Effects of the creation of arteriovenous fistula for hemodialysis on cardiac function and natriuretic peptide levels in CRF

Hemodialysis access type is associated with blood pressure variability and echocardiographic changes in end-stage renal disease patients

Arteriovenous fistula (AVF) strategy has been recommended in clinical guidelines for a long time due to the survival benefits associated with it. However, the underlying mechanism still needs to be explored. This retrospective cohort study included 611 patients who received hemodialysis in West China Hospital Medical Center between January 1, 2014 and December 31, 2014. Patient characteristics, dialysis parameters, and 1-year blood pressure records were collected at baseline. Echocardiographic changes and clinical outcomes were assessed during the 59-month follow-up. Our study showed that fistulas were associated with lower long-term systolic blood pressure (SBP) standard deviation (SD) (P < 0.0001), lower long-term SBP residual metric (P < 0.0001), and lower intradialytic SBP residual (P = 0.001). Fistulas were also associated with a higher but non-significant proportion of the newly developed left ventricular (LV) hypertrophy (8.29% vs. 6.78%, P = 0.116) and increased LV volume (8.29% vs. 4.52%, P = 0.139), as well as a lower proportion of the newly developed left ventricular ejection fraction (LVEF) dysfunction (1.62% vs. 2.82%, P = 0.586). After a median of 59-month follow-up, catheter group showed a higher risk of cardiovascular events (hazard ratio [HR] 1.21; 95% confidence interval [95%CI] 1.01-1.52), all-cause infection (HR 1.25; 95%CI 1.07-1.47), and access-related infection (HR 2.88; 95%CI 1.76-4.68). However, the advantage of fistulas only retained in low-albumin subgroup (serum albumin < 40 g/l) except for access-related infections. Our results suggested the possible attribution of BPV and other patient factors to fistula-associated survival benefits.

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

BACKGROUND

Vascular access for hemodialysis (HD) with an inappropriately high flow may underlie the onset of high output heart failure (HOHF).The aim of this study was to determine the prevalence of high flow access (HFA) in chronic HD patients, and to determine its effects on cardiac functions.

METHODS

This cross sectional study was conducted on 100 chronic hemodialysis patients through arteriovenous fistula (AVF). The study cohort was subdivided into 2 groups based on AVF flow: Group A (Non-HFA group with Qa < 2000 ml/min), and Group B (HFA group with Qa ≥ 2000 ml/min). AVF flow (Qa) was assessed using Color Doppler ultrasonography. Transthoracic echocardiography was performed for all patients to assess cardiac dimensions and functions.

RESULTS

Prevalence of HFA among study population was 24%. Mean AVF Qa was 958.63 ± 487.35 and 3430.13 ± 1256.28 ml/min, for group A and B respectively. The HFA group demonstrated a significant dilatation in LV dimensions and volumes and significantly larger LA volume as compared to non-HFA group. A significantly lower LV ejection fraction [EF] was also observed in group B with a mean value of 57.32 ± 6.19% versus 62.90 ± 5.76%. A significant association between HFA group and high Qa/cardiac output (CO) ratio (≥20%) was also observed.

CONCLUSION

HFA is a prevalent hemodialysis vascular access problem. HFA was associated with dilated LV dimensions, impaired LV systolic function. High Qa/CO ratio (≥20%) was an independent predictor of high output heart failure (HOHF) in our study population.

Relationships of high cardiac output with ventricular morphology, myocardial energetics, and energy costs in hemodialysis patients with preserved ejection fraction

Hemodialysis patients have conditions that increase cardiac output (CO), including arteriovenous fistula, fluid retention, vasodilator use, and anemia. We sought to determine the relationships between these factors and CO and to evaluate the effects of the high-output states on ventricular morphology, function, and myocardial energetics in hemodialysis patients, using noninvasive load-insensitive indices. Cardiovascular function was assessed in hemodialysis patients with high output [ejection fraction ≥ 50%, cardiac index (CI) > 3.5 L/min/m², n = 30], those with normal output (CI < 3.0 L/min/m², n = 161), and control subjects without hemodialysis (n = 155). As compared to control subjects and hemodialysis patients with normal CI, patients with elevated CI were anemic and displayed decreased systemic vascular resistance index (SVRI), excessive left ventricular (LV) contractility, larger LV volume, and tachycardia. Lower hemoglobin levels were correlated with decreased SVRI, excessive LV contractility, and higher heart rate, while estimated plasma volume and interdialytic weight gain were associated with larger LV volume, thus increasing CO. High output patients displayed markedly increased pressure-volume area (PVA) and PVA/stroke volume ratio, which were correlated directly with CO. The use of combination vasodilator therapy (angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker and calcium channel blocker) was not associated with high-output states. In conclusion, anemia and fluid retention are correlated with increased CO in hemodialysis patients. The high-output state is also associated with excessive myocardial work and energy cost.

Right Ventricular Function After Creation of an Atriovenous Fistula in Patients With End Stage Renal Disease

BACKGROUND

Right ventricular (RV) dysfunction is associated with increased risk of heart failure and mortality in end stage renal disease (ESRD) patients. Accumulating evidence suggests an association between atriovenous fistula (AVF) and RV dysfunction; however, there is no adequate data on the relation between AVF characteristics and risk of RV dysfunction after AVF creation.

