assessment & improvement strategies
Flu, H.C.
Citation
Flu, H. C. (2010, March 24). Quality of provided care in vascular surgery : outcome assessment & improvement strategies. Retrieved from
https://hdl.handle.net/1887/15124
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Chapter 4
The Effect of Implementation of Optimised Care Protocol on the Outcome of Arteriovenous Haemodialysis Access Surgery
Flu HC, Breslau PJ, Krol-van Straaten MJ, Hamming JF, Lardenoye JHP
Journal of Vascular Surgery 2008;48:659-68
ABSTRACT
Background: The long term patency of arteriovenous fistulas (AVF) and arteriovenous grafts (AVGs) suffers from a high incidence of primary failure, due to early thrombosis, myointimal hyperplasia at the venous access site or failure to mature. A multidisciplinary meeting in vascular access surgery was initiated to optimize the timing, indication, type of intervention and the logistics of AVFs/AVGs during the pre - and postoperative period.
Objective: The aim of this study was to evaluate the influence of a new optimised care protocol outlined in a multidisciplinary meeting in vascular access surgery on the inci- dence of revisions (surgical and endovascular) and patency rates.
Materials and methods: This protocol for vascular access surgery of AVFs/AVGs for haemodialysis was introduced in January 2004. It was initiated with the presence of the vascular surgeons, nephrologists, interventional radiologists, dialyse nurses and the ultrasound technicians. Every patient who needed an AVF/AVG because of long-term treatment of chronic renal failure or awaiting kidney transplantation, or who needed a revision of an AVF/AVG was discussed in this meeting. Two groups were compared.
Group I, patients treated with an AVF/AVG before the introduction of the new protocol (2001 and 2002) and group II, patients treated with an AVF/AVG after the introduction of the new optimised care protocol (2004 and 2005). Both groups were followed-up after 12 months.
Results: 146 AVFs/AVGs were attempted during the study period. A total of 111 postop- erative revisions (group I: n=63; surgical n=60; radiology n=3 and group II: n=48; surgical n=23; radiology n=25) were performed to restore primary and secondary patency.
Compared to group II significantly more segmental access replacements (P<0.03) oc- curred in group I. Significantly less surgical revisions (P<0.02) and more endovascular balloon angioplasties (P<0.01) occurred in group II. Significantly higher cumulative primary - and secondary patency rates of all AVFs/AVGs (P<0.01), radial-cephalic direct wrist AVFs (P<0.01) and brachial-cephalic forearm looped transposition AVGs (P<0.01) were achieved in group II after follow-up.
Conclusion: The new protocol outlined in a bimonthly multidisciplinary meeting for vas- cular access surgery of AVFs/AVGs for haemodialysis resulted in more effective logistics according to pre-operative diagnostics and operation. More importantly, a significant increase of endovascular balloon angioplasties and a significant decrease of surgical revisions was observed, which resulted in less morbidity for the individual patient. Also, higher primary – and secondary patency were achieved after the introduction of the new optimised care protocol.
INTRODUCTION
Arteriovenous fistulas (AVFs) and arteriovenous grafts (AVGs) are the methods of long- term haemodialysis (HD) access for patients suffering from end-stage renal disease (ESRD). The ideal AVFs/AVGs should be durable, pose minimal risk for infection, and require few revisions to maintain ongoing functional patency. However, AVFs and AVGs suffer from a high incidence of primary failure, due to early thrombosis, myointimal hyperplasia or failure to mature. Vascular access complications substantially contribute to morbidity and hospitalization in haemodialysis patients. Estimates of primary failure, primary patency (PP) and secondary patency (SP) vary considerably. Early thrombosis and failure to mature are significant problems occurring in 20% to 50% of AVFs 1.
The prospective identification of patients who are prone to early AVF/AVG failure is of high clinical importance. Especially these patients may benefit from a multidisciplinary approach in which all factors contributing to access graft failure are assessed. More- over, a standardised pre-operative diagnostic work-up, specific treatment guidelines considering graft type and location and pre-determined postoperative follow-up with a standardised surveillance protocol could be of value in optimising access graft pa- tency and thereby reducing patient morbidity. In 1997, the National Kidney Foundation Disease Outcome Quality Initiative (NKF-DOQI) Work Group and European guidelines for vascular access represented a comprehensive consensus statement using evidence- based methods to provide guidelines to optimize care of patients with ESRD 2-4. The National Vascular Access Improvement Initiative (NVAII) statement recommends a multidisciplinary implementation of protocol-driven surveillance programs for early detection and treatment of failing vascular access conduits 5. Several studies in literature have evaluated individual aspects of these K/DOQI guidelines such as comprehensive follow-up programs to enhance maturation or standard pre-operative work-up with du- plex ultrasound examination (DUE) 6-17. However, the implementation of a standardized protocol with emphasis on pre-operative work-up and postoperative surveillance em- bedded in a bimonthly multidisciplinary meeting on access graft surveillance has been reported scarcely. In the present study we evaluate the effectiveness of a predetermined Optimised Care Protocol (OCP) monitored in a bimonthly multidisciplinary meeting for vascular access surgery of AVFs and AVGs for haemodialysis which was introduced in January 2004. Therefore, the objective of the present study was (1) to evaluate the incidence of surgical and endovascular revisions and (2) to compare the primary - and secondary patency rates between the historical control group and the group treated using the OCP.
