Effect of high flow arteriovenous fistula on cardiac function in hemodialysis patients

Posttraumatic Renal Artery-Inferior Vena Cava Fistula-Induced High-Output Cardiac Failure: A Case Study

High-output cardiac failure is a less prevalent form of heart failure. Most patients with heart failure are typically categorized as having either systolic or diastolic dysfunction with elevated systemic vascular resistance. Individuals with high-output cardiac failure exhibit normal cardiac function and decreased systemic vascular resistance. This reduction may stem from diffuse arteriolar dilation or potential bypass of arterioles and capillary beds, prompting the activation of neurohormones. This case report details the diagnosis and treatment of an unusual etiology of high-output cardiac failure involving an arteriovenous fistula connecting the renal artery to the inferior vena cava and right common iliac vessels, resulting in a left-to-right shunt in a 50-year-old male patient. The report explores the etiology, pathophysiology, and clinical presentation of high-output heart failure, emphasizing the crucial role of radiology in interprofessional teams.

Improving the Quality of Life of a Kidney Transplant Patient With Limb Edema: Amplatzer Vascular Plug Embolization of an Arteriovenous Fistula

An arteriovenous fistula is the preferred vascular access option for hemodialysis patients. However, complications, such as high-output heart failure and upper limb edema due to central vein stenosis, may arise.  We describe a case of a 65-year-old kidney transplant patient with severe edema in the left arm due to central vein stenosis and ipsilateral umerocephalic arteriovenous fistula. He was a previous hemodialysis patient and received his kidney transplant in 2015. This patient had an eight-month waiting list to undergo surgical ligation of the arteriovenous fistula. Since his quality of life was decaying, we decided to perform a peripheral vascular embolization with Amplatzer® vascular plugs (Abbott, Green Oaks, IL). After a two-month follow-up, the arm edema was significantly reduced, and no immediate complications were reported. This case highlights that the Amplatzer® vascular plug is a safe and effective alternative for arteriovenous fistula embolization in patients with arm edema due to central vein stenosis.

Ruminant model for hemodialysis cannulation

BACKGROUND

Preventative strategies that minimize hemodialysis access complications remain limited.

OBJECTIVE

This study aimed to address this gap by developing a Caprine cannulation model to investigate the impact of repeated cannulations on vascular access patency rates.

RESEARCH DESIGN AND MEASURES

In this pilot study, a meta-analysis was conducted using experimental control data from four trials to explore the impact of Caprine breed (independent variable) on the dependent variables that affect hemodialysis cannulation, including AVF growth, AVF depth, and flow rate.

SUBJECTS

Arteriovenous Fistulas (AVFs) were created using the carotid artery and jugular vein in the necks of seven goats from the French alpine, dwarf, and pygmy breeds. All seven AVFs exhibited vessel remodeling patterns similar to that observed in humans and remained patent, enabling hemodialysis access over the 6 month study.

RESULTS

Over the course of 18 weeks, a total of 291 cannulations were completed using standard 15 g dialysis needles without complications demonstrating the feasibility of using the Caprine species as a cannulation model. The ease of access coupled with the animals' cooperative behavior further contributes to the suitability of the Caprine species for hemodialysis investigations. Notably, no infections or clinically significant incidents were observed throughout the study.

CONCLUSIONS

The stability of AVF patency and flow underscores the viability and potential of the Caprine species animal model as a valuable research platform for exploring interventions aimed at improving vascular access survival in hemodialysis patients.

Arteriovenous Access for Hemodialysis: A Review

Importance

Hemodialysis requires reliable vascular access to the patient's blood circulation, such as an arteriovenous access in the form of an autogenous arteriovenous fistula or nonautogenous arteriovenous graft. This Review addresses key issues associated with the construction and maintenance of hemodialysis arteriovenous access.