METHODS

The study included 30 ESRD patients (median age: 44years, 17 male) who had their first autogenous mature AVF. Before and 6months after AVF creation the following were measured: myocardial performance index of RV (MPI-RV) using tissue Doppler imaging echocardiography and flow rate (Qa), feeding artery and receiving vein diameters using colour-flow Doppler ultrasound. Change (Δ) in MPI-RV was calculated by subtracting follow-up value from baseline value. Worsening RV function was defined as Δ MPI-RV>0.015 and high AVF flow as Qa≥950ml/min.

RESULTS

Compared to patients with lower AVF flow, patients with higher flow showed increased Δ in MPI-RV (0.12 vs. -0.03, p=0.04), basal RV diameter (0.3 vs. -0.02cm, p=0.014), left ventricular end diastolic volume index (9.9 vs. 0ml/m², p=0.004) and left atrial volume index (3 vs. 1ml/m², p=0.016). Among all clinical, echocardiographic and AVF-related parameters, univariate predictors of worsening of RV function were: high Qa, upper arm AVF, and large feeding artery diameter at baseline. Δ MPI-RV showed significant correlations with feeding artery diameter at baseline (r=0.46, p=0.01), and Qa (0.37, p=0.04) and no significant correlation with pulmonary artery pressures. Qa≥950ml/min, feeding artery diameter at baseline≥4mm and upper arm AVF can predict worsening of RV function with 73%, 73%, 75% sensitivity and 67%, 67%, 70% specificity, respectively.

CONCLUSIONS

In patients with ESRD, higher AVF flow adversely affects RV remodelling, manifested as increased size and worsening function. Predictors of worsening of RV function are: higher AVF flow rate, AVF in the upper arm, and large feeding artery diameter.

A Report of Two Cases of Hazards Associated with High Flow Arteriovenous Fistula in ESRD Patients

High flow arteriovenous fistulas are a common clinical entity affecting patients with end-stage renal failure receiving hemodialysis. Given the difficulty in predicting who will develop a high flow arteriovenous fistula the exact prevalence is unclear. We present two cases of patients with high flow arteriovenous fistula that developed clinical cardiac failure at a time point after the fistula was placed with findings of significant cephalic arch stenosis. Both patients required treatment of cephalic arch stenosis with balloon angioplasty with subsequent surgical aneurism resection. Accurate and timely diagnosis of high flow arteriovenous hemodynamics by prospective monitoring of volumetric flow and cardiac function is required to halt this process prior to cardiac compromise.

Are high flow arteriovenous accesses associated with worse haemodialysis?

Introduction:

An arteriovenous (AV) access flow (Qa) of 400 mL/min is usually sufficient for an effective hemodialysis (HD), but some accesses continue developing and become high flow accesses (HFA). Some authors postulated that an HFA might shift a significant portion of dialyzed blood from the cardiac output, which could decrease HD efficiency and lead to volume overload.

Objective:

The aim of our study was to evaluate if HFA is associated with reduced HD efficiency and/or volume overload in prevalent HD patients.

Methods:

We performed a 1-year retrospective study and assessed HD efficiency by the percentage of sessions in which the Kt/V > 1.4 and volume overload by bioimpedance spectroscopy.

Results:

The study included 304 prevalent HD patients with a mean age of 67.5 years; 62.5% were males, 36.2% were diabetics, with a median HD vintage of 48 months. Sixteen percent of the patients had a HFA (defined as Qa > 2 L/min). In multivariate analysis, patients with HFA presented higher risk of volume overload (OR = 2.67, 95%CI = 1.06-6.71) and severe volume overload (OR = 4.06, 95%CI = 1.01-16.39) and attained dry weight less frequently (OR = 0.37, 95%CI = 0.14-0.94). However, HFA was not associated with lower Kt/V.

Conclusion:

Our results suggest that patients with HFA have higher risk of volume overload. However, contrarily to what has been postulated, HFA was not associated with less efficient dialysis, measured by Kt/V. Randomized controlled trials are needed to clarify these questions.

Impact of Systemic Volume Status on Cardiac Magnetic Resonance T1 Mapping

Diffuse myocardial fibrosis is a key pathophysiologic feature in heart failure and can be quantified by cardiac magnetic resonance (CMR) T1 mapping. However, increases in myocardial free water also prolong native T1 times and may impact fibrosis quantification. Thus far, the impact of systemic patient volume status remains unclear. In this study, native T1 time by CMR was investigated in hemodialysis (HD) patients (n = 37) and compared with healthy controls (n = 35). Volume status was quantified by bioimpedance spectroscopy and correlated with CMR T1 time. While no differences between HD patients and controls were present with regard to age (p = 0.180), height (p = 0.535), weight (p = 0.559) and left ventricular (LV) ejection fraction (p = 0.273), cardiac size was significantly larger in HD patients (LV end-diastolic volume 164 ± 53 vs. 132 ± 26 ml, p = 0.002). Fluid overloaded HD patients had significantly longer native T1 times than normovolemic HD patients and healthy controls (1,042 ± 46 vs. 1,005 ± 49 vs. 998 ± 47 ms, p = 0.030). By regression analysis, T1 time was significantly associated with fluid status (r = 0.530, p = 0.009, post-HD fluid status). Our data strongly indicate that native CMR T1 time is significantly influenced by systemic volume status. As fluid overload is common in patients with cardiovascular diseases, this finding is important and requires further study.

