| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Vascular and Interventional Radiology |
1 From the Department of Medical Imaging, Division of Vascular and Interventional Radiology (D.K.R.), Clinical Studies Resources Centre (R.P.), and Department of Nephrology (C.E.L.), Toronto General Hospital, University Health Network, University of Toronto, 585 University Ave, NCSB 1C-553, Toronto, ON, Canada M5G 2N2; Department of Radiology, Dalhousie Medical School, Halifax, Nova Scotia, Canada (S.B.); and Department of Radiology, Mayo Clinic, Rochester, Minn (S.M.). From the 2003 RSNA scientific assembly. Received May 8, 2003; revision requested July 16; final revision received November 24; accepted January 2, 2004. Address correspondence to D.K.R. (e-mail: dheeraj.rajan@uhn.on.ca).
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
MATERIALS AND METHODS: The authors reviewed their institutional experience with autogenous fistulas from June 1997 to June 2002. A total of 104 men and 36 women were treated. Mean age ± standard deviation of patient cohort was 62.4 years ± 15.6. Patient age and sex, age of fistula at initial intervention, presence of diabetes, side and location of fistula, location of stenosis, and number of venous stenoses dilated were examined. Patency after angioplasty was estimated by using the Kaplan-Meier method, and predictors of patency were examined by using a Cox proportional hazards model.
RESULTS: One hundred fifty-one dysfunctional fistulas (94 radiocephalic and 57 brachiocephalic) were treated with angioplasty initially. Clinical success rate was 98.0% (297 of 303 interventions). At 3, 6, and 12 months, respectively, primary patency rates ± standard errors of the estimate were 73% ± 6, 51% ± 7, and 39% ± 7 for brachiocephalic fistulas and 85% ± 4, 75% ± 5, and 62% ± 5 for radiocephalic fistulas; secondary patency rates were 96% ± 2.4, 89% ± 4, and 85% ± 5 for brachiocephalic fistulas and 91% ± 3, 88% ± 3, and 86% ± 4 for radiocephalic fistulas. For all time points, there was a significant difference in primary (P = .004) but not secondary (P = .45) patency between radiocephalic and brachiocephalic fistulas. Stenosis was most prevalent within 3 cm of the arteriovenous anastomosis in 74 (64%) of the 116 dysfunctional radiocephalic fistulas and at the cephalic arch in 22 (30%) of the 74 dysfunctional brachiocephalic fistulas. The clinical variables examined did not influence outcome. Complications occurred in seven (2.3%) of 303 interventions.
CONCLUSION: Patency after angioplasty in dysfunctional autogenous hemodialysis fistulas exceeds that observed in hemodialysis grafts. None of the clinical or anatomic variables examined affected patency outcome.
© RSNA, 2004
Index terms: Dialysis, shunts • Fistula, arteriovenous • Veins, transluminal angioplasty, 916.1282
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
However, autogenous hemodialysis fistulas, like polytetrafluoroethylene grafts, are alsosubject to dysfunction and eventual failure. Despite the adoption of K/DOQI clinical guidelines (1–3) and early descriptions of percutaneous interventions in hemodialysis fistulas (4), there is a relative paucity of information on percutaneous management of dysfunctional arteriovenous fistulas and outcomes after percutaneous interventions.
The purpose of our study was to determine the primary and secondary patency rates for fistulas treated with angioplasty, as well as the clinical predictors of fistula patency after angioplasty.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
Patients included in this study were referred for fistulography after dysfunction was identified according to either of two criteria. One criterion was that total access blood flow was less than 500 mL/min at ultrasonographic (US) dilution examination (performed with a Transonic Flow-QC unit [Transonic Systems, Ithaca, NY]) (5–7). The other criterion was that blood flow decreased by more than 20% from baseline blood flow and one of the following occurred: (a) Fistula recirculation was more than 5% at US dilution examination; (b) cannulation was difficult; (c) dynamic venous pressures exceeded threshold levels three consecutive times; or (d) other clinical or hemodynamic findings suggested fistula dysfunction, including variable pump speeds, arm swelling, and extremity pain. US dilution examinations were performed by an assigned nephrology nurse who had 6 years of experience.
