Upper-arm Arteriovenous Fistula Research Articles

Association of anesthetic modality and other variables on 1-year functional patency of cephalic-based arteriovenous fistulae.

ObjectivesSome studies suggest that regional (RA) provides better patency for arteriovenous fistula (AVF) for hemodialysis (HD) access as compared to Local (LA) and General Anesthesia (GA). This study evaluates the impact of anesthetic modality on long term fistula function at 12 months. MethodsA retrospective review of patients undergoing cephalic vein-based HD access in consecutive cases between 2014 and 2019 was conducted from five safety net hospitals. The primary endpoint was functional patency at 12 months. Subset analysis individually evaluated cephalic based lower forearm and wrist versus upper arm AVFs. Bivariate and multivariate logistic regression models evaluated the relationship between anesthetic modality and fistula function at 12 months. ResultsThere were 818 cephalic based fistulas created during the study period. The overall 12-month functional patency rate was 78.7%, including an 81.3% patency for upper arm AVF and 73.3% for wrist AVF (p=0.009). There was no statistically significant difference among patients with functional and nonfunctional AVFs at 12 months with respect to anesthetic modality when comparing regional, local, and general anesthesia (p=0.343). Multivariate regression analysis identified that history of AVF/AVG (OR 0.24, p=0.007), receiving intraoperative systemic anticoagulation (OR 2.49, p<0.001), and vein diameter (OR 1.85, p=0.039) as independently associated with AVF functional patency at 12 months. ConclusionThere was no association between anesthetic modality and functional patency of cephalic based-AVF at 12 months. Further studies are needed to better define which patients may benefit from regional anesthesia.

Analysis of risk factors for late arteriovenous fistula failure and patency rates after angioplasty in hemodialysis patients: a retrospective cohort study.

The incidence of chronic kidney disease (CKD) and end-stage kidney disease (ESKD) is increasing worldwide. Hemodialysis (HD) is the mainstay of renal replacement therapy for patients with ESKD. Risk factors associated with late arteriovenous fistula (AVF) failure in HD patients are poorly investigated. Therefore, the aim of this study was to identify factors associated with late AVF failure in HD patients. Patients with end-stage renal disease (ESRD) who underwent forearm or upper arm AVF angioplasty at Second Affiliated Hospital of Chongqing Medical University between September 2009 and August 2018 were included. Patients were followed up for 36 months. Baseline characteristics were collected using electronic medical records (EMRs). Variables associated with late AVF failure were identified using Cox proportional hazards models. There were 137 patients (64% male, 36% female) included in this study, with 50 (36.5%) experiencing AVF failure. Univariable log-rank analysis showed that age, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), intact parathyroid hormone (iPTH), albumin (ALB), and AVF patency rate were significantly different between patients who did and did not experience AVF failure. Cox regression analysis showed that CRP [P=0.002, hazard ratio (HR) =2.719, 95% confidence interval (CI) for HR: 1.432-5.164], ESR (P=0.030, HR =2.431, 95% CI: 1.088-5.434), iPTH (P=0.013, HR =0.325, 95% CI: 0.133-0.793), and ALB (P=0.040, HR =0.539, 95% CI: 0.299-0.972) were independently associated with AVF failure. Kaplan-Meier survival analysis showed that the cumulative patency rates of AVF at 6, 12, 18, 24, 30, and 36 months were 84%, 74%, 69%, 64%, 64%, and 64%, respectively. CRP, ESR, iPTH, and ALB were associated with AVF failure and should be used as reference in clinical practice.

Arterial revascularization in patients with hand pain dialyzing with upper arm Arteriovenous (AV) fistulas: A single center experience.

