- Email: [email protected]
Functional outcomes of arteriovenous fistulas recruited with regional anesthesia
From the Western Vascular Society
Functional outcomes of arteriovenous fistulas recruited with regional anesthesia Devin S. Zarkowsky, MD,a Bian Wu, MD,a Andew T. Gray, MD,b Adam Z. Oskowitz, MD, PhD,a,b and Shant M. Vartanian, MD,a,b San Francisco, Calif
ABSTRACT Objective: Regional anesthesia (RA)-induced vasodilation increases the proportion of patients with vein anatomy suitable for arteriovenous fistula (AVF) creation. The functional outcomes of AVFs created with veins initially small for size on preoperative duplex ultrasound mapping (#2.4 mm) that are recruited under RA have not been clearly defined. We aimed to evaluate freedom from revision or thrombosis, time to first cannulation, and reintervention rates of AVFs created with veins recruited after induction of RA. Methods: A prospectively maintained quality improvement database from a single institution was queried for patients who had dialysis access created under RA. We compared AVFs created according to the original surgical plan (preoperative minimum vein diameter >2.5 mm) with AVFs recruited with RA (preoperative minimum vein diameter #2.4 mm). End points included freedom from revision or thrombosis, time to first cannulation, and reintervention rates. Results: Between May 2014 and April 2018, there were 208 dialysis access cases performed under RA. Excluding grafts, revisions, patients with previous ipsilateral AVFs, and those without preoperative ultrasound vein mapping, 135 patients were included in our analysis. Induction of RA with intraoperative duplex ultrasound allowed a change in surgical plan in 55 of 135 (42%) patients (recruited with RA), including 31 patients originally scheduled for an arteriovenous graft (mean preoperative distal upper arm cephalic vein diameter of 1.8 mm [standard deviation, 0.2 mm]) who were converted to an AVF (12 brachiobasilic, 11 brachiocephalic, and 8 radiocephalic). The remaining patients in the group of AVFs recruited with RA included 13 scheduled for brachiobasilic configurations who were converted to brachiocephalic or radiocephalic AVFs and 11 scheduled for brachiocephalic AVFs who were converted to radiocephalic AVFs. Comparing AVFs created according to the original surgical plan vs AVFs recruited with RA, there were no differences in reintervention rates (48% vs 49%; P ¼ .90) or functional outcomes at 6 months (60% vs 65% used on hemodialysis [P ¼ .58] and 7% vs 2% primary failure [P ¼ .19]). Conclusions: In this series, RA increased the proportion of patients who underwent AVF creation without compromising functional outcomes. Routine use of RA in access surgery could have significant implications in meeting national guidelines for autogenous access in the prevalent hemodialysis population. (J Vasc Surg 2020;71:584-91.) Keywords: Arteriovenous fistula; Hemodialysis access; Regional anesthesia
Hemodialysis is the dominant form of renal replacement therapy both in the United States and internationally. Arteriovenous fistulas (AVFs) have repeatedly demonstrated superiority to arteriovenous grafts
From the Division of Vascular and Endovascular Surgery, University of California San Franciscoa; and the Department of Surgery, Zuckerberg San Francisco General Hospital.b Author conflict of interest: none. Presented at the Thirty-third Annual Meeting of the Western Vascular Society, Santa Fe, NM, September 22-25, 2018. Additional material for this article may be found online at www.jvascsurg.org. Correspondence: Shant M. Vartanian, MD, Department of Surgery, Zuckerberg San Francisco General Hospital, 1001 Portrero Ave, San Francisco, CA 94110 (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.2019.03.083
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(AVGs) and central venous catheters by a variety of metrics, including mortality, durability, and risk of infection.1,2 A number of additional secondary health care system and economic benefits are derived from these advantages.3,4 The National Kidney Foundation Kidney Disease Outcomes Quality Initiative established benchmarks for a prevalent AVF rate of >66% to more closely mirror those in Europe and Asia.5 Despite efforts from government agencies and multiple medical specialties and societies, the prevalent AVF rates have been relatively flat during the last decade, with the United States Renal Data System currently reporting 62% nationally.6,7 Superficial vein anatomy is one of the most significant determinants of access plan and functional outcomes. For AVFs, minimum vein diameter (MVD) by ultrasound mapping correlates with the risk of primary failure and failure to mature.8 A size threshold for MVD of >2.5 mm is generally accepted as a metric for successful functional AVF outcomes.9,10 Regional anesthesia (RA) for
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dialysis access surgery induces a sympathetic blockade that causes vasodilation, thereby increasing superficial vein diameter.11 Advocates of RA for access surgery note that the vasodilatory effects can recruit patients into AVF who otherwise do not have adequate superficial vein anatomy by preoperative ultrasound vein mapping.12-14 However, as MVD on preoperative duplex ultrasound correlates with risk of primary thrombosis and maturation rate, it is unclear whether these previously small for size veins that are recruited with RA result in dialysis access with functional outcomes equivalent to those of veins that initially had an MVD >2.5 mm.15 This study retrospectively compared fistulas created with veins according to the original surgical plan (OSP; preoperative MVD >2.5 mm) and those recruited with RA (preoperative MVD #2.4 mm) with a goal of assessing functional outcomes. We hypothesized that AVFs recruited with RA have equivalent freedom from revision or thrombosis, primary failure, and reintervention rates.
METHODS Study design. A prospectively maintained quality improvement database for dialysis access outcomes at Zuckerberg San Francisco General Hospital was retrospectively queried to identify all new dialysis accesses created under RA from May 2014 through April 2018. Of the 226 new dialysis accesses created under RA, we excluded patients who had AVGs placed because of extenuating circumstances that precluded awaiting AVF maturity, those with previous ipsilateral dialysis access, and patients with absent ultrasound vein mapping results (venography vein mapping only). Predialysis patients with an urgent need for dialysis (ie, glomerular filtration rate <8 mL/min) underwent placement of an AVG irrespective of vein anatomy and are not included in this analysis. No patient required general anesthesia during the study period. The study was approved by the Committee on Human Research at University of California San Francisco and Zuckerberg San Francisco General Hospital. Access plan selection. Patients referred for new permanent vascular access were evaluated for surgical and anesthesia risk by one of two vascular surgeons. The access plan was created weighing hand dominance, presence of previous central catheters, risks of central vein disease, and superficial vein anatomy. Patients were scheduled for AVF if the MVD in two contiguous segments was $2.5 mm and the vein was continuous to the deep system and compressible along its length. The configuration of AVF was selected for the most favorable distal anatomy first, that is, radiocephalic over brachiocephalic, barring technical barriers (eg, radial artery harvest for coronary artery bypass grafting). All patients scheduled for AVG were consented for possible AVF at the preoperative visit.
ARTICLE HIGHLIGHTS d
d
d
Type of Research: Single-center, retrospective cohort study Key Findings: In this analysis of 135 patients receiving arteriovenous fistulas, regional anesthesia caused venodilation, allowing access creation in those patients deemed to have veins of inadequate diameter on preoperative ultrasound. No difference in functional outcome was discerned in arteriovenous fistulas created from veins recruited with regional anesthesia. Take Home Message: Surgeons would do well to reevaluate patients’ arm veins in the operating room after regional anesthesia is applied.