Pretreatment Evaluation
Diagnostic fistulography was performed with the outer 4-F catheter from a micropuncture set or with a 4-F Kumpe access catheter (Cook, Bloomington, Ind). Access to the fistula was obtained initially with a 19-gauge needle or with the 21-gauge needle from a micropuncture set. The method of access was based on operator preference. Diagnostic imaging was performed by one of six interventional radiologists, including one author (D.K.R., with 4 years of experience); the other five interventionalists were not authors (range of experience, 2–25 years). Fistulography was performed to the level of the right atrium.
After initial fistulography, the fistula was temporarily occluded by means of either digital palpation or inflation of a blood pressure cuff, causing reflux of contrast material across the arterial anastomosis of the fistula. When necessary, a second puncture, directed in retrograde fashion, was made in the more central portion of the fistula, and, if necessary, a catheter was passed into either the brachial artery or the radial artery to enable complete demonstration of the anatomic features of the fistula. Brachial artery puncture was performed by using a micropuncture set in radiocephalic fistulas when a stenosis was suspected to be present in the radial artery because refluxing contrast medium had failed to opacify the artery and a catheter could not be passed into the artery from the fistula. When access was difficult, US guidance was used. If no angiographic abnormality was identified and fistula dysfunction was apparent, blood pressure measurements were obtained across areas of angiographic ambiguity.
Treatment
Stenoses were treated by using a standard angioplasty technique with noncompliant balloons. Angioplasty procedures were performed by one of six fellowship-trained vascular and interventional radiologists, including one author (D.K.R., with 4 years of experience); the other five interventionalists were not authors (range of experience, 2–25 years). When a lesion was detected, a wire was passed again into the fistula and the diagnostic catheter was removed and exchanged for an appropriately sized sheath. The balloon catheter was then advanced to the region of stenosis, and the balloon was inflated until the stenosis was eliminated. Inflation was maintained for a minimum of 30 seconds. When necessary, high-pressure balloons were used to eliminate the lesion. For stenoses in the region of the arteriovenous anastomosis, 4–7-mm balloon catheters were used for angioplasty; for stenoses in the outflow cephalic veins, 6–8-mm balloon catheters were used; and for central venous stenoses, 10–12-mm balloon catheters were used. Heparin (Hepalean; Leo-Pharma, Thornhill, Ontario, Canada) was administered intravenously at the discretion of the treating radiologist in doses of up to 4,000 IU; it was administered in 26 of 299 angioplasty procedures.
All patients were monitored with electrocardiography, pulse oximetry, and standard blood pressure determinations. Intravenous fentanyl citrate (Sublimase; Abbott Laboratories, Abbott Park, Ill) and midazolam hydrochloride (Versed; Roche Laboratories, Nutley, NJ) were used for conscious sedation during interventions. In four patients, later interventions for fistulas required percutaneous declotting. The methods used for declotting have been described by Rajan et al (8).
Study Definitions and End Points
Primary and secondary patencies of the arteriovenous fistulas after percutaneous intervention were defined in accordance with Society of Interventional Radiology reporting standards and quality improvement guidelines (9,10). Primary patency was defined as patency during the interval between primary intervention and fistula thrombosis or repeated radiologic intervention. Secondary patency was defined as patency during the interval between primary intervention and the time when the fistula was surgically declotted, revised, or abandoned; the time when the patient received a renal transplant; or the time when the patient was lost to follow-up.
Clinical success was defined as the ability to provide adequate dialysis for at least one session and was determined by C.E.L. after a review of dialysis charts. Anatomic success was defined as restoration of flow in the fistula with residual stenosis of less than 30% for any underlying significant stenosis. Anatomic success was determined by one of the six interventional radiologists at the time of the procedure and was verified with a retrospective review of images (performed by D.K.R., S.M., and S.B.). Procedure time was considered to be the time from the start of percutaneous puncture to the completion of angiography; procedure time did not include the time to achieve hemostasis (9).
Follow-up information for each patient was obtained from medical records maintained by a nurse coordinator dedicated to dialysis vascular access; seven patients were lost to follow-up. Transonic surveillance of fistulas was performed monthly to determine whether intervention was required. Complications were categorized as major or minor in accordance with the published guidelines of the Society of Interventional Radiology (9).