Effect of Upper arm Brachial Basilic and Prosthetic Forearm Arteriovenous Fistula on Left Ventricular Hypertrophy

Background

Creation of an arteriovenous fistula (AVF) may increase left ventricular hypertrophy in the hemodialysis population. Aim of this study was to compare the effects of a brachial-basilic (BB) AVF and the prosthetic brachial-antecubital forearm loop access (PTFE) on cardiac performance.

Methods

Patients were randomized to receive BB-AVF or prosthetic brachial-antecubital forearm loop access. Before and three months after AVF creation patients underwent an echocardiographic examination. Mann-Whitney U-test was used to compare relative increase between the measured cardiac parameters for the two groups.

Results

Twenty-seven patients participated in the study. The relative increase in left ventricular parameters was not significantly different between the two groups. Only left ventricular end-diastolic diameter tended to be of significance. Mean blood flow through the brachial artery was 1680±156 and 1450±221 mL/min three months after surgery for the PTFE and the BB-AVF group, respectively.

Conclusion

After three months of follow-up, changes in cardiac structure were comparable between patients with BB and PTFE AVFs. Also access flow was comparable at this time. In general, the effects of creation of a fistula on LV structure were limited. Longer follow up time may be needed to explore the long term effects of different vascular accesses on cardiac function.

Association between vascular access creation and deceleration of estimated glomerular filtration rate decline in late-stage chronic kidney disease patients transitioning to end-stage renal disease

Background

Prior studies have suggested that arteriovenous fistula (AVF) or graft (AVG) creation may be associated with slowing of estimated glomerular filtration rate (eGFR) decline. It is unclear if this is attributable to the physiological benefits of a mature access on systemic circulation versus confounding factors.

Methods

We examined a nationwide cohort of 3026 US veterans with advanced chronic kidney disease (CKD) transitioning to dialysis between 2007 and 2011 who had a pre-dialysis AVF/AVG and had at least three outpatient eGFR measurements both before and after AVF/AVG creation. Slopes of eGFR were estimated using mixed-effects models adjusted for fixed and time-dependent confounders, and compared separately for the pre- and post-AVF/AVG period overall and in patients stratified by AVF/AVG maturation. In all, 3514 patients without AVF/AVG who started dialysis with a catheter served as comparators, using an arbitrary 6-month index date before dialysis initiation to assess change in eGFR slopes.

Results

Of the 3026 patients with AVF/AVG (mean age 67 years, 98% male, 75% diabetic), 71% had a mature AVF/AVG at dialysis initiation. eGFR decline accelerated in the last 6 months prior to dialysis in patients with a catheter (median, from -6.0 to -16.3 mL/min/1.73 m2/year, P < 0.001), while a significant deceleration of eGFR decline was seen after vascular access creation in those with AVF/AVG (median, from -5.6 to -4.1 mL/min/1.73 m2/year, P < 0.001). Findings were independent of AVF/AVG maturation status and were robust in adjusted models.

Conclusions

The creation of pre-dialysis AVF/AVG appears to be associated with eGFR slope deceleration and, consequently, may delay the onset of dialysis initiation in advanced CKD patients.

Heart disease in chronic kidney disease – review of the mechanisms and the role of dialysis access

Cardiovascular complications are responsible not only for the high mortality, but also the morbidity of end-stage renal disease patients. Cyclic changes of fluid load, together with the altered metabolism, are responsible and are mirrored in many particular parts of the heart. A review of the mechanisms involved is presented and the role of dialysis access is highlighted.

Hemodialysis Arteriovenous Fistulas: A Nineteenth Century View of a Twenty First Century Problem

This is a literature review which approaches the problem of successful use of arteriovenous fistulas for dialysis within the construct of Virchow's triad. By organizing the literature with regard to Virchow's concepts of blood flow, vascular injury, and thrombophilia an improved understanding arteriovenous fistula placement, maintenance and repair can be obtained. This process is designed to increase understanding and options for treatment by looking at this problem and using scientific knowledge gained in cardiology, oncology and vascular surgery medicine. Future approaches to fistulas will hopefully be a multifaceted and based in cellular pathophysiology as well as surgical and radiologic interventions and repairs.

The management of hemodialysis arteriovenous fistulas in well functioning renal transplanted patients: Many doubts, few certainties

Vascular access (VA) for hemodialysis (HD) is one of the most important clinical problems in end-stage renal disease (ESRD) patients because it can limit a life support system and can influence long-term dialysis patient survival. Nevertheless, VA becomes useless after a successful renal transplant. Therefore, we wanted to evaluate the natural history of arteriovenous fistulas (AVF) in renal transplanted patients and the possibility of maintaining the fistula as patent or not.

Methods

A retrospective study was conducted to evaluate kidney transplant patients in our unit from April 1994 to April 2004. We studied 542 patients.

Results

There were 365 patients with a well functioning kidney. Eighty-six patients died. Ninety-one patients were put back on dialysis: 89 patients on HD and two patients on CAPD. Of the 365 patients with functioning kidney transplants, 198 patients demonstrated a patent fistula, while 167 patients had a closed fistula. One hundred and twenty-five patients had a spontaneous closure and 42 patients had a surgical closure. Of the 89 patients put back on dialysis, 49 patients used the previous AVF, while it was necessary to create a new VA in 40 patients.

