Preferred strategy for hemodialysis access creation in elderly patients

Hemodialysis Patients with High-Flow Arteriovenous Fistulas: An Evaluation of the Impact on Cardiac Function

Purpose

: Patients undergoing hemodialysis often experience changes in cardiac function when they have a high-flow arteriovenous fistula (AVF). This study aimed to assess the effect of high-flow AVFs on cardiac function in patients undergoing hemodialysis.

Materials and Methods

: A longitudinal study was conducted on hemodialysis patients with high-flow AVFs. Echocardiographic parameters, such as left ventricular ejection fraction (LVEF), left atrial diameter (LAD), left ventricular end-diastolic dimension (LVEDD), right ventricular end-diastolic dimension (RVEDD), inferior vena cava diameter (IVCD), systolic blood pressure, and diastolic blood pressure, were measured and compared before and after AVF creation.

Results

: One hundred hemodialysis patients with high-flow AVFs (mean age: 55.95±13.39 years, mean body mass index: 24.71±3.43 kg/m²) were studied. LVEF significantly decreased (51.10%±5.39% to 47.50%±5.79%), while LAD, LVEDD, and IVCD significantly increased after AVF creation (P<0.05). Systolic (132.49±16.42 mmHg to 146.60±17.43 mmHg) and diastolic (79.98±8.40 mmHg to 83.33±9.68 mmHg) blood pressure substantially rose post-fistularization (P<0.001). Notably, LVEF reduction was more significant in brachio-cephalic AVFs (46.29%±4.24%) compared to distal radio-cephalic or snuffbox AVFs (49.17%±7.15%) (P=0.014).

Conclusion

: High-flow AVFs can significantly affect echocardiographic parameters in hemodialysis patients, thereby increasing the risk of cardiac failure. Close cardiac monitoring may be necessary for early intervention. Distal AVFs may be preferable in patients with decreased cardiac function.

The Role of Ultrasound Examination in the Assessment of Suitability of Calcified Arteries for Vascular Access Creation-Mini Review

Arterial calcifications are present in 20-40% of patients with end-stage kidney disease and are more frequent among the elderly and diabetics. They reduce the possibility of arterio-venous fistula (AVF) formation and maturation and increase the likelihood of complications, especially distal ischemia. This review focuses on methods for detecting arterial calcifications and assessing the suitability of calcified arteries for providing inflow before the construction of an AVF. The importance of a clinical examination is stressed. A grading system is proposed for quantifying the severity of calcifications in the arteries of the arm with B-mode and Doppler ultrasound exams. Functional tests to assess the suitability of the artery to provide adequate inflow to the AVF are discussed, including Doppler indices (peak systolic velocity and resistive index during reactive hyperemia). Possible predictors of the development of distal ischemia are discussed (finger pressure, digital brachial index, acceleration and acceleration time), as well as the outcomes of AVFs placed on calcified arteries. It is concluded that a noninvasive ultrasound examination is probably the best tool for a morphologic and functional assessment of the arteries. An arterial assessment is of utmost importance if we are to create distal radiocephalic AVFs in our elderly patients whenever possible without burdening them with futile surgical attempts.

Long-term efficacy and risk factors of balloon-assisted maturation for radial-cephalic arteriovenous fistula with small-caliber veins

INTRODUCTION

Balloon angioplasty maturation (BAM) is a salvage method for autologous arteriovenous fistula (AVF) maturation failure. AVF creation using small-diameter veins is considered to have poor outcomes. Therefore, this study aimed to explore the long-term patency of small-diameter veins (≤3 mm) using BAM.

METHODS

BAM was performed if the fistula failed to mature and function adequately to provide prescribed dialysis.

FINDINGS

Out of 61 AVFs, 22 AVFs successfully matured without further intervention (AVF group) and 39 AVFs failed to mature. Except for 1 patient who required peritoneal dialysis, the remaining 38 patients received salvage BAM, and 36 of those successful matured (BAM group). Kaplan-Meier analysis revealed no significant differences between the AVF and BAM groups in terms of primary functional patency (p = 0.503) and assisted functional patency (p = 0.499). Compared with the AVF group, the BAM group had similar assisted primary functional patency (1-year: 94.7% vs. 93.1%; 3-year: 88.0% vs. 93.1%; 5-year: 79.2% vs. 88.3%). In addition, there were no significant difference between groups in the duration of primary functional patency and assisted primary functional patency (p > 0.05). Multivariate analyses showed that vein diameter and number of BAM procedures were independent predictors of primary functional patency in the AVF group and BAM group, respectively. Patient with 1 mm increase in vein size had 0.13-fold probability of having decreased duration of patency (HR = 0.13, 95% CI: 0.02-0.99, p = 0.049), while patients who received two times of BAM procedures were 2.885 as likely to have decreased duration of primary functional patency (HR = 2.885, 95% CI: 1.09-7.63, p = 0.033) than patients who received one BAM procedure.