Distal hand ischemia syndrome (DHIS) is a well reported adverse outcome in patients with upper arm AV access. 25%-40% of these patients have been reported to be due to primary arterial disease complicated with significant arterial calcification. The effectiveness of revascularization of the distal arterial circulation on symptom resolution has not been reported yet. Retrospective single center analysis of patients evaluated for hand/forearm pain in patients with upper arm AV access who had arterial revascularization between 01/2016 and 12/2020 were included for the analysis. Fifty-one patients met inclusion criteria. Stenotic lesions greater than 70% in the subclavian, axillary, brachial, radial, or ulnar artery were treated with balloon angioplasty. Institutional approval was obtained to review charts. Successful revascularization, improvement in pain in 48 h, 1 month, and 3 months. Seventy six percent of patients had an upper arm Arteriovenous Fistula (AVF) and 24% patients had an upper arm Arteriovenous Graft (AVG). Mean access flow was 1210 (556) ml/min. 55% of patients had radial or ulnar arterial stenosis, 45% had brachial/axillary or subclavian artery stenosis. 45% patients had lesions in both radial and ulnar arteries, 88% of patients were successfully revascularized. 76% (18) of patients had improvement in symptoms within 48 h and 68% remained symptom free in 3 months. Mean DHIS stage was 3.1 before intervention and improved to 1.1 post intervention (p < 0.001). Patient satisfaction with their AV access improved from 34% to 72% (p < 0.01). Multiple regression analysis did not reveal statistically significant correlations between time on dialysis vintage and other chronic medical conditions on post procedure symptom improvement. DHIS with occlusive arterial disease can be successfully revascularized to improve symptoms. Complete evaluation of the inflow arterial segment and optimal endovascular revascularization could decrease the need for access revision procedures or access abandonment.

Dual outflow upper arm arteriovenous fistula: An effective technique to prevent cephalic arch stenosis.

Cephalic arch stenosis (CAS) is critical point to maintain functional arteriovenous fistula (AVF) in patients undergoing hemodialysis with brachio-cephalic AVFs. In this study, we aimed to determine the effectiveness of dual outflow (cephalic and basilic veins) as a surgical method to prevent CAS. Between July 2016 and December 2019, 369 patients underwent upper arm AVF creation. Among them the 251 patients were enrolled in this retrospective study. Two hundred seven underwent brachio-cephalic arteriovenous fistula (BCAVF) and 44 underwent brachio-cephalicbasilic arteriovenous fistula (BCBAVF). From the 251 patients, diabetes mellitus (66.7% vs 36.4%, P < .001) and hypertension (91.3% vs 75%, P = .002) were more common in the patient group who underwent BCAVF surgery; however, the difference in volume flow to the fistula did not differ between the 2 groups. CAS (30.4% vs 9.1%, P = .004) and fistula occlusion (15.9% vs 4.5%, P = .048) were likely to occur in the BCAVF group. The primary patency rates at 12 months were 74.3% and 86.4% for the BCAVFs and BCBAVFs, respectively (P = .075). The primary-assisted patency rates at 12 months were 87.0% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .145). Secondary patency rates at 12 months were 92.2% for BCAVFs and 93.2% for BCBAVFs, respectively (P = .023). Compared to BCAVF, traditional upper arm AVF, upper arm AVF with cephalic and basilic vein dual drainage can be optimal surgical method to preventing CAS.

Is there correlation between flow volume and Kt/V ratio in upper arm arteriovenous fistula in patients end stage renal failure?

Introduction: Chronic kidney disease is irreversible and may result in end-stage renal failure (ESRF). The kidney replacement program is determined by calculating Kt/V ratios, one of the dialysis efficiency indicators in treatment planning in routine dialysis applications in ESRF patients. We aimed to investigate whether there is a correlation between flow rate and Kt/V ratio. Methods: All patients were evaluated by B-mode ultrasonography (US) and color doppler ultrasonography (CDUS). The anastomosis line diameter was measured in the B-mode US. The fistula flow rate was calculated in a spectral examination at the anatomical location where the fistulized flow was best obtained at the anastomosis level. Patients with a fistula flow rate above 300 mL/min in CDUS examinations were considered reasonable flow rates. The fistula flow rate in these patients was compared with the Kt/V ratios. Spearman’s rank correlation coefficient was calculated since the normal distribution condition was not met to determine the relationship between variables. Results: The results of this study showed a high level (r=0.72, P=0.001) of positive and statistically significant correlation between flow rate and Kt/V ratio in upper arm arteriovenous fistula in patients with end stage renal failure. Conclusion: We found a highly positive and statistically significant correlation between fistula flow rate and Kt/V ratio. Low Kt/V ratios have different causes. Low fistula flow should be considered first in low Kt/V values.

