Complications of Native Arteriovenous Fistula: The Role of Color Doppler Ultrasonography

Role of Doppler Evaluation in Assessing the Maturation of the Arteriovenous Fistula for Hemodialysis: An Observational Study

Introduction Arteriovenous fistulas (AVFs) are the preferred type of vascular access for hemodialysis due to their lower risk of complications. This study aimed to determine the role of Doppler evaluation in assessing AVF. Materials and methods We conducted an 18-month prospective observational study of 33 hemodialysis patients who underwent a procedure for the creation of AVF at the Department of Radio-Diagnosis at Sri Devaraj Urs Academy of Higher Education and Research. Patients were evaluated using color Doppler ultrasound. Participants underwent a careful history and clinical examination to diagnose the disease. All relevant parameters were documented in a structured study proforma. AVF maturation was assessed postoperatively at four weeks using Doppler ultrasound color flow evaluation by looking for vascular components (flow volume, vein, and arterial diameter). Data were analyzed using CoGuide V 1.0.3 Statistical Software (CoGuide, Bangalore, India). Results A total of 33 patients, with a mean age of 54.6 ± 7.8 years, were evaluated. Of the 33 participants, 24 (72.7%) were male, and nine (27.3%) were female. The majority (47%, n=16) of participants had diabetes mellitus, eight (24%) had hypertension, and 10 (29%) had both diabetes mellitus and hypertension. A brachiocephalic fistula was created in 45.5% of participants, and 33.33% had radiocephalic anastomoses. Five participants were diagnosed with AVF complications: two had a pseudoaneurysm, and three had a cephalic vein thrombus. Clinical and demographic characteristics (age, vascular components, and complications) were not significantly related to AVF maturation. Conclusions Doppler ultrasound plays an important role in selecting vessels for AVF preoperatively and assessing AVF maturation postoperatively, thus reducing the primary fistula failure rate. The findings suggest that Doppler evaluation can be a reliable tool for assessing AVF maturation and predicting surgical success, which could help healthcare providers make informed decisions about the best course of treatment for their patients. Continued research is warranted in this area to further understand the role of Doppler ultrasound in evaluating AVF surgery.

Arterial diameter ratio as a reliable predictor for upper limb steal syndrome in patients with arteriovenous fistula for hemodialysis

OBJECTIVES

The aim of this study is to assess the association between the anastomosis diameter enlargement and steal syndrome incidence in patients with upper limb arteriovenous fistula using ratios as reliable predictors.

MATERIAL AND METHODS

An analytical cross-sectional prospective study was conducted. A total of 49 patients with AVF hemodialysis access were recruited. Twenty-four participants with positive steal syndrome and 25 control were enrolled in the study. Anastomosis diameter, anastomosis diameter ratio, and volume flow ratio were measured ultrasonographically by two expert vascular sonographers. These clinical parameters were recorded and analyzed to assess the difference and association. Patient risk factors and steal syndrome association were emphasized.

RESULTS

The study analysis indicates a strong association in the anastomosis diameter and anastomosis diameter ratio between steal and non-steal patients with a p-value ≤0.05. Additionally, there was a significant increase in the volume flow ratio in the patients with steal syndrome compared to the control group (p-value ≤0.05). There was a strong relationship between steal syndrome and the presence of peripheral arterial disease (73.9%, p = 0.001). The ICC index of absolute agreement between the two observers was ICC= 0.99 (95% CI 0.99-0.99, n = 10), indicating excellent agreement between observers.

CONCLUSION

Anastomosis diameter and volume flow ratio strongly suggest that steal syndrome is associated with the increased diameter of anastomosis. Patients with a≥1.05 anastomosis diameter ratio have a greater risk of developing steal syndrome than those with an anastomosis ratio of ≤0.8. In addition, patients with a volume flow ratio ≥0.98 have an increased risk of developing steal syndrome than those with a volume flow ratio of ≤0.75.

