Cardiac remodeling after reduction of high-flow arteriovenous fistulas in end-stage renal disease

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.

Management of an aneurysmal arteriovenous fistula in kidney transplant recipients

Aneurysms remain the most common complication of an arteriovenous fistula created for dialysis access. The management of an aneurysmal arteriovenous fistula (AAVF) in kidney transplant recipients remains contentious with a lack of clear clinical guidelines. Recipients of a functioning graft do not require the fistula for dialysis access, however risk of graft failure and needing the access at a future date must be considered. In this review we outline the current evidence in the assessment and management of a transplant recipient with an AAVF. We will describe our recommended five-step approach to assessing an AAVF in transplant patients; 1.) Define AAVF 2.) Risk assess AAVF 3.) Assess transplant graft function and future graft failure risk 4.) Consider future renal replacement therapy options 5.) Vascular mapping to assess future vascular access options. Then we will describe the current therapeutic options and when they would most appropriately be employed.

Effect of proximal artery restriction on flow reduction and cardiac function in hemodialysis patients with high-flow arteriovenous fistulas

OBJECTIVE

Arteriovenous fistula is the preferred vascular access for hemodialysis patients. High-flow arteriovenous fistula may cause high-output heart failure. Various procedures are used to reduce high-flow arteriovenous fistula. This study aimed to assess the efficacy of proximal artery restriction combined with distal artery ligation on flow reduction for high-flow arteriovenous fistula and on cardiac function and echocardiographic changes in patients undergoing hemodialysis.

METHODS

A retrospective analysis was performed on data collected from the medical records of patients undergoing hemodialysis with heart failure and high-flow arteriovenous fistula between May 2018 and May 2021. Thirty-one patients were treated with proximal artery restriction (banding juxta-anastomosis of the proximal artery) combined with distal artery ligation (anastomosis distal artery ligation). Changes in the Acute Dialysis Quality Initiative Workgroup cardiac function class, blood pressure, and echocardiography before and 6 months after flow restriction were compared, and post-intervention primary patency was followed-up.

RESULTS

The technical success rate of the surgery was 100%, and no surgery-related adverse events occurred. Blood flow and blood flow/cardiac output decreased significantly after flow restriction. Blood flow decreased from 2047.21 ± 398.08 mL/min to 1001.36 ± 240.42 mL/min, and blood flow/cardiac output decreased from 40.18% ± 6.76% to 22.34% ± 7.21% (P < .001). Post-intervention primary patency of arteriovenous fistula at 6, 12, and 24 months was 96.8%, 93.5%, and 75.2%, respectively. The Acute Dialysis Quality Initiative Workgroup cardiac function class improved significantly after 6 months of flow restriction (P < .001). The systolic and diastolic left heart function improved, as evidenced by a significant decrease in left atrial volume index, left ventricular end-diastolic/end-systolic diameters, left ventricular end-diastolic volume, left ventricular mass index, cardiac output, and cardiac index and an increase in lateral peak velocity of longitudinal contraction, average septal-lateral s', and lateral early diastolic peak velocity after flow restriction (P < .05). Systolic pulmonary artery pressure decreased from 32.36 ± 8.56 mmHg to 27.57 ± 8.98 mmHg (P < .05), indicating an improvement in right heart function.

CONCLUSIONS

Proximal artery restriction combined with distal artery ligation effectively reduced the blood flow of high-flow arteriovenous fistula and improved cardiac function.

Cure of Refractory Hypotension in a Hemodialysis Patient

We present a case of a 67-year-old male with end-stage renal disease (ESRD) on hemodialysis who was admitted to the hospital after recurrent falls secondary to postural hypotension. He was not able to tolerate fluid removal on dialysis due to persistent hypotension despite maximal doses of midodrine and developed severe edema. A right heart catheterization revealed raised biventricular filling pressure consistent with right heart failure with low systemic vascular resistance and pulmonary hypertension. Duplex ultrasound of the left arm cephalic arteriovenous fistula (AVF) revealed a blood flow of 5.6 L/min. We hypothesized the cause of his high output heart failure from an AV fistula despite the lack of an increase in blood pressure after compression of the AVF. The AVF was ligated and a tunneled hemodialysis catheter was placed. Immediately after ligation, the patient was able to tolerate fluid removal with dialysis without hypotension, leading to a significant improvement in his edema and shortness of breath. This case highlights the potential adverse cardiovascular effects of AVF and the salutary effects on ligation in appropriate clinical settings.

Association between arteriovenous access flow and ventricular function: A cross-sectional study

Background

Permanent hemodialysis access comes with a myriad of problems on top of the well-known benefits; flow disturbances, risk of infection and revision being among them. All of these could eventually lead to impaired cardiac function. Even so, the relationship between impaired cardiac function due to arteriovenous access in patients undergoing hemodialysis has not been clearly described. This study aimed to analyze the relationship of flow in an artificial arteriovenous access with left and right ventricular function in patients with chronic kidney disease (CKD) undergoing hemodialysis at a referral hospital in Indonesia.

Material and methods

This was a cross sectional study with consecutive sampling technique. Samples were patients with CKD undergoing hemodialysis at Dr. Soetomo General Hospital from December 2021to January 2022. A total of 47 patients who met the inclusion criteria underwent Doppler ultrasound to assess arteriovenous access flow and transthoracic echocardiography to assess left and right ventricle function.

Results

From 47 patients, 26 (55.3%) had high arteriovenous access flow. The clinical characteristics of the patients between the high and low arteriovenous access flow groups were not significantly different. We found that the value of left ventricular ejection fraction in the non-high-flow access group was significantly higher than the high-flow access group (p < 0.05). Other than that, the median right ventricle fractional area changes in the non-high-flow access group was also higher than the high-flow access group (p < 0.05).