Influence of Ipsilateral Graft Inflow to Arteriovenous Fistula for Hemodialysis in Coronary Bypass Surgery.

In coronary artery bypass grafting (CABG) for patients on hemodialysis, there has been concern about “coronary steal”. This study aims to evaluate the influence of using an in situ internal thoracic artery (ITA) ipsilateral to a preexisting arteriovenous fistula (AVF) in dialysis-dependent patients undergoing CABG. Between 2004 and 2018, dialysis-dependent patients with AVFs who underwent CABG were enrolled. According to the locational relationship of AVFs and in situ ITA grafts, the patients were divided into the ipsilateral group (n = 22) and the contralateral group (n = 21). Inverse probability weighting analysis was used to estimate and compare the late clinical outcomes. The late cardiac-related adverse events were not significantly different between the two groups: “major adverse cardiovascular and cerebrovascular events (MACCE)” (p = 0.090), “composite outcome of recurrent angina and coronary re-intervention” (p = 0.600). The in situ ITA graft of CABG on the ipsilateral side to AVF was not a significant risk factor for MACCE or the composite outcome of recurrent angina and coronary re-intervention. There was no statistically significant difference in the graft patency between the groups. Therefore, it might not be necessary to avoid using an in situ ITA on the ipsilateral side of an upper-arm AVF for optimal coronary artery bypass grafting in dialysis-dependent patients.

Systemic microvascular endothelial function with arteriovenous fistula creation in chronic kidney disease.

Background:This study aimed to determine changes in microvascular endothelial function with upper arm arteriovenous fistula (AVF) creation and maturation in patients with chronic kidney disease (CKD).Materials and Methods:This prospective cross-sectional study was performed at Hospital Universiti Sains Malaysia, a tertiary hospital in Malaysia. Forty CKD patients (stage 4–5) who were scheduled for elective AVF creation over the upper extremity for maintenance hemodialysis were recruited using convenience sampling method. Microvascular endothelial-dependent vasodilation was measured using laser Doppler flowmetry and the process of iontophoresis preoperatively and postoperatively at weeks 2 and 6. Fistula maturation was assessed at week 6.Results:Thirty-two patients had successful AVF maturation. Endothelial-dependent vasodilation (acetylcholine (Ach)% was higher (246.48 [standard deviation (SD) 209.38] vs. 104.95 [SD 43.29], P = 0.001) while systolic blood pressure was lower (142.25 [SD 21.50] vs. 162.25 [SD 13.26], P = 0.017) in this group as compared to unsuccessful AVF group. No significant changes were seen in overall microvascular endothelial-dependent vasodilation during the 6-week study period (day 0, 246.48 [SD 209.38]; week 2, 201.14 [SD 198.19]; and week 6, 203.53 [SD 145.89]).Conclusion:Upper arm AVF creation does not affect microvascular endothelial function up to 6 weeks post operation and may not contribute to the success of AVF maturation. However, the lower microvascular endothelial-dependent vasodilation and higher systolic blood pressure in unsuccessful AVF subjects need to be further studied.

Vascular Access Perspectives in Patients After Kidney Transplantation.

