biochemical and clinical outcomes of patients receiving either medical treatment or surgery.

METHODS

We aimed to compare overall survival and biochemical control of hemodialysis patients with severe hyperparathyroidism, treated by surgery or medical therapy followed-up for 36 months. Inclusion criteria were age older than 18 years, renal failure requiring dialysis treatment (hemodialysis or peritoneal dialysis) and ability to sign the consent form. A control group of 418 patients treated in the same centers, who did not undergo parathyroidectomy was selected after matching for age, sex, and dialysis vintage.

RESULTS

From 82 Dialysis units in Italy, we prospectively collected data of 257 prevalent patients who underwent parathyroidectomy (age 58.2 ± 12.8 years; M/F: 44%/56%, dialysis vintage: 15.5 ± 8.4 years) and of 418 control patients who did not undergo parathyroidectomy (age 60.3 ± 14.4 years; M/F 44%/56%; dialysis vintage 11.2 ± 7.6 y). The survival rate was higher in the group that underwent parathyroidectomy (Kaplan-Meier log rank test = 0.002). Univariable analysis (HR 0.556, CI: 0.387-0.800, p = 0.002) and multivariable analysis (HR 0.671, CI:0.465-0.970, p = 0.034), identified parathyroidectomy as a protective factor of overall survival. The prevalence of patients at KDOQI targets for PTH was lower in patients who underwent parathyroidectomy compared to controls (PTX vs non-PTX: PTH < 150 pg/ml: 59% vs 21%, p = 0.001; PTH at target: 18% vs 37% p = 0.001; PTH > 300 pg/ml 23% vs 42% p = 0.001). The control group received more intensive medical treatment with higher prevalence of vitamin D (65% vs 41%, p = 0.0001), calcimimetics (34% vs 14%, p = 0.0001) and phosphate binders (77% vs 66%, p = 0.002).

CONCLUSIONS

Our data suggest that parathyroidectomy is associated with survival rate at 36 months, independently of biochemical control. Lower exposure to high PTH levels could represent an advantage in the long term.

MO181: Clinical Characteristics and Short-Term outcomes of Hemodialysis Patients with SARS-COV-2 Infection: The Experience of a Covid Nephrology Unit

BACKGROUND AND AIMS

SARS-CoV-2 pandemic is pressuring healthcare systems worldwide. Disease outcomes in certain subgroups of patients, such as nephropathic patients, are still scarce. Patients with chronic kidney disease (CKD) and on haemodialysis (HD) are at risk of a more severe disease course and worst outcomes. Here, we aimed to describe the characteristics and outcomes of CKD and HD patients with SARS-CoV-2 infection, admitted to the Covid Nephrology Unit in the first three pandemic waves, analysing mortality rate and risk factors for mortality in this subgroup of patients.

METHOD

A Covid Nephrology Unit was organized in March 2020 to manage the high number of CKD and HD patients with SARS-CoV-2 infection. Several ‘spoke’ units were also set to manage HD asymptomatic patients (Hi Hotel and ‘Villa Luce’ Dialysis Center) or with mild symptoms (‘Miulli Hospital’-Acquaviva delle Fonti and ‘Fallacara Hospital’—Triggiano). Clinical and laboratory data in several timepoints were collected using electronic medical records. Primary outcome was to assess the mortality rate. Moreover, we analysed the trend of inflammatory markers in the first 7 days after hospital admission between survivors and non-survivors; finally, risk factors for mortality were analysed by logistic regression.

RESULTS

From March 2020 to May 2021, a total of 221 patients were admitted to the Covid Nephrology Unit; among these, 112 patients on chronic haemodialysis, 21 with acute kidney injury (AKI), 58 with CKD, 24 kidney transplant recipients and 6 patients on peritoneal dialysis (PD). Median age was 71 years (IQR 62.5–80), while male gender predominated (61.5%). Main comorbidities were arterial hypertension (81%), diabetes mellitus (41.8%) and cardiovascular disease (CVD, 60.6%). At admission, 13.2% of patients required non-invasive ventilatory (NIV) support (CPAP, BiPAP) and about 60% presented interstitial pneumonia at CT scan. A total of 80 patients (36.1%) died during hospital stay with a medium length of stay of 15.8 days. In the first 7 days, 29 patients presented respiratory failure requiring transfer to ICU. Conversely, 100 patients were discharged at home, while 48 patients were transferred to the spoke units (39 patients at Miulli and Fallacara Hospitals, 9 patients at Hi Hotel). Compared to survivors, patients who died were older (median age 75.5 versus 66 years, P &lt; .001), characterized by more comorbidities (diabetes mellitus 54.5% versus 35.2%, P = .01; CVD 81.1% versus 51.4%, P &lt; .001; chronic obstructive pulmonary disease (COPD, 41.5% versus 19%, P = .01; peripheral vasculopathy 58.4% versus 34.2%, P = .01) and more severe respiratory compromission at hospital admission (patients in NIV, 22.6% versus 8.1%, P = .005). As shown in Table 1, in the first 7 days of hospital stay, a significant increase in WBC (8.29 versus 12.6 × 106P &lt; .001) was described in the non-survivor group; similarly, inflammatory markers such as CRP and IL-6 did not improve in the non-survivors at day 7 (CRP 81.8 versus 85.7 mg/L, P = .62; IL-6 63.1 versus 79.4 pg/mL, P = .84), while they significantly improved in survivors (median CRP 42.5 versus 10.1 mg/L, P &lt; .001; median IL-6 32.3 versus 13.7 pg/mL, P = .01). In a multivariate logistic regression model, age (OR 1.062, 95% CI 1.007–1.119, P = .025), history of CVD (OR 8.308, 95%CI 1.704–40.499, P = .009) and dyspnoea at hospital admission (OR 9.465, 95%CI 1.231–72.79, P = .031) were associated with risk of mortality in this population.

CONCLUSION

To our knowledge, this is the largest study analyzing characteristics and outcomes of CKD and hemodialysis patients to date. A wide heterogeneity of severity of disease has been documented in our cohort; we documented a higher mortality rate in this cohort of patients compared to general population. The presence of several comorbidities, a more severe disease at hospital admission and the persistence of elevated inflammatory markers during hospital stay are risk factors for mortality.

