Screening for hemodialysis graft stenosis and short-term thrombosis risk: A comparison of the available tools.

INTRODUCTION: Guidelines recommend hemodialysis graft screening to identify and repair significant (>50%) stenosis at high risk of thrombosis, but there is insufficient evidence to prefer one or other screening tool due to the lack of studies comparing all available options. METHODS: Seeking an optimal screening approach, we compared the performance of all currently used tools (duplex ultrasound to detect significant stenosis (StD) and measure access blood flow (QaD), ultrasound dilution access blood flow (QaU), static venous intra-access pressure ratio (VAPR), dynamic arterial and venous pressures measurement, and monitoring) for diagnosing significant angiography-proven stenosis (StA) and predicting incipient thrombosis (occurring within 4 months) in 62 grafts. All thrombotic and symptomatic acute hypotension episodes were recorded during follow-up. RESULTS: VAPR > 0.70 and QaU < 1600 mL/min were the best indicators to angiography for those aiming to identify the majority of StA (91% sensitivity) and QaU < 1000 mL/min or StD for those aiming to avoid unnecessary angiograms (95%-93% positive predictive value). At Cox's analysis, the only significant thrombosis predictors were acute hypotension episodes (relative risk = 4.4 (95% confidence interval = 2.2-8.8), p < 0.0001) and QaU or QaD (14% (95% confidence interval = 8-21) or 16% (95% confidence interval = 6-25) increased risk per 100 mL/min drop in Qa, p < 0.003). Thrombosis risk (adjusted for acute hypotension) became significantly higher at QaU = 1000-700 mL/min (relative risk = 3.6 (95% confidence interval = 1.6-8.2), p < 0.001) and QaD = 1300-1000 mL/min (relative risk = 3.1 (95% confidence interval = 1.1-12.8), p = 0.031). The proportion of thromboses attributable to acute hypotension was 40% (95% confidence interval = 24-57). CONCLUSIONS: Our comparative study showed that an effective screening for graft stenosis and short-term thrombosis risk can rely on Qa surveillance alone, and suggested that avoiding acute hypotension and correcting stenosis at QaU < 1000 mL/min or QaD < 1300 mL/min can contain thrombosis risk.

Pancreatectomy with venous resection for pT3 head adenocarcinoma: Perioperative outcomes, recurrence pattern and prognostic implications of histologically confirmed vascular infiltration.

BACKGROUND: The outcomes of pancreatectomy with superior mesenteric vein (SMV) or portal vein (PV) resection have been mixed. This study investigated the morbidity and mortality profile after SMV-PV resection in comparison with standard pancreatectomy. Furthermore, we assessed whether tumors with histologically proven SMV-PV infiltration differ from other pT3 neoplasms in terms of recurrence pattern and survival. METHODS: All patients with a pT3 head adenocarcinoma resected from 2000 to 2013 were analyzed retrospectively. In the SMV-PV resection group, information on venous wall status was obtained through pathologic reports. Standard statistical methods were used for data analysis. RESULTS: The study population consisted of 651 patients, of whom 81 (12.4%) underwent synchronous SMV-PV resection. Venous resection was not associated with a higher rate of postoperative complications (60.5% versus 50.2%) and mortality (1.2% versus 1.1%) in comparison with standard pancreatectomy. Vascular infiltration was confirmed pathologically in 56/81 patients (69.1%). The median disease-specific survival of the entire population was 27 months (95% CI 24.6-29.3), with a 5-year survival rate of 20.5%. The median recurrence-free survival was 18 months (95% CI 15.0-20.9). On multivariate analysis, ASA score, preoperative pain, Ca 19-9 levels, tumor grade, R-status, lymph-vascular invasion, N-status, and adjuvant therapy resulted to be survival predictors. Similarly, Ca 19.9 levels, R-status, and N-status were predictors of recurrence. SMV-PV infiltration was not a significant prognostic factor. CONCLUSION: Morbidity and mortality rates of pancreatectomy with SMV-PV resection are comparable with standard pancreatectomy. Pancreatic head adenocarcinoma with histologically confirmed SMV-PV infiltration does not segregate prognostically from other pT3 tumors.

Do oxidized polyunsaturated Fatty acids affect endoplasmic reticulum stress-induced apoptosis in human carotid plaques?