Introduction: More attention has been paid to the influence of arteriovenous fistula (AVF) on the cardiovascular system. In renal transplant recipients, some beneficial effect of an elective vascular access (VA) ligation was observed in patients with a high AVF flow. However, this strategy is not widely accepted and is in contradiction to the rule of vasculature preservation for possible future access. The aim of our study is to elucidate the vascular access function and VA perspective in the kidney transplantation (KTx) population.Materials and Methods: KTx patients with a stable graft function were recruited to participate in this single center observational study (NCT04478968). The measurement of VA flow and vessel mapping for future vascular access was performed by a color Doppler ultrasound. The study group included 99 (63%) males and 58 (37%) females; the median age was 57 (IQR 48–64) years. The median time from the transplantation to the baseline visit was 94 (IQR 61–149) months. Median serum creatinine concentration was 1.36 (IQR 1.13–1.67) mg/dl.Results: Functioning VA was found in 83 out of 157 (52.9%) patients. The sites were as follows: snuffbox in six (7.2%), wrist in 41 (49.4%), distal forearm in 18 (21.7%), middle or proximal forearm in eight (9.6%), upper-arm AV graft in one (1.2%), and upper-arm AVFs in nine (10.8%) patients, respectively. Blood flow ranged from 248 to 7,830 ml/min; the median was 1,134 ml/min. From the transplantation to the study visit, 66 (44.6%) patients experienced access loss. Spontaneous thrombosis was the most common, and it occurred in 60 (90.9%) patients. The surgical closure of VA was performed only in six (4%) patients of the study group with a functioning VA at the time of transplantation. Access loss occurred within the 1st year after KTx in 33 (50%) patients. Majority (50 out of 83, 60.2%) of the patients with an active VA had options to create a snuffbox or wrist AVF on the contralateral extremity. In a group of 74 patients without a functioning VA, the creation of a snuffbox or wrist AVF on the non-dominant and dominant extremity was possible in seven (9.2%) and 40 (52.6%) patients, respectively. In 10 (13.1%) patients, the possibilities were limited only to the upper-arm or proximal forearm VA on both sides. Access ligation was considered by 15 out of 83 (18.1%) patients with a patent VA.Conclusions: In the majority of the patients, vascular access blood flow was below the threshold of the negative cardiovascular effect of vascular access. Creation of a distal AVF is a protective measure to avoid a high flow and preserve the vessels for future access. The approach to VA should be individualized and adjusted to the patient's profile.

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

BackgroundAn 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 presentationAn 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.ConclusionsPre-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.

Analyses of hemodialysis arteriovenous fistula geometric configuration and its associations with maturation and reintervention

ObjectiveAn arteriovenous fistula (AVF) is the preferred vascular access for chronic hemodialysis; however, the rates of AVF maturation failure and reintervention remain high. We investigated the AVF geometric parameters and their associations with AVF physiologic maturation and reintervention in a prospective multicenter study. MethodsFrom 2011 to 2016, patients undergoing vein end-to-artery side upper extremity AVF creation surgery were recruited. Contrast-free dark blood and phase-contrast magnetic resonance imaging (MRI) scans were performed using 3.0T scanners to obtain the AVF lumen geometry and flow rates, respectively, at postoperative day 1, week 6, and month 6. The arteriovenous anastomosis angle, nonplanarity, and tortuosity of the fistula were calculated according to the lumen centerlines. AVFs were considered physiologically matured if, using the week 6 MRI data, the flow rate was ≥500 mL/min and the minimum vein lumen diameter was ≥5 mm. The associations of these geometric parameters with AVF maturation and reintervention due to perianastomotic and mid-vein stenosis within 1 year were assessed. ResultsA total of 111 patients had a usable day 1 MRI scan, with most having upper arm AVFs (n = 73). Compared with the forearm AVFs, upper arm AVFs had greater anastomosis angles (P < .001), larger deviations from a plane (nonplanarity; P = .002), and more prominent tortuosity (P = .038) at day 1. These parameters significantly increased between day 1 and week 6 in upper arm AVFs. In contrast, significant changes in these parameters in forearm AVFs were not observed. The rate of maturation was 54% and 86% for forearm and upper arm AVFs, respectively. None of the geometric parameters at day 1 were associated with AVF maturation in either location. The rate of reintervention was 24% and 30% for forearm and upper arm AVFs, respectively, with a larger nonplanarity angle at day 1 associated with less reintervention (30° ± 15° vs 21° ± 10°; P = .034) in upper arm AVFs only. This relationship was unchanged after adjusting for age, sex, race, dialysis status, or diabetes. ConclusionsIn our study, upper arm fistulas had a larger anastomosis angle, were more nonplanar, and had more tortuous veins than forearm fistulas. For upper arm fistulas, a larger nonplanarity angle is associated with a lower rate of reintervention within 1 year. Once confirmed, vascular surgeons could consider increasing the nonplanarity angle by incorporating a tension-free gentle curvature in the proximal segment of the mobilized vein to reduce reinterventions when creating an upper arm fistula.

