No consensus on physicians' preferences on vascular access management after kidney transplantation: Results of a multi-national survey

Brachial artery aneurysm as a late complication of arteriovenous fistula

INTRODUCTION

Brachial artery aneurysm (BAA) is a rare late complication of arteriovenous fistula (AVF). It brings the risk of peripheral embolism and hand ischemia and is defined by brachial artery diameter above 10 mm or by regional dilatation by >50%. BAA is described in the literature in closed radiocephalic arteriovenous fistulas after kidney transplantation. The aim of the study was to analyze the prevalence of BAA and of their more dangerous forms.

METHOD

A observational one center study performed on patients after kidney transplantation with AVF or arteriovenous graft (AVG). We invited all patients followed up for kidney transplantation in our center. Arterial diameter greater than 10 mm was considered as a brachial artery aneurysm to simplify the detection and evaluation of aneurysms.

RESULTS

About 162 patients with AVF after kidney transplantation were examined between 4/2018 and 4/2020. Brachial artery aneurysm was detected in 34 patients (21%) with AVF or AVG, of them 7 had confirmed wall thrombi. AVF flow volume of more than 1500 ml/min increased the risk of BAA development by 4.54x. Eight aneurysms were treated surgically. After this surgery, the primary patency was 87.5% in 12 months.

CONCLUSION

Brachial artery aneurysm was relatively frequent in our study compare to the literature. Aneurysm or dilatation of the brachial artery is more frequent in functional AVFs. Surgical correction is necessary in cases of complicated aneurysms to prevent distal embolization.

Cardiac implications of upper-arm arteriovenous fistulas: A case series

BACKGROUND

Cardiovascular disease is a major cause of morbidity and mortality in patients with end-stage kidney disease. Arterio-venous fistulas (AVF), the gold standard for hemodialysis vascular access, are known to alter cardiac morphology and circulatory hemodynamics. We present a prospective case series of patients after creation of an AVF, explore the timeline for changes in their cardiac morphology, and detail considerations for clinicians.

METHODS

Patients were recruited in 2010 at multiple centers immediately prior to the creation of an upper-arm AVF and the initiation of hemodialysis. Cardiovascular magnetic resonance images were taken at intake before the creation of the AVF, 6-month follow-up, and 12-month follow-up. Image segmentation was used to measure left ventricular volume and mass, left atrial volume, and ejection fraction.

RESULTS

Eight patients met eligibility criteria. All eight patients had a net increase in left ventricular mass over enrollment, with a mean increase of 9.16 g (+2.96 to +42.66 g). Five participants had a net decrease in ejection fraction, with a mean change in ejection fraction of -5.4% (-21% to +5%). Upon visual inspection the patients with the largest ejection fraction decrease had noticeably hypertrophic and dilated ventricles. Left atrial volume change was varied, decreasing in five participants, while increasing in three participants. Changes in morphology were present at 6-month follow-up, even in patients who did not maintain AVF patency for the entirety of the 6-month period.

CONCLUSION

All patients included in this prospective case series had increases in left ventricular mass, with variability in the effects on the ejection fraction and left atrial volume. As left ventricular mass is an independent predictor of morbidity and mortality, further research to determine appropriate vascular access management in both end-stage kidney disease and kidney transplant populations is warranted.

A national cohort study on hemodialysis arteriovenous fistulas after kidney transplantation - long-term patency, use and complications

OBJECTIVE

To describe the long-term hemodialysis arteriovenous fistula (AVF) patency, incidence of AVF use, incidence and nature of AVF complications and surgery in patients after kidney transplantation.

PATIENTS AND METHODS

We retrospectively analysed the AVF outcome and complications in all adult kidney allograft recipients transplanted between January 1st, 2000 and December 31, 2015 with a functional AVF at the time of transplantation. Follow-up was until December 31, 2019.

RESULTS

We included 626 patients. Median AVF follow-up was 4.9 years. One month after kidney transplantation estimated AVF patency rate was 90%, at 1 year it was 82%, at 3 years it was 70% and at 5 years it was 61%; median estimated AVF patency was 7.9 years. The main cause of AVF failure was spontaneous thrombosis occurring in 76% of AVF failure cases, whereas 24% of AVFs were ligated or extirpated. In a Cox multivariate model female sex and grafts were independently associated with more frequent AVF thrombosis. AVF was used in about one third of our patients. AVF-related complications occurred in 29% of patients and included: growing aneurysms, complicated thrombosis, high-flow AVF, signs of distal hypoperfusion, venous hypertension, trauma of the AVF arm, or pain in the AVF/arm.

