Cephalic vein measurement before forearm fistula creation: does use of a tourniquet to meet the venous diameter threshold increase the number of usable fistulas?

Guidelines on vascular access for hemodialysis from the Brazilian Society of Angiology and Vascular Surgery

Chronic kidney disease is a worldwide public health problem, and end-stage renal disease requires dialysis. Most patients requiring renal replacement therapy have to undergo hemodialysis. Therefore, vascular access is extremely important for the dialysis population, directly affecting the quality of life and the morbidity and mortality of this patient population. Since making, managing and salvaging of vascular accesses falls within the purview of the vascular surgeon, developing guideline to help specialists better manage vascular accesses for hemodialysis if of great importance. Thus, the objective of this guideline is to present a set of recommendations to guide decisions involved in the referral, evaluation, choice, surveillance and management of complications of vascular accesses for hemodialysis.

Venous dilation effect of hot towel (moist and dry heat) versus hot pack for peripheral intravenous catheterization: a quasi-experimental study

BACKGROUND

Heat application before peripheral intravenous catheterization is recommended for venous dilation. Hot pack application enlarges the venous diameter in healthy adults; however, hot towels (moist and dry heat) are used often in some medical cases. However, it is unclear whether hot towel application promotes venous dilation better than hot pack application. This study compared the venous dilation effect of using a hot towel (moist and dry heat) to a hot pack before applying the tourniquet at an access site for peripheral intravenous catheterization.

METHODS

Eighty-eight healthy females aged 18-29 years were recruited for this quasi-experimental study. They underwent three types of heat applications (hot pack, moist hot towel, and dry hot towel [moist hot towel wrapped in a dry plastic bag], all of which were warmed to 40 ± 2 °C and performed for 7 min) to their forearm and tourniquet application for 30 s after each heating. Venous diameter and depth were measured using ultrasonography, and venous palpability and visibility (venous assessment score) was observed as venous dilatation effects. In addition, the skin temperature, stratum corneum hydration, and subjective evaluation of the warmth were measured.

RESULTS

There were no significant differences in venous diameter and assessment scores after intervention between the dry hot towel and the hot pack groups, and the effect size was negligible (Cohen's d < 0.20). However, these measurements were significantly lower for the moist hot towel than for the other two heat applications (P < .001). Although there was no significant difference in skin temperature and warmth rating score between the dry hot towel and the hot pack, these were significantly lower for the moist hot towel than for the other two heat applications (P < .001). The amount of change in stratum corneum hydration of the dry hot towel was not significantly different from that of the hot pack; however, that of the moist hot towel was significantly larger than that of the other two heat applications (P < . 001.) CONCLUSIONS: A method in which a towel warmed in hot water is wrapped in a dry barrier may be an alternative to a hot pack.

TRIAL REGISTRATION

This study was registered with University Hospital Medical Information Network in Japan (Registration No.: UMIN000048308. Registered on July 7, 2022).

Small Caliber Distal Cephalic Veins Undergo Significant Dilation under Anesthesia and Can Successfully Be Used for Arteriovenous Fistula Creation

BACKGROUND

Successful arteriovenous fistula (AVF) maturation and use for dialysis is highly dependent on preoperative diameter. Small veins (<2 mm) exhibit high failure rates and are typically avoided. This study investigates the effects of anesthesia on the distal cephalic vein diameter as compared to preoperative outpatient vein mapping for the purpose of hemodialysis access creation.

METHODS

One hundred eight consecutive procedures for dialysis access placement met inclusion criteria and were reviewed. All patients received preoperative venous mapping and postanesthesia ultrasound mapping (PAUS). All patients received either regional and/or general anesthesia. A multiple regression was conducted to determine predictors of venous dilatation. The independent variables included both demographical and operative-specific variables such as the type of anesthesia. Outcomes of fistula maturation (successful cannulation and dialysis) were analyzed.

RESULTS

In this cohort, the mean preoperative vein diameter was 1.85 mm and the mean PAUS diameter was 3.45 mm, a 2.21× increase, with only 2 patient veins failing to increase in diameter. Smaller veins (<2 mm) exhibited significantly more dilation than larger veins after anesthesia (2.73 vs. 1.47×, P < 0.001). In the multiple regression analysis, smaller vein diameter was correlated with a significantly greater degree of dilation (P < 0.001). The degree of venous dilation was not affected by patient demographic-specific factors or by the type of anesthesia (regional block versus general) in the multiple regression analysis. 6 month follow-up data for fistula maturation was available for 75 of 108 patients. Small veins (<2 mm) on preoperative ultrasound matured at a similar rate as larger veins (90% vs. 91.4%, P = 0.833).

CONCLUSIONS

Small caliber distal cephalic veins experience a significant degree of dilation under regional and general anesthesia and can successfully be used for AVF creation. Consideration should be made to perform a postanesthesia vein mapping for all patients undergoing access placement despite preoperative venous mapping results.