High-flow arteriovenous fistula is not associated with increased extracellular volume or right ventricular dysfunction in haemodialysis patients.

High-output congestive heart failure secondary to high-flow arteriovenous fistula (AVF) has been reported in haemodialysis (HD) patients. As high-flow AVF (HFA) would be expected to result in fluid retention, we conducted an observational study to characterize the relationship between AVF flow (Qa) and extracellular water (ECW) in HD patients. We measured Qa by ultrasound dilution in prevalent HD outpatients with an AVF in two dialysis centres. The ECW:total body water (TBW) ratio was measured both pre- and post-dialysis by multifrequency bioimpedance analysis. Transthoracic echocardiograms (TTEs) were performed as part of routine clinical management. We included 140 patients, mean age 62.7 ± 15.7 years, 60.7% male, 47.9% diabetic and 22.9% with coronary revascularization. Mean Qa was 1339 ± 761 mL/min and 22 (15.7%) patients had HFA defined as Qa >2.0 L/min. Qa was positively associated with an upper arm AVF (P = 0.005), body mass index (P = 0.012) and N-terminal pro-brain natriuretic peptide (NT-proBNP) (P = 0.047) and negatively associated with diabetes (P < 0.001) and coronary revascularization (P = 0.005). The ECW:TBW ratio was positively associated with age (P < 0.001), Davies comorbidity index (P = 0.034), peripheral vascular disease (P = 0.030) and NT-proBNP (P = 0.002) and negatively associated with serum albumin (P < 0.001). Qa was not associated with the ECW:TBW ratio (P = 0.744). TTE parameters were not associated with Qa. In our outpatient HD cohort, high AVF flow was not associated with ECW expansion, either pre- or post-dialysis when accounting for potential confounders. By controlling ECW, high access flow should not necessarily be perceived as a threat to cardiovascular physiology.

High-output cardiac failure secondary to arteriovenous fistula: a wide-based literature review

Performing arteriovenous fistula (AVF) has become common among patients requiring hemodialysis. Apart from complications like bleeding, stenosis, infection, and thrombosis, even high-output cardiac failure has been a matter of concern for these patients. Sever risk factors like upper arm AVF with brachial artery anastomosis, male sex, and volume expansion has been identified. The pathophysiology contributing to this disease process is the shunting of blood from the high-resistance arterial system into the lower resistance venous system, increasing the venous return and eventually cardiac failure. It is also believed cardiac failure in AVF is also a reflection of the underlying cardiovascular disease. This is diagnosed using an echocardiogram and cardiac biomarkers (brain natriuretic peptide & atrial natriuretic peptide). AVF ligation has been shown to improve symptoms of cardiac failure at the expense of losing vascular access. Current guidance recommends schematic predialysis planning process with the aim of optimizing the route of dialysis for an individual patient’s unique psychological, medical and wider social implications.