Lesion location and lesion frequency at the time of first intervention for radiocephalic and brachiocephalic fistulas were recorded by using the following anatomic classifications: radial artery adjacent to arteriovenous anastomosis, arteriovenous anastomosis, 3-cm segment of the cephalic vein adjacent to the arteriovenous anastomosis, outflow cephalic vein distal to the elbow, outflow cephalic vein proximal to the elbow, cephalic arch, and central veins. Other anatomic variables documented were the number of stenoses per fistula for which angioplasty was performed, the type of fistula, and the side of fistula placement. Evaluation of these anatomic variables was performed in consensus by two investigators (D.K.R. and S.B.). Clinical variables included patient age and sex, fistula age from the time of creation to the first intervention, type and number of interventions performed for each fistula, and presence of diabetes mellitus. Diabetes was defined either as insulin dependent or as non–insulin dependent not controlled by diet alone.
Statistical Analysis
Primary and secondary patency rates for the dysfunctional arteriovenous fistulas after percutaneous intervention were estimated by using the Kaplan-Meier technique (9,10) and tested by using the log-rank test. Data were censored (ie, excluded beyond the last observed time because it was unknown whether the events of concern—repeat intervention or loss of the fistula—would have occurred or did occur) if patients were transferred to another dialysis center, were lost to follow-up, died of unrelated causes, had functional fistula survival to the end point of the study, or underwent kidney transplantation. The Student t test or the Wilcoxon rank sum test was used for univariate analysis of continuous variables; categorical variables were evaluated by using the 
2 or Fisher exact test, as appropriate.
Predictors of fistula patency after initial angioplasty were determined by using a Cox proportional hazards regression model with clinical and anatomic variables. The hazard ratio "is the risk of having an event if the patient received the treatment relative to the risk of having the event should the patient have received no treatment" (11). Variables identified in the univariate Cox model with P < .2 were included in the multiple regression model by using stepwise regression. A two-sided P value of less than .05 was considered to indicate a statistically significant difference. For the time between fistula creation and the first intervention and for the number of interventions per year of dialysis, the distribution of data was right-skewed; therefore, the nonparametric Wilcoxon test was used. Median time from fistula creation to first intervention, median number of interventions per dialysis-year, and median cumulative patency rates from fistula creation to loss were also determined. The software used for statistical analysis was SAS version 8.02 (SAS Institute, Cary, NC).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
|
The resultant cohort had 151 fistulas and underwent 303 radiologic interventions. A total of 299 angioplasty procedures and four percutaneous declottings with eight stent placements were performed during the study period. The initial interventions in all fistulas were angioplasties. The clinical success rate was 98.0% (297 of 303 interventions), and the anatomic success rate was 89.4% (271 of 303). Of the six interventions that clinically failed, five were attributed to failures of angioplasty and one was attributed to unsuccessful percutaneous declotting. A total of 33 anatomic failures were observed: 32 were attributed to failure of angioplasty, and one was attributed to failure of percutaneous declotting of a radiocephalic fistula.
Outcomes
For brachiocephalic fistulas, primary patency rates ± standard errors of the estimate at 3, 6, and 12 months were 73% ± 6, 51% ± 7, and 39% ± 7, respectively (Fig 1). For radiocephalic fistulas, primary patency rates at 3, 6, and 12 months were 85% ± 4, 75% ± 5, and 62% ± 5, respectively (Fig 2). There was a significant difference in primary patency rates at all time points between brachiocephalic and radiocephalic fistulas (P = .004, log-rank test). For brachiocephalic fistulas, secondary patency rates ± standard errors of the estimate at 3, 6, and 12 months were 96% ± 2.4, 89% ± 4, and 85% ± 5, respectively. For radiocephalic fistulas, secondary patency rates at 3, 6, and 12 months were 91% ± 3, 88% ± 3, and 86% ± 4, respectively. For all time points, no significant difference in secondary patency rates was observed between brachiocephalic and radiocephalic fistulas (Fig 3) (P = .45, log-rank test).
|
|
|
months for brachiocephalic fistulas; this difference was not significant (P = .263). For radiocephalic fistulas, the median time from fistula creation to first intervention was 10.4 months (first quartile, 5.6 months; third quartile, 30.3 months); that for brachiocephalic fistulas was 12.1 months (first quartile, 5.4 months; third quartile, 18.0 months) (P = .36, Wilcoxon rank sum test). The median number of interventions per dialysis-year was 0.77 for brachiocephalic fistulas and 0.41 for radiocephalic fistulas; the difference was statistically significant (P = .001, Wilcoxon rank sum test). The mean procedure time ± standard deviation was 89.1 minutes ± 34.1 (range, 28–218 minutes).