Effect of patient characteristics on vessel enhancement on arterio-venous fistula CT angiography in a retrospective cohort study

To evaluate the effects of various patient characteristics on vessel enhancement on arterio-venous fistula (AVF) computed tomography (CT) angiography (AVF-CT angiography). A total of 127 patients with suspected or confirmed shunt stenosis and internal AVF complications were considered for inclusion in a retrospective cohort study. The tube voltage was 120 kVp, and the tube current was changed from 300 to 770 mA to maintain the image quality (noise index: 14) using automatic tube current modulation. To evaluate the effects of age, sex, body size, and scan delay on the CT number of the brachial artery or vein, we used correlation coefficients and multivariate regression analyses. There was a significant positive correlation between the CT number of the brachial artery or vein and age (R = 0.21 or 0.23, P < .01). The correlations were inverse with the height (r = -0.45 or -0.42), total body weight (r = -0.52 or -0.50), body mass index (r = -0.21 or -0.23), body surface area (body surface area [BSA]; r = -0.56 or -0.54), and lean body weight (r = -0.55 or -0.53) in linear regression analysis (P < .01 for all). There was a significant correlation between the CT number of the brachial artery or vein and scan delay (R = 0.19 or 01.9, P < .01). Only the BSA had significant effects on the CT number in multivariate regression analysis (P < .01). The BSA was significantly correlated with the CT number of the brachial artery or vein on AVF-CT angiography.

Sonographic 3-D Power Doppler Imaging Enhances Rapid Assessment of Morphologic and Pathologic Arteriovenous Fistula Variations

Early detection of pathologic variations in an arteriovenous fistula (AVF) is essential for preventing fistula dysfunction in individuals undergoing hemodialysis. This study aimed to evaluate the clinical applicability of 3-D tomographic ultrasound (tUS) for rapid and simple visualization of AVF morphology and pathology. We assessed 53 AVFs in 50 consecutive patients using 3-D tUS including secondary, blinded reading. For all examinations, a high-end ultrasound (US) device was used with linear probe, attached to a tUS system to allow freehand 3-D scanning. Participants were examined by 2-D US and 3-D tUS with different raw data (B-mode, power Doppler, B-flow). Additional angiography was available for 15 participants with scheduled interventions. In all participants, 3-D tUS allowed a 3-D representation of AVFs in angiographic-like images with good image quality. The 2-D US assessment took 7.9 ± 4.0 min. A 3-D power Doppler scan required, on average, 1.4 ± 0.6 min. Diagnostic accuracy of blinded reading for pathologies was high (86.8% for aneurysms and 79.2% for stenoses). Bland-Altman plots showed an excellent correlation of 3-D tUS with 2-D US and angiography. 3-D tUS is an easily and rapidly applicable method for visualizing morphologic and pathologic AVF variations. Color-coded 3-D reconstruction of power Doppler data simplifies detection of perfused aneurysms and stenoses.

Arteriovenous Fistula Surveillance Using Tomographic 3D Ultrasound

OBJECTIVE

A well functioning arteriovenous fistula (AVF) is essential for haemodialysis. Despite regular duplex ultrasound (DUS) a significant number of AVFs fail. Tomographic 3D ultrasound (tUS) creates a 3D image of the AVF that can be interpreted by the clinician. DUS, tUS, and fistulograms were compared for the identification and measurement of flow limiting stenosis.

METHODS

Patients with AVF dysfunction on routine Transonic surveillance, defined as (1) > 15% reduction in flow on two consecutive occasions, (2) > 30% reduction in flow on one occasion, (3) flow of < 600 mL/sec, (4) presence of recirculation, underwent DUS. AVF tUS imaging was performed prior to fistulography. All fistulograms were reported by the same consultant radiologist and tUS images by the same vascular scientist blinded to the fistulogram results. Maximum diameter reduction in all stenoses were measured using all three imaging techniques.

RESULTS

In 97 patients with 101 stenoses, the mean (± standard deviation [SD]) severity of stenosis was 63.0 ± 13.9%, 65.0 ± 11.6%, and 64.8 ± 11.7% for the fistulograms, DUS, and tUS respectively. The mean (± SD) time between ultrasound and fistulography imaging was 15.0 ± 14.5 days. Assuming the fistulogram as the "gold standard", Bland-Altman agreement for DUS was -1.9 ± 15.5% (limit of agreement [LOA] -32.2 - 28.4) compared with -1.7 ± 15.4% (LOA -31.9 - 28.4) for tUS. Median (± interquartile range) time to complete the investigation was 09:00 ± 03:19 minutes for DUS and 03:13 ± 01:56 minutes for tUS (p < .001).