Duplex ultrasound vein mapping. All ultrasound vein mapping was performed by a registered vascular technologist. Patients were positioned supine on an examination table with the studies performed at room temperature. Venous duplex ultrasound scanning with color flow images was obtained of the jugular, subclavian, and axillary veins using a 3-9 MHz linear array probe (Philips iU-22; Philips Healthcare, Amsterdam, The Netherlands). The basilic and cephalic veins were assessed for size, compressibility, and continuity from the wrist to the shoulder and into the deep system. Eight cephalic vein measurements, a median antecubital measurement, and six basilic vein measurements were made in total. If a measured diameter was <3.0 mm, a 5-cm pneumatic tourniquet was applied to the upper arm (SC5; Hokanson, Bellevue, Wash) and inflated to 80 mm Hg, and 30 seconds of hand pump exercises were performed. The tourniquet was deflated and reapplied for each subsequent measurement of <3.0 mm. A limited arterial study with diameters and pulse wave velocities was also performed of the brachial, radial, and ulnar arteries. RA. A dedicated RA team performed brachial plexus blocks in the preoperative holding unit 30 minutes before surgery. Either a supraclavicular or infraclavicular approach to the brachial plexus was performed, completed by injection of 0.5% ropivacaine around the second part of the axillary artery with an echogenic 21-gauge needle under ultrasound guidance using an in-plane technique.16 In addition, an intercostobrachial cutaneous nerve block was performed in the axilla.17,18 A total of 30 to 40 mL of ropivacaine 0.5% was injected. Surgical approach. Approximately 30 minutes after block induction, vein mapping ultrasound was repeated in the operating room by the surgeon with a 7-12 Hz linear array probe (Philips EPIQ 5) without applying a tourniquet. If the block-induced vasodilation resulted in two contiguous vein measurements of >2.5 mm in a
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more distal vein segment, the surgical plan was changed accordingly (recruited with RA). Otherwise, the OSP was executed. Procedures were performed under moderate sedation and with supplemental local anesthesia of 0.5% lidocaine as needed. All AVFs were created in an end-toside fashion using standard technique with atraumatic vascular clamps. Technical success was confirmed by physical examination or a nondirectional Doppler probe (model 811-B; Parks Medical Electronics, Aloha, Ore). End points. As an urban safety net hospital with a largely underinsured population, nearly all patients received predialysis nephrology care or hemodialysis in units affiliated with our health network. Follow-up of >30 days, until access abandonment or death, was available in 132 of 135 patients. Primary failure was defined as AVF thrombosis within 90 days from creation. For patients already on hemodialysis at time of surgery, functional access was defined as an AVF used successfully on hemodialysis at 6 months after the procedure. Patients had a postoperative clinical examination after 3 weeks, and those with abnormal physical examination findings underwent duplex ultrasound to quantify flow volume and vein diameter. First cannulation was at the discretion of the hemodialysis nurse. A protocol for accessing new fistulas is followed by all affiliated dialysis units, including initial single 17-gauge needle cannulation in the arterial limb at 250 mL/min. The protocol advances to two 16-gauge needles at 350 mL/ min during a 3-week period. Date of central venous catheter removal was a surrogate for first cannulation in patients for whom time to first cannulation was not available. Thrombosis was defined as the date the dialysis unit reported no flow through the fistula. Any procedure other than a planned second-stage basilic vein transposition was considered a revision, irrespective of indication (failure to mature, thrombosis, hand ischemia, or bleeding). Statistical methods. Two-sample statistical tests including c2 test and Student t-test with unequal groups were used to compare categorical variables. Continuous variables were evaluated visually with a histogram plot; those with normal distributions were reported as means with 95% confidence interval bounds, whereas those not distributed normally appear as medians with interquartile ranges. Kaplan-Meier life-table analysis estimated freedom from thrombosis or revision. Cox proportional hazards modeling identified factors associated with fistula revision or thrombosis from variables appearing in Tables I and II as well as the final fistula anatomy. Model creation proceeded by stepwise backward selection, with inclusion at a P value <.1; a Harrell C statistic is reported as an indicator of discrimination. A multivariable logistic regression for factors associated with recruitment with RA was created with stepwise backward selection from those variables appearing in Tables I and II as well as the preoperative surgical plan, with model entry at P value <.1. The area under the receiver operating
Table I. Demographics Intraoperative category
Recruited OSP (n ¼ 80 with RA [59%]) (n ¼ 55 [41%]) P value
Age, years
55 (53-58)
57 (54-60)
.41
Women
24 (30)
18 (33)
.74
9 (11)
5 (9)
Black
10 (13)
16 (29)
Hispanic
27 (34)
15 (27)
Asian
28 (35)
18 (33)
Race/ethnicity White
Native Hawaiian or Pacific Islander Undisclosed
.05
6 (8)
0
0
1 (2)
Tobacco abuse
.86
Current
16 (20)
12 (22)
Former
15 (19)
12 (22)
Diabetes
49 (61)
25 (45)
.07
Hypertension
77 (96)
52 (95)
.64
Coronary artery disease
14 (18)
12 (22)
.53
20 (25)
12 (22)
.67
Cerebrovascular accident
11 (14)
5 (9)
.41
Congenital CKD
5 (6)
2 (4)
.50
Cirrhosis
5 (6)
6 (11)
.33
Congestive heart failure
HIV infection
5 (6)
5 (9)
.54
Intravenous drug abuse
12 (16)
13 (24)
.20
BMI, kg/m2
29 (28-31)
26 (25-28)
.007
BMI, Body mass index; CKD, chronic kidney disease; HIV, human immunodeficiency virus; OSP, original surgical plan; RA, regional anesthesia. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval).
characteristic curve reported model discrimination with 95% confidence intervals, and the Hosmer-Lemeshow goodness-of-fit test described model specification. All analyses were performed with Stata 15.1 software (StataCorp LLC, College Station, Tex).
RESULTS Study population. Of the 226 dialysis access cases performed under RA from May 2014 through April 2018, 135 patients underwent creation of an AVF. Table I shows that 80 patients (59%) underwent the OSP, whereas 55 (41%) had surgical plans altered by RA. Race and ethnicity were different between groups, with a greater proportion of black patients in the recruited with RA group (13% vs 29%; P ¼ .05). The only other significant difference between groups was body mass index (BMI), with greater mean BMI in the OSP group (29 kg/m2 vs 26 kg/m2; P < .05). The proportion of pre-hemodialysis patients was similar between groups (41% vs 36%; P ¼ .57; Table II).
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Table II. Dialysis access history Intraoperative category Prior hemodialysis
OSP
Recruited with RA
P value
47 (59)
35 (64)
.57
44 (55)
35 (64)
.56
Previous access type Catheter Catheter and contralateral AVF
1 (1)
0
Contralateral AVF
1 (1)
0
Contralateral AVG
1 (1)
0
Ipsilateral AVF
2 (3)
0
AVF, Arteriovenous fistula; AVG, arteriovenous graft; OSP, original surgical plan; RA, regional anesthesia. Values are reported as number (%).
Access plan. Before induction of RA, vein diameters on preoperative ultrasound vein mapping were significantly larger in the OSP group. By anastomotic location, upper arm cephalic vein (3.2 mm vs 1.8 mm), distal forearm cephalic vein (2.4 mm vs 1.7 mm), and upper arm basilic vein (3.6 mm vs 2.9 mm) were significantly different in the OSP group vs the recruited with RA group (all P < .001; Supplementary Table I, online only). Vasodilation associated with RA was able to convert 31 AVGs to radiocephalic (8/31), brachiocephalic (11/31), or brachiobasilic (12/31) AVFs. A number of patients also underwent distalization of the OSP, with 13 brachiobasilic configurations converted to radiocephalic (5/13) or brachiocephalic (8/13) AVFs. In addition, 11 patients scheduled for brachiocephalic AVF were converted to radiocephalic AVF (Fig 1). Outcomes. Follow-up beyond 30 days or until access abandonment or death was available in 132 of 135 patients. The mean follow-up for both groups approached 2 years (22 vs 23 months; P ¼ .59; Table III). For patients already on hemodialysis, the time to first cannulation was equivalent in both groups (OSP, 115 days; recruited with RA, 110 days; P ¼ .73; Table III). Supplementary Table II (online only) separates out those patients originally scheduled for an AVG and compares their outcomes with the OSP group; no statistically significant difference is noted on the listed parameters. KaplanMeier analysis demonstrates no difference in the estimated time to cannulation between the OSP and recruited with RA groups (log-rank, P ¼ .73; Fig 2). Both groups were similarly free from revisions or thrombosis (OSP, 58%; recruited with RA, 62%; P ¼ .62). No difference in estimated freedom from revision or thrombosis was observed between groups at 2 years (53% vs 51%; log-rank, P ¼ .35; Fig 3). Predictors of revision. A Cox proportional hazards model describing factors associated with fistula revision and thrombosis is presented in Table IV. Recruitment
with regional block did not correlate with fistula revision (hazard ratio, 0.65; P ¼ .18). Positive HIV status, prior hemodialysis, intravenous drug abuse, increasing BMI, and age are all predictors of revision and thrombosis, whereas hypertension protects against this outcome (all P < .05). A multivariable logistic regression tabulating factors associated with veins recruited with RA suggests that a preoperative plan to create a brachiobasilic fistula correlates with the intraoperative decision to distalize a fistula (odds ratio, 11.55; P < .001; Table V).
