Patients with lower extremity dialysis access have poor primary patency and survival

From the Society for Vascular Surgery

Patients with lower extremity dialysis access have poor primary patency and survival Steven L. Pike, MD,a Alik Farber, MD,a Nkiruka Arinze, MD,a Scott Levin, MD,a Thomas W. Cheng, MS,a Douglas W. Jones, MD,a Tze-Woei Tan, MD,b Mahmoud Malas, MD,c Denis Rybin, PhD,d and Jeffrey J. Siracuse, MD,a Boston, Mass; Tucson, Ariz; and San Diego, Calif

ABSTRACT Objective: Lower extremity arteriovenous (AV) access is an alternative when upper extremity access options have been exhausted. Our goal was to assess short- and medium-term outcomes of lower extremity hemodialysis access. Methods: The Vascular Quality Initiative was reviewed for all lower extremity AV hemodialysis cases. Patient and case details were recorded. Multivariable analysis was used to analyze outcomes. Results: We identified 463 lower extremity AV access cases in the VQI registry. There were 56 AVF (12.1%) and 407 AVG (87.9%). The mean age was 56 6 15 years, 46.9% were male, and 40.7% were Caucasian. The majority (90%) had a previous upper extremity AV access and 25.4% had a prior lower extremity access. More than one-half (57.9%) had a tunneled line at the time of the procedure. Patients undergoing an AVF vs AVG creation were younger, more often ambulatory, and less often with peripheral arterial disease. For AVF, the superficial femoral artery was more often used for access inflow (76.8% vs 49.4%; P < .001), compared with AVG, and there was no difference in using femoral vein as the main outflow (78.6% vs 82.6%; P ¼ .466). For AVF, compared with AVG, there was no difference in wound infection (12.5% vs 9.6%; P ¼ .571), ischemic steal (5% vs 2.2%; P ¼ .273), or leg swelling (2.5% vs 3.3%; P ¼ .99) at 6 months. Kaplan-Meier analysis of the overall cohort showed that freedom from loss of primary patency at 6 months was 52.9%, freedom from any reintervention at 6 months was 75.3%, and the 1-year survival was 81.9%. Survival at 5 years was 65.5%. Multivariable analysis showed no significant association of access type (AVF vs AVG) with primary patency loss or death (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.36-1.5; P ¼ .4), any reintervention or death (HR, 1.65; 95% CI, 0.82-3.33; P ¼ .163), or mortality (HR, 1.94; 95% CI, 0.71-5.33; P ¼ .197). Factors independently associated with primary patency loss or death included peripheral arterial disease (HR, 1.6; 95% CI, 1.06-2.42; P ¼ .03) and obesity (HR, 1.5; 95% CI, 1.1-2.05; P ¼ .01). Any reintervention or death was associated with obesity (HR, 1.67; 95% CI, 1.09-2.56; P ¼ .015). Mortality was associated with congestive heart failure (HR, 1.82; 95% CI, 1.13-2.94; P ¼ .015) and white race (HR, 1.71; 95% CI, 1.08-2.73; P ¼ .023). Conclusions: In our contemporary multicenter analysis, patients undergoing lower extremity AV access creation have low primary access patency and almost 20% mortality at 1 year. These results should be considered when suggesting a lower extremity dialysis access, as well as other dialysis alternatives when available. (J Vasc Surg 2019;-:1-6.) Keywords: Dialysis; Lower extremity; Fistula; Graft

The National Kidney Foundation Disease Outcomes Quality Initiative Guidelines and the Fistula First Initiative have recommended upper arm native arteriovenous fistula (AVF) creation as a best option, followed by

From the Division of Vascular and Endovascular Surgery, Boston Medical Center, Boston University, School of Medicine, Bostona; the Division of Vascular Surgery, University of Arizona, College of Medicine, Tucsonb; the Division of Vascular and Endovascular Surgery, University of California, San Diegoc; and the Boston University, School of Public Health, Boston.d Author conflict of interest: none. Presented at the 2018 Vascular Annual Meeting of the Society for Vascular Surgery, Boston, Mass, June 21-23, 2018. Correspondence: Jeffrey J. Siracuse, MD, FACS, Division of Vascular and Endovascular Surgery, Boston Medical Center, Boston University, School of Medicine, 88 East Newton St, Boston, MA 02118 (e-mail: [email protected]). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest. 0741-5214 Copyright Ó 2019 by the Society for Vascular Surgery. Published by Elsevier Inc. https://doi.org/10.1016/j.jvs.2019.03.037