CONCLUSION

DUS and tUS were equally accurate at detecting AVF complications but tUS investigation requires less skill and was significantly quicker than DUS.

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.

Value of duplex Doppler ultrasonography for the evaluation of dysfunctional hemodialysis access arteriovenous fistulas prior to endovascular interventions

PURPOSE

To demonstrate accuracy of duplex Doppler ultrasonography (DUS) for the evaluation of native-vein arteriovenous fistula (AVF) dysfunction in end-stage renal disease patients.

METHODS

This retrospective study included 60 patients with dysfunctioning native-vein AVF evaluated with DUS and digital subtraction angiography (DSA) whose results were compared for detection, identification, and localization of AVF lesions. We calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of DUS and evaluated the agreement between DUS and DSA by the Cohen's kappa coefficient (κ).

RESULTS

DUS identified correctly 123 of 130 lesions (sensitivity 94.6%, specificity 97.5%, PPV 98.4%, NPV 92%, accuracy of 95.7%). DUS localized correctly 123 of 130 lesions (sensitivity 94.6%, specificity 98.4%, PPV 98.4%, NPV 94.6%, accuracy 96.4%). The κ value was 0.9120 for detection of all lesions (almost perfect agreement).

CONCLUSION

DUS is a reliable method for the initial evaluation of dysfunctional AVFs, with high sensitivity for detecting and correctly localizing circuit problems.

Standardized Protocol for Hemodialysis Vascular Access Assessment: The Role of Ultrasound and ColorDoppler

Introduction: Ultrasound and colorDoppler technique, which is relatively inexpensive, rapid, non-invasive and repeatable is a powerful tool used for early diagnosis of vascular access (VA) complications in hemodialysis patients. To date a standard and widely comprehensible echocolorDoppler (ECD) protocol is not available. Materials and Methods: A simple step-by-step protocol based on anatomical and hemodynamic parameters of VA has been developed during a 3-years VA ECD follow-up. It consists of an ECD study scheme. The algorithm created involves the calculation of brachial artery flow, description of artero-venous and/or graft-vascular anastomosis and efferent vessel and/or graft. Results: The algorithm allows to formulate a medical report that takes into account both anatomic and hemodynamic parameters of the VA. Reduction of complications and the prevention of chronic complications as well as the early detection of acute problems were achieved. Discussion and Conclusion: The creation of a step-by-step protocol may simplify the multidisciplinary management of VA, its monitoring and the early diagnosis of its complications.

Three-dimensional MDCT angiography for the assessment of arteriovenous grafts and fistulas in hemodialysis access

Arteriovenous grafts and fistulas are placed for long-term hemodialysis access, and their associated complications can lead to considerable morbidity. Multi-detector computed tomography (MDCT) images provide accurate delineation of hemodialysis access anatomy and show potential complications. This review makes the reader more familiar with vascular access anatomy and configurations, describes the appearance of access complications encountered on MDCT, and discusses endovascular and surgical treatment options for complications, which should aid in post-treatment evaluation.

Evaluation of Percutaneous Transluminal Angioplasty Screening using Color Doppler Ultrasonography

Purpose

Well-functioning vascular access is important in hemodialysis patients. The aim of this study was to assess stenosis using color Doppler ultrasonography as well as to investigate a possible association between the need for percutaneous transluminal angioplasty and hemodynamic parameters.

Methods

A prospective study of the medical records of color Doppler ultrasonography routine examinations of 372 patients was conducted at a dialysis satellite clinic in Japan. Data were analyzed using logistic regression analysis and the receiver operating characteristic curve. The cutoff point for hemodynamic parameters was determined to explore the predictors of percutaneous transluminal angioplasty.

Results

Logistic regression analysis showed that brachial artery flow volume, brachial artery resistance index and puncture point flow volume divided by the quantity of dialysis blood flow rate were independently associated with percutaneous transluminal angioplasty. Brachial artery resistance index over 0.61, brachial artery blood flow volume under 665 mL/min and puncture point flow volume divided by dialysis blood flow rates under 1.25 were predictive values of the need for percutaneous transluminal angioplasty.

Conclusions

These parameters could be used as markers for assessing percutaneous transluminal angioplasty risk in hemodialysis patients.