Conclusions

As demonstrated by the results of our study, after renal transplantation the possibility of spontaneous AVF closure caused by a thrombosis is not a rare event. The dilemma is whether to preserve a fistula that could be useful in case of restarting HD or to perform a systematic fistula closure because of cardiac output and cardiac failure risks. Concerning this question there is no consensus between different authors in the literature. In reviewing the literature and analyzing our data, we conclude that the definite indications for AVF closure in well functioning renal transplanted patients are heart failure, high flow fistula, VA complications and important aesthetic reasons. Routine AVF closure is not indicated until prospective and randomized studies can demonstrate the ability of this procedure to reduce the high incidence of cardiac morbidity and mortality that is present, even after renal transplantation.

Preoperative management of arteriovenous fistula (AVF) for hemodialysis

Native arteriovenous fistula (AVF) is the favorite access for hemodialysis (HD). The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) recommends its creation in most patients with renal failure. Unfortunately, intensive efforts to promote native AVF in patients with marginal vessels have increased the rate of primary fistula failure. A non-functioning fistula prompts the use of central venous catheter (CVC) that, unlike AVF, has been associated with an increased risk of morbidity and mortality among patients receiving HD. We believe that successful and timely AVF placement relies on the development of a multidisciplinary integrated preoperative program divided into five stages: (i) management of patients with advanced chronic kidney disease (CKD), (ii) management of preoperative risk factors for AVF failure, (iii) planning of native AVF, (iv) assessment of patient eligibility and (v) preoperative vascular mapping. Focusing specifically on native AVF, we review scientific evidence regarding preoperative management of this vascular access in order to favor construction of long-term functioning fistula minimizing development of severe complications.

Controversies in the management of the haemodialysis-related arteriovenous fistula following kidney transplantation

Arteriovenous fistula (AVF) is regarded as the best vascular access for chronic haemodialysis (HD). Still, AVF inherently causes significant haemodynamic changes. Although the necessity for vascular access despite its putative cardiovascular complications favours AVF creation in patients under chronic HD, one may question whether sustaining a functional AVF after successful kidney transplantation extends the haemodynamic threat. Small prospective series suggest that AVF ligation causes rapid and sustained reduction in left ventricular hypertrophy. Still, the benefits of such a cardiac remodelling in long-terms of cardiovascular morbi-mortality still need to be proven. Furthermore, the elevation of diastolic blood pressure and arterial stiffness caused by AVF ligation may blunt the expected cardio-protection. Finally, the closure of a functioning AVF may accelerate the decline of kidney graft function. As a whole, the current management of a functioning AVF in kidney transplant recipients remains controversial and does not rely on strong evidence-based data. The individual risk of graft dysfunction and a return to chronic HD also needs to be balanced. Careful pre-operative functional assessments, including cardio-pulmonary testing and estimated glomerular filtration rate slope estimation, may help better selection of who might benefit the most from AVF closure. Large-scale prospective, ideally multi-centric, trials are essentially needed.

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.

Effects of Cardiac Function with Postoperative Arteriovenous Fistula Blood Flow in Patients with Hemodialysis

Background/Aims: This study was aimed at evaluating the effect of cardiac function with postoperative arteriovenous fistula (AVF) blood flow in hemodialysis (HD) patients. Methods: A total of 45 HD patients were examined at the Juntendo University Hospital. The AVF blood flow was measured using ultrasonography, and the cardiac function was measured using echocardiography. Correlation between these parameters and the rate of change in body weight (BW) was analyzed. Results: The number of postoperative days significantly correlated with the AVF blood flow, and it positively correlated with the stroke volume (SV). The postoperative AVF blood flow in patients with reduced ejection fraction (EF) was lower than that in patients with normal EF. The rate of change of BW negatively correlated with that of SV, positively correlated with cardiac output (CO), and positively correlated with CO in patients with an AVF blood flow of more than 1,000 mL/min. Conclusion: It appears that the cardiac function can be improved by controlling the BW even in patients with high AVF blood flow.

Cardiovascular impact in patients undergoing maintenance hemodialysis: Clinical management considerations

Patients undergoing maintenance hemodialysis develop both structural and functional cardiovascular abnormalities. Despite improvement of dialysis technology, cardiovascular mortality of this population remains high. The pathophysiological mechanisms of these changes are complex and not well understood. It has been postulated that several non-traditional, uremic-related risk factors, especially the long-term uremic state, which may affect the cardiovascular system. There are many cardiovascular changes that occur in chronic kidney disease including left ventricular hypertrophy, myocardial fibrosis, microvascular disease, accelerated atherosclerosis and arteriosclerosis. These structural and functional changes in patients receiving chronic dialysis make them more susceptible to myocardial ischemia. Hemodialysis itself may adversely affect the cardiovascular system due to non-physiologic fluid removal, leading to hemodynamic instability and initiation of systemic inflammation. In the past decade there has been growing awareness that pathophysiological mechanisms cause cardiovascular dysfunction in patients on chronic dialysis, and there are now pharmacological and non-pharmacological therapies that may improve the poor quality of life and high mortality rate that these patients experience.