Conclusion

Arteriovenous access flow as measured by Doppler ultrasonography has a significant relationship with impaired left and right ventricular functions based on systolic function parameters from echocardiography.

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There is an association between arteriovenous access flow and ventricular function.

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The higher the access flow, the lower the left ventricular systolic function.

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The higher the access flow, the lower the right ventricular systolic function.

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It is important to periodically evaluate the access flow of hemodialysis patients.

Preoperative Cardiac Index as a Predictor of Maturation and Primary Patency of Radiocephalic Arteriovenous Fistula in Hemodialysis

BACKGROUND

Radiocephalic arteriovenous fistula (RCAVF) is the best access modality to be considered initially when planning arteriovenous fistula (AVF) for maintenance hemodialysis. Considering the higher incidence of RCAVF failed maturation (M), it is important to perform proper preoperative evaluation and identification of high-risk patients. There has been no study on the influence of preoperative cardiac function on the M and patency of AVFs. The purpose of this investigation is to determine whether preoperative cardiac index (CI) is a predictor of M and primary patency of RCAVF.

METHOD

A total of 365 end-stage renal disease patients undergoing RCAVF surgery were consecutively enrolled with a median follow-up time of 20 months in this prospective cohort study. Demographics, vascular diameters measured by duplex ultrasound examination, and CI measured by echocardiography, were analyzed for effect on RCAVF primary functional M and primary patency.

RESULT

Patients in the group achieving primary RCAVF functional M had a significantly larger mean CI than the group with early RCAVF failure (2.93 ± 0.77 vs. 3.57 ± 0.76 L/min/m2, p < 0.001). The receiver operating characteristic curve was plotted and demonstrated that preoperative vein diameter and CI can predict failure of RCAVF M. The AUC of CI was higher (0.745 vs. 0.666). Multivariate regression analysis, adjusted for age, sex, diabetes, preoperative dialysis status and vessel diameters, showed that decreased CI remained associated with increased risk of failure of M (FM) and worse primary unassisted patency. The Kaplan-Meier survival analysis suggested that patients with CI <3 L/min/m2 had a worse primary unassisted patency rate at all time points compared with patients with CI ≥3 L/min/m2.

CONCLUSION

This study demonstrated that preoperative CI was associated with RCAVF M and long-term patency. A decreased CI may be a possible predictor of an increased risk of FM and a shorter primary patency time.

NT-pro-BNP as marker for cardiac strain that may be caused by high-output arteriovenous shunting in a haemodialysis patient. A case report

BACKGROUND

An arteriovenous fistula (AVF) is the first choice when considering access for haemodialysis (HD). When a forearm AVF fails an upper arm AVF is a frequent subsequent dialysis access option. The latter may cause cardiac strain. NT-pro-B-type natriuretic peptide (NT-NT-proBNP) is a marker used to estimate volume overload and cardiac strain. This case report shows the benefit of using longitudinal individual follow-up of pre-dialysis NT-proBNP in clinical practice to detect changes in cardiac condition that may be due to high-output AVF.

CASE PRESENTATION

An 18 years old patient performed HD via an upper arm AVF before he was admitted to our unit. NT-proBNP was above the upper detection level of 70,000 ng/L. Echocardiography revealed a left-ventricular cardiac insufficiency. Interdialytic weight gain (IDWG) was above 5%. He was instructed to lower fluid intake and IDWG towards 2%. Four months later NT-proBNP surpassed 70,000 ng/L again. Flow in the brachial artery was at 3034 ml/min. Reconstructive surgery of the AVF did not reduce flow and NT-proBNP in the long run. Clinically, he worsened to NYHA class III-IV. It was decided to close the upper arm AVF and to replace it with a lower arm AVF leading to a reduced artery flow of 1344 mL/min. The clinical condition successively recovered and NT-proBNP decreased to 7000 ng/L.

CONCLUSIONS

Pre-dialysis NT-proBNP should be considered as a suitable routine marker for cardiac strain such as caused by high-output AVF besides variables such as IDWG. Brachial artery flow besides AVF flow measurement is helpful.

Arteriovenous Fistula Creation and Estimated Glomerular Filtration Rate Decline in Advanced CKD: A Matched Cohort Study

Background

Kidney failure is associated with a high burden of morbidity and mortality. Previous studies have raised the possibility that arteriovenous fistula (AVF) creation may attenuate eGFR decline. This study aimed to compare eGFR decline in predialysis patients with an AVF, matched to patients oriented toward peritoneal dialysis (PD).

Methods

Predialysis patients with an AVF and those oriented toward PD were retrospectively matched using a propensity score. Time zero was defined as the "AVF creation date" for the AVF group and the "date when eGFR was closest to the matched patient's eGFR at AVF creation" for the PD group. Crude and predicted eGFR decline in AVF and PD groups were compared before and after time zero using mixed-effect linear regressions.

Results

In total, 61 pairs were matched. Crude annual eGFR decline before AVF creation/time zero was -4.1 ml/min per m² per year in the AVF group versus -5.3 ml/min per m² per year in the PD group (P=0.75) and after time zero, -2.5 ml/min per m² per year in the AVF group versus -4.5 ml/min per m² per year in the PD group (P=0.02). The predicted annual decline decreased from -5.1 ml/min per m² per year in the AVF group before AVF creation to -2.8 ml/min per m² per year after (P<0.01), whereas there was no difference in the PD group (-5.5 versus -5.1 ml/min per m² per year respectively, P=0.41).

Conclusions

In this matched study, AVF creation was associated with a deceleration of kidney function decline compared with a control PD-oriented group. Prospective studies are needed to assess the potential mechanisms between vascular access creation and eGFR slope attenuation.

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.

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.