placement of a prosthetic arteriovenous graft (AVG) when adequate vein is not available.1,2 However, in patients with limited upper extremity access options, alternatives include chronic catheter use, peritoneal dialysis, or lower extremity access, either using native autologous vein or with prosthetic graft. Overall, these patients’ care is challenging because they have high rates of comorbidities and limited options for vascular access.3-7 Lower extremity dialysis access creation is a procedure that is not commonly performed, but can be used as an alternative to lifelong catheter dependence for hemodialysis access after upper extremity options are exhausted.1-4 An understanding of contemporary real-world results for lower extremity dialysis access procedures allows for better dialysis access planning based on realistic expectations, as well as the development of more appropriate informed consent discussions. Previous analyses of lower extremity access have been small, single-center studies that commonly focus on only one access conduit type.3-9 Many of these analyses 1

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are also older and do not contain risk-adjusted models. Studies focusing on certain techniques, such as femoral vein transposition AVF, may not be reflective of realworld outcomes, because these procedures are uncommon and may not be performed regularly at many centers and lack standardization.5-7 Our goal was to assess the short-term and mediumterm outcomes of lower extremity AVF and AVG, focusing on primary patency, reinterventions, and overall survival. The Vascular Quality Initiative (VQI) database provides multicenter perioperative and operative data for analysis in a retrospective fashion and allows for analysis of a larger sample for more rarely performed procedures.

METHODS The VQI registry is a prospectively maintained, national database used to analyze outcomes of common vascular procedures and includes a hemodialysis access registry. Records from the VQI dialysis registry, which consists of approximately 30,000 access creations from 2011 to 2017 were queried for patients who underwent any type of lower extremity dialysis access creation. Patients less than 18 years old were excluded. The Boston University School of Medicine Institutional Review Board approved this study, and the requirement to obtain informed consent was waived. Demographics and perioperative comorbidities included age, sex, race, body mass index, smoking status, ambulatory status, history of intravenous drug use, hypertension, diabetes, coronary artery disease (CAD), history of coronary interventions, congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), peripheral arterial disease (PAD), previous arm access, previous leg access, concurrent tunneled catheters, type of access created, and location of the arterial and venous anastomoses. Postoperative outcomes comprised primary patency, wound complications, steal, and swelling. Longer term data included primary patency, any reintervention, and survival. Categorical variables, including demographics, procedural characteristics, and outcomes, were reported using counts and percentages. Continuous measures were reported using means and standard deviations. Demographics, comorbidities, procedural details, and postoperative complications were compared using the t-test for continuous variables and the c2 test for categorical measures. Kaplan-Meier analysis was used to assess freedom from primary patency loss at 6 months, freedom from any reintervention at 6 months, and 1year survival in the combined AVF and AVG sample. Multivariable Cox proportional hazard models were used to analyze 6-month primary patency loss or death, 6-month any reintervention or death, and 1-year mortality. Each model initially included access type (AVF or AVG) and variables found to be different (at a .2

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ARTICLE HIGHLIGHTS Type of Research: Retrospective analysis of prospectively collected Vascular Quality Initiative registry data Key Findings: In this study of 463 lower extremity arteriovenous access, those with fistula, compared with arteriovenous graft, showed no difference in wound infection, ischemic steal, or leg swelling at 6 months. At 6 months, the primary patency was 52.9% and freedom from reintervention was 75.3%; the 1-year survival was 81.9%. There were no significant associations between access type and primary patency loss, any reintervention, or mortality. Take Home Message: Patients undergoing lower extremity arteriovenous access creation have low primary patency and an almost 20% 1-year mortality. These results should be considered when suggesting a lower extremity dialysis access.

significance level) in unadjusted analyses. The association was expressed by hazard ratio (HR) with corresponding confidence limits and P value. A P value of less than .05 was set as significant.