Impact of vascular access intervention therapy on cardiac load in hemodialysis patients

Vascular access intervention therapy (VAIVT) has been positioned as the first choice of treatment for stenosis lesions frequently observed in arteriovenous fistula (AVF) for hemodialysis patients in Japan. Furthermore, increased blood flow can provide a stable dialysis. In contrast, it has been reported that excess blood flow of AVF causes high-output heart failure. Although VAIVT is used to increase blood flow of AVF, the impact of VAIVT on cardiac load has been rarely reported. We examined the factors associated with cardiac load in hemodialysis patients undergoing VAIVT by measuring levels of α human atrial natriuretic polypeptide (hANP) and brain natriuretic peptide (BNP) before and after VAIVT. Data were extracted on hemodialysis patients who underwent measurements of αhANP and BNP in before and after VAIVT at our facility and related facilities between February 2014 and December 2014. Nineteeen patients (median age, 73.0 [66.5-80.5] years; male, 52.6%; 36.8% with diabetes; median duration of dialysis treatment, 50.0 [21-109] months) were enrolled in this study. Flow volume of AVF was higher after VAIVT than that before VAIVT (442.0 vs. 758.0 mL/minute, P < 0.001). Moreover, resistance index (RI) of AVF after VAIVT was lower than that before VAIVT (0.61 vs. 0.53, P < 0.01). Although αhANP did not change before and after VAIVT (55.6 vs. 54.9 pg/mL, P = 0.099), BNP after VAIVT was significantly higher than that before VAIVT (145.2 vs. 175.0 pg/mL, P < 0.05). Factors correlated with the increase in BNP were flow volume of AVF before VAIVT (r = -0.458, P = 0.049) and levels of BNP before VAIVT (r = 0.472, P = 0.041). There was no significant correlation between the increase in αhANP with flow volume of AVF before VAIVT, levels of αhANP before VAIVT. Patients with high levels of BNP and low flow volume of AVF before VAIVT were considered to have a high risk of developing heart failure after VAIVT.

Arteriovenous Vascular Access Selection and Evaluation

When making decisions regarding vascular access creation, the clinician and vascular access team must evaluate each patient individually with consideration of life expectancy, timelines for dialysis start, risks and benefits of access creation, referral wait times, as well as the risk for access complications. The role of the multidisciplinary team in facilitating access choice is reviewed, as well as the clinical evaluation of the patient.

The Pros and Cons of Preserving a Functioning Arteriovenous Fistula after Kidney Transplantation

The autologous arteriovenous fistula (AVF) for hemodialysis burdens the cardiovascular system with increased cardiac output and pulmonary artery pressure, increasing cardiovascular risk. This article reviews literature on the benefits and drawbacks of a functioning AVF after kidney transplantation and discusses the cardiovascular effects of AVF closure. Several cohort studies demonstrate a significant cardiac burden of an AVF and improvement of cardiac dimensions after AVF ligation. However, no randomized trials have been conducted on routine AVF closure after successful kidney transplantation. Therefore, clinical trials are warranted to evaluate whether the cardiovascular benefits of routine AVF closure outweigh the potential harm for patients after successful kidney transplantation.

Permanent Arteriovenous Fistula or Catheter Dialysis for Heart Failure Patients

Heart failure (HF) is the most frequent cardiovascular disease associated with chronic kidney disease and represents a high risk for cardiovascular mortality in incident hemodialysis (HD) patients. This risk is especially high during the arteriovenous fistula (AVF) maturation period due to the marked hemodynamic changes related to the large increase in the blood flow and also within the first 120 days after HD inception because in this period the highest mortality rate occurs. When planning the vascular access for each incident HF patient, the risk of aggravating HF after AVF creation must be evaluated carefully alongside the risk of catheter-related complications, but avoiding a non-selective ‘catheter first’ approach for all these patients. HF patients classified within the New York Heart Association (NYHA) Class I-II and the American College of Cardiology/American Heart Association (ACC/AHA) Stage A-B could initiate HD through a distal arm AVF. High-flow brachial artery-based AVF creation must be avoided because it displays the highest risk of worsening the cardiac function. The decision for AVF creation or tunneled central catheter placement in HF patients classified within the NYHA Class III and the ACC/AHA Stage C must have been individualized according the degree of systolic and/or diastolic dysfunction. HF patients with significant reduction in systolic function (ejection fraction lower than 30%) or classified within the NYHA Class IV and the ACC/AHA Stage D, are candidates for tunneled catheter placement to start HD treatment.

Importance of monitoring and treatment of failed maturation in radiocephalic arteriovenous fistula in predialysis: Role of ultrasound

The aim of the study was to analyse outcomes of AVF-RC in predialysis stage in which a clinical and radiological follow up of its maturation had been done and primary failure had been treated.

MATERIAL AND METHODS

We studied 127 RC-AVF in 117 predialysis patients. All cases had a preoperative map. The RC-AVF was considered mature if it had a brachial artery flow ≥500ml/min and a cephalic vein diameter of ≥4mm. Primary failure was treated radiologically or surgically depending on the type of lesion. Fifty-eight patients started dialysis at the time of the study.

RESULTS

In 106 RC-AVF without thrombosis, 72 (68%) were mature and 34 (32%) were immature. A total of 97% of the immature had at least one lesion, and the most common site was the post-anastomotic vein. Lesions were found in 31% of mature RC-AVF, and 18% of patients required treatment. Radiological treatment was the most frequent for maturation failure. After 6 months, primary and secondary patency were 59% and 78%, while after 12 months they were 48% and 77%, respectively. The 80% of patients started dialysis with a distal AVF (76% RC-AVF and 4% ulnar basilic). None of the patients with treated immature RC-AVF started dialysis with CVC, while 78% of the patients started with said AVF.

CONCLUSION

Ultrasonography for monitoring maturation provides advantages over clinical monitoring. With our management of RC-AVF in predialysis, 80% of patients start dialysis with an adequate distal AVF.