Frequency and Location of Stenoses
Single lesions treated with initial angioplasty were identified in 112 dysfunctional fistulas; two or more lesions were identified in 39 dysfunctional fistulas. The locations and frequencies of stenoses at initial presentation according to fistula type are shown in Fig 4. For radiocephalic fistulas, the most common stenosis location was within 3 cm of the arteriovenous anastomosis (initial frequency, 64% [74 of 116 lesions]). For brachiocephalic fistulas, the most common location was at the cephalic arch (the perpendicular portion of the cephalic vein in the region of the deltopectoral groove, prior to its junction with the subclavian vein) (initial frequency, 30% [22 of 74 lesions]). Primary patency (P = .36) and secondary patency (P = .92) for radiocephalic and brachiocephalic fistulas at the time of the first intervention for single lesions were not affected by the location of the stenosis (Fig 4).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
Percutaneous management of dysfunctional fistulas is often more difficult than management of arteriovenous grafts, as discussed by Turmel-Rodrigues et al (17). These challenges may include (a) a thin and mobile venous wall; (b) anatomic irregularities, which often result in difficult clinical and radiologic identification of the anastomosis; (c) an underlying stenosis located between the feeding artery and the superior vena cava; (d) an underlying stenosis that is often tight and difficult to cross; (e) presence of venous collaterals that may make it difficult to define the fistula anatomically; and (f) acute angulation at the anastomosis between the artery and the vein, which may be difficult to cross.
Furthermore, little is known about the anatomic distribution of fistula stenoses, whether differences exist in the location of the lesion according to the type of fistula, and whether these factors affect their percutaneous management and outcomes. Early reports described the predominant location of stenoses adjacent to the arteriovenous anastomosis without distinguishing among fistulas anatomically, but such distinctions may be clinically important for outcomes. Most fistulas examined in these early studies were radiocephalic (18–22). In other reports, anatomic descriptions of fistula stenoses are unclear, and details of their locations are not provided (23–25).
Patency after percutaneous treatment has been assessed in only a few studies (26–28). Clark et al (26) reported that the most common location of hemodynamically significant stenoses was within 2 cm of the anastomosis for forearm and upper-arm fistulas combined (38%). Turmel-Rodrigues et al (27) noted that stenosis of the cephalic arch (the tangential portion of the cephalic vein where it joins the axillary vein) was relatively common, with a frequency of 55% in dysfunctional upper-arm fistulas, as compared with a frequency of 7% in forearm autogenous fistulas. Our findings confirm these results. We observed stenosis within 3 cm of the arteriovenous anastomosis in 64% of the radiocephalic fistulas and in 24% of the brachiocephalic fistulas. The predominant location of stenosis in brachiocephalic fistulas was the cephalic arch (frequency, 30%).
Our findings suggest that for single punctures, retrograde access for failing radiocephalic fistulas is appropriate, whereas for brachiocephalic fistulas, an antegrade approach near the arteriovenous anastomosis is most likely to provide access to areas of stenosis. Access to the entire fistula can also be obtained through the internal jugular vein (as suggested by Liang et al [29]) or through the brachial artery. We used a transbrachial approach only when necessary. Generally, we believed that this approach was not necessary and that it increased the risk of complications, as observed in a study in which this approach was used routinely and resulted in a complication rate of 12% (28).