Macrophage apoptosis is involved in atherosclerotic plaque development. The aim of this study was to evaluate the interrelationship between macrophage apoptosis and the endoplasmic reticulum (ER) stress in the tissue around the necrotic core (TANC) and in the periphery (P) of the same carotid plaques derived from patients undergoing carotid endarterectomy. Apoptosis was significantly higher in TANC than in P (p<0.001). mRNA and protein expression of the protein kinase-like ER kinase (Perk) and the nuclear erythroid-related factor 2 (Nrf2)-related survival genes was significantly higher in P than in TANC (p<0.01), while CCAAT/enhancer-binding protein homologous protein (Chop) and the apoptosis-related genes were higher in TANC than in P (p<0.01). The TANC extract was characterized by significantly higher concentrations of oxidized derivatives of polyunsaturated fatty acids (PUFAs) than the P extract (p<0.01). When THP-1 cells were incubated with P or TANC extracts there was a dose-dependent increase of Perk and Nrf2 or of Chop and of the apoptosis-related genes, respectively (p<0.01). Our observations lead to the hypothesis that ER stress induced by oxidized derivatives of PUFAs may promote macrophage apoptosis in TANC and favor the expansion of the necrotic core of the plaques, a major feature responsible for its disruption and acute luminal thrombosis.

Should current criteria for detecting and repairing arteriovenous fistula stenosis be reconsidered? Interim analysis of a randomized controlled trial.

BACKGROUND: The vascular access guidelines recommend that arteriovenous fistulas (AVFs) with access dysfunction and an access blood flow (Qa) <300-500 mL/min be referred for stenosis imaging and treatment. Significant (>50%) stenosis, however, may be detected in a well-functioning AVF with a Qa > 500 mL/min, too, but whether it is worth correcting or not remains to be seen. METHODS: In October 2006, we began an open randomized controlled trial enrolling patients with an AVF with subclinical stenosis and Qa > 500 mL/min, to see how elective stenosis repair [treatment group (TX)] influenced access failure (thrombosis or impending thrombosis requiring access revision), or loss and the related cost compared with stenosis correction according to the guidelines, i.e. after the onset of access dysfunction or a Qa < 400 mL/min [control group (C)]. An interim analysis was performed in July 2012, by which time the trial had enrolled 58 patients (30 C and 28 TX). RESULTS: TX led to a relative risk of 0.47 [95% confidence interval (CI): 0.17-1.15] for access failure (P = 0.090), 0.37 [95% CI: 0.12-0.97] for thrombosis (P = 0.033) and 0.36 [95% CI: 0.09-0.99] for access loss (P = 0.041). In the setting of our study (in which all surgery was performed as in patient procedure) no significant differences in costs emerged between the two strategies. The mean incremental cost-effectiveness ratio for TX was €282 or €321 to avoid one episode of thrombosis or access loss, respectively. CONCLUSIONS: Our interim analysis showed that elective repair of subclinical stenosis in AVFs with Qa > 500 mL/min cost-effectively reduces the risk of thrombosis and access loss in comparison with the approach of the Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines, raising the question of whether the currently recommended criteria for assessing and treating stenosis should be reconsidered.

Expansion of necrotic core and shedding of Mertk receptor in human carotid plaques: a role for oxidized polyunsaturated fatty acids?

AIMS: Expansion of necrotic core (NC), a major feature responsible for plaque disruption, is likely the consequence of accelerated macrophage apoptosis coupled with defective phagocytic clearance (efferocytosis). The cleavage of the extracellular domain of Mer tyrosine kinase (Mertk) by metallopeptidase domain17 (Adam17) has been shown to produce a soluble Mertk protein (sMer), which can inhibit efferocytosis. Herein, we analysed the expression and localization of Mertk and Adam17 in the tissue around the necrotic core (TANC) and in the periphery (P) of human carotid plaques. Then we studied the mechanisms of NC expansion by evaluating which components of TANC induce Adam17 and the related cleavage of the extracellular domain of Mertk. METHODS AND RESULTS: We studied 97 human carotid plaques. The expression of Mertk and Adam17 was found to be higher in TANC than in P (P < 0.001). By immunohistochemistry, Mertk was higher than Adam17 in the area of TANC near to the lumen (P < 0.01) but much lower in the area close to NC (P < 0.01). The extract of this portion of TANC increased the expression (mRNA) of Adam17 and Mertk (P < 0.01) in macrophage-like THP-1 cells but it also induced the cleavage of the extracellular domain of Mertk, generating sMer in the medium (P < 0.01). This effect of TANC extract was most evoked by its content in F(2)-isoprostanes, hydroxyoctadecadienoic acids, and hydroxytetraenoic acids. CONCLUSION: Some oxidized derivatives of polyunsaturated fatty acids contained in TANC of human carotid plaques are strong inducers of Adam17, which in turn leads to the generation of sMer, which can inhibit efferocytosis.

