Advancing arteriovenous fistula needling: The role of physical exam and doppler ultrasound

BACKGROUND

The success of haemodialysis (HD) critically depends on the effective use of arteriovenous fistulas (AVFs). The precise needling technique is vital to minimise complications and ensure functional vascular access.

OBJECTIVE

This study assesses the effectiveness of a nursing consultation protocol, which integrates physical examination (PE) with Doppler Ultrasound (DUS), in preparing patients for the first AVF needling.

DESIGN/PARTICIPANTS

A cross-sectional analysis at a Portuguese National Health Service Hospital engaged thirty new HD patients, four HD needling experienced nurses and one HD vascular access nurse. This study examines the accuracy of PE in assessing the matured AVF by the four nurses compared to a trained vascular access nurse encompassing systematic PE and DUS.

MEASUREMENTS

The primary data incorporated AVF characteristics derived from PE (inspection, palpation, and auscultation) and DUS findings (vein depth, diameter, and blood flow). A secondary focus was evaluating the change in nurses' perceived needling complexity following the nursing consultation.

RESULTS

The nursing consultation significantly enhanced the identification of crucial AVF features, such as accessory veins (p = 0.002), and improved the accuracy of AVF morphology assessments. This led to identifying longer needling tracks (p = 0.031) and a higher number of safe needling points (p = 0.016). Nurses reported a notable reduction in perceived complexity and potential adverse events following this method (p = 0.027).

CONCLUSIONS

Integrating structured PE with DUS in a nursing consultation framework significantly improves the preparation for AVF needling. This approach enhances the efficiency and safety of AVF needling and boosts nurse confidence and patient care in HD settings.

Prognostic nomogram for the patency of wrist autologous arteriovenous fistula in first year

Autologous arteriovenous fistula (AVF) is preferred in hemodialysis patients. Maintaining its patency is a critical problem. This study aimed to create a nomogram model for predicting 1-year primary patency of AVF. Consequently, a total of 414 patients were retrospectively enrolled and randomly allocated to training and validation cohorts. Risk factors were identified by multivariable logistic regression and used to create a nomogram model. Performance of the model was evaluated by receiver operating characteristic (ROC) curve, Hosmer-Lemeshow test, and calibration curve. The results suggested that diameter of cephalic vein, low-density lipoprotein, glycosylated hemoglobin (%), and C-reactive protein were risk factors which could predict the patency of AVF. Area under ROC curves for training and validation cohorts were 0.771 and 0.794, respectively. Calibration ability was satisfactory in both cohorts. Therefore, present nomogram model could predict the 1-year primary patency of AVF.

Hemodialysis access flow measurement: Comparison of ultrasound dilution and ultrafiltration method on NIKKISO DBB-EXA™ dialysis machine

BACKGROUND

The methods of estimating vascular access (VA) flow rates are usually based on the indicator dilution theory by measuring recirculation during dialysis sessions.

METHODS

This is an observational study comparing the VA flow rates measured by NIKKISO DBB-EXA™ and Transonic®. Sixty-five patients (38 M/27 F, mean age 72 ± 10 years) participated in the study. We measured the VA flow rates during dialysis twice with each method and repeated the procedure 7 days later.

RESULTS

In 130 double measurements for each method on the same day, mean flow with Transonic® was 1413±715 ml/min and with DBB-EXA™ 1297 ± 664 ml/min. In Bland-Altman analysis, the mean difference between the two methods was 159 ± 211 ml/min (limits of agreement: -274 and 572 ml/min). Eighty-one out of the 130 DBB-EXA™ measurements were within 25% of the Transonic® measurements (62% accuracy). Regarding reproducibility of each method on different days, mean difference in the Bland-Altman analysis was 29 ± 620 ml/min (limits of agreement: -1186 and 1244 ml/min) for the Transonic® measurements and 132 ± 625 ml/min (limits of agreement: -1092 and 1356 ml/min) for the DBB-EXA™ measurements. The measurements on two different days were within 25% of each other for 52 of the 65 patients (80%) with the Transonic® method, and for 35 of the 65 patients (54%) with the DBB-EXA™ method.

CONCLUSIONS

In conclusion, the DBB-EXA™ method underestimates VA flow rates compared to the Transonic® technique, resulting in a limited accuracy of 62%. There was poor reproducibility for both methods in different day measurements with better performance of the Transonic® technique. The DBB-EXA™ method could be used as a simple tool for a rough estimate of VA flow rates but cannot replace the Transonic® reference method.