High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old

Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created. Case. A six-month-old 25-week gestation infant was referred for respiratory distress. Initial exam revealed tachypnea, tachycardia, and hypertension. There was a bruit noted on her left arm. An ultrasound showed an arteriovenous fistula. Its location, however, precluded intervention because of the high risk for limb-loss. An echocardiogram showed evidence of pulmonary hypertension that was treated with sildenafil and furosemide. However, no improvement was seen. On temporary manual occlusion of the fistula, the patient was noted to have increased her blood pressure and decreased her heart rate, suggesting significant hemodynamic effect of the fistula. The fistula was subsequently ligated and the patient clinically and echocardiographically improved. Conclusion. A patient in high output cardiac failure or pulmonary artery hypertension, especially prematüre patients with preexisting lung disease, should be probed for history of multiple punctures, trauma, or surgery and should have prompt evaluation for AVF. If it can be diagnosed and repaired, most of the cases have been shown to decrease the stress on the heart and reverse the pathologic hemodynamics.

Hand Ischemia in a Patient With an Arteriovenous Fistula

An ischemic digit causes significant morbidity due to its associated discomfort and potential for tissue necrosis. Historically, when this phenomenon was peripheral to an ipsilateral arteriovenous access in a hemodialysis patient, it was called "steal syndrome" and was usually treated with access ligation, resulting in loss of the access. We present a dialysis patient with hand pain due to ischemia that was referred for access ligation. Instead, a minimally invasive banding procedure was performed that resulted in access salvage and resolution of symptoms. We present images and a discussion of the diagnosis and treatment of distal hypoperfusion ischemia syndrome in this Imaging Teaching Case.

Systemic Effects of Hemodialysis Access

Patients with advanced chronic kidney disease are at a high risk of cardiovascular events. Patients with end-stage renal disease have a particularly high morbidity and mortality, in part attributed to the complications and dysfunction related to vascular access in this population. Creation of an arteriovenous access for HD is considered standard of care for most patients and has distinct advantages including less likelihood of infections, less need for intervention, and positive impact on survival as compared with usage of a catheter. However, creation of an arteriovenous shunt incites a series of events that significantly impacts cardiovascular and neurohormonal health in both positive and negative ways. This article will review the short- and long-term effects of dialysis access on cardiovascular, neurohormonal, and pulmonary systems as well as a brief review of their effect on survival on HD. Presence of other comorbidities in a patient with dialysis access can amplify these effects, and these considerations are of paramount importance in individualizing the approach to not only the choice of vascular access but also the modality of kidney replacement therapy.

Volume control in treatment-resistant congestive heart failure: role for peritoneal dialysis

Chronic congestive heart failure (HF) has a rising prevalence and increasing impact on health care systems. Current treatment consists of diuretics, renin-angiotensin-aldosterone system blockers, and restriction of salt and fluids. This strategy is often hampered by a drop in effective circulating volume and hence renal perfusion and function, triggering harmful counter regulatory mechanisms. Slow ultrafiltration by peritoneal dialysis (PD) might be an effective treatment strategy to relieve fluid overload without compromising cardiac output and thereby renal function. In this review, we discuss the (patho)physiological mechanisms of the cardiorenal interaction and the current literature on PD strategies in congestive HF.

Cardiac complications of arteriovenous fistulas in patients with end-stage renal disease

Cardiovascular disease is the leading cause of the death in dialysis patients. Arteriovenous fistulas (AVFs) are associated with lower mortality and are viewed as the desired access option in most patients with advanced kidney disease needing dialysis. However, AVFs have significant and potentially deleterious effects on cardiac functions particularly in the setting of preexisting heart disease. This article provides a comprehensive and contemporary review to what is known about the impact of AVFs on: congestive heart failure, left ventricular hypertrophy, pulmonary hypertension, right ventricular dysfunction, coronary artery disease and valvular heart disease.

The deleterious effects of arteriovenous fistula-creation on the cardiovascular system: a longitudinal magnetic resonance imaging study

Aim

Arteriovenous fistula-formation remains critical for the provision of hemodialysis in end-stage renal failure patients. Its creation results in a significant increase in cardiac output, with resultant alterations in cardiac stroke volume, systemic blood flow, and vascular resistance. The impact of fistula-formation on cardiac and vascular structure and function has not yet been evaluated via “gold standard” imaging techniques in the modern era of end-stage renal failure care.

Methods

A total of 24 patients with stage 5 chronic kidney disease undergoing fistula-creation were studied in a single-arm pilot study. Cardiovascular magnetic resonance imaging was undertaken at baseline, and prior to and 6 months following fistula-creation. This gold standard imaging modality was used to evaluate, via standard brachial flow-mediated techniques, cardiac structure and function, aortic distensibility, and endothelial function.

Results

At follow up, left ventricular ejection fraction remained unchanged, while mean cardiac output increased by 25.0% (P<0.0001). Significant increases in left and right ventricular end-systolic volumes (21% [P=0.014] and 18% [P<0.01]), left and right atrial area (11% [P<0.01] and 9% [P<0.01]), and left ventricular mass were observed (12.7% increase) (P<0.01). Endothelial-dependent vasodilation was significantly decreased at follow up (9.0%±9% vs 3.0%±6%) (P=0.01). No significant change in aortic distensibility was identified.

Conclusion

In patients with end-stage renal failure, fistula-formation is associated with an increase in cardiac output, dilation of all cardiac chambers and deterioration in endothelial function.