Observations

All patients with kidney failure should have an individualized strategy (known as Patient Life-Plan, Access Needs, or PLAN) for kidney replacement therapy and dialysis access, including contingency plans for access failure. Patients should be referred for hemodialysis access when their estimated glomerular filtration rate progressively decreases to 15 to 20 mL/min, or when their peritoneal dialysis, kidney transplant, or current vascular access is failing. Patients with chronic kidney disease should limit or avoid vascular procedures that may complicate future arteriovenous access, such as antecubital venipuncture or peripheral insertion of central catheters. Autogenous arteriovenous fistulas require 3 to 6 months to mature, whereas standard arteriovenous grafts can be used 2 to 4 weeks after being established, and "early-cannulation" grafts can be used within 24 to 72 hours of creation. The prime pathologic lesion of flow-related complications of arteriovenous access is intimal hyperplasia within the arteriovenous access that can lead to stenosis, maturation failure (33%-62% at 6 months), or poor patency (60%-63% at 2 years) and suboptimal dialysis. Nonflow complications such as access-related hand ischemia ("steal syndrome"; 1%-8% of patients) and arteriovenous access infection require timely identification and treatment. An arteriovenous access at high risk of hemorrhaging is a surgical emergency.

Conclusions and Relevance

The selection, creation, and maintenance of arteriovenous access for hemodialysis vascular access is critical for patients with kidney failure. Generalist clinicians play an important role in protecting current and future arteriovenous access; identifying arteriovenous access complications such as infection, steal syndrome, and high-output cardiac failure; and making timely referrals to facilitate arteriovenous access creation and treatment of arteriovenous access complications.

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.

Systemic vascular resistance predicts high-output cardiac failure in patients with high-flow arteriovenous fistula

AIMS

Patients with high-flow arteriovenous (AV) access are at risk of developing high-output cardiac failure (HOCF) and subsequent hospitalization. However, diagnosing HOCF is challenging and often requires invasive procedures. The role of systemic vascular resistance (SVR) in diagnosing HOCF is underestimated, and its predictive value is limited. Our study aims to identify non-invasive risk factors for HOCF to facilitate early diagnosis and timely surgical interventions.

METHODS AND RESULTS

We included 109 patients with high-flow AV access who underwent serial echocardiography. The retrospective cohort was divided into two groups based on their hospitalization due to HOCF. The two groups were matched for age and gender. After a mean follow-up of 25.1 months, 19 patients (17.4%) were hospitalized due to HOCF. The two groups had similar baseline characteristics. However, the HOCF group had a higher value of vascular access blood flow (Qa) (2168 ± 856 vs. 1828 ± 617 mL/min; P = 0.045). Echocardiographic analysis revealed that the HOCF group had more pronounced left ventricular diastolic dysfunction (E/e': 21.1 ± 7.3 vs. 16.2 ± 5.9; P = 0.002), more severe pulmonary hypertension (right ventricular systolic pressure: 41.4 ± 16.7 vs. 32.2 ± 12.8; P = 0.009), a higher Doppler-derived cardiac index (CI) (4.3 ± 0.8 vs. 3.7 ± 1.1; P = 0.031), and a lower Doppler-derived estimated SVR (eSVR) value (5.5 ± 0.3 vs. 6.9 ± 0.2; P = 0.002) than the non-HOCF group. Using multivariable Cox regression analysis, a low eSVR value (<6) emerged as an independent predictor of HOCF hospitalization with a hazard ratio of 9.084 (95% confidence interval, 2.33-35.39; P = 0.001). Receiver operating characteristic curve analysis indicated that CI/eSVR values more accurately predicted HOCF hospitalization [sensitivity: 94.7%, specificity: 51.0%, area under the curve (AUC): 0.75, P < 0.001] than the Qa/cardiac output ratio (AUC: 0.50, P = 0.955), Qa values ≥ 2000 mL/min (AUC: 0.60, P = 0.181), and Qa values indexed for height in metres (AUC: 0.65, P = 0.040).