RESULTS We identified 463 lower extremity AV access cases in the VQI registry. This series was composed of 56 AVF (12.1%) and 407 AVG (87.9%). The mean age was 56 6 15 years, 46.9% of the patients were male, and 40.7% were of white race. Comorbidities included hypertension (91.1%), diabetes (45.9%), obesity (39%), nonambulatory status (32.6%), CHF (25.9%), CAD (20.5%), COPD (17.1%), current smoking (18%), and PAD (12.7%). The majority (90%) had a history of prior upper extremity AV access and 25.4% had prior lower extremity access. More than one-half (57.9%) had a tunneled line at the time of the procedure. Patients undergoing AVF compared with AVG creation were younger (49.8 6 16 years vs 56.8 6 15 years; P ¼ .001), more often ambulatory (81.8% vs 65.4%; P ¼ .015), and less likely to have PAD (1.8% vs 14.3%; P ¼ .009). For AVF compared with AVG creation, the superficial femoral artery was more often used for the inflow (76.8% vs 49.4%; P < .001), and there was no difference in the use of the femoral vein for outflow (78.6% vs 82.6%; P ¼ .466; Table I). Surgical site outcomes at 6 months are listed in Table II. There were no significant differences in wound infection (12.5% vs 9.6%; P ¼ .571), ischemic steal (5% vs 2.2%; P ¼ .273), or leg swelling (2.5% vs 3.3%; P ¼ .99) between AVF and AVG. The 6-month follow-up was similar in both groups (62.5% vs 56%; P ¼ .391). Kaplan-Meier analysis of the overall cohort showed that freedom from loss of primary patency at 6 months was 52.9% (Fig 1), freedom from any reintervention at 6 months was 75.3% (Fig 2),

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Table I. Patient demographics, comorbidities, and procedural details Characteristic

Overall (N ¼ 463)

AVF (n ¼ 56)

AVG (n ¼ 407)

56 6 15

49.8 6 16

56.8 6 15

P value

Demographics Age, years

.001

Male sex

217 (46.9)

31 (55.4)

186 (45.7)

White race

177 (40.7)

19 (42.2)

158 (40.5)

.175 .825

Preadmission from home

429 (92.9)

53 (94.6)

376 (92.6)

.824

Obese (BMI $ 30)

180 (39.0)

20 (35.7)

160 (39.5)

.586

Current smoking

83 (18.0)

10 (17.9)

73 (18.1)

.969

308 (67.4)

45 (81.8)

263 (65.4)

.015

Comorbidities

Ambulatory Prior IV drug use

8 (1.7)

0 (0)

8 (2)

.289

Hypertension

422 (91.1)

50 (89.3)

372 (91.4)

.601

Diabetes

212 (45.9)

23 (41.1)

189 (46.6)

.44

CAD

95 (20.5)

15 (26.8)

80 (19.7)

.215

Prior CABG

33 (7.4)

4 (7.5)

29 (7.4)

.969

Prior PCI

41 (9.2)

4 (7.5)

37 (9.4)

.659 .253

CHF

120 (25.9)

11 (19.6)

109 (26.8)

COPD

79 (17.1)

6 (10.7)

73 (17.9)

PAD

59 (12.7)

1 (1.8)

58 (14.3)

.009

417 (90)

49 (87.5)

368 (90.4)

.195 .89

Previous arm access

.18

Previous leg access None

344 (74.6)

40 (71.4)

304 (75.1)

Ipsilateral

27 (5.9)

3 (5.4)

24 (5.9)

Contralateral

74 (16.1)

11 (19.6)

63 (15.6)

Bilateral Tunneled catheter

16 (3.5)

2 (3.6)

14 (3.5)

268 (57.9)

35 (62.5)

233 (57.2)

.398

<.001

Procedure Arterial anastomosis Common femoral

219 (47.3)

13 (23.2)

206 (50.6)

Superficial femoral

244 (52.7)

43 (76.8)

201 (49.4)

Venous anastomosis Saphenous Femoral

83 (17.9)

12 (21.4)

71 (17.4)

380 (82.1)

44 (78.6)

336 (82.6)

.466

AVF, Arteriovenous fistula; AVG, arteriovenous graft; BMI, body mass index; CABG, coronary artery bypass graft; CAD, coronary artery disease; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; IV, intravenous; PAD, peripheral arterial disease; PCI, percutaneous coronary intervention. Values are presented as mean 6 standard deviation or number (%).