Effectiveness of Flow Volume Measurement Training Using a Custom-Made Doppler Flow Simulator

INTRODUCTION

This study was conducted to analyze the effectiveness of a custom-made Doppler ultrasound (DUS) flow simulator, vascular phantom, and Doppler test fluid in the training of dialysis staff in flow volume (FV) measurements for arteriovenous (AV) access in hemodialysis (HD) patients.

METHODS

A DUS flow simulator was constructed using a continuous renal replacement therapy machine. Vascular phantoms were constructed using a rubber enema tube and keyboard cleaning gel. The Doppler test fluid consisted of freeze-dried instant coffee granules and 0.9% saline. This easy and affordable simulator was used to train 12 dialysis staff members, with no previous experience in DUS FV measurement. After a 3-day lecture course, the staff members performed DUS analyses on the AV access of HD patients. Thereafter, they underwent a 3-day training course using the simulator and then performed the DUS analyses of the AV access again. Each staff member assessed the FV 3 times, and the mean values of the measurements pretraining and posttraining were analyzed using paired t tests.

RESULTS

The difference in the mean value of FV measurements and the reference value decreased from 131.6 mL/min to 62.5 mL/min (95% confidence interval = 30.0-108.0, P = 0.002), and the standard deviation of the FV measurements decreased from 96.9 mL/min to 47.0 mL/min (95% confidence interval = 7.9-91.8, P = 0.023) after DUS training with the simulator.

CONCLUSIONS

The accuracy and reproducibility of FV measurements markedly improved after training with the simulator; it may be helpful for medical practitioners involved in AV access for HD treatment.

Use of blood temperature monitor with Twister device for the surveillance of vascular access in maintenance hemodialysis: Comparison with Doppler ultrasonography

BACKGROUND

Regular monitoring of vascular access in patients on maintenance hemodialysis is important to detect early vascular access complications. We compared vascular access blood flow determined by blood temperature monitor and Doppler ultrasonography to evaluate the usefulness of blood temperature monitor.

METHODS

In total, 70 patients on maintenance hemodialysis were enrolled from three dialysis centers. Vascular access blood flow was measured thrice at 6-month intervals using Doppler ultrasonography to determine arterial inflow (Q-DUa), venous outflow (Q-DUv), and flow between punctures (Q-DUb) using BTM® (Q-BTM). Twister® was placed between the hemodialysis needle and blood lines, allowing simple reversal of flow without stopping the hemodialysis pump.

RESULTS

In total, 203 measurements were recorded, with median values (interquartile range) for Q-BTM, Q-DUa, Q-DUv, and Q-DUb of 1139.0 (868.0-1588.0) mL/min, 960.3 (658.7-1380.4) mL/min, 946.0 (552.0-1515.0) mL/min, and 1067.7 (544.8-1635.0) mL/min, respectively. For all measurements, the mean intraclass correlation coefficients were 0.52 (95% confidence interval, 0.36-0.64) for Q-DUa; 0.37 (95% confidence interval, 0.15-0.53) for Q-DUv; and 0.45 (95% confidence interval, 0.26-0.59) for Q-DUb. Analysis of a receiver operating characteristics curve yielded a cut-off of 627 mL/min for Q-BTM to predict stenosis.

CONCLUSION

In patients on maintenance hemodialysis, blood flow measured by blood temperature monitor moderately correlated with Doppler blood flow. It was more related to arterial inflow than venous outflow or flow between punctures. The blood temperature monitor method was not inferior to Doppler ultrasonography. Therefore, blood temperature monitor could be recommended for routine vascular access monitoring because it can be done quickly without interrupting dialysis.

Randomised clinical study of the impact of routine preoperative Doppler ultrasound for the outcome of autologous arteriovenous fistulas for haemodialysis

Background:

Arteriovenous fistulas are the gold standard of vascular accesses in haemodialysis; however, they have a considerable primary failure rate. This study evaluated the comparative reliability of routine preoperative Doppler ultrasound with an isolated physical examination of autologous arteriovenous fistulas within the Single Health System of Brazil and analysed the potential clinical benefit, improvement in primary failure rates and its economic impact.