The feasibility and efficiency for constructing arteriovenous fistula with <2 mm vein-a systematic review and meta-analysis

Background

Autogenous arteriovenous fistula (AVF) is an efficient hemodialysis access for patients with end-stage kidney disease (ESKD). The specific threshold of vein diameter still not reached a consensus.

Method

We conducted a comprehensive search in PubMed, Embase, and Web of Science databases for articles which comparing the treatment outcomes of AVF with 2 mm as vein diameter threshold. Fixed and random effect model were used for synthesis of results. Subgroup analysis was designed to assess the risk of bias.

Result

Eight high-quality articles were included finally. Among a total of 1,075 patients (675 males and 400 females), 227 and 809 patients possessed <2 mm and ≥2 mm vein respectively. Apart from gender and coronary artery disease (P < 0.05), there was no significant difference in age, diabetes, hypertension or radial artery between maturation and non-maturation groups. The functional maturation rate was lower in patients with <2 mm vein according to fixed effect model [OR = 0.19, 95% CI (0.12, 0.30), P < 0.01]. There was no significant difference in primary [OR = 0.63, 95% CI (0.12, 3.25), P = 0.58] or cumulative patency rates [OR = 0.40, 95% CI (0.13, 1.19), P = 0.10].

Conclusion

Vein diameter less than 2 mm has a negative impact on the functional maturation rate of AVF, while it does not affect the primary and cumulative patency rates (12 months).

The FACT : Use of a novel intermittent pneumatic compression device to promote pre-surgery arm vein dilation in patients with chronic renal failure

BACKGROUND

Arteriovenous fistula (AVF) creation and maturation for hemodialysis is globally a topic of importance given the poor results and high costs associated with renal care. Successful AVF (surgical or endovascular) creation requires appropriate superficial veins and quality arteries. Many procedures fail due to initial small veins with limited blood flow capacity and distensibility. Intermittent pneumatic compression has previously shown success in trials to increase superficial veins in patients with end stage renal disease post AVF. The objective of this study is to investigate the role of an intermittent pneumatic device, the Fist Assist®, to dilate cephalic arm veins in patients with advanced chronic kidney disease (CKD) prior to AVF placement.

METHODS

Three centers enrolled subjects from June 2019 through July 2021. Baseline Doppler measurements of the cephalic vein in standard locations the forearm and upper arm with and without a blood pressure cuff were recorded. Patients were instructed and used Fist Assist® on their non-dominant arm for up to 4 h daily for 90 days. At approximately 3 months, Doppler measurements were repeated. The primary endpoint was cephalic vein enlargement with secondary endpoints based on percentage of veins approaching 2.5 mm in the forearm and 3.5 mm in the upper arm.

RESULTS

Thirty-seven subjects with CKD (mean eGFR 13.8 mL/min) were enrolled and completed the trial. Paired-difference t-tests (one tail) for aggregate data showed significant venous dilation of the cephalic vein in both the forearm and upper arm after use with the Fist Assist® (p < 0.05). Mean differences in the forearm veins were approximately 0.6 and 1.1 mm in the upper arm cephalic vein after Fist Assist® application. There were no major complications reported by any subject during the trial.

CONCLUSIONS

Fist Assist® use in patients with CKD is effective to enhance vein dilation. Forearm and upper arm cephalic veins increased on average 0.6 and 1.1 mm respectively after Fist Assist® application. This is the first trial to evaluate the effect of intermittent, focal pneumatic compression on pre-surgery vein diameter in patients with advanced CKD before AVF creation.

Superficial venous morphometry in the antecubital fossa: An autonomous robotic ultrasound-based analysis

BACKGROUND

The antecubital fossa is an important site for venepuncture and intravenous procedures. The size and location of a vein can affect the success of venepuncture and intravenous access. Several studies have investigated the superficial vein morphometry, but they had small sample sizes or focused on specific populations or groups. Therefore, we conducted a prospective study with large participants in general population to analyse the morphology of the antecubital superficial vein and identify the association of sex, age and body mass index (BMI) with the size and location of the vein.

METHODS

This study collected images of superficial veins prospectively using autonomous robotic ultrasound on the antecubital area between October and November 2020. We measured the superficial vein depth, vertical diameter and horizontal diameter at the antecubital area, extracted population characteristics (sex, age and BMI), and analysed a relationship between the vein dimensions and the characteristics.

RESULTS

In this study, data from 461 participants (201 males and 260 females) with mean age of 41.1 years were produced. The mean vein depth, mean vertical diameter and mean horizontal diameter (±standard deviation) were 4.81 (±2.17), 3.01 (±1.10) and 4.46 (±1.60) mm, respectively. We found significant differences in vein dimensions between males and females, with males having larger vertical and horizontal diameters than females (p < 0.001). The study also revealed significant differences in vein depth and dimensions among age groups and BMI subgroups (p < 0.001).

CONCLUSIONS

These findings revealed that the superficial vein in the antecubital area was oval, with a larger horizontal diameter than vertical diameter. Morphometry revealed differences in sex, age and BMI. Understanding variations in vein dimensions among different subgroups can help medical professionals improve success rate of venous access and patient safety.