Comparison of vascular access patency and patient survival between native arteriovenous fistula and synthetic arteriovenous graft according to age group.

Arteriovenous fistula (AVF) is historically known to be the ideal option for vascular access (VA) for hemodialysis compared with arteriovenous graft (AVG). However, this approach has been recently questioned in the aging population because of their poor vessel quality and multiple comorbidities. Data from a total of 2200 patients from the VA category of The Catholic Medical Center nephrology registry from March 2009 to February 2017 were analyzed. We compared VA patency and patient survival between two groups, AVF and AVG, according to age. Compared with the AVG group, survival benefit in the AVF group continued even in patients ≥80 years. In the whole population, all the primary patency (PP), primary-assisted patency (PAP), and secondary patency (SP) measures were superior in the AVF group. With regard to subgroups, PP was comparable between the two groups in patients ≥65 years, whereas PAP and SP were superior in the AVF group even in septuagenarian patients who are from 70 to 79 years old. In patients ≥80 years, all the patency measures were comparable between the two groups. When the separate comparison of lower-arm AVF (or upper-arm AVF) and AVG, lower-arm AVF failed to demonstrate its superiority in any kind of patency in septuagenarian patients compared with AVG, whereas upper-arm AVF demonstrated its superiority in PAP and SP in septuagenarian patients. However, even upper-arm AVF failed to demonstrate its superiority in any kind of patency in patients ≥80 years. Arteriovenous fistula if using upper-arm vessel showed the superior VA patency up to septuagenarian patients, whereas, in HD patients ≥80 years, AVF and AVG were comparable in VA patency.

Correlation of Hand Ischemic Questionnaire with Digital Brachial Index In Patient with Upper Arm Native Arteriovenous Fistula

Introduction: Steal syndrome is one of the most feared complications in maintaining arteriovenous fistula (AVF) for hemodialysis. The incidence of steal syndrome in worldwide is estimated to be 0.5-5%. There are various non-invasive examinations to assess the degree of stealing, one of which is the digital brachial index (DBI). In this study, subjects with brachiocephalic AVF were assessed by the hand ischemic questionnaire (HIQ) to assess the manifestations of steal syndrome complained by the patient, which are the sensation of cold, pain, the decrease in sensation and strength, and cramps. The literature about the correlation of DBI with other assessment is still limited. Method: The subjects of this study were all patients undergoing hemodialysis with upper arm AVF at Cipto Mangunkusumo Hospital in the period May – June 2019. Patients will be asked about various symptoms of stealing syndrome, the severity, and also frequency, according to HIQ. The scores were then calculated, followed by scores of DBI measurements using a plethysmograph. The DBI values that considered to be meaningful as stealing syndrome were &lt;0.6. The correlation between the two parameters was then analyzed. Results: From demographic data, characteristics of patients with native AVF by sex were 37 (46.2%) men and 43 (53.8%) women with an average age of 53 years. The minimum value of the HIQ score was 0, and the maximum value was 70, with a median value of 3. The correlation test between the total value of the HIQ questionnaire score and the DBI value found a significant correlation (r = -0.0798, p &lt;0.001). A diagnostic tests was performed between HIQ scores using a cut-off value ≥50 with a DBI value &lt;0.6 as a reference. It was obtained a sensitivity value of 15.3% and a specificity value of 100%, with a diagnostic accuracy of 58.75%. Conclusion: There was a good correlation between HIQ and DBI in patients undergoing hemodialysis using upper arm native AVF. The use of HIQ as a screening tool in native upper arm AVF patients is less recommended, but its use for patients who are suggestive of stealing syndrome has good specificity results. Keywords: digital brachial index, hand ischemic questionnaire, native arteriovenous fistula upper arm.

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

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. 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. 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). 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.