DISCUSSION Superficial vein anatomy is one of the principal determinants of access plan and long-term AVF functionality. In this study of 135 patients who had new dialysis access placed, the vasodilation associated with RA resulted in a change in surgical plan in 42% of patients, including 24% of patients originally thought to be candidates only for AVG. In addition, 18% of patients underwent distalization of the access, changing the plan from a brachiobasilic or brachiocephalic AVF to a radiocephalic AVF. Although MVD on preoperative ultrasound vein mapping has repeatedly been shown to be an important predictor of functional outcomes, it is unclear whether AVFs recruited with RA have functional outcomes equivalent to those of AVFs created on the basis of preoperative ultrasound MVD of >2.5 mm. In this cohort, the mean preoperative cephalic vein diameter on vein mapping ultrasound was 1.8 mm, and yet the functional outcomes of these AVFs recruited with RA are no different, including similar rates of primary failure and time to first cannulation and equivalent primary patency and revision rates. In this study, the proportion of patients with unsuitable superficial vein anatomy who were recruited with RA is broadly similar to what has been reported previously. Multiple studies have confirmed the vasodilatory effects of RA, including the magnitude of change in vein diameter by ultrasound. Laskowski et al13 showed that in a cohort of 26 patients having AVF constructed under RA with repeated ultrasound vein mapping, the surgical plan was modified in 19%. In a group of 62 patients scheduled to receive an AVG, Schenk14 showed that RA with repeated ultrasound was able to convert 37% of patients into an AVF. Reynolds et al19 prospectively studied a group of 30 patients, noting that RA modified the OSP in 14% of their patients. Hui et al12 described 65 patients who had dialysis access created under RA, with 40% of AVGs being converted to AVFs. Much like these reports, our study confirms that a large proportion of patients who are to undergo creation of an AVG are actually candidates for an AVF when it is performed under RA. This study is the first to examine the long-term functional outcomes for AVFs created with target veins initially <2.5 mm that subsequently dilate under RA.
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OSP (n=80)
RC
(n=16, 20%)
BC
(n=49, 61%)
BB
(n=15, 19%)
New AVF w RA (n=135)
RWR (n=55)
AVG, BC or BB
Æ RC
(n=24, 44%)
AVG, BB
Æ BC
(n=19, 34%)
AVG
Æ BB
(n=12, 22%)
Fig 1. Cohort development. AVF, Arteriovenous fistula; AVG, arteriovenous graft; BB, brachiobasilic; BC, brachiocephalic; OSP, original surgical plan; RA, regional anesthesia; RC, radiocephalic; RWR, recruited with regional anesthesia.
Table III. Outcomes Intraoperative category
OSP
Recruited with RA
P value
Follow-up, months
22 (19-25)
23 (20-27)
0.59
Days to first cannulationa
115 (96-134)
110 (86-134)
.73
Primary failure
3 (4)
0 (0)
.15
Freedom from revision or thrombosis
46 (58)
34 (62)
.62
Primary assisted patency
51 (64)
35 (64)
.99
Secondary patency
74 (93)
51 (93)
.96
Revisions
1.8 (1.2-2.4)
1.6 (1.1-2.2)
.65
IR
17 (21)
15 (27)
OR
8 (10)
3 (5)
Revision
Types of revision
IR and OR Deceased
.62
5 (6)
2 (4)
9 (11)
6 (11)
.96
IR, Interventional radiology; OR, operating room; OSP, original surgical plan; RA, regional anesthesia. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval). a Includes only patients on hemodialysis before arteriovenous fistula creation (OSP, n ¼ 41; recruited with RA, n ¼ 29).
These fistulas perform equally well, with equivalent time to first cannulation and similar rates of primary thrombosis, revision, and patency. Our results question whether MVD alone on preoperative ultrasound vein mapping is the best metric for predicting long-term success of an AVF.10 In this study, the mean cephalic vein diameter of the recruited with RA group was 1.8 mm, and yet the functional outcomes in this group were equivalent. These findings suggest that rather than simple MVD on preoperative ultrasound imaging, vein dilation is also relevant and should be factored into surgical decision-making.
Patient-specific factors that influence superficial vein diameter, including volume status and temperature, are often difficult to control. Vein mapping done immediately after hemodialysis could result in smaller diameters as a result of volume contraction. In this study, 61% of our patients were pre-hemodialysis, and on subset analysis, there were similar vein diameter changes with RA in this group, implying that the effects of sympathetic blockade supersede the effect of volume status alone. In addition, our preoperative vein mapping protocol includes application of a pneumatic tourniquet inflated to 80 mm Hg with 30 seconds of hand exercises, yet even with this technique, there remains a large proportion of patients who had significant anatomic changes after induction of RA. Finally, routine use of RA has the potential for a positive public health impact. Through the use of initiatives, guidelines, and policy changes, the prevalent AVF rate in the United States increased from 32% in 2003 to 63% in 2014, but this percentage has been stagnant during the last 5 years.20 Few end-stage renal disease networks have met society guidelines for prevalent AVF proportion at 90 days, and considerable variation in the prevalence of AVF use among different networks remains.7 In particular, black patients have disproportionately higher rates of AVG use, and black men have the lowest prevalent AVF rates reported by the United States Renal Data System (57%).6,21 In our analysis, black race was not a predictor of thrombosis or revision, suggesting that AVF recruited with RA in this group of patients is durable. Recruitment with RA is a potential method to reduce AVG placement in this disproportionately affected population of hemodialysis patients. As performing access surgery under RA has been able to safely convert a large proportion of AVGs to AVFs in this study and in others, this may be an effective strategy to increase the prevalence of AVF broadly.
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Fig 2. Time to successful cannulation. OSP, Original surgical plan; RWR, recruited with regional anesthesia.
Fig 3. Kaplan-Meier curve demonstrating freedom from intervention or thrombosis. OSP, Original surgical plan; RWR, recruited with regional anesthesia.
This study is limited in its retrospective nature, and although intraoperative vein mapping did drive decision-making, these results were not captured and therefore not reported. Accordingly, the changes in absolute vein diameter as a result of the sympathetic
blockade and patient-level anatomic variation are not known. Although this is a retrospective review, our health network with affiliated dialysis units allowed us to capture all major dialysis access events, and a strength of this study is the long-term follow-up of 132 patients.
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Table IV. Cox proportional hazards model for factors associated with revision and thrombosis Hazard ratio
95% CI
P value
Recruited with RA
0.65
0.34-1.23
.18
HIV infection
7.15
2.24-22.81
.001
Native Hawaiian or Pacific Islander
3.35
1.09-10.29
.03
Hispanic ethnicity
2.30
1.20-4.42
.01
Intravenous drug abuse
2.20
0.92-5.27
.08
Prior hemodialysis
2.12
1.08-4.17
.03
BMI, kg/m
2
1.05
1.01-1.09
1.03
1.01-1.06
Coronary artery disease
0.37
0.15-0.96
.04
Hypertension
0.21
0.5-0.78
.02
Age, years
.009 0.02
BMI, Body mass index; CI, confidence interval; HIV, human immunodeficiency virus; RA, regional anesthesia. Harrell C statistic ¼ 0.72. Adjusted for all variables in Tables I and II as well as for fistula anatomy.
Table V. Multivariable logistic regression describing factors associated with intraoperative decision to distalize an arteriovenous fistula (AVF) Odds ratio Planned brachiobasilic AVF
11.55
Intravenous drug abuse
0.18
95% CI
P value
3.14-38.80
<.001
0.03-1.16
.07
CI, Confidence interval. Area under the receiver operating characteristic curve ¼ 0.72 (0.600.84). Hosmer-Lemeshow goodness of fit, 0.68; P ¼ .41. Adjusted for all variables in Tables I and II as well as for preoperative plan.