Comparison of distal radiocephalic fistula vs proximal radiocephalic fistula

Background:

Distal radiocephalic fistula (DRCF) at wrist is the first option of vascular access in patients undergoing hemodialysis. In patients with a failed DRCF or unsuitable for DRCF the current recommendation is to perform a brachiocephalic fistula. Proximal forearm radiocephalic fistulas (PRCF) are created less frequently. The aim of the present study was to evaluate the outcomes of PRCF and DRCF.

Material and Methods:

A longitudinal study was conducted in the department of MKCG Medical College from January 2018 to July 2019. Data was collected and entered in Microsoft excel. The analysis was done by R version 3.6.1. Quantitative data were presented in the form of Mean and SD and were tested by unpaired t-test. Categorical data were presented as count and proportion and was tested by Chi-square test or if applicable Fischer's exact test. Comparison between two procedures was done by Kaplan-Meier method and evaluated by the log-rank test. With the 95% of Level of significance, P value <0.05 was consider statistically significant during analysis.

Results:

The demographic data of the two patient groups were similar except that those with PRCF were more likely to have had a previous access and caliber of distal vessel was less. Early failure was lower for PRCF than DRCF (6.06% vs 15%). Primary patency rate at one year was 87.87% in PRCF vs 70% in DRCF.

Conclusion:

A PRCF can be a suitable alternative to a brachiocephalic fistula in patients who cannot receive a DRCF.

Ferumoxytol MR Angiography versus Duplex US for Vascular Mapping before Arteriovenous Fistula Surgery for Hemodialysis

Background Duplex US is performed routinely for vascular mapping prior to arteriovenous fistula (AVF) creation for hemodialysis but cannot demonstrate the central vasculature. Ferumoxytol, an iron oxide nanoparticle, provides an alternative to gadolinium contrast material for MR angiography for safe use in chronic kidney disease (CKD). Purpose To assess the clinical utility of ferumoxytol-enhanced MR angiography compared with duplex US for vascular mapping before upper limb AVF creation in participants with CKD. Materials and Methods In a prospective comparative study (ClinicalTrials.gov: NCT02997046) from December 2016 to August 2018, participants with CKD underwent ferumoxytol-enhanced MR angiography and duplex US. Two independent readers evaluated vessels for diameter, stenosis or occlusion, arterial disease, and central stenosis. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to assess intra- and interreader variability. On the basis of accepted standards for AVF creation, an algorithm was developed to predict AVF outcome based on imaging findings. Multivariable regression models used AVF success as the dependent variable and age, sex, and duplex US or ferumoxytol-enhanced MR angiography findings as independent variables. Results Fifty-nine participants with CKD (mean age, 59 years ± 13 [standard deviation]; 30 women) were evaluated. A total of 51 fistulas were created, of which 24 (47%) were successful. Ferumoxytol-enhanced MR angiography showed excellent inter- and intrareader repeatability (ICC, 0.84-0.99) for all variables assessed. In addition to revealing 15 central vasculature stenoses, ferumoxytol-enhanced MR angiography resulted in characterization of 88 of 236 (37%) of the arterial sections examined as unsuitable for AVF creation compared with 61 of 236 (26%) sections with duplex US (P = .01). Ferumoxytol-enhanced MR angiography independently predicted AVF success in models including (odds ratio, 6.5; 95% confidence interval: 1.7, 25; P = .006) and those excluding (odds ratio, 4.6; 95% confidence interval: 1.3, 17; P = .02) the central vasculature. Conclusion In addition to enabling identification of central vessel pathologic features, ferumoxytol-enhanced MR angiography revealed peripheral arterial disease not recognized with duplex US and was more predictive than duplex US of the outcome of arteriovenous fistula surgery. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Finn in this issue.

Early Predictors of Arteriovenous Fistula Maturation: A Novel Perspective on an Enduring Problem

BACKGROUND

Preoperative ultrasound mapping is routinely used to select vessels meeting minimal threshold diameters for surgical arteriovenous fistula (AVF) creation but fails to improve AVF maturation rates. This suggests a need to reassess the preoperative ultrasound criteria used to optimize AVF maturation.

METHODS

We retrospectively identified 300 catheter-dependent patients on hemodialysis with a new AVF created between 2010 and 2016. We then evaluated the associations of preoperative vascular measurements and hemodynamic factors with unassisted AVF maturation (successful use for dialysis without prior intervention) and overall maturation (successful use with or without prior intervention). Multivariable logistic regression was used to identify preoperative factors associated with unassisted and overall AVF maturation.