In search of an optimal bedside screening program for arteriovenous fistula stenosis.

BACKGROUND AND OBJECTIVES: Guidelines recommend systematically screening for stenosis using various methods, but no studies so far have compared all of the options. A prospective blinded study was performed to compare the performance of several bedside tests performed during dialysis in diagnosing angiographically proven >50% fistula stenosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In an unselected population of 119 hemodialysis patients with mature fistulas, physical examination (PE) was conducted; dynamic and derived static venous pressure (VAPR), blood pump flow/arterial pressure (Qb/AP) ratio, recirculation (R), and access blood flow (Qa) were measured; and angiography was performed. RESULTS: Angiography identified 59 stenotic fistulas: 43 stenoses were located upstream from the venous needle (inflow stenosis), 12 were located downstream (outflow stenosis), and 4 were located at both sites. The optimal tests for identifying an inflow stenosis were Qa < 650 ml/min and the combination of a positive PE "or" Qa < 650 ml/min (accuracy 80% and 81%, respectively), the latter being preferable because it was more sensitive (85% versus 65%, respectively) for a comparable specificity (79% versus 89%, respectively). The best tests for identifying outflow stenosis were PE and VAPR, with no difference between the two (accuracy 91% and 85%, sensitivity 75% and 81%, specificity 93% and 86%, respectively), the former being preferable because it was more reproducible, easier to perform, and applicable to all fistulas. CONCLUSIONS: This study showed that fistula stenosis can be detected and located during dialysis with a moderate-to-excellent accuracy using PE and Qa measurement as screening procedures.

Bedside screening for fistula stenosis should be tailored to the site of the arteriovenous anastomosis.

BACKGROUND AND OBJECTIVES: Given different sites of stenosis and access blood flow rates (Qa), the criteria for diagnosing fistula stenosis might vary according to anastomotic site. To test this, we analyzed the database of a prospective blinded study seeking an optimal bedside screening program for fistula stenosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Several methods used during dialysis (physical examination [PE], dynamic and derived static venous pressure [VAPR], dialysis blood pump flow/arterial pressure ratio, and Qa measurement) to diagnose angiographically-proven >50% stenosis were assessed in an unselected population of hemodialysis patients with mature fistulae (43 at the wrist [distal fistulae], 76 at mid-forearm or the elbow [proximal fistulae]). RESULTS: Prevalence of inflow stenosis was uninfluenced by anastomotic site, whereas outflow stenoses were more prevalent in proximal fistulae. The best test for inflow stenosis was Qa <650 ml/min in distal fistulae and a combination of a positive PE and Qa <900 ml/m in proximal fistulae. In proximal fistulae, PE and VAPR >0.5 were both equally highly diagnostic of outflow stenosis. Tailoring choice of test to site of the anastomosis may also contain the screening-associated workload, by reducing the need to perform PE and measure VAPR, compared with a screening approach regardless of the access location. CONCLUSIONS: Our study shows that an effective bedside screening program with ≥85% accuracy for fistula stenosis can be tailored to the site of the anastomosis, Qa being the tool of choice for the wrist, and PE alone or combined with Qa and VAPR measurements for more proximally-located accesses.

Adding access blood flow surveillance to clinical monitoring reduces thrombosis rates and costs, and improves fistula patency in the short term: a controlled cohort study.