Methods:

A non-blind randomised clinical study group of patients undergoing a vessel mapping with preoperative Doppler ultrasound (ultrasound group) and a control group who had undergone only a physical examination (clinical group) before the vascular procedures was performed. The role of the arteriovenous fistula in dialysis and possible alterations was evaluated in both the groups and followed up for 6 months.

Results:

Of the initial 248 eligible patients, there was a randomisation of 230 patients, 228 of whom were submitted for surgery, 114 in each group. In the clinical group, a significantly higher rate of primary failure was recorded, with 13.6% versus 4.4% in the ultrasound group (p = 0.002). The Kaplan–Meier curve with log-rank analysis showed a significantly higher primary patency in the ultrasound group (p = 0.042). Regarding the cost-effectiveness of the use of Doppler ultrasound, there was no increase in the final cost compared to the physical examination (US$1.28/fistula day × US$1.29/fistula day).

Conclusion:

It was concluded that Doppler ultrasound contributed to the reduction of primary failure, leading to a significantly superior primary patency of arteriovenous fistulas, and no increase in the final cost. This justifies its routine preoperative use in the Single Health System. Registration number RBR-474xhn (http://www.ensaiosclinicos.gov.br).

The influence of a doppler ultrasound in arteriovenous fistula for dialysis failure related to some risk factors

INTRODUCTION

The increasing prevalence of chronic kidney disease has increased the demand for arteriovenous fistula (AVF) care. The objective of this study was to assess the relationship between some risk factors for AVF failure (advanced age, female sex, diabetes, obesity, central venous catheter, previous fistula, and hospitalization) and having a Doppler ultrasound performed preoperatively.

METHODS

A prospective study was performed with 228 dialysis patients from Imperatriz, Maranhão. Half of the sample was randomly selected to receive preoperative Doppler ultrasound and the other half did not, from the period of October 2016 to September 2018.

RESULTS

There were 53 total failures corresponding to 23.2% of our sample, which is almost double that of the patients in the clinical group. Considering the failures and risk factors associated with the overall sample, there was a statistically significant association between a central venous catheter on the same side of the AVF with P = 0.04 (Odds Ratio 1.24) and obesity with P = 0.05 (Odds Ratio 1.36), which was not repeated in the Doppler ultrasound group individually. There was no statistically significant difference between the Doppler group and clinical group with respect to the amount of days of previous AVF hospitalization and failure.

CONCLUSIONS

We concluded that the reduction of failures with an introduction of the Doppler was statistically significant in the overall sample, but establishing a relationship between specific risk factors and failure was only possible with two of the risk factors in the study - obesity and central venous catheter on the same side of the AVF.

The clinical importance of color Doppler ultrasonography in puncture related complications of hemodialysis vascular access

Background

The long-term survival of patients on hemodialysis (HD) is dependent on adequate HD which depends on quality and degree of functionality of vascular access. The aim of our study is to detect the role of color Doppler ultrasonography in evaluation of arteriovenous fistula (AVF).

Materials and methods

Between January 2017 and October 2017, 60 patients had complicated AVF at Qena General Hospital & Qena University Hospital as primary and tertiary centers respectively with the same age group between 18 and 50 years old, had no diabetes mellitus were evaluated using color duplex-Doppler ultrasound (CDUS) after AVF maturation for detection of complications and comparison between primary and tertiary centers of its incidence.

Results

The overall results revealed that 11 patients from 30 patients that had been referred to tertiary centers have complicated AVF (36.7%), and 19 patients had no shunt complication (63.3%). Twenty-two patients from 30 patients that had been referred to primary HD centers had complicated shunts. Thrombosis at tertiary centers represents 13.3%, stenosis 3.3% (1 patient), aneurysmal formation had 6.6% for (2 patients), hematoma 6.6%(2 patients), infection 3.3% (1 patient), venous hypertension 3.3% (1 patient), thrombosis and hematoma at primary centers 16.6% (5 patients for each), aneurysmal formation and infection 13.3% for each, and stenosis 10%.

Conclusions

CDUS is a readily-available, non-invasive, risk-free, bed-side technique that allows precise anatomic knowledge, qualitative, and quantitative data of the upper limb vascular system which greatly help in preoperative planning of AVF creation, assessment of prime time for puncture (maturation), early detection of complications, and choice of appropriate therapeutic procedure for their treatment.