RESULTS

Unassisted AVF maturation associated with preoperative arterial diameter (adjusted odds ratio [aOR], 1.50 per 1-mm increase; 95% confidence interval [95% CI], 1.23 to 1.83), preoperative systolic BP (aOR, 1.16 per 10-mm Hg increase; 95% CI, 1.05 to 1.28), and left ventricular ejection fraction (aOR, 1.07 per 5% increase; 95% CI, 1.01 to 1.13). Overall AVF maturation associated with preoperative arterial diameter (aOR, 1.36 per 1-mm increase; 95% CI, 1.10 to 1.66) and preoperative systolic BP (aOR, 1.17; 95% CI, 1.06 to 1.30). Using receiver operating curves, the combination of preoperative arterial diameter, systolic BP, and left ventricular ejection fraction was fairly predictive of unassisted maturation (area under the curve, 0.69). Patient age, sex, race, diabetes, vascular disease, obesity, and AVF location were not associated with maturation.

CONCLUSIONS

Preoperative arterial diameter may be an under-recognized predictor of AVF maturation. Further study evaluating the effect of preoperative arterial diameter and other hemodynamic factors on AVF maturation is needed.

KDOQI Clinical Practice Guideline for Vascular Access: 2019 Update

The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has provided evidence-based guidelines for hemodialysis vascular access since 1996. Since the last update in 2006, there has been a great accumulation of new evidence and sophistication in the guidelines process. The 2019 update to the KDOQI Clinical Practice Guideline for Vascular Access is a comprehensive document intended to assist multidisciplinary practitioners care for chronic kidney disease patients and their vascular access. New topics include the end-stage kidney disease "Life-Plan" and related concepts, guidance on vascular access choice, new targets for arteriovenous access (fistulas and grafts) and central venous catheters, management of specific complications, and renewed approaches to some older topics. Appraisal of the quality of the evidence was independently conducted by using a Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, and interpretation and application followed the GRADE Evidence to Decision frameworks. As applicable, each guideline statement is accompanied by rationale/background information, a detailed justification, monitoring and evaluation guidance, implementation considerations, special discussions, and recommendations for future research.

Influence of cephalic vein dilation on arteriovenous fistula maturation in patients with small cephalic veins

A substantial limitation of dialysis fistulas is their high primary failure rate due to nonmaturation. Various studies have documented that patients with larger vein diameters exhibit reduced risks for nonmaturation. Nevertheless, some patients have small veins. Few studies have focused on patients with small veins. We hypothesize that sufficient venous dilation contributes to fistula maturation. Therefore, we studied the influence of cephalic vein dilation on fistula maturation in patients with small veins.Patients with small cephalic veins (diameter <2 mm) undergoing initial arteriovenous fistulae (AVF) operation were included. A total of 72 patients were enrolled in this study. A prospective study was performed, and the patients were followed for 6 weeks after surgery. Preoperative and postoperative duplex ultrasound mapping of veins was performed, and dilation of the cephalic vein was evaluated.The fistula maturation rate was 44.44%. Multivariate logistic regression analysis revealed a significant relationship between fistula maturation and preoperative cephalic vein dilation. Based on the results of ROC analysis, the fistula maturation rate in patients with vein dilation greater than or equal to the cut-off was 57.14% in the training data set and 54.55% in the testing data set. The independent influencing factors for fistula maturation were used to establish a combined index with logistic regression analysis. The fistula maturation rate in patients with combined indexes greater than or equal to the cut-off was 80.95% in the training data set and 77.78% in the testing data set.Our results demonstrated that preoperative venous dilation was associated with AVF maturation. For patients with small veins, venous distensibility needs to be carefully assessed before surgery, as it may be a better predictor of AVF maturation than venous diameter.

Effect of isometric handgrip exercise on the size of cephalic veins in patients with stage 3 and 4 chronic kidney disease: A randomized controlled trial

Background:

Proper vascular access is essential for the long-term survival of chronic haemodialysis patients. The preferred vascular access in terms of long-term function is the native arteriovenous fistula. The success of native arteriovenous fistula depends mainly on a sufficient vein diameter. Thus, any intervention that could increase vein diameter before arteriovenous fistula creation could improve its patency. We conduct a study to investigate the effect of local physical training, namely handgrip exercise, on the distal forearm cephalic vein diameter in patients with chronic renal disease.

Material and methods:

A total of 34 chronic renal disease patients (stage 3 and 4) were recruited in a randomized controlled trial. Handgrip exercise was performed for 8 weeks in the intervention group. Handgrip-strength measurement and distal forearm cephalic vein diameter of a non-dominant hand with and without tourniquet was recorded (measurement is taken 1 cm proximal to the radial styloid).

Results:

After 8 weeks, the mean cephalic vein diameter in the intervention group increased from 1.77 and 1.97 mm to 2.15 and 2.43 mm, without and with a tourniquet, respectively ( p < 0.05). There is also a significant change in the mean diameter of distal forearm cephalic vein ( p < 0.05) in the intervention group when measured in both the absence (mean change 0.39 ± 0.06 mm vs 0.01 ± 0.02 mm) and the presence of tourniquet (mean change 0.47 ± 0.07 mm vs 0.01 ± 0.01 mm).

Conclusion:

These findings suggest that non-invasive handgrip exercise can increase in the diameter of the distal forearm cephalic vein, thereby increasing the rate of successful arteriovenous fistula creation.