BACKGROUND: Access blood flow (Qa) measurement is the recommended method for fistula (AVF) surveillance for stenosis, but whether it may be beneficial and cost-effective is controversial. METHODS: We conducted a 5-year controlled cohort study to evaluate whether adding Qa surveillance to unsystematic clinical monitoring (combined with elective stenosis repair) reduces thrombosis and access loss rates, and costs in mature AVFs. We prospectively collected data in 159 haemodialysis patients with mature AVFs, 97 followed by unsystematic clinical monitoring (Control) and 62 by adding Qa surveillance to monitoring (Flow). Indications for imaging and stenosis repair were clinically evident access dysfunction in both groups and a Qa < 750 ml/min or dropping by >20% in Flow. RESULTS: Adding Qa surveillance prompted an increase in access imaging (HR 2.96, 95% CI 1.79-4.91, P < 0.001), stenosis detection (HR 2.55, 95% CI 1.48-4.42, P = 0.001) and elective repair (HR 2.26, 95% CI 1.16-4.43, P = 0.017), and a reduction in thromboses (HR 0.27, 95% CI 0.09-0.79, P = 0.017), central venous catheter placements (HR 0.14, 95% CI 0.03-0.42, P = 0.010) and access losses (HR 0.35, 95% CI 0.11-1.09, P = 0.071). In the Kaplan-Meier analysis, adding Qa surveillance only extended short-term cumulative patency (P = 0.037 in the Breslow test). Mean access-related costs were 1213 Euro/AVF-year in Control and 743 in Flow (P < 0.001). CONCLUSIONS: Our controlled cohort study shows that adding Qa surveillance to monitoring in mature AVFs is associated with a better detection and elective treatment of stenosis, and lower thrombosis rates and access-related costs, although the cumulative access patency was only extended in the first 3 years after fistula maturation. We are aware of the limitations of our study (non-randomization and the possible centre effect) and that further, better-designed trials are needed to arrive at a definitive answer concerning the role of Qa surveillance for fistulae.

Outcomes of surgical revision of stenosed and thrombosed forearm arteriovenous fistulae for haemodialysis.

BACKGROUND: Surgery is an established treatment for stenosed and thrombosed forearm arteriovenous fistulae (AVFs), but the literature on its outcome is limited. We report our experience of the surgical repair of stenosis in patent and thrombosed forearm AVFs and evaluate the outcome of two procedures, proximal neo-anastomosis (NEO) vs replacement of the stenosed segment with a polytetrafluoroethylene graft interposition (GI). METHODS: Sixty-four stenosed forearm AVFs underwent surgery, 32 pre-emptively and 32 post-thrombosis. End points of the study were initial success, restenosis and access loss rates. After treatment, AVFs were surveilled for restenosis by measuring access flow quarterly and performing at least one follow-up angiogram. RESULTS: Initial procedural success was 92%; 100% for patent and 84% for thrombosed AVFs. The restenosis rate was 0.189 events/AVF-year for both patent and thrombosed AVFs, while the access loss rate was 0.016 events/AVF-year in patent and 0.148 in thrombosed AVFs. Stenosis was corrected by NEO in 27 AVFs and by GI in 30. The restenosis and access loss rates were 0.151 vs 0.214 and 0.033 vs 0.019 events/AVF-year for NEO vs GI, respectively. At Cox's hazard analysis, no variable was significantly associated with restenosis, while the timing of intervention was the only significant determinant of access loss, repaired clotted accesses carrying an 8.0-fold relative risk of access loss compared with patent AVFs (P=0.048). CONCLUSION: Our study shows that surgery remains a valid option for the pre-emptive repair of stenosis and to salvage clotted forearm AVFs, offering an excellent initial success rate and low restenosis rate. It confirms that it is better to treat stenosis pre-emptively than post-thrombosis (though the restenosis rate appears to be uninfluenced by the timing of intervention) and suggests that GI compares favourably with conventional NEO.

Endovascular versus surgical preemptive repair of forearm arteriovenous fistula juxta-anastomotic stenosis: analysis of data collected prospectively from 1999 to 2004.