Table II. Surgical site outcomes at 6 months Characteristic Wound infection Ischemic steal Swelling 6-Month follow-up

Overall (N ¼ 463)

AVF (n ¼ 56)

AVG (n ¼ 407)

31 (9.9)

5 (12.5)

26 (9.6)

.571

8 (2.6)

.273

P value

2 (5)

6 (2.2)

10 (3.2)

1 (2.5)

9 (3.3)

.99

263 (56.8)

35 (62.5)

228 (56)

.391

AVF, Arteriovenous fistula; AVG, arteriovenous graft. Values are presented as number (%).

and 1-year survival was 81.9% (Fig 3). Survival at 5 years was 65.5%. Multivariable analysis demonstrated no significant association of access type (AVF vs AVG) with loss of patency or death (HR, 0.74; 95% CI, 0.36-1.51; P ¼ .4; Table III), any

reintervention or death (HR, 1.65; 95% CI, 0.82-3.33; P ¼ .163; Table IV), or mortality (HR, 1.94; 95% CI, 0.71-5.33; P ¼ .197; Table V). Factors independently associated with primary patency loss or death included PAD (HR, 1.6; 95% CI, 1.06-2.42; P ¼ .03) and obesity (HR, 1.5; 95%

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Fig 1. Freedom from primary patency loss for overall lower extremity arteriovenous access cohort.

Fig 2. Freedom from reintervention for overall lower extremity arteriovenous access cohort.

CI, 1.1-2.05; P ¼ .01; Table III). Any reintervention or death was associated with obesity (HR, 1.67; 95% CI, 1.09-2.56; P ¼ .015; Table IV). Mortality was associated with CHF (HR, 1.82; 95% CI, 1.13-2.94; P ¼ .015) and white race (HR, 1.71; 95% CI, 1.08-2.73; P ¼ .023; Table V).

DISCUSSION Our study demonstrated a high rate of primary patency loss of leg AV access at 6 months. Conduit type did not affect outcomes. Obesity was a risk factor for both patency loss and access reintervention. Patients undergoing lower extremity hemodialysis access creation had high rates of comorbidities and almost 20% did not survive 1 year after the access creation. The primary patency of lower extremity hemodialysis access in our analysis was 52.9% at 6 months in our cohort of mostly AVG, consistent with previous findings reported in single-centers studies.4 Historically, leg AVG has been reported to have poor patency as demonstrated in a single-center study of 63 lower extremity

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Fig 3. Survival for overall lower extremity arteriovenous access cohort.

AVG where the median time to reintervention was 3.9 months, the median time to thrombosis was 5.7 months, and the median cumulative access survival was 14.8 months.3 Another analysis of 125 lower extremity AVGs showed primary and secondary patency rates of 19% and 54% at 2 years.4 Finally, one small singlecenter cohort analyzing 17 AVG showed a 1-year primary patency rate of 37.5%.7 Our cohort was mixed, with most patients having an AVG. The smaller autogenous group used femoral vein only 79% of the time. In our series, we did not see a difference in outcomes comparing AVF with AVG. This result is different than historical single-center studies that demonstrated primary patency rates for AVF using femoral vein ranging from 73% to 91%.5,7,9 One must keep in mind that these centers have developed and standardized this operation over time.5 In real-world practice, there is little standardization of techniques for lower extremity AVF creation, the details of which cannot be determined in the VQI registry. Other autogenous access used was the great saphenous vein. AVF using the saphenous vein have historically been associated with lower reported patency compared with those based on the femoral vein.10-14 Unfortunately, our autogenous AVF cohort numbers were too small for meaningful subgroup analysis. Although our analysis did not find a difference in outcomes based on access type, we found that PAD and obesity were associated with lower primary patency. It is not surprising that PAD was associated with lower primary patency in our study, because inflow arterial stenosis has been previously shown to impair access function and patency.15 Obesity was also an independent risk factor for loss of primary patency and for reinterventions.16-19 This risk factor has been shown previously with suspected reasons attributed to both systemic factors as well as local compression and depth of access.16-19