Recently, reports of three large studies in which outcomes for autogenous hemodialysis fistulas were examined indicated success rates ranging from 91% to 97% and 1-year primary patency rates ranging from 44% to 51% (26–28) (Table 3). Secondary patency rates of 85% in the forearm and 82% in the upper arm were achieved at 1 year, but with more frequent reintervention in upper-arm fistulas (a reintervention time interval of 11 months compared with one of 18 months) (27). Turmel-Rodrigues et al (27) also reported the effect of the age of the fistula on outcome: The older the fistula at the time of the first dilation, the better the results. These patency rates are similar to ours, although we did not find that outcome was affected by the age of the fistula before the first intervention.
|
Clark et al (26) observed 2.3–2.5 interventions—including declottings—per dialysis-year, whereas we found a significantly lower intervention rate of 0.41–0.77 interventions per dialysis-year. This difference may be attributed to their inclusion of dysfunctional fistulas that initially presented as thrombosed and may have required more interventions than their nonthrombosed counterparts. Our results are consistent with those of a study by Schwab et al (16), who found that a successfully performed transluminal angioplasty procedure resulted in maintenance of intervention-free fistula flows for 11.4 months.
Manninen et al (28) reported primary patency rates of 58% at 6 months and 44% at 1 year. Secondary patency rates were 90% at 6 months and 85% at 1 year. Procedures were performed in radiocephalic fistulas only, and 12 thrombosed fistulas were included in the outcome analysis. We observed a higher primary patency rate for radiocephalic fistulas (75% at 6 months and 62% at 12 months) and a lower complication rate (2.3%, versus 12% in the study of Manninen et al). Our secondary patency rates were similar. Perhaps the outcomes were different because the Manninen et al study included declotted fistulas. Another observation made by Manninen et al was that stenosis at or near the arteriovenous anastomosis was a significant predictor (P = .03) of poorer outcome. In our study, we did not observe a similar finding, and the initial location of stenosis was not predictive of outcome.
In a smaller study, Lay et al (30) found that the most common location of stenosis in 31 patients with forearm Brescia-Cimino fistulas was within 2 cm of the draining vein, a finding that is consistent with our findings. Lay et al found that after angioplasty of forearm autogenous fistulas, primary patency rates were 77% at 6 months and 64% at 1 year; secondary patency rates were 85% at 6 months and 81% at 12 months. Although only 31 fistulas were treated in their study, the observed outcomes were within the standard error of our observed outcomes.
Our findings showed that after angioplasty, primary patency rates but not secondary patency rates were significantly different between radiocephalic and brachiocephalic autogenous fistulas. Our primary and secondary patency rates were consistent with the outcomes observed by Turmel-Rodrigues et al (17). We found no significant difference in outcome between fistulas containing one stenosis and those with two or more stenoses.
For comparison with surgical outcomes, Hodges et al (15) examined surgical cumulative patency after fistula creation. No distinction was made between upper-arm and lower-arm fistulas. With the exclusion of fistulas that failed to mature, cumulative primary patency was 54% and secondary patency was 55% 1 year after surgical revisions. For dysfunctional fistulas being treated with initial angioplasty, we observed a median cumulative patency of 123 months for radiocephalic fistulas and 72 months for brachiocephalic fistulas. Kalman et al (31) showed that female sex was a predictor of failure for autogenous dialysis fistula insertion. However, sex was not a predictor of outcome after angioplasty in our study. Oakes et al (32) reported a 1-year primary patency rate of 57% after surgical treatment of failing or thrombosed fistulas, which is within our observed range of 39%–62%, depending on the anatomic location of the fistula.
In our study, a high clinical success rate was observed (98.0%) despite an anatomic success rate of 89.4%. The current anatomic success standard of postangioplasty residual stenosis of less than 30% applies to dialysis grafts. In our study, angioplasty was performed in an autogenous vein that is subject to spasm, elastic recoil, and other factors, which may result in persistent residual stenosis greater than 30%. Clark et al (26) found no difference in long-term patency between treated fistulas with more than 30% residual stenosis and treated fistulas with less than 30% residual stenosis. This suggests that the current standard of anatomic success for angioplasty is not applicable to autogenous fistulas. Further evaluation of this standard is warranted to avoid potential overuse of stents with questionable long-term patency in patients undergoing hemodialysis (33–35).