Evaluation of hemodynamic impact of absorbable sutures in native arteriovenous fistulas: A retrospective study

One of the major causes of arteriovenous fistula failure is the venous stenosis due to aggressive neointimal hyperplasia. The aim of the study was to assess the arteriovenous fistula maturation comparing absorbable sutures and non-absorbable ones in native vessels. Surgeries performed during a period of 24 months by a single team of expert surgeons were evaluated. Surgeries that met the inclusion criteria, namely, age ⩾ 18 years and radio-cephalic arteriovenous fistula, were considered. According to type of suture, patients were classified as Max group (absorbable suture) and Prol group (non-absorbable). Data pertaining to 70 patients were collected; 51% were men and the mean age was 73 ± 12 years. In Max group, an increasing blood flow was observed during the first 4 weeks without post-operative complications. In Prol group, six patients had thrombosis that resulted in vascular access failure. After the first week, the duplex Doppler ultrasound of both groups showed a regular arteriovenous fistula maturation, with an increase of blood flow rate. Although pre-operative post-tourniquet mean vein diameters of Max group were not adequate, the mean vein diameter and mean blood flow rate increased after 4 weeks, respectively. On the contrary, in Prol group, mean vein diameters and blood flow rate decreased. The maturation of arteriovenous fistula and its functional performance were not altered by the type of suture (absorbable/non-absorbable). Absorbable sutures were associated with good results considering arteriovenous fistula maturation.

A Meta-analysis of Preoperative Duplex Ultrasound Vessel Diameters for Successful Radiocephalic Fistula Placement

Background

The Kidney Dialysis Outcomes Quality Initiative (K/DOQI) guidelines for vascular access recommend the use of radiocephalic wrist arteriovenous fistulas (RCAVFs) as the initial option for dialysis access. The survival rate of a successfully placed fistula is excellent. However, 10–24% of RCAVFs fail to reach functional status as the result of early thrombosis or maturation failure. Many authors have investigated the utility of preoperative vascular mapping by Duplex ultrasound to predict adequate vessel size for successful fistula placement. This meta-analysis is the first in which preoperative radial arterial (RAD) and cephalic venous diameters (CVD) required for favorable fistula outcomes are reviewed.

Methods

A literature search was performed by use of the MEDLINE electronic base for “arteriovenous, fistula, ultrasound, and hemodialysis.” The analysis yielded 166 studies, of which 20 studies included preoperative duplex data. Meta-analysis was performed by applying the statistical test of comparing two proportions, assuming equal variances.

Results

A total of 433 patients were duplexed for preoperative evaluation of the RAD and 386 for CVD. The total number of subjects ranged from 21 to 91, mean age 58.7 years. The subjects were 55.5% male, 39.0% with diabetes mellitus. Meta-analysis yielded 2.0 mm for RAD and 2.0 mm for CVD as designated cutoff vessel diameters. Our study showed the mean fistula success rate was significantly different between RAD >2.0 mm (59%) and RAD >2.0 mm (40%). The mean fistula success rate was also significantly different between CVD > 2.0 mm (71%) and >2.0 mm (29%). Successful fistula placement was defined as a functional fistula at least 4–6 weeks after creation.

Conclusion

On the basis of our study, the use of Duplex ultrasound is important in determining preoperative vessel diameter size, and subsequent functional success rate of fistula placement.

Outcomes of arteriovenous fistula creation, effect of preoperative vein mapping and predictors of fistula success in incident haemodialysis patients: A single-centre experience

AIM

Vascular access in haemodialysis is critical for effective therapy. We aim to evaluate the outcomes of arteriovenous fistula (AVF) creation in incident haemodialysis patients, impact of preoperative vein mapping and predictors of successful AVF maturation in our centre.

METHODS

Data of End-stage Renal Disease (ESRD) patients initiated on haemodialysis from January 2010 to December 2012 in our centre were retrospectively obtained from electronic medical records and clinical notes. Demographic characteristics, medical comorbidities, perioperative details were collected, and patients were followed up until 1 January 2014.

RESULTS

A total of 708 patients (median age 64, IQR 55-72) were included with mean duration of follow up of 2.3 ± 1.2 years, with access of AVF and arteriovenous graft (AVG) in 694 (98%) and 14 (2%) patients respectively. Eight patients were lost to follow-up. Successful AVF maturation was achieved in 542 patients (78%), with 1-year cumulative patency rate of 74%. Multivariate analysis revealed male gender, upper arm AVF and good postoperative thrill and pulse as predictors of successful AVF maturation. Preoperative vein mapping was performed in 42.5% (295/694) of patients, with mean vein diameter of 2.44 ± 0.82 mm. Maturation rates with and without vein mapping were 72.2% and 82.4%, respectively, (P = 0.001). In patients with vein diameters of <2 mm and ≥2 mm, there was no statistically significant difference in maturation rates (71.3% vs. 72.6%; P = 0.887) and median maturation time (66 vs. 78 days; P = 0.73).