CONCLUSIONS

In patients with high-flow AV access, low eSVR values obtained through non-invasive Doppler echocardiography were associated with a high rate of HOCF hospitalizations. Therefore, routine eSVR screening in these patients might expedite the diagnosis of HOCF.

Impact of arteriovenous fistula on flow states in the evaluation of aortic stenosis among ESKD patients on dialysis

INTRODUCTION

An arteriovenous fistula (AVF) in patients with end-stage kidney disease (ESKD) can influence flow states. We sought to evaluate if assessment of aortic stenosis (AS) by transthoracic echocardiographic (TTE) differs in the presence of AVF compared to other dialysis accesses in patients on dialysis.

METHODS

We identified consecutive ESKD patients on dialysis and concomitant AS from a single center between January 2000 and March 2021. We analyzed TTE parameters of AS severity (velocities, gradients, aortic valve area [AVA]) and hemodynamics (cardiac output [CO], valvuloarterial impedance [Zva]) and compared AS parameters in patients with AVF versus other dialysis access.

RESULTS

The cohort included 94 patients with co-prevalent ESKD and AS; mean age 66 years, 71% male; 43% Black, 24% severe AS. Dialysis access: 53% AVF, 47% others. In the overall cohort, no significant differences were noted between AVF versus non-AVF in AVA/CO/Zva, but with notable subgroup differences. In mild AS, CO was significantly higher in AVF versus non-AVF (6.3 vs. 5.2 L/min; p = .04). In severe AS, Zva was higher in the AVF versus non-AVF (4.6 vs. 3.6 mm Hg/mL/m2 ). With increasing AS severity in the AVF group, CO decreased, coupled with increase in Zva, likely counterbalancing the net hemodynamic impact of the AVF.

CONCLUSION

Among ESKD patients with AS, TTE parameters of flow states and AS severity differed in those with AVF versus other dialysis accesses and varied with progression in severity of AS. Future longitudinal assessment of hemodynamic parameters in a larger cohort of co-prevalent ESRD and AS would be valuable.

Hemodialysis Access: US for Preprocedural Mapping and Evaluation of Maturity and Access Dysfunction

Patients with kidney failure require kidney replacement therapy. While renal transplantation remains the treatment of choice for kidney failure, renal replacement therapy with hemodialysis may be required owing to the limited availability and length of time patients may wait for allografts or for patients ineligible for transplant owing to advanced age or comorbidities. The ideal hemodialysis access should provide complication-free dialysis by creating a direct connection between an artery and vein with adequate blood flow that can be reliably and easily accessed percutaneously several times a week. Surgical arteriovenous fistulas and grafts are commonly created for hemodialysis access, with newer techniques that involve the use of minimally invasive endovascular approaches. The emphasis on proactive planning for the placement, protection, and preservation of the next vascular access before the current one fails has increased the use of US for preoperative mapping and monitoring of complications for potential interventions. Preoperative US of the extremity vasculature helps assess anatomic suitability before vascular access creation, increasing the rates of successful maturation. A US mapping protocol ensures reliable measurements and clear communication of anatomic variants that may alter surgical planning. Postoperative imaging helps assess fistula maturation before cannulation for dialysis and evaluates for early and late complications associated with arteriovenous access. Clinical and US findings can suggest developing stenosis that may progress to thrombosis and loss of access function, which can be treated with percutaneous vascular interventions to preserve access patency. Vascular access steal, aneurysms and pseudoaneurysms, and fluid collections are other complications amenable to US evaluation. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