The role of Doppler ultrasonography in vascular access surveillance-controversies continue

Chronic hemodialysis therapy required regular entry into the patient’s blood stream with adequate flow. The use of arteriovenous fistulas and grafts is linked with lower morbidity and mortality than the use of catheters. However, these types of accesses are frequently affected by stenoses, which decrease the flow and lead to both inadequate dialysis and access thrombosis. The idea of duplex Doppler ultrasound surveillance is based on the presumption that in-time diagnosis of an asymptomatic significant stenosis and its treatment prolongs access patency. Details of performed trials are conflicting, and current guidelines do not support ultrasound surveillance. This review article summarizes the trials performed and focuses on the reasons of conflicting results. We stress the need of precise standardized criteria of significant access stenosis and the weakness of the metaanalyses performed.

MO787USE OF THE PREVENTIVE HAEMOSTASIS IN SURGICAL COMPLICATIONS OF VASCULAR ACCESS

Background and Aims

Arteriovenous fistula (AVF) is currently the recommended vascular access type and its preservation is required to ensure a safe treatment for HD patients. Nevertheless, reinterventions are often needed to treat life threatening complications such as eschars, aneurysms, high flow.These surgical procedures are at high risk of bleeding, time-consuming and technically demanding. Here we describe our approach by using preventive hemostasis to treat different types of AVF complications, such as aneurysmectomy, high flow fistula correction, ulcerectomy.

Method

The technique consists of a few steps. First, regional anesthesia is performed by brachial plexus nerve block and intravenous antibiotic prophylactic therapy is administered. Then, an inflatable tourniquet is placed on the arm, proximally to the elbow joint, after wrapping the site with a soft gauze to prevent postoperative discomfort and bruising due to accidental pinch of the skin. The arm is then elevated to allow passive exsanguination and a 5” Esmarch bandage is applied from the hand to the tourniquet cuff. The methodical application of the Esmarch bandage requires an assistant to hold the arm properly in the upright position. Once the bandage is applied, the tourniquet is inflated to complete the exsanguination of the extremity. The inflation pressure has to be adapted to patient systolic pressure, generally a 'suitable' pressure for an upper limb tourniquet is 250-300 mmHg. Lastly, the Esmarch bandage is unwrapped and, after sterile surgical draping, it is possible to proceed to skin incision.

Results

From Jan 2019 to Dec 2020, we enrolled 9 patients with AVF complications treated with the preventive emostasis. The mean age of the patients was 62 years (range, 45-80 years). Table 1 shows types of AVFs and complications, performed revisions, outcomes, short and long term complications. The tourniquet average time of application was 29 + 7,7 min. Preventive hemostasis ensures absence of blood loss, even during high flow access revision. In one patient, a moderate subcutaneous hemorrhage occurred 8 hours after the end of the surgical procedure, requiring further revision. No vascular or soft tissue complications were reported except for temporary dysesthesias.

Conclusion

Our experience shows that preventive haemostasis offers several advantages for surgeons and patients, allowing a clear operative field and avoidance of application of clamps, prevents blood loss, and reduce the need for blood transfusion. Furthermore, reperfusion injury risk is minimized. The only complication occurred suggests the recommendation to suture skin incision after removing the tourniquet to reduce risk of postoperative bleeding. In conclusion, the technique is reliable and safely applicable to surgical treatment of vascular access complication.

MO891HEMODIALYSIS PATIENTS AMID COVID-19 PANDEMIC: A COMPARISON BETWEEN FIRST AND SECOND WAVE

Background and Aims

Data about HD patients and how to best dialyze them during the COVID-19 pandemic are scarce. The aim of the study is to describe the organizational model and clinical outcomes of patients confirmed COVID-19 needing renal replacement therapy, admitted in a COVID Hospital in Southern Italy during the first and second pandemic wave.

Method

All the consecutive patients requiring chronic HD, during the first and second wave were considered. Due to local resources, we have implemented an organizational model based on the HD bedside with Genius system. The machine was prepared in the Dialysis Unit and then transferred to the COVID Hospital. After treatment, the monitor was sterilized and carefully cleaned with chlorine wipes and re-transferred into the dialysis Unit to be prepared for the next dialysis. Demographic data, clinical symptoms at presentation, and laboratory results were extracted by the electronic medical record. Patients hospitalized during the first wave (FW) and second wave (SW) were compared.

Results

From March 10 through December 31 2020, we enrolled a cohort of 40 patients (37.5% F), with COVID-19 infection requiring HD; 11 (27.5%) during first and 29 (72.5%) during second wave. The phenotype and clinical symptoms at the admission were not different between two groups. Compared to FW, the SW patients were younger (70.1±9.5 vs 77.3±5.9 years; p&lt;0.03) with lower dialysis vintage (35±18 vs 60±48 months; p&lt;0.05), and lower Charlson Comorbidity Index scores (2.8 ± 1.8 vs 5.09 ± 2.0; p&lt;0.05). No differences were observed between the first and second wave as far as inflammatory markers IL6 (51.9 ± 44.8 vs 55.45 ± 40.52 pg/mL; ns) and C-reactive protein (4.74 ± 3.8 vs 6.70 ± 5.44 mg/L; ns) as well as the hospital stay (21.1±10 vs 24.4.8±10 days; ns) and in-hospital mortality (28.1% vs 18.2%; ns). Overall, 354 bedside treatments were performed; mean session time and mean weekly sessions were 3.64 ± 0.40 hours, and 3.4 ± 0.45 HD/week, with no differences between FW and SW patients.

Conclusion

Our data show that the higher spread of Sars-cov2 during the second wave has infected younger and less comorbid HD patients, with no significant differences in clinical and laboratory parameters. Our organizational model based on the HD bedside with the Genius system, allowed a personalized treatment with efficacy and safety for the patients and staff.

MO1052GREEN DIALYSIS: FROM MITH TO FUTURE

Background and Aims

Over 2 million persons of the 7.8 billion world population undergo hemodialysis (HD). The need is underestimated because dialysis is not available free of charge for more of half of the word population. HD is costly process and produces a large quantity of medical waste. Reducing the environmental burden should be addressed as part of implementation dialysis programs.

While collaboration between physicians and several different professionals is needed to design and develop projects in this direction, these are lingering and the literature is still scant. We overviewed literature to frame what is in progress and find clues for development.