CONCLUSION

Arteriovenous fistula can be successfully created in most incident haemodialysis patients. Routine vein mapping is not necessary if veins are suitable on physical examination alone, and vein sizes of <2 mm on ultrasound is not associated with lower AVF maturation rate.

The Significance of Inflow Artery and Tourniquet Derived Cephalic Vein Diameters on Predicting Successful Use and Patency of Arteriovenous Fistulas for Haemodialysis

OBJECTIVE

To investigate the significance of inflow artery and cephalic vein diameters on predicting patency of radiocephalic and brachiocephalic arteriovenous fistulas (AVFs).

DESIGN

Single centre study with retrospective analysis of prospectively collected data between November 2010 and July 2015.

METHODS

A detailed history and physical examination was undertaken, including age, gender, history and duration of haemodialysis, cause of chronic kidney disease, and the presence of comorbidities/risk factors. Pre-operative arterial and venous upper extremity mapping was performed and inner vessel diameter was recorded, using a tourniquet for the veins. Outcome measures included AVF use (functionality), primary, primary assisted, secondary, and functional secondary patency.

RESULTS

One hundred and thirty five AVFs (57 and 78 radiocephalic and brachiocephalic AVFs, respectively) were constructed and followed up for 5 years. A cephalic vein diameter <4.3 mm (lower three quartiles) was the single independent predictor of inferior secondary and also functional secondary patency of radiocephalic AVFs (p = .02, HR 11.2, 95% CI 1.44-90.9). A brachial artery diameter ≤4.1 mm (lowest quartile) was an independent predictor of AVF functionality (57% vs. 83% for larger arteries, p = .017), and inferior primary, primary assisted, secondary, and functional secondary patency of brachiocephalic AVFs (primary assisted patency 21.9% vs. 55.9% at 3 years, p = .001/log-rank test, HR 3.1, p = .002/Cox regression). The presence of lower extremity PAD or use of dual antithrombotics was also independently associated with an inferior secondary patency. The number of risk factors (brachial artery diameter ≤4.1 mm, PAD, and use of dual antithrombotics) demonstrated risk stratification capabilities for functional secondary patency.

CONCLUSIONS

Among patients undergoing radiocephalic AVFs, a tourniquet derived cephalic vein diameter <4.3 mm was the single independent predictor of inferior secondary and functional secondary patency. Among patients undergoing brachiocephalic AVFs, all patency rates were inferior in the presence of a brachial artery diameter ≤4.1 mm and secondary patency was inferior in the presence of multiple risk factors.

Preoperative vessel mapping in chronic kidney disease patients - a center experience

PURPOSE

Hemodialysis (HD) is the main treatment modality in stage 5 chronic kidney disease, and vascular access planning is a crucial step in the path to dialysis treatment. Beyond detailed patient history and physical examination, duplex ultrasound (DU) evaluation is essential in preoperative vascular mapping.

METHODS

A retrospective descriptive nonrandomized study was performed and included 108 end-stage kidney disease patients referred from eight HD centers to be assessed for creation of an arteriovenous (AV) access (AV fistula or AV graft). We assessed primary failure, primary unassisted patency (PP) and primary assisted patency (PAP) rates and cumulative survival of AV accesses at 6 and 12 months.

RESULTS

We created 86 AV accesses of which 79 (91.9%) were AV fistulas (AVFs) (29 distal AVFs, 49 proximal AVFs and 1 femorofemoral AVF) and 7 (8.1%) arteriovenous grafts (AVGs). Fifteen percent (15%) (n = 12) of primary failure occurred in the AVF group. Any case of primary failure was observed between AVGs.In the AVF group, PP at 6 months was 63.8 % and at 12 months was 48.3%, PAP was 80.7% at 6 and 12 months. PP excluding primary failures was 73.0% and 55.3% at 6 and 12 months, respectively. The cumulative survival at 6 and 12 months was 80.7%.In the AVG group, PP at 6 months and 12 months was 66.7%, PAP and cumulative survival at 6 and 12 months were of 100%.

CONCLUSIONS

This study demonstrates that preoperative vascular mapping with a patient-centered approach may be critical to achieve good outcomes allowing the increase in AVF access.

Impact of a preoperative evaluation on the outcomes of an arteriovenous fistula

PURPOSE

The aim of this study was to determine the possible predictors of primary arteriovenous fistula (AVF) failure and examine the impact of a preoperative evaluation on AVF outcomes.

METHODS

A total of 539 patients who underwent assessment for a suitable site for AVF creation by physical examination alone or additional duplex ultrasound were included in this study. Demographics, patient characteristics, and AVF outcomes were analyzed retrospectively.