High-flow arteriovenous fistula in X-linked Alport syndrome: a case report

Most male X-linked Alport syndrome patients with COL4A5 nonsense mutations experience end-stage kidney failure by 30 years old. Although there is no definition of high-flow arteriovenous fistula, access blood flows greater than 2000 mL/min might predict the occurrence of high-output heart failure. A 50-year-old Japanese man had suffered from proteinuria at 4 years old and sensorineural hearing loss and a lenticular lens at 20 years old. He had started to receive hemodialysis treatment due to end-stage kidney disease at 22 years old. A genetic test confirmed a novel hemizygous nonsense variant COL4A5 c.2980G > T (p.Gly994Ter), and he was diagnosed with X-linked Alport syndrome. COL4A5 c.2980G > T was considered "pathogenic" according to the American College of Medical Genetics and Genomics guidelines and in vitro experiments. Shortness of breath on exertion was exaggerated, his brachial artery blood flow was over 4,236-4,353 mL/min, his cardiac output was 5,874 mL/min, and he needed radial artery banding at 51 years old. After radial artery banding surgery, the brachial artery blood flow decreased to 987-1,236 mL/min, and echocardiography showed a cardiac output at 5100 mL/min with improved E' and E/E'. His shortness of breath on exertion improved gradually. Although rare, high-output heart failure due to high-flow arteriovenous fistula should be kept in mind as a complication in X-linked Alport syndrome patients, and our patient was successfully treated with radial artery banding surgery.

Novel external stenting for reconstruction of high flow arteriovenous fistula

BACKGROUND

High-flow arteriovenous fistulae (HF-AVF) may lead to adverse cardiac remodeling in hemodialysis patients. We have investigated whether a novel external stent is safe and effective in reducing and stabilizing flow rates during a 1-year follow-up after HF-AVF reconstruction.

METHODS

All patients with HF-AVF (access flow rate ⩾ 1500 ml/min), who underwent HF-AVF reconstruction with external stenting in two centers between June 2018 and May 2020, were included in this retrospective analysis. During HF-AVF reconstruction, the dilated vein segment was resected, underwent volume reduction, and was externally stabilized using a braided cobalt-chromium external stent. AVF flow rates were assessed preoperatively, intraoperatively, and at follow up visits using duplex ultrasound.

RESULTS

Forty-three HF-AVFs in 42 patients were reconstructed and supported with an external stent (mean age 49 years, range 20-86 years; 74% men). Fifty-one percent were forearm AVFs, 49% were upper arm. The mean preoperative flow rate was 2622 ± 893 ml/min (range: 1500-6000 ml/min) and was decreased to 710 ± 221 ml/min (range: 300-1300 ml/min) intra-operatively after HF-AVF reconstruction. At 6 and 12-months follow-up, the mean flow rates were 1132 ± 320 ml/min (range: 470-1700 ml/min) and 1453 ± 888 ml/min (range: 300-3800 ml/min), respectively. Recurrence of high flow (>1500 ml/min) occurred in 16% and 25% of the patients at 6 and 12 months and primary patency rates were 86% and 70%, respectively.

CONCLUSIONS

This early experience with novel external stenting for HF-AVF reconstruction demonstrates that it is a safe and effective method for reducing and stabilizing flow rates up to 1-year post procedure. Additional studies are required to evaluate the durability of this procedure over the longer term and assess its effect on cardiac remodeling.

Clinical and Haemodynamic Effects of Arteriovenous Shunts in Patients with Heart Failure with Preserved Ejection Fraction

The arteriovenous shunt (AVS) is the most commonly used vascular access in patients receiving regular haemodialysis. The AVS may have a significant haemodynamic impact on patients with heart failure. Many studies have sought to understand the effect of AVS creation or closure on heart structure and functions, most of which use non-invasive methods, such as echocardiography or cardiac MRI. Data are mainly focused on heart failure with reduced ejection fraction and there are limited data on heart failure with preserved ejection fraction. The presence of an AVS has a significant haemodynamic impact on the cardiovascular system and it is a common cause of high-output cardiac failure. Given that most studies to date use non-invasive methods, invasive assessment of the haemodynamic effects of the AVS using a right heart catheter may provide additional valuable information.