Method

We conducted a systematic review of the literature from 2000 searching in PubMed, Scopus, Web of Science, and Google Scholar using search keywords including dialysis, green, recycling, ecology. We retrieved 41 publications in medical and technological fields. The results were summarized in a narrative review.

Results

Facilities: the points on which attention is focused are the design of new buildings, whose project should encompass green solutions, including solar power and water conservation, to reduce long-term expenses and ensure an eco-friendly development.

Water: water consumption remains high, and the essential targets to improve efficiency are the optimization of the reverse osmosis system, and of the dialysate flow rate, and the waste-water management. The current idea is to substitute standard reverse osmosis, which have a high percent of waste-water, with recirculating systems. Likewise, lowering of dialysate flow rate could spare water consumption with no significant difference in term of efficiency. Moreover, different solutions have been proposed to reuse reject water: local sanitation, laundry departments, sterilization units within health facilities using redirected water, landscaping and irrigation.

Power: electricity needed per dialysis session is twice the average daily consumption of a family of four people. Use of renewable energies, as solar or wind power, has been proposed, and are occasionally applied to home HD. To date just one attempt has been made to recycling energy by using hydroturbine.

Disposable materials: most of dialysis disposables is made of plastic, over half of which is labeled as “potentially hazardous”. Only a minimal part of the plastic used in dialysis disposables is recyclable, both because of its composition and its assembly which makes in fact impossible the segregation of the different components. Present research regards bioplastics, new assembling techniques, alternative technologies of incineration, microwave treatment, alkaline hydrolysis, biological treatment and the new steam sterilize-then-shred system.

Dialysis machines: at the best of our knowledge there are no studies available about dialysis machine recycling.

Personnel education: the role of dialysis staff is essential in recycling and reusing materials as well as in correctly dividing contaminated and non-contaminated waste.

Conclusion

The development of sustainable buildings, devices and procedures requires a multidisciplinary approach: medical, chemical, biological, engineering; in addition producers contribution and government regulation are needed. Talking about these issues, involving specialists, spreading the concepts of planet friendly treatments, gives the opportunity to share ideas, experiences and turn them into relevant innovations. A good starting point could be data collection to identify critical issues and outline pragmatic operational possibilities to reduce consumption, increase reuse and recycle, involve and instruct health care personnel, integrate dialysis facilities in the environment they are built in.

A call to optimize haemodialysis vascular access care in healthcare disrupted by COVID-19 pandemic

The COVID-19 pandemic has resulted in major disruption to the delivery of both routine and urgent healthcare needs in many institutions across the globe. Vascular access (VA) for haemodalysis (HD) is considered the patient's lifeline and its maintenance is essential for the continuation of a life saving treatment. Prior to the COVID-19 pandemic, the provision of VA for dialysis was already constrained. Throughout the pandemic, inevitably, many patients with chronic kidney disease (CKD) have not received timely intervention for VA care. This could have a detrimental impact on dialysis patient outcomes in the near future and needs to be addressed urgently. Many societies have issued prioritisation to allow rationing based on clinical risk, mainly according to estimated urgency and need for treatment. The recommendations recently proposed by the European and American Vascular Societies in the COVID-19 pandemic era regarding the triage of various vascular operations into urgent, emergent and elective are debatable. VA creation and interventions maintain the lifeline of complex HD patients, and the indication for surgery and other interventions warrants patient-specific clinical judgement and pathways. Keeping the use of central venous catheters at a minimum, with the goal of creating the right access, in the right patient, at the right time, and for the right reasons, is mandatory. These strategies may require local modifications. Risk assessments may need specific "renal pathways" to be developed rather than applying standard surgical risk stratification. In conclusion, in order to recover from the second wave of COVID-19 and prepare for further phases, the provision of the best dialysis access, including peritoneal dialysis, will require working closely with the multidisciplinary team involved in the assessment, creation, cannulation, surveillance, maintenance, and salvage of definitive access.

Hemodialysis vascular access affects heart function and outcomes: Tips for choosing the right access for the individual patient

Chronic kidney disease is associated with increased cardiovascular morbidity and mortality. A well-functioning vascular access is associated with improved survival and among the available types of vascular access the arterio-venous (AV) fistula is the one associated with the best outcomes. However, AV access may affect heart function and, in some patients, could worsen the clinical status. This review article focuses on the specific cardiovascular hemodynamics of dialysis patients and how it is affected by the AV access; the effects of an excessive increase in AV access flow, leading to high-output heart failure; congestive heart failure in CKD patients and the contraindications to AV access; pulmonary hypertension. In severe heart failure, peritoneal dialysis (PD) might be the better choice for cardiac health, but if contraindicated suggestions for vascular access selection are provided based on the individual clinical presentation. Management of the AV access after kidney transplantation is also addressed, considering the cardiovascular benefit of AV access ligation compared to the advantage of having a functioning AVF as backup in case of allograft failure. In PD patients, who need to switch to hemodialysis, vascular access should be created timely. The influence of AV access in patients undergoing cardiac surgery for valvular or ischemic heart disease is also addressed. Cardiovascular implantable electronic devices are increasingly implanted in dialysis patients, but when doing so, the type and location of vascular access should be considered.

P1357SODIIUM BICARBONATE CAN REPLACE THE HEPARIN AS “CATHETER LOCK SOLUTION” OF CENTRAL CATHETERS (CVC) FOR HEMODIALYSIS (HD)?

Background and Aims

The CVC often faces thrombosis and/or infection and currently there are no interventions that guarantee the efficiency of the CVC and the absence of bacterial infections. Recently Adel S. El-Hennawy et al. NDT, 2019, have shown that the use of sodium bicarbonate as “catheter lock solution” (SBCLS) in HD patients has a local anticoagulant effect and reduces the frequency of thrombosis and infections. Therefore, we wanted to use SBCLS in the management of our dialysis patients who needed HD treatment through CVC.

Method

The study included n. 15 HD patients (8M and 7F) with a CVC (see tab.1), whose CVC were previously medicated with heparin or citrate. At the time of the introduction of the SBCLS, patients showed no signs of CVC thrombosis or bacteremia; 2 patients had previously had haemorrhagic complications, 3 had malfunctioning thrombotic CVC. The observation period was 2379 days (mean 158 ± 50). Upon the conclusion of HD treatment, each port of all two-port catheters was flushed and locked with 10 mL of SBCLS (NaHCO3 at 8.4% -pH 7-8.5) and approximately 2 mL of the injected solution remained locked within the catheter. One patient who was allergic to heparin was included in the study.