RESULTS

AVF creation was proposed in 469 patients (87.0%) according to physical examination alone (351 patients) or additional duplex ultrasound (118 patients); a prosthetic arteriovenous graft was initially placed in the remaining 70 patients (13.0%). Although the primary failure rate was significantly higher in patients assessed by duplex ultrasound (P = 0.001), ultrasound information changed the clinical plan, increasing AVF use for dialysis, in 92 of the 188 patients (48.9%) with an insufficient physical examination. Female sex and diabetes mellitus were risk factors significantly associated with primary AVF failure. Because of different inclusion criteria and a lack of adjustment for baseline differences, Kaplan-Meier survival analysis showed better AVF outcomes in patients assessed by physical examination alone; an insufficient physical examination was the only risk factor significantly associated with AVF outcomes.

CONCLUSION

Routine use of duplex ultrasound is not necessary in chronic kidney disease patients with a satisfactory physical examination. Given that female gender and diabetes mellitus are significantly associated with primary AVF failure, duplex ultrasound could be of particular benefit in these subtypes of patients without a sufficient physical examination.

Current tools for prediction of arteriovenous fistula outcomes

It remains challenging to accurately predict whether an individual arteriovenous fistula (AVF) will mature and be useable for haemodialysis vascular access. Current best practice involves the use of routine clinical assessment and ultrasonography complemented by selective venography and magnetic resonance imaging. The purpose of this literature review is to describe current practices in relation to pre-operative assessment prior to AVF formation and highlight potential areas for future research to improve the clinical prediction of AVF outcomes.

The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic

This best evidence topic was investigated according to a described protocol. We asked the question: what is the minimal vein diameter that can successfully predict maturation of an arteriovenous fistula (AVF) in patients undergoing dialysis. Using the reported search 804 papers were found, of which five represented the best evidence to answer the clinical question. All studies assessed the association between successful AVF maturation and the size of vein used. The strongest evidence came from a nonrandomised controlled follow-up study in which 76% of fistulas created using >2 mm cephalic vein successfully matured compared to 16% when the vein measured ≤2 mm. Another prospective, multicentre study showed 65% successful maturation using veins >4 mm compared to 45% with veins <3 mm. Vein diameter was found to be an independent predictor of maturation in multivariate regression analysis in two retrospective observational studies. Another retrospective observational study found that using venous measurements of ≥2.5 mm following tourniquet application resulted in more fistulas been created that would have otherwise been denied based on venous ultrasound mapping. A large multicentre randomised clinical trial assessing the use of different vein sizes both with and without tourniquet application using proper statistical tools - such as receiver operating characteristic - is required to make a final recommendation. Until then, a vein diameter of <2.5 mm should be considered inadequate for formation of an AVF, particularly if those measurements remain unchanged following the use of tourniquet.

G. Value of preoperative sonographic vascular evaluation of haemodialysis access in upperlimb

OBJECTIVE

To know the value of preoperative Dopplerultrasonography vascular mapping of upper limb for hemodialysis access placement.

MATERIALS AND METHODS

Prospective ultrasonographic assess- ment of upper extremity vessels was performed in 60 patients prior to hemodialysis access placement and potential access sites were selected (based on the standard criteria). The findings were correlated with the operative findings. Discrepancies found between ultrasonographic and operative findings were analysed.

RESULTS

All the 60 patients who underwent vascular mapping had vascular access placed. 80% of them had native arteriovenous fistulae (AVF) placed. In 95% of patients, at the selected sites, the vascular parameters as determined by ultrasonography matched with the operative findings. In 5% of patients there were discrepancies between the ultrasonography findings and operative findings. There was no negative surgical exploration. There was strong correlation between the diameters measured by ultrasonography and surgery.

CONCLUSION

Preoperative ultrasonography vascular mapping prior to hemodialysis access placement has facilitated definite selection of potential sites in difficult patient population in whom evaluation by physical examination was inconclusive. It also helped in maximizing the native AVFs and decreasing the negative surgical exploration rates.

Color Doppler ultrasound and arteriovenous fistulas for hemodialysis

Native arteriovenous fistula (AVF) is the vascular access of choice for hemodialysis patients. Compared with grafts and central venous catheters, AVFs last longer and are associated with fewer complications. The widespread use of the Doppler ultrasound (DUS) has increased the number of patients who are eligible for AVF by facilitating the identification of vessels that are suitable for fistula construction (preoperative vascular mapping). DUS can also extend native AVF survival by improving the early detection of complications (post-operative surveillance). It is the only imaging modality that furnishes both morphological and functional data on the native vascular access, and it is also the only imaging tool that can be used directly by the surgeon, an indisputable advantage. This review examines the numerous roles played by DUS in the construction and postoperative follow-up of AVFs, including preoperative vascular mapping, AVF maturation, and surveillance.

Vein diameter after intraoperative dilatation with vessel probes as a predictor of success of hemodialysis arteriovenous fistulas

Background

Vascular access is “the life line” for patients on chronic hemodialysis. The autogenous arteriovenous fistula provides the best access to the circulation because of low complication rate, long-term use, and lower cost, compared to arteriovenous graft and central venous catheter. The primary objective of this prospective study was to investigate the predictive value of vein diameter after intraoperative dilatation with vessel probes on hemodialysis fistula maturation.