Distribution of Flow in an Arteriovenous Fistula Using Reduced-Order Models

The creation of a communication between an artery and a vein (arteriovenous fistula or AVF), to speed up the blood purification during hemodialysis of patients with renal insufficiency, induces significant rheological and mechanical modifications of the vascular network. In this study, we investigated the impact of the creation of an AVF with a zero-dimensional network model of the vascular system of an upper limb and a one-dimensional model around the anastomosis. We compared the simulated distribution of flow rate in this vascular system with Doppler ultrasound measurements. We studied three configurations: before the creation of the AVF, after the creation of the AVF, and after a focal reduction due to a hyper flow rate. The zero-dimensional model predicted the bounds of the diameter of the superficial vein that respects the flow constraints, assuming a high capillary resistance. We indeed highlighted the importance of knowing the capillary resistance as it is a decisive parameter in the models. We also found that the model reproduced the Doppler measurements of flow rate in every configuration and predicted the distribution of flow in cases where the Doppler was not available. The one-dimensional model allowed studying the impact of a venous constriction on the flow distribution, and the capillary resistance was still a crucial parameter.

An indolent cause of high-output heart failure in end-stage kidney disease-Application of the Nicoladoni-Israel-Branham test: A case report

BACKGROUND

A hemodynamically significant arteriovenous fistula (AVF) in end-stage kidney disease (ESKD) causes a high flow state, resulting in pathologic cardiovascular remodeling, and deserves timely clinical recognition.

CASE

A 55-year-old woman with history of ESKD with deceased donor kidney transplant with failing graft function and baseline creatinine of 2.8 mg/dl presented to the clinic with nocturnal cough, orthopnea, dyspnea on exertion and pedal edema. Physical exam was notable for large, aneurysmal right brachial AVF. Transthoracic echocardiography (TTE) revealed left ventricular (LV) enlargement and hypertrophy and elevated cardiac output (CO) of 10 L/min, raising a clinical concern for high-output heart failure.

DECISION MAKING

A non-invasive assessment of the hemodynamic significance of the AVF was performed using a TTE. During temporary occlusion of the AVF, it was determined that about 27% of the resting CO was attributed to the AVF, suggesting hemodynamic significance. Nicoladoni-Israel-Branham sign was negative as there was no change in patient's heart rate, but this was potentially attributed to beta-blockade and chronic loading conditions. She underwent AVF banding and 2-month later her presenting symptoms resolved, and a TTE showed a decrease in resting CO of 7.6 L/min with normalization of LV size.

CONCLUSION

This case highlights several teaching points. Firstly, in patients with ESKD, a large AVF can contribute to a high CO state resulting in maladaptive cardiovascular remodeling. Secondly, TTE evaluation of the hemodynamic contribution of an AVF can be performed with the application of the Nicoladoni-Israel-Branham sign. Finally, some experts recommend pre-emptive banding or ligation of AVF after successful kidney transplantation as this has been shown to have symptomatic and cardiovascular benefits.

Arteriovenous Fistula-induced Cardiac Remodeling Shows Cardioprotective Features in Mice

Objective

Arteriovenous fistulae (AVF) placed for hemodialysis have high flow rates that can stimulate left ventricular (LV) hypertrophy. LV hypertrophy generally portends poor cardiac outcomes, yet clinical studies point to superior cardiac-specific outcomes for patients with AVF when compared with other dialysis modalities. We hypothesize that AVF induce physiologic cardiac hypertrophy with cardioprotective features.

Methods

We treated 9- to 11-week-old C57Bl/6 male and female mice with sham laparotomy or an aortocaval fistula via a 25G needle. Cardiac chamber size and function were assessed with serial echocardiography, and cardiac computed tomography angiography. Hearts were harvested at 5 weeks postoperatively, and the collagen content was assessed with Masson's trichrome. Bulk messenger RNA sequencing was performed from LV of sham and AVF mice at 10 days. Differentially expressed genes were analyzed using Ingenuity Pathway Analysis (Qiagen) to identify affected pathways and predict downstream biological effects.