CONCLUSIONS

AVFs remain functional after kidney transplantation in the majority of patients and are often re-used after graft failure. AVF-related complications are common and require proper care.

The impact of location and patency of the arteriovenous fistula on quality of life of kidney transplant recipients

Background

Arteriovenous fistulae (AVFs) may remain patent after kidney transplantation (KTx), contributing to maladaptive cardiac remodeling. The flow in AVFs is associated with the diameter of its vessels and thus with the AVF location. The main objective of this study is to assess the influence of AVF location and its patency on the self-reported quality of life (QOL) of kidney transplant recipients (KTRs) with past history of hemodialysis.

Methods

To gain clinical data, during a scheduled visit, 353 KTRs were asked to fill out an anonymous questionnaire. From this group, 284 respondents were found eligible for analysis. The outcome was defined as prevalence of symptoms and health status, measured with the Left Ventricular Dysfunction-36 (LVD-36) Questionnaire in symptomatic patients.

Results

The hemodialysis patients (n = 243) were divided into two groups according to AVF location, i.e., DAVF – distally located AVF – (n = 174) and PAVF – proximally located AVF – (n = 69). The proportion of patients with heart failure (HF) was higher in PAVF group (24% vs. 12%, p = 0.0482). In the multivariable regression, PAVF, serum creatinine levels, and the presence of HF or coronary artery disease (CAD) remained independent predictors of lower functional capacity. Among patients with heart disease, the presence of active AVF was independently associated with worse functional outcome (higher LVD-36 scores).

Conclusions

The influence of persistent PAVF in KTRs seems to be unfavorable, especially when coexisting with CAD or HF. Abbreviations: AVF arteriovenous fistula; BMI body mass index; CAD coronary artery disease; D-AVF distally-located arteriovenous fistula; EC exercise capacity; HD hemodialysis; HF heart failure; KTx kidney transplantation; KTR kidney transplant recipient; LVD-36 Left Ventricle Disfunction – 36; LVEF left ventricle ejection fraction; LVH left ventricle hypertrophy; NYHA New York Heart Association; P-AVF proximally located arteriovenous fistula; PD peritoneal dialysis; PRO patient-reported outcomes; QOL quality of life.

Long-Term Impact of Arteriovenous Fistula Ligation on Cardiac Structure and Function in Kidney Transplant Recipients: A 5-Year Follow-Up Observational Cohort Study

Background

The long-term effects of arteriovenous fistula (AVF) ligation on cardiovascular structure following kidney transplantation remain uncertain. A prospective randomized, controlled trial (RCT) examined the effect of AVF ligation at 6 months on cardiovascular magnetic resonance imaging (CMR)-derived parameters in 27 kidney transplant recipients compared with 27 controls. A mean decrease in left ventricular mass (LVM) of 22.1 g (95% CI, 15.0 to 29.1) was observed compared with an increase of 1.2 g (95% CI, -4.8 to 7.2) in the control group (P<0.001). We conducted a long-term follow-up observational cohort study in the treated cohort to determine the evolution of CMR-derived parameters compared with those documented at 6 months post-AVF ligation.

Methods

We performed CMR at long-term follow-up in the AVF ligation observational cohort from our original RCT published in 2019. Results were compared with CMR at 6 months postintervention. The coprimary end point was the change in CMR-derived LVM and LVM index at long-term follow-up from imaging at 6 months postindex procedure.

Results

At a median of 5.1 years (interquartile range, 4.7-5.5 years), 17 patients in the AVF ligation group were studied with repeat CMR with a median duration to follow-up imaging of 5.1 years (IQR, 4.7-5.5 years). Statistically significant further reductions in LVM (-17.6±23.0 g, P=0.006) and LVM index (-10.0±13.0 g/m², P=0.006) were documented.

Conclusions

The benefit of AVF ligation on LVM and LVM index regression appears to persist long term. This has the potential to lead to a significant reduction in cardiovascular mortality.

Reduction of arteriovenous access blood flow leads to biventricular unloading in haemodialysis patients

AIMS

Patients on chronic haemodialysis have a wide range of changes in cardiac function and structure, including left ventricular hypertrophy, dilation and diastolic dysfunction or pulmonary hypertension. All these changes were linked to increased mortality in previous studies. High-flow arteriovenous fistulas (AVF) are supposed to be a factor contributing to their development. This study investigated the early effect of surgical AVF blood flow (Qa) reduction on these changes in patients with or without heart failure changes.