Although this is not a prospective study, the results in our OSP control arm are broadly similar to long-term outcomes reported in other studies.1,22
CONCLUSIONS Performing dialysis access surgery under RA coupled with a flexible surgical plan and intraoperative ultrasound vein mapping can convert AVG to AVF in a significant proportion of patients. Fistulas recruited under RA have long-term functional outcomes similar to those with nominal superficial vein anatomy on preoperative duplex ultrasound. As access choice has profound implications at the health systems level, routine use of RA has the potential for positive public health impact by increasing the proportion of patients dialyzed with AVF in the prevalent hemodialysis population.
AUTHOR CONTRIBUTIONS Conception and design: DZ, AG, AO, SV Analysis and interpretation: DZ, BW, AO, SV Data collection: DZ, BW, SV Writing the article: DZ, BW, SV Critical revision of the article: DZ, BW, AG, AO, SV
Final approval of the article: DZ, BW, AG, AO, SV Statistical analysis: DZ, SV Obtained funding: Not applicable Overall responsibility: SV
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Volume 71, Number 2 16. Sandhu NS, Capan LM. Ultrasound-guided infraclavicular brachial plexus block. Br J Anaesth 2002;89:254-9. 17. Seidel R, Gray AT, Wree A, Schulze M. Surgery of the axilla with combined brachial plexus and intercostobrachial nerve block in the subpectoral intercostal plane. Br J Anaesth 2017;118:472-4. 18. Magazzeni P, Jochum D, Iohom G, Mekler G, Albuisson E, Bouaziz H. Ultrasound-guided selective versus conventional block of the medial brachial cutaneous and the intercostobrachial nerves: a randomized clinical trial. Reg Anesth Pain Med 2018;43:832-7. 19. Reynolds TS, Kim KM, Dukkipati R, Nguyen TH, Julka I, Kakazu C, et al. Pre-operative regional block anesthesia enhances operative strategy for arteriovenous fistula creation. J Vasc Access 2011;12:336-40. 20. Robinson BM, Akizawa T, Jager KJ, Kerr PG, Saran R, Pisoni RL. Factors affecting outcomes in patients reaching
end-stage kidney disease worldwide: differences in access to renal replacement therapy, modality use, and haemodialysis practices. Lancet 2016;388:294-306. 21. Zarkowsky DS, Arhuidese IJ, Hicks CW, Canner JK, Qazi U, Obeid T, et al. Racial/ethnic disparities associated with initial hemodialysis access. JAMA Surg 2015;150: 529-36. 22. Dember LM, Beck GJ, Allon M, Delmez JA, Dixon BS, Greenberg A, et al. Effect of clopidogrel on early failure of arteriovenous fistulas for hemodialysis: a randomized controlled trial. JAMA 2008;299:2164-71. Submitted Nov 29, 2018; accepted Mar 27, 2019.
Additional material for this article may be found online at www.jvascsurg.org.
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Supplementary Table vascular measurements Intraoperative category Axillary vein preoperative diameter, mm
I
(online
OSP
only). Preoperative Recruited with RA P value
6.5 (6.1-6.9) 6.3 (5.7-7.0)
.76
Supplementary Table II (online only). Outcomes of patients in the recruited with regional anesthesia (RA) group scheduled for arteriovenous graft (AVG)
Intraoperative category Follow-up, months
Cephalic vein preoperative diameter, mm
Recruited OSP (n ¼ 80 with RA [72%]) (n ¼ 31 [28%]) P value 22 (19-25)
Days to first cannulationa 115 (96-134)
Proximal brachium
3.5 (3.3-3.8) 2.4 (2.1-2.8)
<.001
Primary failure
Upper third of brachium
3.4 (3.1-3.7) 2.1 (1.8-2.5)
<.001
Mid brachium
3.2 (2.9-3.5) 1.9 (1.6-2.3)
<.001
Freedom from revision or 32 (40) thrombosis
Distal three-fourths of brachium
3.2 (2.9-3.5) 1.8 (1.5-2.1)
<.001
Distal brachium
3.4 (3.1-3.7) 2.1 (1.7-2.5)
<.001
Proximal forearm
2.9 (2.6-3.1) 1.9 (1.6-2.2)
<.001
Mid forearm
2.6 (2.3-2.8) 1.7 (1.4-2.0)
<.001
Distal forearm
2.4 (2.1-2.6) 1.7 (1.4-2.0)
.001
Median antecubital vein 2.0 (1.7-2.3) 1.5 (1.1-1.8) preoperative diameter, mm
.01
Basilic vein preoperative diameter, mm Proximal brachium
4.2 (3.9-4.4) 3.6 (3.2-4.00)
.009
Mid brachium
3.9 (3.7-4.2) 3.3 (3.0-3.6)
.003
Distal brachium
3.6 (3.4-3.9) 2.9 (2.6-3.2)
Proximal forearm
2.2 (2.0-2.4) 1.5 (1.3-1.7)
<.001
Mid forearm
2.1 (1.8-2.3) 1.3 (1.1-1.5)
<.001
Distal forearm
1.8 (1.6-2.0) 1.2 (1.0-1.4)
<.001
Brachial artery diameter, mm 4.6 (4.5-4.8) 4.6 (4.4-4.8)
.003
.68
Radial artery diameter, mm
2.3 (2.2-2.4) 2.3 (2.2-2.4)
.47
Ulnar artery diameter, mm
2.2 (1.9-2.6) 2.0 (1.8-2.1)
.14
Anastomotic site
3.7 (3.5-3.9) 2.4 (2.1-2.7)
<.001
Distal vein segment 1
3.6 (3.4-3.8) 2.4 (2.1-2.7)
<.001
Distal vein segment 2
3.7 (3.5-4.0) 2.6 (2.2-2.9)
<.001
4.1 (3.9-4.4) 3.6 (3.2-3.9)
.005
Target vein diameter, mm
Donor artery diameter, mm
OSP, Original surgical plan; RA, regional anesthesia. Variables are presented as mean (95% confidence interval).
3 (4)
22 (17-26)
.79
115 (87-143)
.97
0
.27
14 (45)
.62
Primary assisted patency
51 (64)
17 (55)
.39
Secondary patency
74 (93)
29 (94)
.85
IR
17 (21)
11 (35)
OR
8 (10)
2 (6)
IR and OR
5 (6)
1 (3)
9 (11)
5 (17)
Types of revision
Deceased
.44
.46
IR, Interventional radiology; OR, operating room; OSP, original surgical plan. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval). a Includes only patients on hemodialysis before arteriovenous fistula creation (OSP, n ¼ 41; recruited with RA, n ¼ 18).