Results

Mice with AVF had similar body weight and wet lung mass, but increased cardiac mass compared with sham-operated mice. AVF increased cardiac output while preserving LV systolic and diastolic function, as well as indices of right heart function; all four cardiac chambers were enlarged, with a slight decrement in the relative LV wall thickness. Histology showed preserved collagen density within each of the four chambers without areas of fibrosis. RNA sequencing captured 19 384 genes, of which 857 were significantly differentially expressed, including transcripts from extracellular matrix-related genes, ion channels, metabolism, and cardiac fetal genes. The top upstream regulatory molecules predicted include activation of angiogenic (Vegf, Akt1), procardiomyocyte survival (Hgf, Foxm1, Erbb2, Lin9, Areg), and inflammation-related (CSF2, Tgfb1, TNF, Ifng, Ccr2, IL6) genes, as well as the inactivation of cardiomyocyte antiproliferative factors (Cdkn1a, FoxO3, α-catenin). The predicted downstream effects include a decrease in heart damage, and increased arrhythmia, angiogenesis, and cardiogenesis. There were no significant sex-dependent differences in the AVF-stimulated cardiac adaptation.

Conclusions

AVF stimulate adaptive cardiac hypertrophy in wild-type mice without heart failure or pathologic fibrosis. Transcriptional correlates suggest AVF-induced cardiac remodeling has some cardioprotective, although also arrhythmogenic features. (JVS–Vascular Science 2021;2:110-28.)

Clinical Relevance

Arteriovenous fistulae (AVF) are commonly used as access for hemodialysis in patients with end-stage renal disease. AVF induce a high-output state that is associated with long-term structural cardiac remodeling, including left ventricle hypertrophy, but this element has uncertain clinical significance. Although left ventricle hypertrophy has traditionally been associated with an increased risk of cardiovascular disease, clinical studies have suggested that cardiac-specific outcomes of patients with end-stage renal disease were better with AVF compared with other dialysis modalities. This study uses a mouse model of AVF to study the structural, functional, and molecular correlates of AVF-induced cardiac remodeling. It finds that AVF causes an adaptive cardiac hypertrophy without functional decline or fibrosis. Transcriptional correlates suggest an electrical remodeling and the upregulation of proangiogenic, procardiogenic, and prosurvival factors, implying that AVF-induced cardiac hypertrophy is potentially cardioprotective, but also arrhythmogenic.

Can We Create an Arteriovenous Fistula for Hemodialysis through 0.5-1.0 cm Incision without Using Vascular Clamps?

Background A native arteriovenous fistula (AVF) is a gold standard for renal replacement therapy, where regular hemodialysis is the mainstay of survival in the majority of patients suffering from end-stage renal disease. Appropriate vascular clamps are routinely used to occlude an artery and a vein before an arteriotomy or a venotomy is done to prevent blood loss and have a clear field and an ease of anastomosis. The title makes one wonder, is it then possible to create an AVF without using vascular clamps? And through incisions as small as 0.5to 1.0 cm? This is made possible by a very simple new technique, presented here, that helps to occlude vessels to create an AVF through minimal access, and minimize blood loss and postoperative pain.

Material and Method  Total 622 AVFs were created between 1998 and 2019. With regular forceps or an AVF platform (design given), an AVF was created without using a vascular clamp. Total 321 cases were operated with 0.5 to 1.0 cm and 215 cases within 1.5 cm skin incision approach.

Results  There were ~85% successful functional fistulas. The blood loss was negligible, and only one in three required pain killer in postoperative period.

Conclusion  A simple new technique described here makes it possible to create a functional AVF through a small incision, without using vascular clamps.

Intradialysis hypotension and hypertension in patients with end stage kidney disease in Nigeria: risk factors and clinical correlates

Background

Many shortcomings associated with haemodialysis for instance, intradialysis blood pressure changes, often lead to inadequate dialysis dose. Measures are needed to improve on this.