One limitation of our study was that the results arose from a single institutional experience, and, therefore, selection bias was possible. This was a retrospective nonrandomized study with no prospective comparison of outcomes after surgical revision, and not all confounders, such as variation in methods of treatment between physicians, could be controlled for in statistical analysis. However, to our knowledge, our study was the second-largest study in which the outcome of angioplasty in dysfunctional autogenous dialysis fistulas was examined. Furthermore, we also attempted to identify anatomic and clinical factors that may influence outcome after angioplasty. Only dysfunctional fistulas were examined in this study. Overall patency of dysfunctional autogenous hemodialysis fistulas was not determined because fistulas in patients who did not present for percutaneous intervention were excluded.
With continuous surveillance and repeat interventions, the patency of dysfunctional autogenous hemodialysis fistulas can be safely prolonged without the sacrifice of venous segments after surgical revision. Primary patency following angioplasty that exceeds the K/DOQI clinical guideline can be achieved. Brachiocephalic fistulas require more frequent intervention than do radiocephalic fistulas; however, excellent secondary fistula patency can be achieved in both kinds of fistulas with proper surveillance and reintervention. In our study, the variables examined, which included location of stenosis, age of fistula before first intervention, and diabetes, did not influence patency outcome.
|
FOOTNOTES |
|---|
Author contributions: Guarantor of integrity of entire study, D.K.R.; study concepts, D.K.R., S.B.; study design, R.P., D.K.R., S.B.; literature research, D.K.R., C.E.L.; clinical studies, D.K.R., C.E.L., S.B.; data acquisition, D.K.R., S.B., C.E.L.; data analysis/interpretation, D.K.R., C.E.L., R.P.; statistical analysis, D.K.R., C.E.L., R.P.; manuscript preparation and revision/review, all authors; manuscript definition of intellectual content, D.K.R., S.B., R.P., C.E.L.; manuscript editing, D.K.R., S.M., C.E.L., R.P.; manuscript final version approval, D.K.R., S.B., S.M., C.E.L.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  C.-C. Wu, S.-C. Wen, M.-K. Chen, C.-W. Yang, S.-Y. Pu, K.-C. Tsai, C.-J. Chen, and C.-H. Chao Radial artery approach for endovascular salvage of occluded autogenous radial-cephalic fistulae Nephrol. Dial. Transplant., March 3, 2009; (2009) gfp087v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-C. Wu, S.-C. Wen, C.-W. Yang, S.-Y. Pu, K.-C. Tsai, and J.-W. Chen Plasma ADMA Predicts Restenosis of Arteriovenous Fistula J. Am. Soc. Nephrol., January 1, 2009; 20(1): 213 - 222. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Lipari, N. Tessitore, A. Poli, V. Bedogna, A. Impedovo, A. Lupo, and E. Baggio Outcomes of surgical revision of stenosed and thrombosed forearm arteriovenous fistulae for haemodialysis Nephrol. Dial. Transplant., September 1, 2007; 22(9): 2605 - 2612. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. E. Lok Fistula First Initiative: Advantages and Pitfalls Clin. J. Am. Soc. Nephrol., September 1, 2007; 2(5): 1043 - 1053. [Full Text] [PDF]
|
|
|
|
 |
|
 D. R. Warakaulle, A. L. Evans, A. J. Cornall, C. R. Darby, P. Boardman, and R. Uberoi Diagnostic Imaging of and Radiologic Intervention for Bovine Ureter Grafts Used as a Novel Conduit for Hemodialysis Fistulas Am. J. Roentgenol., March 1, 2007; 188(3): 641 - 646. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J. Naoum, C. Irwin, and G. C. Hunter The Use of Covered Nitinol Stents to Salvage Dialysis Grafts After Multiple Failures Vascular and Endovascular Surgery, August 1, 2006; 40(4): 275 - 279. [Abstract] [PDF]
|
|
|
|
|
|
N. Tessitore, G. Mansueto, G. Lipari, V. Bedogna, S. Tardivo, E. Baggio, D. Cenzi, G. Carbognin, A. Poli, and A. Lupo Endovascular versus Surgical Preemptive Repair of Forearm Arteriovenous Fistula Juxta-Anastomotic Stenosis: Analysis of Data Collected Prospectively from 1999 to 2004 Clin. J. Am. Soc. Nephrol., May 1, 2006; 1(3): 448 - 454. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| RADIOLOGY | RADIOGRAPHICS | RSNA JOURNALS ONLINE |