Functional outcomes of arteriovenous fistulas recruited with regional anesthesia Devin S. Zarkowsky, MD,a Bian Wu, MD,a Andew T. Gray, MD,b Adam Z. Oskowitz, MD, PhD,a,b and Shant M. Vartanian, MD,a,b San Francisco, Calif
ABSTRACT Objective: Regional anesthesia (RA)-induced vasodilation increases the proportion of patients with vein anatomy suitable for arteriovenous fistula (AVF) creation. The functional outcomes of AVFs created with veins initially small for size on preoperative duplex ultrasound mapping (#2.4 mm) that are recruited under RA have not been clearly defined. We aimed to evaluate freedom from revision or thrombosis, time to first cannulation, and reintervention rates of AVFs created with veins recruited after induction of RA. Methods: A prospectively maintained quality improvement database from a single institution was queried for patients who had dialysis access created under RA. We compared AVFs created according to the original surgical plan (preoperative minimum vein diameter >2.5 mm) with AVFs recruited with RA (preoperative minimum vein diameter #2.4 mm). End points included freedom from revision or thrombosis, time to first cannulation, and reintervention rates. Results: Between May 2014 and April 2018, there were 208 dialysis access cases performed under RA. Excluding grafts, revisions, patients with previous ipsilateral AVFs, and those without preoperative ultrasound vein mapping, 135 patients were included in our analysis. Induction of RA with intraoperative duplex ultrasound allowed a change in surgical plan in 55 of 135 (42%) patients (recruited with RA), including 31 patients originally scheduled for an arteriovenous graft (mean preoperative distal upper arm cephalic vein diameter of 1.8 mm [standard deviation, 0.2 mm]) who were converted to an AVF (12 brachiobasilic, 11 brachiocephalic, and 8 radiocephalic). The remaining patients in the group of AVFs recruited with RA included 13 scheduled for brachiobasilic configurations who were converted to brachiocephalic or radiocephalic AVFs and 11 scheduled for brachiocephalic AVFs who were converted to radiocephalic AVFs. Comparing AVFs created according to the original surgical plan vs AVFs recruited with RA, there were no differences in reintervention rates (48% vs 49%; P ¼ .90) or functional outcomes at 6 months (60% vs 65% used on hemodialysis [P ¼ .58] and 7% vs 2% primary failure [P ¼ .19]). Conclusions: In this series, RA increased the proportion of patients who underwent AVF creation without compromising functional outcomes. Routine use of RA in access surgery could have significant implications in meeting national guidelines for autogenous access in the prevalent hemodialysis population. (J Vasc Surg 2020;71:584-91.) Keywords: Arteriovenous fistula; Hemodialysis access; Regional anesthesia
Hemodialysis is the dominant form of renal replacement therapy both in the United States and internationally. Arteriovenous fistulas (AVFs) have repeatedly demonstrated superiority to arteriovenous grafts
From the Division of Vascular and Endovascular Surgery, University of California San Franciscoa; and the Department of Surgery, Zuckerberg San Francisco General Hospital.b Author conflict of interest: none. Presented at the Thirty-third Annual Meeting of the Western Vascular Society, Santa Fe, NM, September 22-25, 2018. Additional material for this article may be found online at www.jvascsurg.org. Correspondence: Shant M. Vartanian, MD, Department of Surgery, Zuckerberg San Francisco General Hospital, 1001 Portrero Ave, San Francisco, CA 94110 (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.2019.03.083
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(AVGs) and central venous catheters by a variety of metrics, including mortality, durability, and risk of infection.1,2 A number of additional secondary health care system and economic benefits are derived from these advantages.3,4 The National Kidney Foundation Kidney Disease Outcomes Quality Initiative established benchmarks for a prevalent AVF rate of >66% to more closely mirror those in Europe and Asia.5 Despite efforts from government agencies and multiple medical specialties and societies, the prevalent AVF rates have been relatively flat during the last decade, with the United States Renal Data System currently reporting 62% nationally.6,7 Superficial vein anatomy is one of the most significant determinants of access plan and functional outcomes. For AVFs, minimum vein diameter (MVD) by ultrasound mapping correlates with the risk of primary failure and failure to mature.8 A size threshold for MVD of >2.5 mm is generally accepted as a metric for successful functional AVF outcomes.9,10 Regional anesthesia (RA) for
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dialysis access surgery induces a sympathetic blockade that causes vasodilation, thereby increasing superficial vein diameter.11 Advocates of RA for access surgery note that the vasodilatory effects can recruit patients into AVF who otherwise do not have adequate superficial vein anatomy by preoperative ultrasound vein mapping.12-14 However, as MVD on preoperative duplex ultrasound correlates with risk of primary thrombosis and maturation rate, it is unclear whether these previously small for size veins that are recruited with RA result in dialysis access with functional outcomes equivalent to those of veins that initially had an MVD >2.5 mm.15 This study retrospectively compared fistulas created with veins according to the original surgical plan (OSP; preoperative MVD >2.5 mm) and those recruited with RA (preoperative MVD #2.4 mm) with a goal of assessing functional outcomes. We hypothesized that AVFs recruited with RA have equivalent freedom from revision or thrombosis, primary failure, and reintervention rates.
METHODS Study design. A prospectively maintained quality improvement database for dialysis access outcomes at Zuckerberg San Francisco General Hospital was retrospectively queried to identify all new dialysis accesses created under RA from May 2014 through April 2018. Of the 226 new dialysis accesses created under RA, we excluded patients who had AVGs placed because of extenuating circumstances that precluded awaiting AVF maturity, those with previous ipsilateral dialysis access, and patients with absent ultrasound vein mapping results (venography vein mapping only). Predialysis patients with an urgent need for dialysis (ie, glomerular filtration rate <8 mL/min) underwent placement of an AVG irrespective of vein anatomy and are not included in this analysis. No patient required general anesthesia during the study period. The study was approved by the Committee on Human Research at University of California San Francisco and Zuckerberg San Francisco General Hospital. Access plan selection. Patients referred for new permanent vascular access were evaluated for surgical and anesthesia risk by one of two vascular surgeons. The access plan was created weighing hand dominance, presence of previous central catheters, risks of central vein disease, and superficial vein anatomy. Patients were scheduled for AVF if the MVD in two contiguous segments was $2.5 mm and the vein was continuous to the deep system and compressible along its length. The configuration of AVF was selected for the most favorable distal anatomy first, that is, radiocephalic over brachiocephalic, barring technical barriers (eg, radial artery harvest for coronary artery bypass grafting). All patients scheduled for AVG were consented for possible AVF at the preoperative visit.
ARTICLE HIGHLIGHTS d
d
d
Type of Research: Single-center, retrospective cohort study Key Findings: In this analysis of 135 patients receiving arteriovenous fistulas, regional anesthesia caused venodilation, allowing access creation in those patients deemed to have veins of inadequate diameter on preoperative ultrasound. No difference in functional outcome was discerned in arteriovenous fistulas created from veins recruited with regional anesthesia. Take Home Message: Surgeons would do well to reevaluate patients’ arm veins in the operating room after regional anesthesia is applied.
Duplex ultrasound vein mapping. All ultrasound vein mapping was performed by a registered vascular technologist. Patients were positioned supine on an examination table with the studies performed at room temperature. Venous duplex ultrasound scanning with color flow images was obtained of the jugular, subclavian, and axillary veins using a 3-9 MHz linear array probe (Philips iU-22; Philips Healthcare, Amsterdam, The Netherlands). The basilic and cephalic veins were assessed for size, compressibility, and continuity from the wrist to the shoulder and into the deep system. Eight cephalic vein measurements, a median antecubital measurement, and six basilic vein measurements were made in total. If a measured diameter was <3.0 mm, a 5-cm pneumatic tourniquet was applied to the upper arm (SC5; Hokanson, Bellevue, Wash) and inflated to 80 mm Hg, and 30 seconds of hand pump exercises were performed. The tourniquet was deflated and reapplied for each subsequent measurement of <3.0 mm. A limited arterial study with diameters and pulse wave velocities was also performed of the brachial, radial, and ulnar arteries. RA. A dedicated RA team performed brachial plexus blocks in the preoperative holding unit 30 minutes before surgery. Either a supraclavicular or infraclavicular approach to the brachial plexus was performed, completed by injection of 0.5% ropivacaine around the second part of the axillary artery with an echogenic 21-gauge needle under ultrasound guidance using an in-plane technique.16 In addition, an intercostobrachial cutaneous nerve block was performed in the axilla.17,18 A total of 30 to 40 mL of ropivacaine 0.5% was injected. Surgical approach. Approximately 30 minutes after block induction, vein mapping ultrasound was repeated in the operating room by the surgeon with a 7-12 Hz linear array probe (Philips EPIQ 5) without applying a tourniquet. If the block-induced vasodilation resulted in two contiguous vein measurements of >2.5 mm in a