Objectives

To determine the risk factors and clinical correlates of intradialysis blood pressure variations.

Methods

Maintenance haemodialysis sessions for 232 consented patients with end stage kidney disease who had 1248 sessions were studied. Data collected was from history, examination findings, serum electrolytes and hematocrit. Blood pressure reading was taken manually at rest. Statistical analysis was with SPSS 22. Chi square and t-test were used to compare proportions and means respectively while regression analysis was used to determine predictors of blood pressure changes.

Results

The mean age of participants was 49.9 ± 4.6. More participants (38.8%) had hypertension associated CKD, than chronic glomerulonephritis, (37.9%). Majority (60.7%) had internal jugular catheter. Intradialysis hypertension was commoner than intradialysis hypotension (24.4% versus 19.4%). Intradialysis hypotension was commoner in females, diabetics and with less frequent dialysis while intradialysis hypertension was commoner in males, frequent erythropoietin use. The mean dialysis dose (Kt/V) was 1.02 ± 0.4, with 0.68 ± 0.1 for intradialysis hypotension and 0.84 ± 0.2 for intradialysis hypertension.

Conclusion

Risk factors for intradialysis hypertension were males, frequent erythropoietin use while for intradialysis hypotension, were female gender and less frequent dialysis. Effective intra and inter-dialytic blood pressure control with adequate pre dialysis work up should be carried out to lessen the degree, burden and outcome of these variations.

Funding

None declared.

Translational Sciences in Cardiac Failure Secondary to Arteriovenous Fistula in Hemodialysis Patients

High-output cardiac failure is a rare form of heart failure associated with the formation of arteriovenous fistula (AVF) in hemodialysis patients. The pathophysiology underlying the HOCF is complex and multifactorial. Presence of AVF can cause long term hemodynamic changes that ultimately lead to increased cardiac output and consequently cardiac failure. A number of risk factors have been associated with the development of HOCF post-AVF construction, including male sex, a proximally located AVF and a state of volume overload. Dysregulation of tissue inhibitor of matrix metalloproteinase 4, Sirtuin-1 and Sirtuin-3 gene expression have been associated with the development of heart failure. The differences observed between genders have been attributed to altered activity of the β-adrenoceptor system. Numerous biomarkers including cardiac troponin T and I, atrial natriuretic peptide, brain natriuretic peptide among others have shown both prognostic and diagnostic potential; however further research is needed to establish their utility in clinical practice for patients with AVF associated HOCF. In recent years risk stratification models have been developed to help identify patients at the highest risk of developing HOCF post AVF which could be revolutionary in its identification and management. Potential options for managing HOCF post-AVF include AVF ligation, banding and anastoplasty however these procedures are not without their own associated risks. In this review, we discuss the pathophysiology, risk stratification and management of patients with AVF associated HOCF.

Challenges and novel therapies for vascular access in haemodialysis

Advances in standards of care have extended the life expectancy of patients with kidney failure. However, options for chronic vascular access for haemodialysis - an essential part of kidney replacement therapy - have remained unchanged for decades. The high morbidity and mortality associated with current vascular access complications highlights an unmet clinical need for novel techniques in vascular access and is driving innovation in vascular access care. The development of devices, biological approaches and novel access techniques has led to new approaches to controlling fistula geometry and manipulating the underlying cellular and molecular pathways of the vascular endothelium, and influencing fistula maturation and formation through the use of external mechanical methods. Innovations in arteriovenous graft materials range from small modifications to the graft lumen to the creation of completely novel bioengineered grafts. Steps have even been taken to create new devices for the treatment of patients with central vein stenosis. However, these emerging therapies face difficult hurdles, and truly creative approaches to vascular access need resources that include well-designed clinical trials, frequent interaction with regulators, interventionalist education and sufficient funding. In addition, the heterogeneity of patients with kidney failure suggests it is unlikely that a 'one-size-fits-all' approach for effective vascular access will be feasible in the current environment.