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Patients in our cohort had an overall low survival at 1 year of 81.9%. Previously reported 1-year survival rates for patients on dialysis in general range higher from 87.5% to 89%.20,21 Overall, our patients had high rates of comorbidities and, although this information is not included in the VQI dataset, these patients most likely were on dialysis for a long period before the procedures included in this study, as evidenced by their history of previous access and the need to resort to a leg access.22 Single-center studies of the leg AV access have demonstrated median survival of 24 months and 67% survival at 20 months.4,22 Mortality was predicted by CHF and white race in our analysis. CHF is a challenging problem to manage in patients on dialysis owing to complex volume management and is a leading source of morbidity in the dialysis population.23 Caucasian patients have also been previously shown to have higher mortality rates once initiated on hemodialysis than patients of other races.24 The overall wound infection rates were 12.5% in the AVF cohort and 9.6% in the AVG cohort, but had no statistically significant difference. Leg AV access is at risk of both surgical site infection and secondary infection from being accessed. Previously reported rates for AVG infection requiring abandonment of access have been 12%.3 An analysis of 125 lower extremity AVG has shown infection rates up to 41%, including 11% in the perioperative time period.4 The remainder of these infections occurred at a mean of 19 months.4 In contrast with our findings, there have been reports that AVF, using the femoral vein, have fewer infectious complications compared with AVG.7 There have been conflicting outcomes regarding the development of steal syndrome. Consistent with our study, one analysis showed similar steal symptoms between AVF and AVG.3 A singlecenter analysis showed a high rate of steal at more than 30% for femoral vein-based AVF. However, once this center started banding the femoral vein before anastomosis, the rates of steal decreased significantly.5,6 Our overall study population, compared with one study that analyzed tapered vs nontapered upper extremity accesses in the VQI database, was younger (56.0 years vs 64.8 years), had fewer Caucasian patients (40.7% vs 50.7%), and more patients with previous arm access (90% vs 73%).25 However, our study population’s rates for other comorbidities such as diabetes, CAD, CHF, and COPD were lower, which may suggest that selection bias heavily influences whether a patient receives a lower extremity access.25 Nevertheless, the overall similarity in baseline characteristics is seen in other studies, such as one study that investigated outcomes of one-stage and two-stage upper arm brachiobasilic AVFs in the VQI database and another study that analyzed predictors for early fistula failure in patients undergoing an index AVF in the Vascular Study Group of New England.26,27 Additionally, survival at 1 year in our study was 81.9%,

Table III. Multivariable analysis of primary patency loss or death HR AVF vs AVG

95% CI

P value

0.74

0.36-1.51

.4

PAD

1.6

1.06-2.42

.03

Obese (BMI $ 30)

1.5

1.1-2.05

0.99

0.98-0.998

Age

.01 .022

AVF, Arteriovenous fistula; AVG, arteriovenous graft; BMI, body mass index; CI, Confidence interval; HR, hazard ratio; PAD, peripheral arterial disease.

Table IV. Multivariable analysis of any reintervention or death

AVF vs AVG Obese (BMI $ 30)

HR

95% CI

1.65

0.82-3.33

P value .163

1.67

1.09-2.56

.015

Age

0.98

0.97-0.99

.006

CFA anastomosis

0.67

0.44-1.04

.07

AVF, Arteriovenous fistula; AVG, arteriovenous graft; BMI, body mass index; CI, confidence interval; CFA, common femoral artery; HR, hazard ratio.

Table V. Multivariable analysis of mortality P value

HR

95% CI

AVF vs AVG

1.94

0.71-5.33

.197

CHF

1.82

1.13-2.94

.015

White race

1.71

1.08-2.73

.023

Age

1.02

1.01-1.04

Diabetes

1.38

0.86-2.2

.012 .182

AVF, Arteriovenous fistula; AVG, Arteriovenous graft; CHF, congestive heart failure; CI, confidence interval; HR, hazard ratio.

which was lower compared with a previously reported 1-year survival rates of 84% for AVG and 89% for AVF in the United States Renal Data System.28 These results demonstrate that our study population may be different from those undergoing an upper extremity access, because these patients have more advanced comorbidities, which may require closer follow-up. Our study has several limitations. It is a retrospective review of a database. Some details, such as graft type or procedural techniques of AVF creation, such as banding of the femoral vein before anastomosis, are unknown. Our numbers, particularly of AVF based on femoral vein transposition and saphenous vein, are low and do not allow for further subgroup analysis. Surgeon bias data as to the location and conduit for access performed is also unavailable. Furthermore, characteristics of patients opting for peritoneal dialysis, rather than leg AV access, are unknown.

CONCLUSIONS In our contemporary multicenter study, patients undergoing lower extremity AV access creation had low primary access patency and a high 1-year mortality,

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consistent with historical single-center studies. Autogenous access exhibited no benefit over graft conduits. These results should be considered when suggesting a lower extremity dialysis access, as well as other dialysis alternatives when available.