DISCUSSION

BAM is a relatively effective salvage management option with an acceptable long-term patency rate, even for small cephalic veins.

Prognosis Factors of Patients Undergoing Renal Replacement Therapy

BACKGROUND

Survival in patients with end-stage kidney disease (ESKD) on renal replacement therapy (RRT) is less than that of the general population of the same age, and depends on patient factors, the medical care received, and the type of RRT used. The objective of this study is to analyze the factors associated with survival in patients undergoing RRT.

METHODS

We conducted a retrospective observational study of adult patients with an incident of ESKD on RRT in Andalusia from 1 January 2008 to 31 December 2018. Patient characteristics, nephrological care received, and survival from the beginning of RRT were evaluated. A survival model for the patient was developed according to the variables studied.

RESULTS

A total of 11,551 patients were included. Median survival was 6.8 years (95% CI (6.6; 7.0)). After starting RRT, survival at one year and five years was 88.7% (95% CI (88.1; 89.3)) and 59.4% (95% CI (58.4; 60.4)), respectively. Age, initial comorbidity, diabetic nephropathy, and a venous catheter were independent risk factors. However, non-urgent initiation of RRT and follow-up in consultations for more than six months had a protective effect. It was identified that renal transplantation (RT) was the most influential independent factor in patient survival, with a risk ratio of 0.13 (95% CI (0.11; 0.14)).

CONCLUSIONS

The receiving of a kidney transplant was the most beneficial modifiable factor in the survival of incident patients on RRT. We consider that the mortality of the renal replacement treatment should be adjusted, taking into account both modifiable and nonmodifiable factors to achieve a more precise and comparable interpretation.

Access flow volume (Qa) and survival in a hemodialysis population: An analysis of 5208 Qa measurements over a 9-year period

BACKGROUND

Aim of the study was to determine associations between characteristics of arteriovenous access (AVA) access flow volume (Qa, mL/min) and four year freedom from cardiovascular mortality (4yr-CVM) in hemodialysis (HD) patients.

METHODS

HD patients who received a primary AVA between January 2010 and December 2017 in one center were analyzed. Initial Qa was defined as the first Qa value obtained in a well-functioning AVA by a two-needle dilution technique. Actual Qa was defined as access flow at a random point of time. Changes in actual Qa were expressed per 3-month periods. CVM was assessed according to the ERA-EDTA classification. The optimal cut-off point for initial Qa was identified by a receiver operating characteristic curve. A joint modelling statistical technique determined longitudinal associations between Qa characteristics and 4yr-CVM.

RESULTS

A total of 5208 Qa measurements (165 patients, male n = 103; age 70±12 years, autologous AVA n = 146, graft n = 19) were analyzed. During follow-up (Dec 2010-Jan 2018, median 36 months), 79 patients (48%) died. An initial Qa < 900 mL/min was associated with an increased 4y-CVM risk (HR: 4.05; 95% CI [1.94-8.43], P<0.001). After 4 years, freedom from CVM was 34% lower in patients with a Qa < 900 mL/min (53 ±7% vs. Qa ≥ 900 mL/min: 87 ±4%, P <0.001). An association between increases in actual Qa over 3-month periods and mortality was found (HR: 4.48 per 100mL/min, 95% CI [1.44-13.97], P =0.010) indicating that patients demonstrating increasing Qa were more likely to die. By contrast, actual Qa per se was not related to survival.

CONCLUSIONS

Studying novel arteriovenous access Qa characteristics may contribute to understanding excess CVM in HD patients.

Multicenter Investigation of the Initial Hemodialysis Vascular Access and Its Related Factors in Hangzhou of China

Objective

To investigate the initial hemodialysis vascular access in Hangzhou and provide evidence for improving the use of autologous arteriovenous fistula by identifying factors associated with the choice of initial vascular access.

Methods

We retrospectively studied the initial hemodialysis vascular access of 257 patients in five hemodialysis units in Hangzhou of China during a 21-month period (January 2018 to September 2019). A logistic regression was used to identify the risk factors of failing to use an arteriovenous fistula at the initiation of hemodialysis.