Surgery is the traditional treatment for juxta-anastomotic stenoses in forearm arteriovenous fistulas (AVF), but percutaneous transluminal angioplasty (PTA) is a suitable alternative. No prospective comparative trials between the two have been reported to date, however. A retrospective analysis of prospectively, concurrently collected data was performed to compare the outcome and cost of surgery and PTA in the preemptive repair of juxta-anastomotic stenosis in lower forearm AVF. Sixty-four AVF with >50% venous juxta-anastomotic stenosis were considered: 21 were treated surgically (11 proximal neo-anastomosis and 10 polytetrafluoroethylene interposition graft) and 43 by PTA. After treatment, AVF were monitored by quarterly ultrasound dilution access blood flow measurement. End points were restenosis and procedure failure rate (re-intervention by another technique or access loss), and determinants were analyzed using Cox hazard model. Initial procedural success was 100% for surgery and 95% for PTA (P = 0.539). Restenosis rate was 0.168 and 0.519 events/AVF-year for surgery and PTA, respectively (P = 0.009). The type of procedure was the only variable that was significantly associated with restenosis, the adjusted relative risk being 2.77-fold higher (95% confidence interval 1.07 to 7.17; P = 0.036) after PTA than surgery. The procedure failure rate was 0.110 and 0.097 events/AVF-year for surgery and PTA, respectively (P = 0.736). The cost profile also was similar for the two procedures. This prospective comparative study confirms a higher restenosis rate after PTA than surgery, but with strict surveillance for restenosis, the two procedures show similar assisted primary patency and cost, suggesting that they should be considered equally valid, complementary alternatives in the preemptive treatment of juxta-anastomotic stenosis in forearm AVF.

Diagnosis of pelvic endometriosis with use of macroscopic versus histologic findings.

OBJECTIVE: To obtain histologic confirmation of lesions suspected of endometriosis at laparoscopy. DESIGN: Prospective clinical study. SETTING: Patients in an academic hospital. PATIENT(S): Women of reproductive age who complained of chronic pelvic pain. INTERVENTION(S): A total of 122 biopsies were obtained from 54 patients undergoing laparoscopy, after exclusion of other potential causes of pelvic pain. MAIN OUTCOME MEASURE(S): Lack of consistency between laparoscopic and histologic diagnosis of endometriosis, in particular for minimal/mild stages. RESULTS: Endometriosis was confirmed by histology in 54% of the excised lesions. Diagnosis was more often confirmed among classic lesions than for all atypical lesions considered together. The histologic diagnosis of fibrosis was the most common among those biopsies, which lacked the presence of endometriosis. The revised American Fertility Association (AFS) scores before and after histologic confirmation differed significantly. In particular, 20 patients in either revised AFS class I or II were down-graded to stage 0. No single anatomical site turned out to be particularly prone to misdiagnosis at laparoscopy, in comparison to the other sites. CONCLUSION(S): These results confirm the need of histologic confirmation to obtain a diagnosis of endometriosis. However, the clinical impact of such findings remains a matter of debate.

Can blood flow surveillance and pre-emptive repair of subclinical stenosis prolong the useful life of arteriovenous fistulae? A randomized controlled study.

BACKGROUND: Stenosis is the main cause of arteriovenous fistula (AVF) failure. It is unclear, however, if surveillance for stenosis enhances AVF function and longevity and if there is an ideal time for intervention. METHODS: In a 5-year randomized, controlled, open trial we compared blood flow surveillance and pre-emptive repair of subclinical stenoses (one or both of angioplasty and open surgery) with standard monitoring and intervention based upon clinical criteria alone to determine if the former prolonged the longevity of mature forearm AVFs. Surveillance with blood pump flow (Qb) monitoring during dialysis sessions and quarterly shunt blood flow (Qa) or recirculation measurements identified 79 AVFs with angiographically proven, significant (>50%) stenosis. The AVFs were randomized to either a control group (intervention done in response to a decline in the delivered dialysis dose or thrombosis; n = 36) or to a pre-emptive treatment group (n = 43). To evaluate a possible relationship between outcome and haemodynamic status of the access, AVFs were divided into functional and failing subgroups, according to Qa values higher or lower than 350 ml/min or the absence or presence of recirculation. RESULTS: A Kaplan-Meier analysis showed that pre-emptive treatment reduced failure rate (P = 0.003) and the Cox hazards model identified treatment (P = 0.009) and higher baseline Qa (P = 0.001) as the only variables associated with favourable outcome. Primary patency rates were higher in treatment than in control AVFs in both functional (P = 0.021) and failing subgroups (P = 0.005). They were also higher in functional than in failing AVFs in both control (P<0.001) and treatment groups (P = 0.023). Access survival was significantly higher in pre-emptively treated than in control AVFs (P = 0.050), a higher post-intervention Qa being the only variable associated with improved access longevity (P = 0.044). Secondary patency rates were similar in pre-emptively treated and control AVFs in both functional (P = 0.059) and failing subgroups (P = 0.394). They were also similar in functional and failing AVFs in controls (P = 0.082), but were higher in pre-emptively treated functional AVFs than in pre-emptively treated failing AVFs (P = 0.033) or in the entire control group (P = 0.019). CONCLUSIONS: We provide evidence that active blood flow surveillance and pre-emptive repair of subclinical stenosis reduce the thrombosis rate and prolong the functional life of mature forearm AVFs. We also show that Qa is a crucial indicator of access patency and a Qa >350 ml/min portends a superior outcome with pre-emptive action in AVFs.