Results

At the end of the study, only 3 patients had thrombotic problems with CVC and none had infections. However, none of the enrolled patients had to replace the CVC. The treatment was well tolerated by all patients who did not present complications.

Conclusion

In our short and brief experience, SBCLS has proved effective and safe in the prevention of thrombosis and infection of CVC. SBCLS appears to be an effective alternative to heparin and citrate in the management of CVC in the absence of bleeding complications. Finally SBCLS is a valid medical solution in patients allergic to heparin.

P1405ETELCALCETIDE USE IN HEMODIALYTIC PATIENTS: A SINGLE CENTER EXPERIENCE

Background and Aims

Etelcalcetide is an injectable calcimimetic, utilized to treat secondary hyperparathyroidism. Recently introduced as alternative to cinacalcet, it acts on a different CaSR (Calcium Sensor Receptor) binding site. Outlined advantages are the intravenous formulation, which solves non adherence, the lower gastrointestinal side effects incidence. The main limitation is iatrogenic hypocalcemia. We show our experience to evaluate findings of our initial fieldwork in order to optimize drug efficacy, safety and tolerability

Method

We included 27 patients during 2018 (15 M and 12 F, Caucasian, mean age 60,7±13,7 years), followed for at least 6 months. Initial etelcalcetide dose was 15 mg in all patients. PTH, Calcium, Phosphorus monitoring was done every month. Concomitant drugs as phosphorus binders, Vitamin D or analogues, Calcium and the switch from cinacalcet were considered. Therapeutic variations and side effects were recorded. Data are registered at the beginning and the end of follow up.

Results

Starting values are: PTH 1298±545 pg/ml, Calcium 9,1±0,9, Phosphorus 5,1±1,4. 14 patients already took phosphorus binders, 10 paricalcitol. 12 patients were switched from Cinacalcet because of non-adherence or inefficacy, the other 15 patients never took calcimimetics. Mean values after 6 months are: PTH 661±469 pg/ml, Calcium 8,2±0,5 mg/ml, Phosphorus 4,1±1,6 mg/ml. These data point out a mean decrease in PTH value of 49%, reaching the therapeutic target in 18 patients, that is the 75% of the total population studied.

It have been necessary dose modifications in 15 patients (62.5%): 9 etelcalcetide dose variations (37,5%), 6 vitamin D and Calcium supplementation, both the changes in 5 of them. Side effects were hypocalcemia (14), pruritus (1), diarrhea (1), low platelet count (1), registered in 17 patients (63%), 3 of them withdrew therapy and then refused to start it again. It has to be said that thrombocytopenia, occurred after the follow up time (at 7th month), solve after etelcacetide withdrawal. Subgroup analysis pointed out a statistically significant correlation between drug efficacy and switch from cinacalcet, both in terms of extent of iPTH reduction (65% vs 42% - p value &lt; 0,05 ) and of achievement of the therapeutic target (89% vs 66% - p value &lt; 0,05), and between concomitant paricalcitol therapy at zero-time and lower hypocalcemia incidence (10% vs 76% - p value &lt; 0,05).

Conclusion

Results confirm etelcalcetide efficacy and suggest a correlation between concomitant paricalcitol therapy at baseline and lower hypocalcemia incidence and between greater efficacy and switch from cinacalcet. These data, if confirmed in larger sample, could be useful to guide the starting approach and the maintaining treatment with etelecalcetide.

P0263A NEPHROLOGIST'S LOOK AT HYPERTENSIVE DISORDERS OF PREGNANCY

Background and Aims

Preeclampsia (PE) is a pregnancy-related syndrome of variable severity that falls under the broad category of hypertensive disorders of pregnancy (HDP). The relationship between PE and chronic kidney disease (CKD) is not entirely understood. Once considered a self-limited disease healed by delivery, it is now acknowledged that PE is a marker of cardiovascular and kidney health in the long term. The aim of this study was to review the data of women with hypertensive disorders of pregnancy at our institution, to identify need and to organize a conjoint nephrology and obstetrical activity in our setting

Method

We retrospectively reviewed all the medical charts of the patients hospitalized in the last two years for hypertensive disorders of pregnancy and who delivered in our Hospital. The cohort was divided into two groups: gestational hypertension (GH) and PE. A descriptive analysis of the clinical-laboratoristic was performed (t-test for continuous data with normal distribution).

Results

We identified 93 cases of hypertensive disorders of pregnancy on a total of 3279 deliveries (2.8%), 47 GH and 46 PE [2 cases of HELLP syndrome and 1 of eclampsia included in the PE group]. These two groups showed similar mean age: 33.5±6 vs 34.9±6 years (p value= 0.25); serum creatinine (sCr) and uric acid at admission were statistically different, and higher in the PE group (sCr 0.57±0.15 and 0.66±0.2 – p=0.01 and uric acid 4.5±1.38 and 5.6±1.47 – p=0.01).

Comorbidities were frequent in the PE group: thyroid disfunction was found in 17% of cases (7 hypothyroidism and 1 hyperthyroidism, all under treatment), coagulation abnormalities were present in 15% of cases (4 MTHFR mutation, 1 protein S deficiency, 1 prothrombin-gene mutation, 1 patient was positive for LLAC); gestational diabetes was diagnosed in 13% of the cases. We identified 1 renal transplant recipient, 1 IgA-vasculitis patient, 1 patient with family medical history positive for PE (in her twin sister); none of these patients had been identified as at high risk for PE. At hospital admission, 54% of the patients were on antihypertensive treatment, 7 of them for chronic hypertension and 18 for gestational hypertension (12 of these patients underwent a previous hospitalization during the same pregnancy, diagnosed with gestational hypertension); at admission only 24% of PE patients were treated with anticoagulant or antiplatelet prophylaxis. Caesarean section was performed in 36 cases (78%). All but one children live-born, the exception being a child from a multiple pregnancy (quadruplets).