Custom-made Doppler ultrasound flow simulator for dialysis access using continuous renal replacement therapy machine

The purpose of this article was to introduce an easy and inexpensive way of making a simulator for training in Doppler ultrasound flow rate measurement using a continuous renal replacement therapy machine and home-made phantoms. A Doppler ultrasound flow simulator was made using a continuous renal replacement therapy machine and vascular phantoms for flow rate assessment of dialysis access with readily accessible components including rubber tube, keyboard cleaning gel, and freeze-dried instant coffee granules. The simulator is an affordable and easy method of Doppler ultrasound flow rate measurement training for dialysis staff using materials readily available in dialysis centers.

Value of Doppler evaluation of physically abnormal fistula: hemodynamic guidelines and access outcomes

BACKGROUND/AIMS

The strategy of access care at out center involves the use of ultrasound (USG) in case of physical examination (PE) abnormality. USG determines the need of angiography. This study investigated the possible association between the need for percutaneous transluminal angioplasty (PTA) and hemodynamic parameters of USG. The study also assessed the effects of this monitoring strategy on outcomes in comparison with a historical control.

METHODS

A retrospective study of the medical records of 127 patients (65 PTA, 62 non-PTA) was conducted. Data were analyzed using logistic regression analysis and receiver operating characteristic curve. Fistula outcomes and intervention rates were calculated and compared with 100 historic controls.

RESULTS

Logistic regression analysis showed that brachial artery flow volume (FV) < 612.9 mL/min or brachial artery resistance index (RI) > 0.63 was independently associated with the need for PTA. This monitoring strategy showed an a reduction in thromboses (0.02 ± 0.11 events/arteriovenous fistula [AVF]-year vs. 0.07 ± 0.23 events/AVF-year, p = 0.046), reduction in central venous catheter placement (0.01 ± 0.05 events/AVF-year vs. 0.06 ± 0.22 events/AVF-year, p = 0.010), reduction in access loss (0.02 ± 0.13 events/AVF-year vs. 0.19 ± 0.34 events/AVF-year, p = 0.015), and increase in access selective repair (0.49 ± 0.66 events/AVF-year vs. 0.21 ± 0.69 events/AVF-year, p = 0.003), compared to historic control.

CONCLUSION

There was significant stenosis if brachial artery FV was < 612.9 mL/min or RI was > 0.63 for PE abnormality. These parameters should be used as markers for assessing PTA risk in hemodialysis patients. Addition of USG to determine the need of angiography after detection of PE abnormality leads to decreases in access thrombosis, catheter placement, and access loss despite increasing access intervention rates compared to clinical monitoring.

Application of ultrasonography in monitoring the complications of autologous arteriovenous fistula in hemodialysis patients

This study aims to evaluate the application of color Doppler ultrasound in monitoring the complications of autologous arteriovenous fistula in hemodialysis patients.Patients with maintenance hemodialysis who underwent autologous arteriovenous fistula were enrolled in this cross-sectional study. Ultrasound was used to detect fistula complications (stenosis and thrombosis), brachial artery diameter, and hemodynamic parameters. The ultrasound parameters were analyzed and screened to identify the most important indicator for monitoring complications.In all, 89 patients were included. Ultrasound showed 72 cases (80.90%) had normal fistula structure, and 17 cases (19.10%) had complications. The diameter, time-averaged mean velocity, flow volume, and diastolic peak velocity of brachial artery in complication group were significantly lower than those of noncomplication group (P < .05). The brachial artery pulsatility index and resistance index of complication group were significantly higher than those of noncomplication group (P < .05). There was no significant difference in peak flow velocity between complication and noncomplication group (P > .05). Indicators showed statistical significance were grouped based on quantiles. The incidence of complications was higher when the brachial artery diameter was ≤5.40 mm, or brachial artery flow was ≤460 mL/ min, or brachial artery pulsatility index was >1.04, or brachial artery resistance index was >0.60.Ultrasound monitoring of brachial artery diameter and hemodynamic parameters can help early detection of fistula complications. When the brachial artery diameter was ≤5.40 mm, or brachial artery flow was ≤460 mL/min, or brachial artery pulsatility index was >1.04, or brachial artery resistance index >0.60, stenosis or thrombosis should be checked to prevent fistula failure.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Clinical experience with ultrasound guided angioplasty for vascular access

Background

The use of ultrasound guided percutaneous transluminal angioplasty (UG-PTA), which use ultrasound as an imaging modality, is an evolving strategy. But, in Korea, this method is rarely used. We report our experiences with UG-PTA with respect to technical success rates and complication rates compared to conventional PTA (C-PTA), performed between 2010 and 2015 at Samsung Changwon Hospital, Korea.

