Background and objectives: Physical examination has been highlighted to detect vascular access stenosis; however, its accuracy in the identification of stenoses when compared with the gold standard (angiography) has not been validated in a systematic manner.Design, setting, participants, & measurements: A prospective study was conducted of 142 consecutive patients who were referred for an arteriovenous fistula dysfunction to examine the accuracy of physical examination in the detection of stenotic lesions when compared with angiography. The findings of a preprocedure physical examination and diagnosis were recorded and secured in a sealed envelope. Angiography from the feeding artery to the right atrium was then performed. The images were reviewed by an independent interventionalist who had expertise in endovascular dialysis access procedures and was blinded to the physical examination, and the diagnosis was rendered. Cohen's was used as a measurement of the level of agreement beyond chance between the diagnosis made by physical examination and angiography.Results: There was strong agreement between physical examination and angiography in the diagnosis of outflow (agreement 89.4%, ‫؍‬ 0.78) and inflow stenosis (agreement 79.6%, ‫؍‬ 0.55). The sensitivity and specificity for the outflow and inflow stenosis were 92 and 86% and 85 and 71%, respectively. There was strong agreement beyond chance regarding the diagnosis of coexisting inflow-outflow lesions between physical examination and angiography (agreement 79%, ‫؍‬ 0.54).Conclusions: The findings of this study demonstrate that physical examination can accurately detect and localize stenoses in a great majority of arteriovenous fistulas.

The frequency of primary failure in arteriovenous fistulas (AVFs) remains unacceptably high. This lack of improvement is due in part to a poor understanding of the pathobiology underlying AVF nonmaturation. This observational study quantified the progression of three vascular features, medial fibrosis, intimal hyperplasia (IH), and collagen fiber organization, during early AVF remodeling and evaluated the associations thereof with AVF nonmaturation. We obtained venous samples from patients undergoing two-stage upper-arm AVF surgeries at a single center, including intraoperative veins at the first-stage access creation surgery and AVFs at the second-stage transposition procedure. Paired venous samples from both stages were used to evaluate change in these vascular features after anastomosis. Anatomic nonmaturation (AVF diameter never ≥6 mm) occurred in 39 of 161 (24%) patients. Neither preexisting fibrosis nor IH predicted AVF outcomes. Postoperative medial fibrosis associated with nonmaturation (odds ratio [OR], 1.55; 95% confidence interval [95% CI], 1.05 to 2.30; =0.03, per 10% absolute increase in fibrosis), whereas postoperative IH only associated with failure in those individuals with medial fibrosis over the population's median value (OR, 2.63; 95% CI, 1.07 to 6.46;=0.04, per increase of 1 in the intima/media ratio). Analysis of postoperative medial collagen organization revealed that circumferential alignment of fibers around the lumen associated with AVF nonmaturation (OR, 1.38; 95% CI, 1.03 to 1.84; =0.03, per 10° increase in angle). This study demonstrates that excessive fibrotic remodeling of the vein after AVF creation is an important risk factor for nonmaturation and that high medial fibrosis determines the stenotic potential of IH.

Background The contribution of intimal hyperplasia (IH) to arteriovenous fistula (AVF) failure is uncertain. This observational study assessed the relationship between preexisting, postoperative, and change in IH over time and AVF outcomes. Study Design Prospective cohort study with longitudinal assessment of IH at the time of AVF creation (pre-existing) and transposition (postoperative). Patients were followed-up for up to 3.3 years. Setting & Participants 96 patients from a single center who underwent AVF surgery initially planned as a two-stage procedure. Veins and AVF samples were collected from 66 and 86 patients, respectively. Matched-pair tissues were available from 56 of these patients. Predictors Pre-existing, postoperative and change in IH over time. Outcomes Anatomic maturation failure was defined as an AVF that never reached a diameter greater than 6 mm. Primary unassisted patency was defined as the time elapsed from the second-stage surgery until first intervention. Measurements Maximal intimal thickness in veins and AVF and change in intimal thickness over time. Results Pre-existing IH (> 0.05 mm) was present in 98% of the patients. In this group, the median intimal thickness increased 4.40-fold (IQR, 2.17- to 4.94-fold) between the AVF creation and transposition. However, this change was not associated with the preexisting thickness (r2=0.002; p=0.7). Ten of 96 AVFs (10%) never achieved maturation, while 70% of the vascular accesses remained patent at the end of the observational period. Postoperative IH was not associated with anatomic maturation failure using a univariate logistic regression. Pre-existing, postoperative, and change in IH over time had no effects on primary unassisted patency. Limitations The low number of patients from whom longitudinal tissue samples were available and the low incidence of anatomic maturation failure, which decreased the statistical power to find associations between end points and IH. Conclusions Pre-existing, postoperative, and change in IH over time were not associated with two-stage AVF outcomes.

While hemodialysis access ligation has been used to manage pacemaker (PM) and implantable cardioverter-defibrillator (ICD) lead-induced central venous stenosis (CVS), percutaneous transluminal balloon angioplasty (PTA) has also been employed to manage this complication. The advantages of PTA include minimal invasiveness and preservation of arteriovenous access for hemodialysis therapy. In this multi-center study we report the patency rates for PTA to manage lead-induced CVS. Consecutive PM/ICD chronic hemodialysis patients with an arteriovenous access referred for signs and symptoms of CVS due to lead-induced CVS were included in this analysis. PTA was performed using the standard technique. Technical and clinical success was examined. Technical success was defined as the ability to successfully perform the procedure. Clinical success was defined as the ability to achieve amelioration of the signs and symptoms of CVS. Both primary and secondary patency rates were also analyzed. Twenty-eight consecutive patients underwent PTA procedure. Technical success was 95%. Postprocedure clinical success was achieved in 100% of the cases where the procedure was successful. The primary patency rates were 18% and 9% at 6 and 12 months, respectively. The secondary patency rates were 95%, 86%, and 73% at 6, 12, and 24 months, respectively. On average, 2.1 procedures/year were required to maintain secondary patency. There were no procedure-related complications. This study finds PTA to be a viable option in the management of PM/ICD lead-induced CVS. Additional studies with appropriate design and sample size are required to conclusively establish the role of PTA in the management of this problem.

Transvenous leads of cardiac rhythm devices (CRDs) are known to cause central stenosis and are vulnerable to contamination during hemodialysis access-related bacteremia. In this retrospective study, nine consecutive chronic hemodialysis patients with transvenous CRD infection due to dialysis access-related bacteremia and recurrent central stenosis are presented. Four patients with tunneled hemodialysis catheters (TDCs) and three with arteriovenous grafts experienced access-related bacteremia that spread to the transvenous CRD. Two patients required repeated angioplasty procedures (less than 3 months apart) for central venous stenosis. Transvenous CRD was removed and replaced with an epicardial system in all. One patient with TDC switched to peritoneal dialysis and did not experience infection of the epicardial system despite two episodes of peritonitis. The remaining TDC (n=3) and graft patients (n=3) received a new TDC after the resolution of bacteremia. While all six experienced on average 1.5 episodes of catheter-related bacteremia (average follow-up = 14.5 months), none developed infection of the epicardial system. The patients with central stenosis have required only one angioplasty each for the past 8 and 6 months. To the best of our knowledge this is the first study to suggest that an epicardial approach might be a preferred method over transvenous leads for chronic hemodialysis patients.