Percutaneous Transluminal Angioplasty for Central Venous Disease in Dialysis Patients: Influence on Cardiac Function

Purpose

Increased vascular access flow after percutaneous transluminal angioplasty (PTA) for central venous stenosis and occlusion (central venous disease, CVD) can affect cardiac function in hemodialysis (HD) patients. We evaluated the cardiac function, etiology, and treatment in HD patients with CVD.

Methods

HD patients with CVD treated by PTA between June 2006 and February 2013 were studied.

Results

Of the 26 patients, 22 had left arteriovenous fistulas (AVFs), 1 left arteriovenous graft (AVG), 2 right AVFs, and 1 right AVG. CVD sites were the left brachiocephalic vein (LBCV; n=13), left subclavian vein (LSCV; n=7), both LBCV and LSCV (n=3), right BCV (n=2), and right SCV (n=1). Computed tomography findings indicated a high extrinsic compression rate for the LBCV (91%) and LSCV (50%). The success rate of PTA was 96%. The primary patency rates at 3, 6, 9, and 12 months were 81%, 73%, 65%, and 57%, respectively. The post-PTA brachial artery flow volume was significantly increased compared with the pre-PTA volume (1306 vs. 957 ml/min; p=0.005). The post-PTA left ventricular ejection fraction and expiration inferior vena cava diameter were the same as the pre-PTA values (57% versus 60%, p=0.2 and 17 versus 17 mm, p=0.9, respectively).

Conclusions

Our findings suggest that increased vascular access flow after PTA for CVD has no relation to cardiac function.

Temporal trajectory of B-type natriuretic peptide in patients with CKD stages 3 and 4, dialysis, and kidney transplant

BACKGROUND AND OBJECTIVES

B-type natriuretic peptide (BNP) concentration predicts outcome in patients undergoing dialysis. Because survival and cardiovascular risk change across the CKD continuum, serial changes in BNP were compared in patients at different CKD stages and after kidney transplantation.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with CKD stages 3 and 4 (CKD 3-4), dialysis patients, and kidney transplant recipients (KTRs) from one center had two measurements of BNP taken a median of 161 days apart in 2003-2004 and were followed until July 2012. Both BNP-32 (Triage BNP; Biosite Diagnostics) and NT-BNP-76 (proBNP; Roche Diagnostics) were assayed. The interaction between change in log-transformed BNP concentration over time and patient group was tested by fitting regression models on panel data with random effects. Survival after the second measurement was compared by tertile of change in BNP.

RESULTS

Patients with CKD 3-4 (n=48), dialysis patients (n=102), and KTRs (n=73) were followed for a median of 5.7, 4.8, and 5.9 years, respectively. The interaction between patient group and BNP measurements over time was significant for NT-BNP-76 (P<0.001) and BNP-32 (P<0.01). Median NT-BNP-76 increased in dialysis patients and those with CKD 3-4 from 3850 pg/ml (interquartile range [IQR], 1776-12,323 pg/ml) to 18,830 pg/ml (IQR, 6114-61,009 pg/ml; P<0.001) and from 698 pg/ml (IQR, 283-2922 pg/ml) to 2529 pg/ml (IQR, 347-9277 pg/ml; P=0.002), respectively. Change was not significant for KTRs or comparisons made with BNP-32. Survival rate was significantly lower for patients with the highest tertile of change in NT-BNP-76 among patients with CKD 3-4 (P=0.02), but not in the dialysis or KTR groups. In 11 patients who received a kidney transplant during the study, median NT-BNP-76 decreased from 9607 pg/ml (IQR, 2292-31,282 pg/ml) to 457 pg/ml (IQR, 203-863 pg/ml) after transplant (P<0.01).

CONCLUSIONS

The temporal trajectory of BNP differs between dialysis patients and those with CKD 3-4 and KTRs. This has important implications for the development of BNP-guided management strategies in CKD.

A case series of real-time hemodynamic assessment of high output heart failure as a complication of arteriovenous access in dialysis patients

Congestive heart failure (CHF) is an important source of morbidity and mortality in end-stage renal disease patients. Although CHF is commonly associated with low cardiac output (CO), it may also occur in high CO states. Multiple conditions are associated with increased CO including congenital or acquired arteriovenous fistulae or arteriovenous grafts. Increased CO resulting from permanent AV access in dialysis patients has been shown to induce structural and functional cardiac changes, including the development of eccentric left ventricle hypertrophy. Often, the diagnosis of high output heart failure requires invasive right heart monitoring in the acute care setting such as a medical or cardiac intensive care unit. The diagnosis of an arteriovenous access causing high output heart failure is usually confirmed after the access is ligated surgically. We present for the first time, a case for real-time hemodynamic assessment of high output heart failure due to AV access by interventional nephrology in the cardiac catheterization suite.

Effect of the arteriovenous access for hemodialysis on subendocardial viability ratio, pulse pressure and hospitalizations

BACKGROUND

In some patients the potential benefits of the arteriovenous (AV) access over catheter for hemodialysis seem to be outweighed by global cardiovascular status deterioration.

METHODS

We prospectively evaluated 44 pre-dialysis chronic kidney disease patients submitted to vascular access creation during a follow-up of 25 ± 9 months. We performed pulse wave analysis and biochemical assessment before and 2 months after AV access construction, and we registered premature vascular access thrombosis, and all-cause and cardiovascular hospitalizations throughout follow-up.