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more distal vein segment, the surgical plan was changed accordingly (recruited with RA). Otherwise, the OSP was executed. Procedures were performed under moderate sedation and with supplemental local anesthesia of 0.5% lidocaine as needed. All AVFs were created in an end-toside fashion using standard technique with atraumatic vascular clamps. Technical success was confirmed by physical examination or a nondirectional Doppler probe (model 811-B; Parks Medical Electronics, Aloha, Ore). End points. As an urban safety net hospital with a largely underinsured population, nearly all patients received predialysis nephrology care or hemodialysis in units affiliated with our health network. Follow-up of >30 days, until access abandonment or death, was available in 132 of 135 patients. Primary failure was defined as AVF thrombosis within 90 days from creation. For patients already on hemodialysis at time of surgery, functional access was defined as an AVF used successfully on hemodialysis at 6 months after the procedure. Patients had a postoperative clinical examination after 3 weeks, and those with abnormal physical examination findings underwent duplex ultrasound to quantify flow volume and vein diameter. First cannulation was at the discretion of the hemodialysis nurse. A protocol for accessing new fistulas is followed by all affiliated dialysis units, including initial single 17-gauge needle cannulation in the arterial limb at 250 mL/min. The protocol advances to two 16-gauge needles at 350 mL/ min during a 3-week period. Date of central venous catheter removal was a surrogate for first cannulation in patients for whom time to first cannulation was not available. Thrombosis was defined as the date the dialysis unit reported no flow through the fistula. Any procedure other than a planned second-stage basilic vein transposition was considered a revision, irrespective of indication (failure to mature, thrombosis, hand ischemia, or bleeding). Statistical methods. Two-sample statistical tests including c2 test and Student t-test with unequal groups were used to compare categorical variables. Continuous variables were evaluated visually with a histogram plot; those with normal distributions were reported as means with 95% confidence interval bounds, whereas those not distributed normally appear as medians with interquartile ranges. Kaplan-Meier life-table analysis estimated freedom from thrombosis or revision. Cox proportional hazards modeling identified factors associated with fistula revision or thrombosis from variables appearing in Tables I and II as well as the final fistula anatomy. Model creation proceeded by stepwise backward selection, with inclusion at a P value <.1; a Harrell C statistic is reported as an indicator of discrimination. A multivariable logistic regression for factors associated with recruitment with RA was created with stepwise backward selection from those variables appearing in Tables I and II as well as the preoperative surgical plan, with model entry at P value <.1. The area under the receiver operating
Table I. Demographics Intraoperative category
Recruited OSP (n ¼ 80 with RA [59%]) (n ¼ 55 [41%]) P value
Age, years
55 (53-58)
57 (54-60)
.41
Women
24 (30)
18 (33)
.74
9 (11)
5 (9)
Black
10 (13)
16 (29)
Hispanic
27 (34)
15 (27)
Asian
28 (35)
18 (33)
Race/ethnicity White
Native Hawaiian or Pacific Islander Undisclosed
.05
6 (8)
0
0
1 (2)
Tobacco abuse
.86
Current
16 (20)
12 (22)
Former
15 (19)
12 (22)
Diabetes
49 (61)
25 (45)
.07
Hypertension
77 (96)
52 (95)
.64
Coronary artery disease
14 (18)
12 (22)
.53
20 (25)
12 (22)
.67
Cerebrovascular accident
11 (14)
5 (9)
.41
Congenital CKD
5 (6)
2 (4)
.50
Cirrhosis
5 (6)
6 (11)
.33
Congestive heart failure
HIV infection
5 (6)
5 (9)
.54
Intravenous drug abuse
12 (16)
13 (24)
.20
BMI, kg/m2
29 (28-31)
26 (25-28)
.007
BMI, Body mass index; CKD, chronic kidney disease; HIV, human immunodeficiency virus; OSP, original surgical plan; RA, regional anesthesia. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval).
characteristic curve reported model discrimination with 95% confidence intervals, and the Hosmer-Lemeshow goodness-of-fit test described model specification. All analyses were performed with Stata 15.1 software (StataCorp LLC, College Station, Tex).
RESULTS Study population. Of the 226 dialysis access cases performed under RA from May 2014 through April 2018, 135 patients underwent creation of an AVF. Table I shows that 80 patients (59%) underwent the OSP, whereas 55 (41%) had surgical plans altered by RA. Race and ethnicity were different between groups, with a greater proportion of black patients in the recruited with RA group (13% vs 29%; P ¼ .05). The only other significant difference between groups was body mass index (BMI), with greater mean BMI in the OSP group (29 kg/m2 vs 26 kg/m2; P < .05). The proportion of pre-hemodialysis patients was similar between groups (41% vs 36%; P ¼ .57; Table II).
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Table II. Dialysis access history Intraoperative category Prior hemodialysis
OSP
Recruited with RA
P value
47 (59)
35 (64)
.57
44 (55)
35 (64)
.56
Previous access type Catheter Catheter and contralateral AVF
1 (1)
0
Contralateral AVF
1 (1)
0
Contralateral AVG
1 (1)
0
Ipsilateral AVF
2 (3)
0
AVF, Arteriovenous fistula; AVG, arteriovenous graft; OSP, original surgical plan; RA, regional anesthesia. Values are reported as number (%).
Access plan. Before induction of RA, vein diameters on preoperative ultrasound vein mapping were significantly larger in the OSP group. By anastomotic location, upper arm cephalic vein (3.2 mm vs 1.8 mm), distal forearm cephalic vein (2.4 mm vs 1.7 mm), and upper arm basilic vein (3.6 mm vs 2.9 mm) were significantly different in the OSP group vs the recruited with RA group (all P < .001; Supplementary Table I, online only). Vasodilation associated with RA was able to convert 31 AVGs to radiocephalic (8/31), brachiocephalic (11/31), or brachiobasilic (12/31) AVFs. A number of patients also underwent distalization of the OSP, with 13 brachiobasilic configurations converted to radiocephalic (5/13) or brachiocephalic (8/13) AVFs. In addition, 11 patients scheduled for brachiocephalic AVF were converted to radiocephalic AVF (Fig 1). Outcomes. Follow-up beyond 30 days or until access abandonment or death was available in 132 of 135 patients. The mean follow-up for both groups approached 2 years (22 vs 23 months; P ¼ .59; Table III). For patients already on hemodialysis, the time to first cannulation was equivalent in both groups (OSP, 115 days; recruited with RA, 110 days; P ¼ .73; Table III). Supplementary Table II (online only) separates out those patients originally scheduled for an AVG and compares their outcomes with the OSP group; no statistically significant difference is noted on the listed parameters. KaplanMeier analysis demonstrates no difference in the estimated time to cannulation between the OSP and recruited with RA groups (log-rank, P ¼ .73; Fig 2). Both groups were similarly free from revisions or thrombosis (OSP, 58%; recruited with RA, 62%; P ¼ .62). No difference in estimated freedom from revision or thrombosis was observed between groups at 2 years (53% vs 51%; log-rank, P ¼ .35; Fig 3). Predictors of revision. A Cox proportional hazards model describing factors associated with fistula revision and thrombosis is presented in Table IV. Recruitment
with regional block did not correlate with fistula revision (hazard ratio, 0.65; P ¼ .18). Positive HIV status, prior hemodialysis, intravenous drug abuse, increasing BMI, and age are all predictors of revision and thrombosis, whereas hypertension protects against this outcome (all P < .05). A multivariable logistic regression tabulating factors associated with veins recruited with RA suggests that a preoperative plan to create a brachiobasilic fistula correlates with the intraoperative decision to distalize a fistula (odds ratio, 11.55; P < .001; Table V).
DISCUSSION Superficial vein anatomy is one of the principal determinants of access plan and long-term AVF functionality. In this study of 135 patients who had new dialysis access placed, the vasodilation associated with RA resulted in a change in surgical plan in 42% of patients, including 24% of patients originally thought to be candidates only for AVG. In addition, 18% of patients underwent distalization of the access, changing the plan from a brachiobasilic or brachiocephalic AVF to a radiocephalic AVF. Although MVD on preoperative ultrasound vein mapping has repeatedly been shown to be an important predictor of functional outcomes, it is unclear whether AVFs recruited with RA have functional outcomes equivalent to those of AVFs created on the basis of preoperative ultrasound MVD of >2.5 mm. In this cohort, the mean preoperative cephalic vein diameter on vein mapping ultrasound was 1.8 mm, and yet the functional outcomes of these AVFs recruited with RA are no different, including similar rates of primary failure and time to first cannulation and equivalent primary patency and revision rates. In this study, the proportion of patients with unsuitable superficial vein anatomy who were recruited with RA is broadly similar to what has been reported previously. Multiple studies have confirmed the vasodilatory effects of RA, including the magnitude of change in vein diameter by ultrasound. Laskowski et al13 showed that in a cohort of 26 patients having AVF constructed under RA with repeated ultrasound vein mapping, the surgical plan was modified in 19%. In a group of 62 patients scheduled to receive an AVG, Schenk14 showed that RA with repeated ultrasound was able to convert 37% of patients into an AVF. Reynolds et al19 prospectively studied a group of 30 patients, noting that RA modified the OSP in 14% of their patients. Hui et al12 described 65 patients who had dialysis access created under RA, with 40% of AVGs being converted to AVFs. Much like these reports, our study confirms that a large proportion of patients who are to undergo creation of an AVG are actually candidates for an AVF when it is performed under RA. This study is the first to examine the long-term functional outcomes for AVFs created with target veins initially <2.5 mm that subsequently dilate under RA.