Results

(1) 257 participants with mean age 67.65 ± 13.43 years old were reviewed, including 165 males (64.2%) and 92 females (35.8%). The etiologies of end-stage renal disease included diabetic nephropathy (37.35%), chronic glomerulonephritis (31.13%), hypertensive nephropathy (14.01%), and other diseases (17.51%). Only 51 patients (19.84%) received arteriovenous fistula, whereas the remaining 206 patients (80.16%) initiated dialysis with a central venous catheter. (2) Logistic regression analysis revealed that the independent risk factors for central venous catheter at the initial hemodialysis were age >70 years old (OR = 4.827, p < 0.01 versus ≤70 years old), chronic glomerulonephritis as the primary etiology (OR = 2.565, p < 0.05 versus nonchronic glomerulonephritis) and eGFR <8.5 mL/min/1.73m² (OR = 2.283, p < 0.05 versus eGFR ≥8.5 mL/min/1.73m²).

Conclusion

The proportion of patients using arteriovenous fistula as the initial hemodialysis vascular access in Hangzhou was still low. The choice of vascular access for the first hemodialysis was related to age, eGFR, and the primary etiology of end-stage renal disease. Increasing the proportion of planned vascular access and arteriovenous fistula at the initiation of hemodialysis is still our current goal.

Age is just a number: Is frailty being ignored in vascular access planning for dialysis?

Current international guidelines advocate fistula creation as first choice for vascular access in haemodialysis patients, however, there have been suggestions that in certain groups of patients, in particular the elderly, a more tailored approach is needed. The prevalence of more senior individuals receiving renal replacement therapy has increased in recent years and therefore including patient age in decision making regarding choice of vascular access for dialysis has gained more relevance. However, it seems that age is being used as a surrogate for overall clinical condition and it can be proposed that frailty may be a better basis to considering when advising and counselling patients with regard to vascular access for dialysis. Frailty is a clinical condition in which the person is in a vulnerable state with reduced functional capacity and has a higher risk of adverse health outcomes when exposed to stress inducing events. Prevalence of frailty increases with age and has been associated with an increased risk of mortality, hospitalisation, disability and falls. Chronic kidney disease is associated with premature ageing and therefore patients with kidney disease are prone to be frailer irrespective of age and the risk increases further with declining kidney function. Limited data exists on the relationship between frailty and vascular access, but it appears that frailty may have an association with poorer outcomes from vascular access. However, further research is warranted. Due to complexity in decision making in dialysis access, frailty assessment could be a key element in providing patient-centred approach in planning and maintaining vascular access for dialysis.

Creation of arteriovenous fistula for hemodialysis in the older population

OBJECTIVE

To evaluate the results of arteriovenous fistula (AVF) created for haemodialysis in patients older than 65 years of age.

SUBJECTS AND METHODS

A retrospective analysis of patients with AVF or arteriovenous graft (AVG) creation, who were older than 65 years of age and were operated on at the II. Surgical Clinic at the University Hospital in Olomouc from 2014 - 2018 was performed.

RESULTS

212 patients were evaluated and a total of 239 AVF/AVG were created. 194 AVFs (81.18%) and 45 AVGs (18.82%) were created. Primary failure was seen in 19 arteriovenous fistulas (9.8%) and 2 arteriovenous grafts (4.44%). The primary patency of AVF was 69.9%, 62.8% after 12 and 24 months, respectively, and in the case of AVG it was 54.7% and 32.3% after 12 and 24 months, respectively. Primarily assisted patency of AVF was 77.6% and 66.3% after 12 and 24 months, respectively, and in case of AVG it was 69.1% and 39.7% after 12 and 24 months, respectively. Secondary patency of AVF was 77.6% and 66.3% after 12 and 24 months, respectively, and for AVG it was 69.1% and 39.7% after 12 and 24 months, respectively.

CONCLUSION

The type of vascular access should be selected based on a thorough, protocol-based examination. In most seniors, AVF is the method of choice. The AVG is a suitable choice for patients with an exhausted venous bed, in acute need of haemodialysis, in the elderly and in females. A "customized" approach should be matter of fact for older generations.