METHODS AND RESULTS

Forty-two patients in chronic haemodialysis programme with high-flow AVF (Qa over 1500 mL/min), indicated for surgery for ≥1 of the following indications: 1.manifest heart failure; 2.hand ischemia; 3.advanced structural heart changes detected by echocardiography. The patients underwent echocardiography on selection visit, before blood flow reducing surgery and six weeks thereafter. The Qa reduction led to decrease of left ventricular mass (p = 0.02), end-diastolic volume (p = 0.008), end-diastolic diameter (p = 0.003) and left atrial volume (p = 0.0006). Diastolic function improved. Similarly, right ventricular diameter and right atrial volume decreased (p = 0.000001 and 0.00009, respectively) together with the decrease of estimated pulmonary artery systolic pressure. 81% of patients suffered from pulmonary hypertension prior to surgery, only 36% thereafter.

CONCLUSION

The surgical restriction of the hyperkinetic circulation leads to several improvements of heart structure and function, which was linked to higher mortality in other studies. The beneficial effect of Qa reduction is present even in patients without symptoms of heart failure. The contribution of AVF must be considered with structural or functional heart changes.

Vascular Access Perspectives in Patients After Kidney Transplantation

Introduction: More attention has been paid to the influence of arteriovenous fistula (AVF) on the cardiovascular system. In renal transplant recipients, some beneficial effect of an elective vascular access (VA) ligation was observed in patients with a high AVF flow. However, this strategy is not widely accepted and is in contradiction to the rule of vasculature preservation for possible future access. The aim of our study is to elucidate the vascular access function and VA perspective in the kidney transplantation (KTx) population.

Materials and Methods: KTx patients with a stable graft function were recruited to participate in this single center observational study (NCT04478968). The measurement of VA flow and vessel mapping for future vascular access was performed by a color Doppler ultrasound. The study group included 99 (63%) males and 58 (37%) females; the median age was 57 (IQR 48–64) years. The median time from the transplantation to the baseline visit was 94 (IQR 61–149) months. Median serum creatinine concentration was 1.36 (IQR 1.13–1.67) mg/dl.

Results: Functioning VA was found in 83 out of 157 (52.9%) patients. The sites were as follows: snuffbox in six (7.2%), wrist in 41 (49.4%), distal forearm in 18 (21.7%), middle or proximal forearm in eight (9.6%), upper-arm AV graft in one (1.2%), and upper-arm AVFs in nine (10.8%) patients, respectively. Blood flow ranged from 248 to 7,830 ml/min; the median was 1,134 ml/min. From the transplantation to the study visit, 66 (44.6%) patients experienced access loss. Spontaneous thrombosis was the most common, and it occurred in 60 (90.9%) patients. The surgical closure of VA was performed only in six (4%) patients of the study group with a functioning VA at the time of transplantation. Access loss occurred within the 1st year after KTx in 33 (50%) patients. Majority (50 out of 83, 60.2%) of the patients with an active VA had options to create a snuffbox or wrist AVF on the contralateral extremity. In a group of 74 patients without a functioning VA, the creation of a snuffbox or wrist AVF on the non-dominant and dominant extremity was possible in seven (9.2%) and 40 (52.6%) patients, respectively. In 10 (13.1%) patients, the possibilities were limited only to the upper-arm or proximal forearm VA on both sides. Access ligation was considered by 15 out of 83 (18.1%) patients with a patent VA.

Conclusions: In the majority of the patients, vascular access blood flow was below the threshold of the negative cardiovascular effect of vascular access. Creation of a distal AVF is a protective measure to avoid a high flow and preserve the vessels for future access. The approach to VA should be individualized and adjusted to the patient's profile.

Elective Resection of Symptomatic Arteriovenous Fistulae and Grafts in Patients with Functioning Renal Allografts at A High Volume Transplant Hospital

OBJECTIVE

Patients with functioning renal allografts may need ligation of pre-existing hemodialysis conduits. Chronic immunosuppression for renal allografts may adversely affect wound healing and perioperative complications following these procedures. We sought to analyze outcomes following elective ligation and resection of symptomatic arteriovenous (AV) access in immunosuppressed patients with renal allografts no longer requiring dialysis at a high-volume renal transplant hospital.

METHODS

We retrospectively reviewed procedure codes for hemodialysis access resection and revision from 2014-2020 at a single academic tertiary care hospital. Patients who underwent complete or subtotal dialysis access resection with a functioning renal allograft were included for analysis of preoperative, operative, and postoperative outcomes. We performed descriptive statistics, and student's t-test using Microsoft Excel.