Conclusion

A multidisciplinary approach and a nephrological follow-up are increasingly indicated in PE. Our series underlines a high prevalence of comorbidity or risk factors, including thyroid disfunction, gestational diabetes and coagulation abnormalities. The high prevalence (7/46) of chronic hypertension and the fact that the two patients with kidney disease were not identified as at risk for PE underlines the potential role for developing a synergic approach between nephrologist and obstetricians.

How to manage catheter-related right atrial thrombosis: Our conservative approach

BACKGROUND

Catheter-related right atrial thrombosis is an underestimated, severe, and life-threatening complication of any type of central venous catheters. No clear-cut epidemiological data are available. Catheter-related right atrial thrombosis is often asymptomatic; however, it can lead to serious complications and death.

CASE SERIES

We report seven catheter-related right atrial thrombosis events occurred in five hemodialysis patients; two recurrences following primary treatment are included in the report, all of them managed with a conservative approach without catheter removal. Systemic anticoagulation (vitamin K antagonists), having a well-defined target of International Normalized Ratio of 2.5-3.0, combined with urokinase as a locking solution at the end of each hemodialysis session were the therapeutic strategy used in all patients. After the first month, the anticoagulation target was reduced to an International Normalized Ratio value of 1.5-2.0 and urokinase to a weekly administration. After sixth months, when no thrombus was identified at transthoracic echocardiographic examinations, the treatment was stopped. No bleeding complications were reported.

CONCLUSION

The combination therapy here described is safe, quick, and effective, achieving the goal of not removing catheters.

Green nephrology and eco-dialysis: a position statement by the Italian Society of Nephrology

High-technology medicine saves lives and produces waste; this is the case of dialysis. The increasing amounts of waste products can be biologically dangerous in different ways: some represent a direct infectious or toxic danger for other living creatures (potentially contaminated or hazardous waste), while others are harmful for the planet (plastic and non-recycled waste). With the aim of increasing awareness, proposing joint actions and coordinating industrial and social interactions, the Italian Society of Nephrology is presenting this position statement on ways in which the environmental impact of caring for patients with kidney diseases can be reduced. Due to the particular relevance in waste management of dialysis, which produces up to 2 kg of potentially contaminated waste per session and about the same weight of potentially recyclable materials, together with technological waste (dialysis machines), and involves high water and electricity consumption, the position statement mainly focuses on dialysis management, identifying ten first affordable actions: (1) reducing the burden of dialysis (whenever possible adopting an intent to delay strategy, with wide use of incremental schedules); (2) limiting drugs and favouring "natural" medicine focussing on lifestyle and diet; (3) encouraging the reuse of "household" hospital material; (4) recycling paper and glass; (5) recycling non-contaminated plastic; (6) reducing water consumption; (7) reducing energy consumption; (8) introducing environmental-impact criteria in checklists for evaluating dialysis machines and supplies; (9) encouraging well-planned triage of contaminated and non-contaminated materials; (10) demanding planet-friendly approaches in the building of new facilities.

[Nephrologists' role in a changing climate]

Human-induced climate changes represent an increasing concern in recent years. Among the medical specialties, Nephrology is the most interested in the negative effects of climate changes on human health. Kidneys in fact play a crucial role in blood volume regulation as well as in the extra- and intracellular osmolality that allow normal metabolism. Furthermore, urinary concentration minimizes fluid losses, while also insuring the excretion of nitrogenous wastes. The harmful effects of heat can lead to both acute and chronic kidney diseases, electrolyte abnormalities, kidney stone formation and urinary tract infections. As global warming increases, major efforts are required worldwide to assure adequate hydration and prevent overheating in vulnerable populations. While our activities make us responsible agents, there are also several opportunities to change the game, both individually and as a scientific society. This call to action intends to raise awareness on environmentally sustainable practices and encourage the nephrology community in Italy to participate in this important discussion.

[Membranoproliferative glomerulonephritis with relapsing episodes of acute kidney injury in the Schnitzler syndrome]

The Schnitzler syndrome (SS) is a rare and underdiagnosed entity that associates a chronic urticarial rash, monoclonal IgM (or sometimes IgG) gammopathy and signs and symptoms of systemic inflammation. During the past 45 years the SS has evolved from an elusive, little-known disorder to the paradigm of a late-onset auto-inflammatory acquired syndrome. Though there is no definite proof of its precise pathogenesis, it should be considered as an acquired disease involving abnormal stimulation of the innate immune system, which can be reversed by the interleukin 1 (IL-1) receptor antagonist anakinra. Here we describe the case of a 56-year-old male Caucasian patient affected by SS and hospitalized several times in our unit because of relapsing episodes of acute kidney injury. He underwent an ultrasound-guided percutaneous kidney biopsy in September 2012, which showed the histologic picture of type I membranoproliferative glomerulonephritis. He has undergone conventional therapies, including nonsteroidal anti-inflammatory drugs, steroids and immunosuppressive drugs; more recently, the IL-1 receptor antagonist anakinra has been prescribed, with striking clinical improvement. Although the literature regarding kidney involvement in the SS is lacking, it can however be so severe, as in the case reported here, to lead us to recommend the systematic search of nephropathy markers in the SS.

Should a fistula first policy be revisited in elderly haemodialysis patients?

Life-sustaining haemodialysis requires a durable vascular access (VA) to the circulatory system. The ideal permanent VA must provide longevity for use with minimal complication rate and supply sufficient blood flow to deliver the prescribed dialysis dosage. Arteriovenous fistulas (AVFs) have been endorsed by many professional societies as the VA of choice. However, the high prevalence of comorbidities, particularly diabetes mellitus, peripheral vascular disease and arterial hypertension in elderly people, usually make VA creation more difficult in the elderly. Many of these patients may have an insufficient vasculature for AVF maturation. Furthermore, many AVFs created prior to the initiation of haemodialysis may never be used due to the competing risk of death before dialysis is required. As such, an arteriovenous graft and, in some cases, a central venous catheter, become a valid alternative form of VA. Consequently, there are multiple decision points that require careful reflection before an AVF is placed in the elderly. The traditional metrics of access patency, failure and infection are now being seen in a broader context that includes procedure burden, quality of life, patient preferences, morbidity, mortality and cost. This article of the European Dialysis (EUDIAL) Working Group of ERA-EDTA critically reviews the current evidence on VA in elderly haemodialysis patients and concludes that a pragmatic patient-centred approach is mandatory, thus considering the possibility that the AVF first approach should not be an absolute.