Material/Methods

Ninety-three fistulas were performed by a single surgeon from February 1, 2006 to January 31, 2009. Intraoperative vein dilatation with vessel probes was attempted in all fistulas. Measurements of the feeding artery diameter, vein diameter and the increased vein diameter after intraoperative dilatation were performed and immediate failure, early patency, early failure, primary patency, and fistula survival outcomes were recorded during 48-month follow-up.

Results

Early failure occurred in 20% of fistulas and 70% matured sufficiently for cannulation. Variables with significant impact on the failure to mature by univariate analysis were: body-mass index (P=0.041), artery diameter (P<0.001), vein diameter (P=0.004), and vein diameter after dilatation (P=0.002). However, multivariate analysis showed that only body-mass index (P=0.038), artery diameter (P=0.001), and the diameter of the vein after dilatation (P=0.018) significantly affected maturation. In a group of 56 (60%) patients with vein diameter before dilatation ≤2 mm, among vessel characteristics found by multivariate analysis, only vein diameter after dilatation (P=0.004) significantly affected function.

Conclusions

Artery diameter and vein diameter after intraoperative dilatation with vessel probes were the main predictors of fistula function.

Complications of arteriovenous fistulae: beyond venous stenosis

Vascular access is the lifeline of hemodialysis patients. Currently, arteriovenous fistulae and grafts are considered permanent options for vascular access, and they share common access problems. The successful creation of a permanent vascular access depends on patient characteristics, vessel parameters, and possibly genetic factors. Utilization of a dialysis access at least 3 times a week leads to significant wear and tear of the access. The buttonhole technique is associated with a higher incidence of infection, and evidence regarding various perceived advantages remain contradictory. Infiltration and aneurysm formation of an access are common, and the literature on its impact on vascular access outcomes is limited. A patient who undergoes hemodialysis often requires multiple accesses during his or her lifetime, and the maintenance of a persistent vascular access may require creative solutions. Intensified research is crucial to comprehending the pathophysiology and treatment options for some of the common problems of vascular accesses.

Mapping of superficial extremity veins: normal diameters and trends in a vascular patient-population

Ultrasonic measurement of superficial extremity veins is a common procedure. To establish normal values for vein-size in a population of vascular patients and to assess if measurements remain unchanged over time, we analyzed a database with results of 28,130 measurements in 2420 separate saphenous and 3206 cephalic veins. Mean size of the great saphenous vein ranges from 2.3 mm to 4.4 mm but did not follow a tapering pattern as is often assumed. The distal calf segment is smaller than the ankle segment. The mean cephalic vein size in the upper arm (2.4 mm) was smaller than at the antecubital level (2.7 mm). A decrease in vein diameter over time was noted in many locations and this reached statistical significance (p < 0.005 for the thigh segment). The clinical significance of this is a need to repeat ultrasonic vein-mapping if more than a year elapses between ultrasound and surgical vein harvest.

Comparison of radiocephalic fistulas placed in the proximal forearm and in the wrist

Non-maturation is a common problem in patients receiving an arteriovenous fistula. The first vascular access choice is a distal radiocephalic fistula (dRCF) at the wrist. Patients with a failed dRCF or with vessels unsuitable for dRCF, the recommendation is to place a brachiocephalic fistula in the upper arm. Proximal forearm radiocephalic fistulas (pRCF) are created infrequently, but may permit a second forearm fistula before proceeding to the upper arm. The goal of the present study was to compare the outcomes of them. We retrospectively analyzed a computerized access database to compare the outcomes of 19 RCF and 39 dRCF placed during a 6-month period. The baseline characteristics were similar, except those with a pRCF were more likely to have previous access and be male. Primary failure (non-maturation) was lower for pRCF than dRCF (32 vs. 59%, p = 0.05); and excluding secondary failures, cumulative fistula survival was similar (92 vs. 86% at 1 year and 74 vs. 76% at 2 years, p = 0.56). pRCF may be an attractive alternative to a brachiocephalic fistula in patients who cannot receive a dRCF. pRCF has a lower non-maturation rate than that of a dRCF, and a comparable cumulative survival once it is used successfully for dialysis.

Duplex sonography in the planning and evaluation of arteriovenous fistulae for haemodialysis

This paper describes how to perform duplex sonography in the planning and evaluation of arteriovenous fistulae in haemodialysis patients, discusses its roles in these settings, and presents a review of commonly encountered complications.

Unexpected Doppler Waveform Patterns in the Lower Extremity Arteries

Unexpected Doppler findings in the arteries of the lower extremity may be found during a routine noninvasive vascular examination. Low-resistive Doppler arterial waveforms in the external iliac and femoral arteries are abnormal and often indicators of proximal high-grade stenosis. Occasionally, other medical conditions could also cause anomalous low-resistive arterial waveforms in the arteries of lower extremities. Detailed knowledge of vascular anatomy, careful sonographic scanning, and meticulous analysis of Doppler waveforms in all examined vessels are paramount for adequate examination and reporting. Vascular sonographers should consider different clinical scenarios whenever abnormal Doppler waveforms are detected.