Effect of Blood Pump Flow and Arteriovenous Fistula Blood Flow on the Blood Pressure and Cardiac Function in Patients Undergoing Maintenance Hemodialysis

The effect of blood pump flow rate on the cardiac functions of hemodialysis patients with arteriovenous fistula (AVF) is largely unknown. This study aimed to investigate if blood pump flow rate (Qb) and AVF access flow rate (Qa) can affect the cardiac function of Chinese hemodialysis patients. A total of 72 patients undergoing AVF hemodialysis were included from March 2010 to June 2014 and dichotomized into the high- and low-flow groups using the medians of Qb (220 mL/min) and Qa (1000 mL/min) as the cutoffs. The cardiac function parameters were measured by ultrasound dilution technique within the first (t + 30) and the last (t - 30) 30 min of dialysis. At t + 30, Qb-high group had significantly higher systolic blood pressure (SBP) and mean arterial pressure (MAP) than Qb-low group. At t - 30, Qb-high group had higher SBP, diastolic blood pressure (DBP), and MAP than Qb-low group. Qa-high group had higher SBP, MAP, cardiac output (CO), cardiac index (CI), central blood volume (CBV), and lower peripheral resistance than Qa-low group. Multiple linear regression showed that at t - 30, Qb was positively correlated with SBP and MAP. Qa was positively correlated with CO, CI, CBV, and PR but negatively correlated with heart rate. Although Qb > 220 mL/min and Qa >1000 mL/min would elevate some parameters, the means of SBP, DBP, MAP remain within the normal range, indicating that appropriate increase in blood pump flow rate has little effect on the cardiac function of hemodialysis patients.

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.

Correlation between preoperative vein and artery diameters and arteriovenous fistula outcome in patients with end-stage renal disease

BACKGROUND AND AIMS

Arteriovenous fistula (AVF) maturation failure rates remain high in patients with end-stage renal disease (ESRD). Although preoperative morphological and functional assessment of blood vessels by duplex ultrasonography (DUS) has been shown to improve AVF maturation, there is no consensus regarding the optimal vein (VD) and artery (AD) diameters to be universally used for AVF creation. To improve patient selection, set out to investigate if there is a correlation between preoperative VD/AD and clinical covariates, and postoperative AVF outcome.

METHODS

This was a prospective cohort study conducted during January-August 2014. ESRD patients referred to "Niculae Stăncioiu" Heart Institute Cluj-Napoca, who had a VD ≥1.9 mm and AD ≥1.5 mm, as measured by DUS, and underwent AVF creation were enrolled. We assessed whether preoperative VD/AD and clinical covariates were associated with AVF maturation rate and primary patency at 2 years after AVF creation.

RESULTS

Of 115 patients referred for AVF creation, 93 were included in the study. Mean (± standard deviation) VD was 3.3 ± 1.1 mm and VDs were distributed in quartile Q1 <2.55 mm, Q2: 2.56-3.10 mm, Q3: 3.11-3.70 mm and Q4: >3.71 mm. Mean AD was 3.3 ± 1.4 mm and ADs were distributed in Q1 <2.55 mm, Q2: 2.56-3.10 mm, Q3: 3.11-3.70 mm, and Q4, >3.71 mm. AVF maturation rate increased proportionally with VD from Q1 (62%) to Q2 (70%), Q3 (82%) to Q4 (96%) (p=0.03). Based on AD, a higher AVF maturation rate was observed in Q3 (86%), Q4 (83%) vs Q1 (71%) and Q2 (67%). Long-term primary patency of AVFs seemed not to be influenced by VD and AD. In older patients and those with peripheral arterial disease, AVF maturation failure tended to be higher.

CONCLUSIONS

Our findings suggest that a preoperative VD ≥1.9 mm and AD ≥1.5 mm have a successful maturation rate of AVF greater than 60% in ESRD patients. The maturation rate of surgical AVF increases proportionally with the size of VD used for AVF creation.

Elderly patient: which vascular access? Choice and management of vascular access in the elderly patient

The optimal vascular access for elderly patients remains a challenge due to the difficult balance between risks and benefits in a population with increased comorbidity and decreased survival. Long dependence to central vein catheter, patient comorbidities, life expectancy, and complication rates are important influencing the indications for arteriovenous fistula or an arteriovenous graft. Although central vein catheters are simpler way to start a hemodialysis treatment, elderly patients are also at higher risk of death from infection or other complications associated with them more than for younger patients. The discussion revolves around the following key questions:

What are the limiting factors for a vascular access in the elderly patients? Central venous catheter—is it still an option for elderly patients? Is still the autologous arteriovenous fistula playing a pivotal role as hemodialysis access in the elderly patients? Are there any real surgical contraindication to perform a vascular access in elderly patients? Is the old age a limiting factor for the vascular access management?

Impaired maturation of arteriovenous fistula for haemodialysis due to forearm artery stenosis: percutaneous endovascular treatment

INTRODUCTION

Distal autogenous arteriovenous fistula (dAVF), considered the "gold standard" vascular access for haemodialysis, suffers from a high rate of impaired maturation. One of the usual causes is low-flow associated forearm arterial stenosis. In such cases, endovascular treatment by percutaneous transluminal angioplasty represents a helpful option to enable maturation of the vascular access.Currently, there are few reports concerning the treatment of this complication. Therefore, we describe our single-centre experience based on a retrospective review of prospectively collected data.