Dialysate bicarbonate concentration: Too much of a good thing?

Acid-base equilibrium is a complex and vital system whose regulation is impaired in chronic kidney disease (CKD). Metabolic acidosis is a common complication of CKD. It is typically due to the accumulation of sulfate, phosphorus, and organic anions. Metabolic acidosis is correlated with several adverse outcomes, such as morbidity, hospitalization and mortality. In patients undergoing hemodialysis, acid-base homeostasis depends on many factors: net acid production, amount of alkali given by the dialysate bath, duration of interdialytic period, as well as residual diuresis, if any. Recent literature data suggest that the development of postdialysis metabolic alkalosis may contribute to adverse clinical outcomes. Unfortunately, no randomized studies exist about the effect of different dialysate bicarbonate concentrations on hard outcomes, such as mortality. Like everything else in dialysis, the quest for the "ideal" dialysate bicarbonate concentration is far from over. The Latin aphorism "ne quid nimis" ie "nothing in excess" (excess of neither acid nor base) probably best summarizes our current state of knowledge in this field. For the present, the clinician should understand that target values for predialysis serum bicarbonate concentrations have been established primarily based on observational studies and expert opinion. On the basis of this information, we should keep predialysis serum bicarbonate concentrations at least at 22 mEq/L. Furthermore, a specific focus should be addressed to the clinical and nutritional status of the major outliers on both the acid and alkaline sides of the curve.

Is the removal of a central venous catheter always necessary in the context of catheter-related right atrial thrombosis?

Catheter-related right atrial thrombosis is a severe and life-threatening complication of central venous catheters in both adult and young patients. Catheter-related right atrial thrombosis can occur with any type of central venous catheters, utilized either for hemodialysis or infusion. Up to 30% of patients with central venous catheter are estimated to be affected by catheter-related right atrial thrombosis; however, neither precise epidemiological data nor guidelines regarding medical or surgical treatment are available. This complication seems to be closely associated with positioning of the catheter tip in the atrium, whereas it is unlikely with a tip located within superior vena cava. Herein, we report the case of a patient affected by catheter-related right atrial thrombosis, who showed a quick resolution of thrombosis with a new therapeutic scheme combining loco-regional thrombolytic therapy (urokinase as a locking solution) and systemic anticoagulation therapy (vitamin K antagonists), thus avoiding catheter removal. Neither complications of the combination therapy were reported, nor recurrence of catheter-related right atrial thrombosis occurred. In conclusion, the combination therapy here described was safe, quick and effective, achieving the goal of not removing the catheter.

A Modified Two-Bun Method for Routine Urea Modeling: Clinical Validation in 120 Patients on a Free Diet

Recently, a modified algorithm of the Two-BUN method (MA2p), avoiding dialyzer clearance measurement, was presented for routine assessment of Kt/V and NPCR. To validate MA2p in patients on a free diet (FDP), we studied 120 stable dialysis FDP by measuring Kt/V and NPCR with both MA2p and a modified version of the standard Three-BUN method (MA3p), for the 3 weekly sessions. The NPCR values (g/kg/day), calculated by MA3p for the 3 interdialyses were: 1.286∓0.274, 1.256∓0.276, and 1.116∓0.230, respectively. The correlation coefficient (r) for averaged Kt/V values obtained by the two methods was 0.999 and the percent error (Error%) for MA2p vs. MA3p results ranged from -1.5 to +0.78%. The respective results for NPCR were: r=0.967, Error% range from -11.7 to +13.9%. In conclusion, MA2p can be safely used in patients on a free diet. The lowest NPCR values were observed during the long interdialysis.

Kidney involvement in the Schnitzler syndrome, a rare disease

The Schnitzler syndrome (SS) is a rare and underdiagnosed entity that associates a chronic urticarial rash, monoclonal IgM (or sometimes IgG) gammopathy and signs and symptoms of systemic inflammation. During the past 45 years, the SS has evolved from an elusive little-known disorder to the paradigm of a late-onset acquired auto-inflammatory syndrome. Though there is no definite proof of its precise pathogenesis, it should be considered as an acquired disease involving abnormal stimulation of the innate immune system, which can be reversed by the interleukin-1 receptor antagonist anakinra. It clearly expands our view of this group of rare genetic diseases and makes the concept of auto-inflammation relevant in polygenic acquired diseases as well. Increasing numbers of dermatologists, rheumatologists, allergologists, haematologists and, more recently, nephrologists, recognize the SS. The aim of this review is to focus on kidney involvement in the SS. Although the literature regarding kidney involvement in the SS is very poor it can be severe, as in our own case here reported, leading us to recommend the systematic search for nephropathy markers in the SS.

The complex relationship among arteriovenous access, heart, and circulation

There are currently near 400 000 patients on hemodialysis in the United States. More than 50% of those treated by chronic hemodialysis die because of a cardiovascular (CV) event. The majority of these patients have functional arteriovenous fistulas (AVFs). AVFs have an adverse effect on cardiac function, but their exact contribution to CV morbidity is not clear. It has long been known that a vascular access with an inappropriately high-flow rate may cause high-output heart failure. Paradoxically, there may be hemodynamic and cardiopulmonary benefits conferred by AVF particularly in severe chronic obstructive pulmonary disease. While Brescia-Cimino`s basic idea of the AVF has saved millions of lives, we would like to stress that there are dangers from their often high blood flow rates, which unfortunately have proved difficult to evaluate.

Clinical use of computational modeling for surgical planning of arteriovenous fistula for hemodialysis

BACKGROUND

Autogenous arteriovenous fistula (AVF) is the best vascular access (VA) for hemodialysis, but its creation is still a critical procedure. Physical examination, vascular mapping and doppler ultrasound (DUS) evaluation are recommended for AVF planning, but they can not provide direct indication on AVF outcome. We recently developed and validated in a clinical trial a patient-specific computational model to predict pre-operatively the blood flow volume (BFV) in AVF for different surgical configuration on the basis of demographic, clinical and DUS data. In the present investigation we tested power of prediction and usability of the computational model in routine clinical setting.