RESULTS

Thirty-four patients met inclusion criteria. The majority were male, 56%, and the most common causes of renal failure were hypertension and diabetes, respectively. Ligation and resection of proximal upper extremity access was performed in 68%. The mean operative time was 126 minutes with pain being the most common indication for intervention. Four patients required arterial reconstruction. Mean postoperative follow-up was 13 months. Arm pain and swelling resolved in 100% and 88% of patients following AV access resection, respectively. No impairment in mean postoperative glomerular filtration rates were noted. One patient required hemodialysis and died three months after fistula resection following complications from treatment of a newly diagnosed neuroendocrine tumor and subsequent fungemia, CONCLUSION: Elective operative resection of symptomatic AV access may be performed safely in immunosuppressed patients with functioning renal transplants. The risk of allograft impairment and/or failure as a result of AV access resection in our series was low. Elective ligation and resection can be achieved with low mortality, excellent symptomatic relief, and few wound complications despite chronic immunosuppression.

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

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

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.

The attitude of kidney transplant recipients towards elective arteriovenous fistula ligation

Background

Arteriovenous fistulas (AVF) are a source of various complications. Among previously hemodialyzed kidney transplant recipients (KTxR), the AVF may persist over time. The patients’ decisions whether to ligate the functioning AVF may be prompted by many factors. Our knowledge of benefits concerning the procedure as well as patients' attitude towards it is scarce.

Aim

Evaluation of the patients’ opinion on the persistent AVF ligation after a successful kidney transplantation.

Materials and methods

An anonymous survey was carried out among 301 previously hemodialyzed KTxR. The patients were recruited during scheduled visits in the Transplantation Outpatient Unit. All subjects completed an anonymous questionnaire including questions about their attitude towards the matter in question.

Results

69 patients (22.9%) have considered AVF closure. The most common causes for such attitude were esthetic reasons (n = 29) and concerns about heart health (n = 13). Among those 69 subjects, 18 have presented with symptomatic AVF due to multiple symptoms. Symptomatic AVFs were localized on the forearm in 14 out of 18 cases. As many as 116 (38.5%) cases have never wanted to ligate the AVF and 116 (38.5%) subjects did not have a clear opinion. In our study we report 158 (52.5%) cases of non-functioning AVFs. The main reason for the above was spontaneous AVF thrombosis (121 cases). Only 24 subjects reported to rely on the physician-provided information about the AVF management.

Conclusions

One fourth of KTRs have ever considered AVF ligation. There is a distinct need for educating patients on the possibilities of post-transplantation AVF management.

Creating arteriovenous fistulas for children in Guatemala

OBJECTIVE

The Guatemalan Foundation for Children with Kidney Diseases was established in 2003 as the first and only comprehensive pediatric nephrology program and hemodialysis unit in Guatemala. Bridge of Life (BOL) is a not-for-profit charitable organization focused on chronic kidney disease and supplied equipment, training and support during formation of the hemodialysis unit. Pediatric permanent vascular access (VA) expertise had not been established and noncuffed dialysis catheters provided almost all VA, many through subclavian vein access sites. BOL assistance was requested for establishing a VA surgical program, resulting in recurring BOL surgical missions to create arteriovenous fistulas (AVF) in these children. This study analyzes the BOL pediatric VA missions to Guatemala.

METHODS

Three surgical pediatric VA missions were conducted in Guatemala from 2015 to 2017. Each mission was led by two or three surgeons. All supplies and equipment (including ultrasound units) were taken as part of each mission. The BOL surgical VA mission teams work with local pediatric surgeons, pediatric nephrologists, and dialysis nurses to establish collegial relationships and foster teaching interactions. We retrospectively reviewed the patient demographic data, procedures, and outcomes for these missions.

RESULTS

AVFs were created in 54 new pediatric patients. Ages were 8 to 19 years (13.4 ± 2.8 years) and 29 patients (54%) were male. Patient weights were 28 to 50 kg (30.8 ± 8.3 kg) with body mass indexes of 12 to 25 kg/m² (17.9 ± 2.9 kg/m²). Radiocephalic AVFs were created in 21 children (39%), proximal radial artery AVFs in 12 (22%). and brachial artery inflow AVFs in 5 (9%). Sixteen patients (30%) required transpositions and one a translocation; two of these were femoral procedures. Primary and cumulative patency rates were 83% and 85% at 12 months and 62% and 85% at 36 months, respectively. The median follow-up was 17 months. Interventions with fistulagram and balloon angioplasty options were not available for AVF dysfunction or access salvage during the study period. However, six patients underwent an AVF revision and salvage during subsequent missions or by one of the Guatemalan surgeons (R.S.). Four individuals underwent successful transplantation during the study period. There were no operative deaths or major complications.

CONCLUSIONS

Pediatric VA missions to Guatemala created safe and functional AVFs in concert with local pediatric surgeons and pediatric nephrologists. Three surgical missions included access operations in 54 new patients. Cumulative AVF patency was 85% at 36 months.