Methods

In our series, 53 cases of UG-PTA and 90 cases of C-PTA were reviewed, respectively. Cases of central vein stenosis, cephalic arch stenosis, arterial stenosis and thrombosis were excluded. However, cases of juxta-anastomotic stenosis and outflow vein stenosis were included.

Results

Technical success was achieved in 96.2% (51 of 53) of cases in the UG-PTA group and in 93.3% (84 of 90) of cases in the C-PTA group, respectively (P = 0.710). Technical failure was experienced in a total 8 cases (UG-PTA group: 2/53, 3.8%; C-PTA group: 6/90, 6.7%). No differences were observed in complications.

Conclusion

Duplex ultrasound-guided angioplasty for dialysis access in the outpatient setting is feasible, safe, and effective for peripheral venous stenotic lesions. It offers many advantages over conventional angiographic procedures, and, in the future, it has great potential to play a significant role in the management of these challenging patients.

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.

Does pre- and post-angioplasty Doppler ultrasound evaluation help in predicting vascular access outcome?

BACKGROUND

Kidney Disease - Improving Global Outcomes (KDIGO) recommends post-percutaneous transluminal angioplasty (PTA) <30% residual stenosis (RS) and hemodynamic parameters improvement. Primary end point: how post-PTA access blood flow (ABF) improvement predicts vascular access (VA) outcome. Secondary: compare Doppler ultrasound (DU) and angiography diagnostic accuracy; determine how other factors predict outcome.

METHODS

Eighty patients. DU evaluation performed pre- and post-PTA. Several parameters recorded. Secondary patency verified after 6 months.

RESULTS

Initial ABF 537 ± 248 mL/min; final ABF 1013 ± 354 mL/min. Number and location of stenosis was highly correlated between DU and angiography (p<0.001); central vessels mismatching. First semester overall survival was 63%; significantly better for fistulas (76%) than grafts (51.7%), p 0.044. Final RS>30% associated to better survival, p 0.038. Initial ABF<500 mL/min and multiple stenosis did not affect outcome (p>0.05). A >2-fold ABF increase had no significant impact on fistulas (p>0.05) but was significantly associated with worst outcomes in grafts (23.1% vs. 73.5%, p 0.009). Grafts had lower survival (HR 3.3, p 0.034).

CONCLUSIONS

Although less accurate for central lesions, DU has a key role on VA surveillance, allowing a morphologic and hemodynamic assessment. Angioplasty is effective in preserving VA; however, it may increase restenosis due to accelerated neointimal hyperplasia. Current parameters are not useful. Trials addressing this issue are needed.

Surveillance for Hemodialysis Access Stenosis: Usefulness of Ultrasound Vector Volume Flow

Purpose

To investigate if ultrasound vector-flow imaging (VFI) is equal to the reference method ultrasound dilution technique (UDT) in estimating volume flow and changes over time in arteriovenous fistulas (AVFs) for hemodialysis.

Materials and methods

From January 2014 to January 2015, patients with end-stage renal disease and matured functional AVFs were consecutively solicited to participate in this prospective study. All patients were included after written informed consent and approval by the National Committee on Biomedical Research Ethics and the local Ethics Committee (journal no. H-4-2014-FSP). VFI and UDT measurements were performed monthly over a six-month period. Nineteen patients were included in the study. VFI measurements were performed before dialysis, and UDT measurements after. Statistical analyses were performed with Bland-Altman plot, Student's t-test, four-quadrant plot, and regression analysis. Repeated measurements and precision analysis were used for reproducibility determination.

Results

Precision measurements for UDT and VFI were 32% and 20%, respectively (p = 0.33). Average volume flow measured with UDT and VFI were 1161 mL/min (±778 mL/min) and 1213 mL/min (±980 mL/(min), respectively (p = 0.3). The mean difference was -51 mL/min (CI: -150 mL/min to 46 mL/min) with limits of agreement from -35% to 54%, with a strong correlation (r2 = 0.87). A large change in volume flow between dialysis sessions detected by UDT was confirmed by VFI (p = 0.0001), but the concordance rate was poor (0.72).

Conclusions

VFI is an acceptable method for volume flow estimation and volume flow changes over time in AVFs.