PATIENTS AND METHODS

We treated 18 consecutive patients from July 2007 to January 2014 (16 radio-cephalic, 2 ulno-basilic distal AVF). A low flow due to forearm artery stenosis was diagnosed by duplex examination, as routinely performed one month after dAVF creation. An anterograde trans-brachial access was used for a 4-mm high-pressure angioplasty of the stenosed artery.

RESULTS

All interventions resulted in patent fistulas. Isolated percutaneous transluminal angioplasty (PTA) was required without need of stent placement. Mean blood flow increased from 304 mL/min, preoperatively, to 671 mL/min (p<0.01), as checked one week after the procedure. One-year primary and secondary patency were 84% ±7.3% and 92% ± 9.2%, respectively. Under no circumstances did access-induced distal ischemia occurred during follow-up.

CONCLUSIONS

Endovascular approach is a helpful and minimally invasive procedure for treatment of delayed maturation of dAVF related to forearm artery stenosis.

Vascular access scenario in Italy: evolution and comparison by two surveys (1998-2013)

PURPOSE

Dialysis settings have generally improved over the last decades, but the vascular access setting did not see significant advances and experienced a progressive worsening in epidemiology and clinical features. The aim of the study was to describe and compare evolution of vascular access in Italy over time.

METHODS

A national survey implemented in Italy last year is presented and compared to a previous survey performed in 1998. Present survey collected data from almost 50% of centers involved in vascular access.

RESULTS

The nephrologist participates in the management of vascular access in 97% of centers. Almost 40% of centers declare more than 40% of central venous catheters (CVCs) at first dialysis with maximum value being 60%. Prevalence of CVCs is greater than 20% in chronic prevalent patients in 38.8% of centers. According to the 2013 survey, CVCs account for 51.6% of procedures, while arteriovenous fistulae (AVF) and prostheses represent 42.4% and 6%, respectively. Nephrologists perform 73% of procedures on CVCs.From 1998 to 2013, a sharp increase in CVC prevalence was seen, in both incident and prevalent dialysis patients. This activity, mostly due to CVC management, is almost completely carried by nephrologists.

DISCUSSION

The variability in CVC utilization among centers suggests the lack of a shared policy in patients and access coupling. Quantitative criteria should be used to reduce inappropriate strategy in vascular access creation. Since this activity in Italy is organized at a local level without a shared organizational model, we should inquire whether a system managed so well in the past should now be rebuilt on the model of organ transplantation.

Future research directions to improve fistula maturation and reduce access failure

With the increasing prevalence of end-stage renal disease, there is a growing need for hemodialysis. Arteriovenous fistulae (AVF) are the preferred type of vascular access for hemodialysis, but maturation and failure continue to present significant barriers to successful fistula use. AVF maturation integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes in the setting of uremia, systemic inflammation, oxidative stress, and pre-existent vascular pathology. AVF can fail due to both failure to mature adequately to support hemodialysis and development of neointimal hyperplasia that narrows the AVF lumen, typically near the fistula anastomosis. Failure due to neointimal hyperplasia involves vascular cell activation and migration and extracellular matrix remodeling with complex interactions of growth factors, adhesion molecules, inflammatory mediators, and chemokines, all of which result in maladaptive remodeling. Different strategies have been proposed to prevent and treat AVF failure based on current understanding of the modes and pathology of access failure; these approaches range from appropriate patient selection and use of alternative surgical strategies for fistula creation, to the use of novel interventional techniques or drugs to treat failing fistulae. Effective treatments to prevent or treat AVF failure require a multidisciplinary approach involving nephrologists, vascular surgeons, and interventional radiologists, careful patient selection, and the use of tailored systemic or localized interventions to improve patient-specific outcomes. This review provides contemporary information on the underlying mechanisms of AVF maturation and failure and discusses the broad spectrum of options that can be tailored for specific therapy.

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.

Arteriovenous fistula in dialysis patients: Factors implicated in early and late AVF maturation failure

Increasing numbers of patients are being diagnosed with end-stage renal disease (ESRD), and the demand for on haemodialysis (HD) is rising. Arteriovenous fistulae (AVFs) remain the best conduit for adequate HD, with fewer complications associated with long-term use compared to bypass grafts and central venous catheters. However, it is known that many newly formed fistulae do not mature to provide useful HD access. The paper provides a narrative overview of factors influencing the process of AVF maturation failure.