RESULTS

We found a statistically significant decrease in the subendocardial viability ratio (SEVR) and pulse pressure (PP) parameters after AV access creation while brain natriuretic peptide significantly increased. Receiver operating characteristic curve analysis identified SEVR ≤113 % evaluated 2 months after vascular access construction as the best cutoff value for predicting all-cause and cardiovascular hospitalizations. Kaplan-Meier analysis showed that a SEVR ≤113 % was associated with all-cause (p = 0.010) and cardiovascular (p = 0.029) hospitalizations; Cox regression analysis verified a 4.9-fold higher risk of all-cause hospitalization in patients with SEVR ≤113 % (p = 0.005).

CONCLUSION

To our best knowledge, this report indicates, for the first time, that despite the decrease in PP parameters, the creation of a vascular access for hemodialysis was also associated with a reduction of SEVR which predicted a worse clinical outcome. We argue that the decrease of pulse pressure after arteriovenous construction may reflect a new hemodynamic set-point after vascular access creation and may not indicate a protective cardiovascular effect.

High-output heart failure: how to define it, when to treat it, and how to treat it

Although hemodialysis patients who initiate and maintain a permanent form of dialysis vascular access have improved all-cause and cardiovascular survival compared with those who use catheters, the presence of an arteriovenous fistula has been shown to have a short-term, adverse effect on cardiac function. Through its effect as a left-to-right extracardiac shunt, the arteriovenous fistula can increase cardiac workload substantially, and, in certain patients, result in a high-output state and resultant heart failure over time. Here we review the mechanisms by which dialysis arteriovenous access may promote the development of high-output cardiac failure in end-stage renal disease patients, describe risk factors for and the diagnosis of high-output heart failure, and suggest management strategies for patients who develop high-output heart failure.

Challenges and management of high-flow arteriovenous fistulae

The Kidney Dialysis Outcomes Quality Initiative and Fistula First Initiative have embraced the arteriovenous fistula as the gold standard for hemodialysis accesses. Despite this status, fistulae are fraught with complex issues ranging from a high primary failure rate to high flow resulting in increased cardiovascular morbidity. It is important not to overlook the insidious peril of a hyperfunctioning access that may actively promote cardiac overload, cardiopulmonary recirculation, rapid access growth with aneurysm enlargement, recurrent venous stenosis resulting in access failure, and inflow/outflow mismatch. Once recognized, flow can and should be reduced to mitigate these and other negative effects.

Native arterio-venous fistula is the vascular access of choice for hemodialysis in end stage renal disease

OBJECTIVES

THE AIM OF THE STUDY WAS: Is primary Arterio-venous fistula the vascular access of choice for adequate dialysis and better patient outcome in end stage renal disease.

MATERIALS AND METHODS

The present study was done in the department of cardiovascular and thoracic surgery at Sher-i-Kashmir institute of medical sciences, Soura, Srinagar Kashmir. Native Arterio-Venous (AV) fistulas were made in the patients with end stage renal disease for performing hemodialysis. They were followed for patency and adequacy of blood flow during hemodialysis. All the patients were operated under local anesthesia.

RESULTS

The results showed that 77% of the AV fistulas based on radial artery with side-to-side anastomosis and 80% of those with end-to-side anastomosis were functionally patent after one year. After two years, the patency rate in side-to-side and end-to-side anastomosis was 50% and 55%, respectively. In addition, the patency rate was 90% in brachial artery based AV fistula with end-to-side anastomosis, whether done primarily or secondarily, at the end of one year. However, a rapid decline was observed in the patency rate during the third year in both radial artery based and brachial artery based AV fistulas.

CONCLUSIONS

We concluded that Arterialised arm superficial veins after primary AV fistula was the optimal and rational vascular access for hemodialysis providing adequate blood flow during this process. Besides, failure of primary AV fistula should be replaced by secondary AV fistula preferably based on brachial artery.

Aortocaval fistula delays gastric emptying of liquid test meal in awake rats

Arteriovenous anastomoses disrupt cardiovascular and renal homeostasis, eliciting hemodynamic adjustments, resetting the humoral pattern, and inducing cardiac hypertrophy. Because acute circulatory imbalance alters gut motor behavior, we studied the effects of arteriovenous fistula placement on the gastric emptying (GE) of a liquid meal in awake rats. After laparotomy, we created an aortocaval fistula (ACF) by aorta and cava wall puncture with a 21-, 23-, or 26-gauge needle. The ACF was not created in the control group, which underwent sham operation. After 12, 24, or 48 h, mean arterial pressure, heart rate, and central venous pressure were continuously recorded, and cardiac output was estimated by thermal dilution. The rats were then gavage fed a test meal (i.e., phenol red in glucose solution), and fractional dye retention was determined 10, 20, or 30 min later. The effect of prior bleeding on ACF-induced GE delay, the role of neuroautonomic pathways, and changes in plasma hormone levels (i.e., angiotensin II, arginine vasopressin, atrial natriuretic peptide, corticosterone, and oxytocin) were evaluated. When compared with the sham-operated group, ACF rats exhibited arterial hypotension, higher ( P < 0.05) heart rate, central venous pressure, and cardiac output values and increased ( P < 0.05) gastric dye retention, a phenomenon prevented by bilateral subdiaphragmatic vagotomy and hexamethonium treatment. Pirenzepine also impaired the occurrence of gastric delay in subjects with ACF. In addition to causing hyperkinetic circulation, ACF placement delayed the GE of liquid in awake rats, an effect that likely involves a parasympathetic pathway.