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OSP (n=80)
RC
(n=16, 20%)
BC
(n=49, 61%)
BB
(n=15, 19%)
New AVF w RA (n=135)
RWR (n=55)
AVG, BC or BB
Æ RC
(n=24, 44%)
AVG, BB
Æ BC
(n=19, 34%)
AVG
Æ BB
(n=12, 22%)
Fig 1. Cohort development. AVF, Arteriovenous fistula; AVG, arteriovenous graft; BB, brachiobasilic; BC, brachiocephalic; OSP, original surgical plan; RA, regional anesthesia; RC, radiocephalic; RWR, recruited with regional anesthesia.
Table III. Outcomes Intraoperative category
OSP
Recruited with RA
P value
Follow-up, months
22 (19-25)
23 (20-27)
0.59
Days to first cannulationa
115 (96-134)
110 (86-134)
.73
Primary failure
3 (4)
0 (0)
.15
Freedom from revision or thrombosis
46 (58)
34 (62)
.62
Primary assisted patency
51 (64)
35 (64)
.99
Secondary patency
74 (93)
51 (93)
.96
Revisions
1.8 (1.2-2.4)
1.6 (1.1-2.2)
.65
IR
17 (21)
15 (27)
OR
8 (10)
3 (5)
Revision
Types of revision
IR and OR Deceased
.62
5 (6)
2 (4)
9 (11)
6 (11)
.96
IR, Interventional radiology; OR, operating room; OSP, original surgical plan; RA, regional anesthesia. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval). a Includes only patients on hemodialysis before arteriovenous fistula creation (OSP, n ¼ 41; recruited with RA, n ¼ 29).
These fistulas perform equally well, with equivalent time to first cannulation and similar rates of primary thrombosis, revision, and patency. Our results question whether MVD alone on preoperative ultrasound vein mapping is the best metric for predicting long-term success of an AVF.10 In this study, the mean cephalic vein diameter of the recruited with RA group was 1.8 mm, and yet the functional outcomes in this group were equivalent. These findings suggest that rather than simple MVD on preoperative ultrasound imaging, vein dilation is also relevant and should be factored into surgical decision-making.
Patient-specific factors that influence superficial vein diameter, including volume status and temperature, are often difficult to control. Vein mapping done immediately after hemodialysis could result in smaller diameters as a result of volume contraction. In this study, 61% of our patients were pre-hemodialysis, and on subset analysis, there were similar vein diameter changes with RA in this group, implying that the effects of sympathetic blockade supersede the effect of volume status alone. In addition, our preoperative vein mapping protocol includes application of a pneumatic tourniquet inflated to 80 mm Hg with 30 seconds of hand exercises, yet even with this technique, there remains a large proportion of patients who had significant anatomic changes after induction of RA. Finally, routine use of RA has the potential for a positive public health impact. Through the use of initiatives, guidelines, and policy changes, the prevalent AVF rate in the United States increased from 32% in 2003 to 63% in 2014, but this percentage has been stagnant during the last 5 years.20 Few end-stage renal disease networks have met society guidelines for prevalent AVF proportion at 90 days, and considerable variation in the prevalence of AVF use among different networks remains.7 In particular, black patients have disproportionately higher rates of AVG use, and black men have the lowest prevalent AVF rates reported by the United States Renal Data System (57%).6,21 In our analysis, black race was not a predictor of thrombosis or revision, suggesting that AVF recruited with RA in this group of patients is durable. Recruitment with RA is a potential method to reduce AVG placement in this disproportionately affected population of hemodialysis patients. As performing access surgery under RA has been able to safely convert a large proportion of AVGs to AVFs in this study and in others, this may be an effective strategy to increase the prevalence of AVF broadly.
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Fig 2. Time to successful cannulation. OSP, Original surgical plan; RWR, recruited with regional anesthesia.
Fig 3. Kaplan-Meier curve demonstrating freedom from intervention or thrombosis. OSP, Original surgical plan; RWR, recruited with regional anesthesia.
This study is limited in its retrospective nature, and although intraoperative vein mapping did drive decision-making, these results were not captured and therefore not reported. Accordingly, the changes in absolute vein diameter as a result of the sympathetic
blockade and patient-level anatomic variation are not known. Although this is a retrospective review, our health network with affiliated dialysis units allowed us to capture all major dialysis access events, and a strength of this study is the long-term follow-up of 132 patients.
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Table IV. Cox proportional hazards model for factors associated with revision and thrombosis Hazard ratio
95% CI
P value
Recruited with RA
0.65
0.34-1.23
.18
HIV infection
7.15
2.24-22.81
.001
Native Hawaiian or Pacific Islander
3.35
1.09-10.29
.03
Hispanic ethnicity
2.30
1.20-4.42
.01
Intravenous drug abuse
2.20
0.92-5.27
.08
Prior hemodialysis
2.12
1.08-4.17
.03
BMI, kg/m
2
1.05
1.01-1.09
1.03
1.01-1.06
Coronary artery disease
0.37
0.15-0.96
.04
Hypertension
0.21
0.5-0.78
.02
Age, years
.009 0.02
BMI, Body mass index; CI, confidence interval; HIV, human immunodeficiency virus; RA, regional anesthesia. Harrell C statistic ¼ 0.72. Adjusted for all variables in Tables I and II as well as for fistula anatomy.
Table V. Multivariable logistic regression describing factors associated with intraoperative decision to distalize an arteriovenous fistula (AVF) Odds ratio Planned brachiobasilic AVF
11.55
Intravenous drug abuse
0.18
95% CI
P value
3.14-38.80
<.001
0.03-1.16
.07
CI, Confidence interval. Area under the receiver operating characteristic curve ¼ 0.72 (0.600.84). Hosmer-Lemeshow goodness of fit, 0.68; P ¼ .41. Adjusted for all variables in Tables I and II as well as for preoperative plan.
Although this is not a prospective study, the results in our OSP control arm are broadly similar to long-term outcomes reported in other studies.1,22
CONCLUSIONS Performing dialysis access surgery under RA coupled with a flexible surgical plan and intraoperative ultrasound vein mapping can convert AVG to AVF in a significant proportion of patients. Fistulas recruited under RA have long-term functional outcomes similar to those with nominal superficial vein anatomy on preoperative duplex ultrasound. As access choice has profound implications at the health systems level, routine use of RA has the potential for positive public health impact by increasing the proportion of patients dialyzed with AVF in the prevalent hemodialysis population.