Diagnostic accuracy of ultrasound dilution access blood flow measurement in detecting stenosis and predicting thrombosis in native forearm arteriovenous fistulae for hemodialysis.

BACKGROUND: Vascular access surveillance by ultrasound dilution blood flow rate (Qa) measurement is widely recommended; however, optimal criteria for detecting stenosis and predicting thrombosis in arteriovenous fistulae (AVFs) are still not clearly defined. METHODS: In a blinded trial, we evaluated the accuracy of single Qa measurement, Qa adjusted for mean arterial pressure (Qa/MAP), and decrease in Qa over time (dQa) in detecting stenosis and predicting thrombosis in an unselected population of 120 hemodialysis subjects with native forearm AVFs (91 AVFs, located at the wrist; 29 AVFs, located at the midforearm). All AVFs underwent fistulography, which identified greater than 50% stenosis in 54 cases. RESULTS: Receiver operating characteristic curve analysis showed that dQa, Qa, and Qa/MAP have a high stenosis discriminative ability with similar areas under the curve (AUCs), ie, 0.961 +/- 0.025, 0.946 +/- 0.021, and 0.912 +/- 0.032, respectively. In the population as a whole, optimal thresholds for stenosis were Qa less than 750 mL/min alone and in combination with dQa greater than 25% (efficiency, 90%); however, the best threshold depended on anastomotic site; it was Qa less than 750 mL/min for an AVF at the wrist and Qa less than 1,000 mL/min for an AVF in the midforearm. Qa was the best predictor of incipient thrombosis (AUC, 0.981 +/- 0.013) with an optimal threshold at less than 300 mL/min (efficiency, 94%). Pooled intra-assay and interassay variation coefficients were 8.2% for MAP, 7.9% for Qa, and 11.2% for Qa/MAP. CONCLUSION: Our study shows that ultrasound dilution Qa measurement is a reproducible and highly accurate tool for detecting stenosis and predicting thrombosis in forearm AVFs. Neither Qa/MAP nor dQa improve the diagnostic performance of Qa alone, although its combination with dQa increases the test's sensitivity for stenosis.

A prospective controlled trial on effect of percutaneous transluminal angioplasty on functioning arteriovenous fistulae survival.

Balloon angioplasty (PTA) is an established treatment modality for stenosis in dysfunctional arteriovenous fistulae (AVF), although most studies showing efficacy have been retrospective, uncontrolled, and nonrandomized. In addition, it is unknown whether correction of stenosis not associated with significant hemodynamic, functional, and clinical abnormality may improve survival in AVF. This study was a prospective controlled open trial to evaluate whether prophylactic PTA of stenosis not associated with access dysfunction improves survival in native, virgin, radiocephalic forearm AVF. Sixty-two stenotic, functioning AVF, i.e., able to provide adequate dialysis, were enrolled in the study: 30 were allocated to control and 32 to PTA. End points of the study were either AVF thrombosis or surgical revision due to reduction in delivered dialysis dose. Kaplan-Meier analysis showed that PTA improved AVF functional failure-free survival rates (P = 0.012) with a fourfold increase in median survival and a 2.87-fold decrease in risk of failure. Cox proportional hazard model identified PTA as the only variable associated with outcome (P = 0.012). PTA induced an increase in access blood flow rate (Qa) by 323 (236 to 445) ml/min (P < 0.001), suggesting that improved AVF survival is the result of increased Qa. PTA was also associated with a significant decrease in access-related morbidity by approximately halving the risk of hospitalization, central venous catheterization, and thrombectomy (P < 0.05). This study shows that prophylactic PTA of stenosis in functioning forearm AVF improves access survival and decreases access-related morbidity, supporting the usefulness of preventive correction of stenosis before the development of access dysfunction. It also strongly supports surveillance program for early detection of stenosis.