AIUM Practice Parameter for the Performance of Ultrasound Vascular Mapping for Preoperative Planning of Dialysis Access

AIUM Practice Parameter for the Performance of Ultrasound Vascular Mapping for Preoperative Planning of Dialysis Access

Pulmonary Hypertension and Hemodialysis Access

The purpose of this project was to identify the patient's features and the technical factors related to an increased risk of heart failure with the creation of dialysis vascular access (DVA). The study included 269 patients with chronic kidney disease who had a baseline and postoperative echocardiogram within 6 months of fistula creation at a single institution between January 2000 and March 2015. There were 37 patients with α1-antitrypsin disease, pulmonary fibrosis or sarcoidosis, and a heart or lung transplant who were excluded, leaving 232 patients in the final cohort. Patients with pulmonary hypertension (pHTN; n = 70 [30.2%]) were compared with patients without pHTN (n = 162 [69.8%]). Patients with pHTN were younger (P = .01) and were less likely to have congestive heart failure (P = .032), peripheral vascular disease (P = .044), or history of a percutaneous coronary intervention (P = .018). Patients with pHTN were more likely to have obstructive sleep apnea (P = .023). Survival was not affected by pHTN status (P = .16). The overall fistula maturation rate (defined as successful two-needle cannulation for 4 weeks) was 78.9%. An upper arm arteriovenous fistula (P = .46), an infraclavicular nonautologous graft of any diameter (P = .38), a two-stage surgery (P = .14), the history of a prior dialysis catheter (P = .56), and pharmacomechanical thrombectomy (P = .98) were not associated with the development pHTN. Patients who underwent cleaner thrombectomy (P = .048) or a subsequent 4- to 7-mm chest wall graft (P = .031) after the index fistula failed were more likely to have pHTN. Only one patient had the fistula ligated for worsening heart failure. Patients who experienced the onset of pHTN after DVA (DVA-pHTN; n = 34 [48.6%]) were compared with patients who had pHTN before DVA (pHTN-DVA; n = 36 [51.4%]). pHTN-DVA patients were less likely to have a history of a myocardial infarction (P = .029). There is no difference in the mean change in right ventricular systolic function after arteriovenous fistula creation in comparing patients with pHTN with patients without pHTN (P = .067) and comparing DVA-pHTN with pHTN-DVA (P = .77). DVA surgery does lead to pHTN, and patients should be monitored for the development of clinically significant symptoms that merit intervention. In general, it is safe to create DVA and to perform the necessary maintenance interventions regardless of the presence or severity of pHTN. Direct central venous outflow may pose a higher risk for severe pHTN warranting DVA ligation.

The impact of haemodialysis arteriovenous fistula on haemodynamic parameters of the cardiovascular system.

BackgroundSatisfactory vascular access flow (Qa) of an arteriovenous fistula (AVF) is necessary for haemodialysis (HD) adequacy. The aim of the present study was to further our understanding of haemodynamic modifications of the cardiovascular system of HD patients associated with an AVF. The main objective was to calculate using real data in what way an AVF influences the load of the left ventricle (LLV).MethodsAll HD patients treated in our dialysis unit and bearing an AVF were enrolled into the present observational cross-sectional study. Fifty-six patients bore a lower arm AVF and 30 an upper arm AVF. Qa and cardiac output (CO) were measured by means of the ultrasound dilution Transonic Hemodialysis Monitor HD02. Mean arterial pressure (MAP) was calculated; total peripheral vascular resistance (TPVR) was calculated as MAP/CO; resistance of AVF (AR) and systemic vascular resistance (SVR) are connected in parallel and were respectively calculated as AR = MAP/Qa and SVR = MAP/(CO − Qa). LLV was calculated on the principle of a simple physical model: LLV (watt) = TPVR·CO2. The latter was computationally divided into the part spent to run Qa through the AVF (LLVAVF) and that part ensuring the flow (CO − Qa) through the vascular system. The data from the 86 AVFs were analysed by categorizing them into lower and upper arm AVFs.ResultsMean Qa, CO, MAP, TPVR, LLV and LLVAVF of the 86 AVFs were, respectively, 1.3 (0.6 SD) L/min, 6.3 (1.3) L/min, 92.7 (13.9) mmHg, 14.9 (3.9) mmHg·min/L, 1.3 (0.6) watt and 19.7 (3.1)% of LLV. A statistically significant increase of Qa, CO, LLV and LLVAVF and a statistically significant decrease of TPVR, AR and SVR of upper arm AVFs compared with lower arm AVFs was shown. A third-order polynomial regression model best fitted the relationship between Qa and LLV for the entire cohort (R2 = 0.546; P < 0.0001) and for both lower (R2 = 0.181; P < 0.01) and upper arm AVFs (R2 = 0.663; P < 0.0001). LLVAVF calculated as % of LLV rose with increasing Qa according to a quadratic polynomial regression model, but only in lower arm AVFs. On the contrary, no statistically significant relationship was found between the two parameters in upper arm AVFs, even if mean LLVAVF was statistically significantly higher in upper arm AVFs (P < 0.0001).ConclusionsOur observational cross-sectional study describes statistically significant haemodynamic modifications of the CV system associated to an AVF. Moreover, a quadratic polynomial regression model best fits the relationship between LLVAVF and Qa, but only in lower arm AVFs.