AUTHOR CONTRIBUTIONS Conception and design: DZ, AG, AO, SV Analysis and interpretation: DZ, BW, AO, SV Data collection: DZ, BW, SV Writing the article: DZ, BW, SV Critical revision of the article: DZ, BW, AG, AO, SV
Final approval of the article: DZ, BW, AG, AO, SV Statistical analysis: DZ, SV Obtained funding: Not applicable Overall responsibility: SV
REFERENCES 1. Bylsma LC, Gage SM, Reichert H, Dahl SL, Lawson JH. Arteriovenous fistulae for haemodialysis: a systematic review and meta-analysis of efficacy and safety outcomes. Eur J Vasc Endovasc Surg 2017;54:513-22. 2. Ravani P, Palmer SC, Oliver MJ, Quinn RR, MacRae JM, Tai DJ, et al. Associations between hemodialysis access type and clinical outcomes: a systematic review. J Am Soc Nephrol 2013;24:465-73. 3. Leermakers JJ, Bode AS, Vaidya A, van der Sande FM, Evers SM, Tordoir JH. Cost-effectiveness of vascular access for haemodialysis: arteriovenous fistulas versus arteriovenous grafts. Eur J Vasc Endovasc Surg 2013;45:84-92. 4. Ramanathan V, Chiu EJ, Thomas JT, Khan A, Dolson GM, Darouiche RO. Healthcare costs associated with hemodialysis catheter-related infections: a single-center experience. Infect Control Hosp Epidemiol 2007;28:606-9. 5. KDOQI. KDOQI Clinical Practice Guidelines and Clinical Practice Recommendations for Diabetes and Chronic Kidney Disease. Am J Kidney Dis 2007;49:S12-154. 6. Saran R, Robinson B, Abbott KC, Agodoa LY, Albertus P, Ayanian J, et al. US Renal Data System 2016 annual data report: epidemiology of kidney disease in the United States. Am J Kidney Dis 2017;69(Suppl 1):A7-8. 7. Saran R, Robinson B, Abbott KC, Agodoa LY, Bhave N, BraggGresham J, et al. US Renal Data System 2017 annual data report: epidemiology of kidney disease in the United States. Am J Kidney Dis 2018;71(Suppl 1):A7. 8. Lauvao LS, Ihnat DM, Goshima KR, Chavez L, Gruessner AC, Mills JL. Vein diameter is the major predictor of fistula maturation. J Vasc Surg 2009;49:1499-504. 9. Dageforde LA, Harms KA, Feurer ID, Shaffer D. Increased minimum vein diameter on preoperative mapping with duplex ultrasound is associated with arteriovenous fistula maturation and secondary patency. J Vasc Surg 2015;61: 170-6. 10. Bashar K, Clarke-Moloney M, Burke PE, Kavanagh EG, Walsh SR. The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic. Int J Surg 2015;15:95-9. 11. Shemesh D, Olsha O, Orkin D, Raveh D, Goldin I, Reichenstein Y, et al. Sympathectomy-like effects of brachial plexus block in arteriovenous access surgery. Ultrasound Med Biol 2006;32:817-22. 12. Hui SH, Folsom R, Killewich LA, Michalek JE, Davies MG, Pounds LL. A comparison of preoperative and intraoperative vein mapping sizes for arteriovenous fistula creation. J Vasc Surg 2018;67:1813-20. 13. Laskowski IA, Muhs B, Rockman CR, Adelman MA, Ranson M, Cayne NS, et al. Regional nerve block allows for optimization of planning in the creation of arteriovenous access for hemodialysis by improving superficial venous dilatation. Ann Vasc Surg 2007;21:730-3. 14. Schenk WG. Improving dialysis access: regional anesthesia improves arteriovenous fistula prevalence. Am Surg 2010;76: 938-42. 15. Renaud CJ, Leong CR, Bin HW, Wong JC. Effect of brachial plexus block-driven vascular access planning on primary distal arteriovenous fistula recruitment and outcomes. J Vasc Surg 2015;62:1266-72.
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Volume 71, Number 2 16. Sandhu NS, Capan LM. Ultrasound-guided infraclavicular brachial plexus block. Br J Anaesth 2002;89:254-9. 17. Seidel R, Gray AT, Wree A, Schulze M. Surgery of the axilla with combined brachial plexus and intercostobrachial nerve block in the subpectoral intercostal plane. Br J Anaesth 2017;118:472-4. 18. Magazzeni P, Jochum D, Iohom G, Mekler G, Albuisson E, Bouaziz H. Ultrasound-guided selective versus conventional block of the medial brachial cutaneous and the intercostobrachial nerves: a randomized clinical trial. Reg Anesth Pain Med 2018;43:832-7. 19. Reynolds TS, Kim KM, Dukkipati R, Nguyen TH, Julka I, Kakazu C, et al. Pre-operative regional block anesthesia enhances operative strategy for arteriovenous fistula creation. J Vasc Access 2011;12:336-40. 20. Robinson BM, Akizawa T, Jager KJ, Kerr PG, Saran R, Pisoni RL. Factors affecting outcomes in patients reaching
end-stage kidney disease worldwide: differences in access to renal replacement therapy, modality use, and haemodialysis practices. Lancet 2016;388:294-306. 21. Zarkowsky DS, Arhuidese IJ, Hicks CW, Canner JK, Qazi U, Obeid T, et al. Racial/ethnic disparities associated with initial hemodialysis access. JAMA Surg 2015;150: 529-36. 22. Dember LM, Beck GJ, Allon M, Delmez JA, Dixon BS, Greenberg A, et al. Effect of clopidogrel on early failure of arteriovenous fistulas for hemodialysis: a randomized controlled trial. JAMA 2008;299:2164-71. Submitted Nov 29, 2018; accepted Mar 27, 2019.
Additional material for this article may be found online at www.jvascsurg.org.
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Supplementary Table vascular measurements Intraoperative category Axillary vein preoperative diameter, mm
I
(online
OSP
only). Preoperative Recruited with RA P value
6.5 (6.1-6.9) 6.3 (5.7-7.0)
.76
Supplementary Table II (online only). Outcomes of patients in the recruited with regional anesthesia (RA) group scheduled for arteriovenous graft (AVG)
Intraoperative category Follow-up, months
Cephalic vein preoperative diameter, mm
Recruited OSP (n ¼ 80 with RA [72%]) (n ¼ 31 [28%]) P value 22 (19-25)
Days to first cannulationa 115 (96-134)
Proximal brachium
3.5 (3.3-3.8) 2.4 (2.1-2.8)
<.001
Primary failure
Upper third of brachium
3.4 (3.1-3.7) 2.1 (1.8-2.5)
<.001
Mid brachium
3.2 (2.9-3.5) 1.9 (1.6-2.3)
<.001
Freedom from revision or 32 (40) thrombosis
Distal three-fourths of brachium
3.2 (2.9-3.5) 1.8 (1.5-2.1)
<.001
Distal brachium
3.4 (3.1-3.7) 2.1 (1.7-2.5)
<.001
Proximal forearm
2.9 (2.6-3.1) 1.9 (1.6-2.2)
<.001
Mid forearm
2.6 (2.3-2.8) 1.7 (1.4-2.0)
<.001
Distal forearm
2.4 (2.1-2.6) 1.7 (1.4-2.0)
.001
Median antecubital vein 2.0 (1.7-2.3) 1.5 (1.1-1.8) preoperative diameter, mm
.01
Basilic vein preoperative diameter, mm Proximal brachium
4.2 (3.9-4.4) 3.6 (3.2-4.00)
.009
Mid brachium
3.9 (3.7-4.2) 3.3 (3.0-3.6)
.003
Distal brachium
3.6 (3.4-3.9) 2.9 (2.6-3.2)
Proximal forearm
2.2 (2.0-2.4) 1.5 (1.3-1.7)
<.001
Mid forearm
2.1 (1.8-2.3) 1.3 (1.1-1.5)
<.001
Distal forearm
1.8 (1.6-2.0) 1.2 (1.0-1.4)
<.001
Brachial artery diameter, mm 4.6 (4.5-4.8) 4.6 (4.4-4.8)
.003
.68
Radial artery diameter, mm
2.3 (2.2-2.4) 2.3 (2.2-2.4)
.47
Ulnar artery diameter, mm
2.2 (1.9-2.6) 2.0 (1.8-2.1)
.14
Anastomotic site
3.7 (3.5-3.9) 2.4 (2.1-2.7)
<.001
Distal vein segment 1
3.6 (3.4-3.8) 2.4 (2.1-2.7)
<.001
Distal vein segment 2
3.7 (3.5-4.0) 2.6 (2.2-2.9)
<.001
4.1 (3.9-4.4) 3.6 (3.2-3.9)
.005
Target vein diameter, mm
Donor artery diameter, mm
OSP, Original surgical plan; RA, regional anesthesia. Variables are presented as mean (95% confidence interval).
3 (4)
22 (17-26)
.79
115 (87-143)
.97
0
.27
14 (45)
.62
Primary assisted patency
51 (64)
17 (55)
.39
Secondary patency
74 (93)
29 (94)
.85
IR
17 (21)
11 (35)
OR
8 (10)
2 (6)
IR and OR
5 (6)
1 (3)
9 (11)
5 (17)
Types of revision
Deceased
.44
.46
IR, Interventional radiology; OR, operating room; OSP, original surgical plan. Categorical variables are presented as number (%). Continuous variables are presented as mean (95% confidence interval). a Includes only patients on hemodialysis before arteriovenous fistula creation (OSP, n ¼ 41; recruited with RA, n ¼ 18).