METHODS

We developed a web-based system (AVF.SIM) that integrates the computational model in a single procedure, including data collection and transfer, simulation management and data storage. A usability test on observational data was designed to compare predicted vs. measured BFV and evaluate the acceptance of the system in the clinical setting. Six Italian nephrology units were involved in the evaluation for a 6-month period that included all incident dialysis patients with indication for AVF surgery.

RESULTS

Out of the 74 patients, complete data from 60 patients were included in the final dataset. Predicted brachial BFV at 40 days after surgery showed a good correlation with measured values (in average 787 ± 306 vs. 751 ± 267 mL/min, R = 0.81, p < 0.001). For distal AVFs the mean difference (±SD) between predicted vs. measured BFV was -2.0 ± 20.9%, with 50% of predicted values in the range of 86-121% of measured BFV. Feedbacks provided by clinicians indicate that AVF.SIM is easy to use and well accepted in clinical routine, with limited additional workload.

CONCLUSIONS

Clinical use of computational modeling for AVF surgical planning can help the surgeon to select the best surgical strategy, reducing AVF early failures and complications. This approach allows individualization of VA care, with the aim to reduce the costs associated with VA dysfunction, and to improve AVF clinical outcome.

The impact of haemodialysis arteriovenous fistula on haemodynamic parameters of the cardiovascular system

BACKGROUND

Satisfactory vascular access flow (Qa) of an arteriovenous fistula (AVF) is necessary for haemodialysis (HD) adequacy. The aim of the present study was to further our understanding of haemodynamic modifications of the cardiovascular system of HD patients associated with an AVF. The main objective was to calculate using real data in what way an AVF influences the load of the left ventricle (LLV).

METHODS

All HD patients treated in our dialysis unit and bearing an AVF were enrolled into the present observational cross-sectional study. Fifty-six patients bore a lower arm AVF and 30 an upper arm AVF. Qa and cardiac output (CO) were measured by means of the ultrasound dilution Transonic Hemodialysis Monitor HD02. Mean arterial pressure (MAP) was calculated; total peripheral vascular resistance (TPVR) was calculated as MAP/CO; resistance of AVF (AR) and systemic vascular resistance (SVR) are connected in parallel and were respectively calculated as AR = MAP/Qa and SVR = MAP/(CO - Qa). LLV was calculated on the principle of a simple physical model: LLV (watt) = TPVR·CO(2). The latter was computationally divided into the part spent to run Qa through the AVF (LLVAVF) and that part ensuring the flow (CO - Qa) through the vascular system. The data from the 86 AVFs were analysed by categorizing them into lower and upper arm AVFs.

RESULTS

Mean Qa, CO, MAP, TPVR, LLV and LLVAVF of the 86 AVFs were, respectively, 1.3 (0.6 SD) L/min, 6.3 (1.3) L/min, 92.7 (13.9) mmHg, 14.9 (3.9) mmHg·min/L, 1.3 (0.6) watt and 19.7 (3.1)% of LLV. A statistically significant increase of Qa, CO, LLV and LLVAVF and a statistically significant decrease of TPVR, AR and SVR of upper arm AVFs compared with lower arm AVFs was shown. A third-order polynomial regression model best fitted the relationship between Qa and LLV for the entire cohort (R (2) = 0.546; P < 0.0001) and for both lower (R (2) = 0.181; P < 0.01) and upper arm AVFs (R (2) = 0.663; P < 0.0001). LLVAVF calculated as % of LLV rose with increasing Qa according to a quadratic polynomial regression model, but only in lower arm AVFs. On the contrary, no statistically significant relationship was found between the two parameters in upper arm AVFs, even if mean LLVAVF was statistically significantly higher in upper arm AVFs (P < 0.0001).

CONCLUSIONS

Our observational cross-sectional study describes statistically significant haemodynamic modifications of the CV system associated to an AVF. Moreover, a quadratic polynomial regression model best fits the relationship between LLVAVF and Qa, but only in lower arm AVFs.

The vascular access in the elderly: a position statement of the Vascular Access Working Group of the Italian Society of Nephrology

The incident hemodialysis (HD) population is aging, and the elderly group is the one with the most rapid increase. In this context it is important to define the factors associated with outcomes in elderly patients. The high prevalence of comorbidities, particularly diabetes mellitus, peripheral vascular disease and congestive heart failure, usually make vascular access (VA) creation more difficult. Furthermore, many of these patients may have an insufficient vasculature for fistula maturation. Finally, many fistulas may never be used due to the competing risk of death before dialysis initiation. In these cases, an arteriovenous graft and in some cases a central venous catheter become a valid alternative form of VA. Nephrologists need to know what is the most appropriate VA option in these patients. Age should not be a limiting factor when determining candidacy for arteriovenous fistula creation. The aim of this position statement, prepared by experts of the Vascular Access Working Group of the Italian Society of Nephrology, is to critically review the current evidence on VA in elderly HD patients. To this end, relevant clinical studies and recent guidelines on VA are reviewed and commented. The main advantages and potential drawbacks of the different VA modalities in the elderly patients are discussed.

The choice of dialysate bicarbonate: do different concentrations make a difference?

Metabolic acidosis is a common complication of chronic kidney disease; it is typically caused by the accumulation of sulfate, phosphorus, and organic anions. Metabolic acidosis is correlated with several adverse outcomes, such as morbidity, hospitalization, and mortality. Thus, correction of metabolic acidosis is fundamental for the adequate management of many systemic complications of chronic kidney disease. In patients undergoing hemodialysis, acid-base homeostasis depends on many factors including the following: net acid production, amount of alkali given by the dialysate bath, duration of the interdialytic period, and residual diuresis, if any. Recent literature data suggest that the development of metabolic alkalosis after dialysis may contribute to adverse clinical outcomes. Our review is focused on the potential effects of different dialysate bicarbonate concentrations on hard outcomes such as mortality. Unfortunately, no randomized studies exist about this issue. Acid-base equilibrium is a complex and vital system whose regulation is impaired in chronic kidney disease. We await further studies to assess the extent to which acid-base status is a major determinant of overall survival in patients undergoing hemodialysis. For the present, the clinician should understand that target values for predialysis serum bicarbonate concentration have been established primarily based on observational studies and expert opinion. Based on this, we should keep the predialysis serum bicarbonate level at least at 22 mmol/l. Furthermore, a specific focus should be addressed by the attending nephrologist to the clinical and nutritional status of the major outliers on both the acid and alkaline sides of the curve.