Association of Genetic Polymorphisms of Renin-Angiotensin-Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients.

Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001), lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025), right-sided (31.8% vs. 18.4%, p = 0.002) and upper arm AVF (26.6% vs. 9.7%, p < 0.001), and higher mean dynamic venous pressure (DVP) (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021). In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs), rs275653 (Odds ratio 1.90, p = 0.038) and rs1492099 (Odds ratio 2.29, p = 0.017) of angiotensin II receptor 1 (AGTR1), were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA) of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005). In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could be a potential genetic risk factor of AVF malfunction in male HD patients.

Acute Complications after Balloon-assisted Maturation

Balloon-assisted maturation (BAM) of arteriovenous fistula (AVF) is a fairly new procedure used to accelerate the process of maturation. As with any procedure, complications do arise. In this retrospective analysis of 336 office-based BAM procedures, 5 major complications were analyzed. These were categorized as formation of wall hematoma, extravasation or rupture, spasm, thrombosis, and formation of puncture-site hematoma. Prospective data were collected from May 14, 2009 to March 3, 2011 on 336 office-based duplex-guided BAM procedures. Access site puncture, vessel cannulation, wire placement, and balloon advancement and insufflation were duplex guided. Balloon calibers were chosen based on duplex vein measurements and surgeon preference (approximately 1-2 mm larger than minimal vein diameter). Vascular injuries were classified based on postprocedural duplex assessment. All patients had follow-up duplex scans within a week after BAM. Of the 336 procedures, the most common injury was formation of wall hematoma (136, 40.5%) followed by extravasation or rupture (32, 9.5%), spasm (26, 7.7%), formation of puncture-site hematoma (13, 3.9%), and thrombosis (5, 1.5%). The injuries were further compared based on balloon size, ranging from small balloon group (3-6 mm) to large balloon group (7-12 mm); entry position, retrograde (n=177) versus antegrade (n=159); and type of fistula; radial-cephalic (n=232), brachial-cephalic (n=64), brachial-basilic (n=34), brachial-brachial (n=4), and ulnar-cephalic (n=2). A significant increase in complications was noted in BAM procedures performed in forearm AVF versus upper arm AVF (67% vs 54%, P=0.02) and in the large balloon group versus small balloon group (72% vs 52%, P<0.001). The data suggest that office-based BAM procedures are safe. Fortunately, major complications are not seen at an alarming rate. While increased complications are seen in BAM procedures performed in the forearm and with larger balloons, except for wall hematoma formation (40.19%), each complication occurs in <10% of the procedures. Further studies to help clarify the nature of these complications and their relationship to fistula maturation are warranted.