AUTHOR CONTRIBUTIONS Conception and design: SP, AF, JS Analysis and interpretation: SP, NA, SL, TC, DJ, AF, TT, MM, JS, DR Data collection: JS Writing the article: SP, NA, SL, TC, JS Critical revision of the article: SP, NA, SL, TC, DJ, AF, TT, MM, JS, DR Final approval of the article: SP, NA, SL, TC, DJ, AF, TT, MM, JS, DR Statistical analysis: JS, DR Obtained funding: Not applicable Overall responsibility: JS

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12. Pierre-Paul D, Williams S, Lee T, Gahtan V. Saphenous vein loop to femoral artery arteriovenous fistula: a practical alternative. Ann Vasc Surg 2004;18:223-7. 13. Illig KA, Orloff M, Lyden SP, Green RM. Transposed saphenous vein arteriovenous fistula revisited: new technology for an old idea. Cardiovasc Surg 2002;10:212-5. 14. Shankar VK, Handa A. Saphenous loop av fistula for haemodialysis-A failed experiment. EJVES Extra 2004;7:13-4. 15. Duijm LE, Liem YS, van der Rijt RH, Nobrega FJ, van den Bosch HC, Douwes-Draaijer P, et al. Inflow stenoses in dysfunctional hemodialysis access fistulae and grafts. Am J Kidney Dis 2006;48:98-105. 16. Kim JK, Choi SR, Lee WY, Park MJ, Lee HS, Song YR, et al. Leptin, pre-existing vascular disease, and increased arteriovenous fistula maturation failure in dialysis patients. J Vasc Surg 2016;64:402-10.e1. 17. Miles Maliska C 3rd, Jennings W, Mallios A. When arteriovenous fistulas are too deep: options in obese individuals. J Am Coll Surg 2015;221:1067-72. 18. Plumb TJ, Adelson AB, Groggel GC, Johanning JM, Lynch TG, Lund B. Obesity and hemodialysis vascular access failure. Am J Kidney Dis 2007;50:450-4. 19. Kats M, Hawxby AM, Barker J, Allon M. Impact of obesity on arteriovenous fistula outcomes in dialysis patients. Kidney Int 2007;71:39-43. 20. Haapio M, Helve J, Grönhagen-Riska C, Finne P. One- and 2year mortality prediction for patients starting chronic dialysis. Kidney Int Rep 2017;2:1176-85. 21. Pruthi R, Steenkamp R, Feest T. UK Renal Registry 16th annual report: chapter 8 survival and cause of death of UK adult patients on renal replacement therapy in 2012: national and centre-specific analyses. Nephron Clin Pract 2013;125:139-69. 22. Taylor SM, Eaves GL, Weatherford DA, McAlhany JC Jr, Russell HE, Langan EM 3rd. Results and complications of arteriovenous access dialysis grafts in the lower extremity: a five year review. Am Surg 1996;62:188-91. 23. Rangaswami J, McCullough PA. Heart failure in end-stage kidney disease: pathophysiology, diagnosis, and therapeutic strategies. Semin Nephrol 2018;38:600-17. 24. Siracuse JJ, Gill HL, Epelboym I, Wollstein A, Kotsurovskyy Y, Catz D, et al. Effect of race and insurance status on outcomes after vascular access placement for hemodialysis. Ann Vasc Surg 2014;28:964-9. 25. Roberts L, Farber A, Jones DW, Woo K, Eslami MH, Simons J, et al. Tapered arteriovenous grafts do not provide significant advantage over nontapered grafts in upper extremity dialysis access. J Vasc Surg 2019;69:1552-8. 26. Tan TW, Siracuse JJ, Brooke BS, Baril DT, Woo K, Rybin D, et al. Comparison of one-stage and two-stage upper arm brachiobasilic arteriovenous fistula in the Vascular Quality Initiative. J Vasc Surg 2019;69:1187-95.e2. 27. Eslami MH, Zhu CK, Rybin D, Doros G, Siracuse JJ, Farber A. Simple predictive model of early failure among patients undergoing first-time arteriovenous fistula creation. Ann Vasc Surg 2016;35:46-52. 28. Malas MB, Canner JK, Hicks CW, Arhuidese IJ, Zarkowsky DS, Qazi U, et al. Trends in incident hemodialysis access and mortality. JAMA Surg 2015;150:441-8.

Submitted Dec 17, 2018; accepted Mar 4, 2019.