[An unusual cause of ureteral obstruction in kidney transplant]

Inguinal herniation of the ureter in a kidney transplantation is a rare cause of late distal ureteral obstruction. Herniation is usually secondary to the implant of a long redundant ureter and to its course on the spermatic cord. This clinical condition can worsen graft function in the presence of ipsilateral hydroureteronephrosis. In this review, we describe the case of an asymptomatic 51-year-old man with a history of right iliac renal allotransplantation 12 years before. Kidney ultrasound showed moderate hydroureteronephrosis and ureteral kneeling at the upper third of the inguinal canal. The patient presented a mild increase in serum creatinine; physical examination revealed an ipsilateral inguinal hernia. A CT scan of the abdomen with no contrast medium confirmed middle-distal ureteral kneeling engaging in the sac of the right inguinal hernia. The patient underwent surgical hernia repair with no complications and his renal function recovered completely.

[An unusual cause of acute pyelonephritis: the retrocaval ureter]

Retrocaval ureter is a rare congenital malformation in which the proximal right ureter courses toward the midline on the posterior aspect of the inferior vena cava before emerging medial and anterior to this structure and then descending into the pelvis. This anatomical anomaly may be asymptomatic or manifest clinically, usually starting from the fourth decade of life, with flank pain, pyelonephritis, gross hematuria or other rarer signs. We describe the case of a young woman being hospitalized because of acute pyelonephritis; she had previously complained of flank pain associated with episodes of high fever. Computed tomography of the abdomen identified the malformation. The patient underwent surgical correction by laparoscopy and, at one year of follow-up, did not show any further clinical problem.

A neglected issue in dialysis practice: haemodialysate

The intended function of dialysate fluid is to correct the composition of uraemic blood to physiologic levels, both by reducing the concentration of uraemic toxins and correcting electrolyte and acid-base abnormalities. This is accomplished principally by formulating a dialysate whose constituent concentrations are set to approximate normal values in the body. Sodium balance is the cornerstone of intradialysis cardiovascular stability and good interdialytic blood pressure control; plasma potassium concentration and its intradialytic kinetics certainly play a role in the genesis of cardiac arrhythmias; calcium is related to haemodynamic stability, mineral bone disease and also cardiac arrhythmias; the role of magnesium is still controversial; lastly, acid buffering by means of base supplementation is one of the major roles of dialysis. In conclusion, learning about the art and the science of fashioning haemodialysates is one of the best ways to further the understanding of the pathophysiologic processes underlying myriad acid-base, fluid, electrolyte as well as blood pressure abnormalities of the uraemic patient on maintenance haemodialysis.

Preoperative assessment and planning of haemodialysis vascular access

Effective haemodialysis (HD) requires a reliable vascular access (VA). Clinical practice guidelines strongly recommend the arteriovenous fistula (AVF) as the preferred VA in HD patients. The creation of an AVF should be promoted in all eligible patients who choose HD, as it improves outcomes and reduces costs when compared with central venous catheters. Fistula eligibility is a ‘work in progress’. Three steps in order to increase the pool of eligible patients can be individualized: (i) process of care, which includes three fundamental items: the VA team, early VA education and timely VA surgery referral; (ii) preoperative evaluation; (iii) surgical strategy. Nephrologists should be able to play a leading and coordinating role of the VA team. They should design a plan that identifies a sequence of options that can be used to provide adequate renal replacement therapy throughout the life span of every end-stage renal disease patient. The main points of this strategy are (i) early vascular education, in which a ‘save the vein program’ should always be implemented; (ii) timely VA surgery referral and preoperative evaluation: careful examination of arterial and venous beds is mandatory before VA placement; physical examination in addition to colour Doppler ultrasound mapping improves AVF outcomes; (iii) surgical strategy: a successful VA strategy must take into account vascular anatomy, clinical factors and prognosis.

Efficacy and Safety of a New Technique of Conversion from Temporary to Tunneled Central Venous Catheters

The usually applied conversion technique from temporary to tunneled central venous catheters (CVCs) using the same venous insertion site requires a peel-away sheath. We propose a conversion technique without peel-away sheath: a guide wire is advanced through the existing temporary CVC; then, a subcutaneous tunnel is created from the exit to the venotomy site. After removing the temporary CVC, the tunneled one is advanced along the guide wire. The study group included all patients requiring a catheter conversion from January 2012 to June 2014; the control group included incident patients who had received de novo placement of tunneled CVCs from January 2010 to December 2011. The main outcome measures were technical success and immediate complications. Seventy-two tunneled catheters (40 with our conversion technique and 32 with the traditional one) were placed in 72 patients. The technical success was 95% in the study group and 75% in the controls (p = 0.019). The immediate complications were one bleeding in the study group (2.5%) and one air embolism, one pneumothorax, and four bleedings (18.7%) in the controls (p = 0.039). Conversion from temporary to tunneled CVC using a guide wire and without a peel-away sheath is an effective and safe procedure.

The key role of color Doppler ultrasound in the work-up of hemodialysis vascular access

Vascular access (VA) is the lifeline for the hemodialysis patient and the native arterio-venous fistula (AVF) is the first-choice access. Among the different tests used in the VA domain, color Doppler ultrasound (CD-US) plays a key role in the clinical work-up. At the present time, three are the main fields of CD-US application: (i) evaluation of forearm arteries and veins in surgical planning; (ii) testing of AVF maturation; (iii) VA complications. Specifically, during the AVF maturation, CD-US allows to measure the diameter and flow volume in the brachial artery and calculate the peak systolic velocity (PSV) of the arterial axis, anastomosis and efferent vein, to detect critical stenosis. The borderline stenosis, revealed by the discrepancies between access flow rate and PSV, should be followed up with subsequent tests to detect progression of stenosis; the cases with significant changes in brachial flow should be referred to angiography. In conclusion, clinical monitoring remains the backbone of any VA program. CD-US is of utmost importance in a patient-centered VA evaluation, because it allows the appropriate management of all aspects of VA care. These are the main reasons why we strongly advocate the adoption of a VA surveillance program based on CD-US.