MATERIALS AND METHODS
Patient demographic characteristics
Patient characteristics and medical history (cardiac disease, pulmonary disease, cerebral disease, diabetes mellitus, hypertension, hyperlipidaemia and age) were collected prospectively during their admission intake and classified according to the Society of Vascular Surgery/North American Chapter, International Society of Cardiovascular Surgery (SVS-ISCVS) standards 18-20 and graded in severity. The American Society of Anaesthesiologists (ASA) classification 21 of patients was determined according to their general condition. The primary cause of ESRD (diabetic, hypertension, medication abuse such as analgesic/ciclosporine/lithium, obstructive nephropathy and collagen vascular diseases) were registered and are listed combined with the other patient characteristics in Table 1.
Study period and follow-up
A retrospective observational clinical review was conducted of data for patients referred for permanent HD access to the vascular surgery practice in a single major dialysis centre, at the Haga Hospital of The Hague, the Netherlands. Results of dialysis access procedures were compared between two periods: January 2001 -December 2002 (follow-up till December 2003: maximum one year) vs. January 2004 - December 2005 (follow-up till December 2006: maximum one year). The AVFs/AVGs initiated in the later group were after institution of a new OCP (January 2004) outlined in a multidisciplinary bimonthly meeting (every other week) for planning therapy for these patients. Since then all patients with indication of vascular access surgery (primary surgery or a revi- sion) were evaluated according to this protocol and assessed in this meeting in order to optimize patient outcome. Important to stress is that the same amount of patients were dependent on dialysis at the time of access placement during these both periods. AVFs/
AVGs performed in 2003 were excluded because during this year the new protocol was not in practice, therefore this year was used as independent follow-up year of the AVFs/
AVGs performed in January 2001 -December 2002.
The Optimised Care Protocol
Every patient who will receive an AVF/AVG because of long-term treatment of chronic renal failure or awaiting kidney transplantation, or who will receive a revision of an AVF/
AVG was evaluated according to our new protocol outlined in a bimonthly multidis- ciplinary meeting of vascular access surgery of AVFs/AVGs for HD. In this meeting the
Table 1. Patient demographic characteristics, comorbidity risk factors and primary renal disease.
Characteristics Total
n = 146
Group I n = 72
Group II n = 74
P-value
Gender Male Female Age <55 years
Between 55 to 69 years Between 70 to 79 years > 80 years
82 (56) 64 (44)
26 (18) 38 (26) 59 (40) 23 (16)
35 (49) 37 (51)
13 (18) 15 (21) 38 (53) 6 (8)
47 (64) 27 (36)
13 (18) 23 (31) 21 (28) 17 (23)
0.09
0.01
ASA-classification Classification 2 Classification 3 Classification 4 Comorbidity Cardiac disease Pulmonary disease Carotid disease Diabetes mellitus Hypertension Hhyperlipidaemia Dilatating arterial disease Occlusive arterial disease SVS-ISCVS risk score (SD)
69 (47) 75 (51) 2 (1)
73 (50) 30 (21) 25 (17) 32 (22) 109 (75) 53 (36) 13 (9) 24 (16) 1.27
31 (43) 41 (57) 0 (0)
40 (56) 11 (15) 16 (22) 13 (18) 55 (76) 22 (31) 6 (8) 11 (15) 1.34 (0.44)
38 (51) 34 (46) 2 (3)
33 (45) 19 (26) 9 (12) 19 (26) 54 (73) 31 (42) 7 (9) 13 (18) 1.22 (0.41)
0.19
0.25 0.15 0.13 0.32 0.71 0.17 0.81 0.82 0.08 Primary renal disease
Diabetic nephropathy Hypertension nephropathy Glomerulonephritis Polycystic renal disease Nephrosclerosis Medication
Obstructive nephropathy Collagen vascular disease Miscellaneous/unknown
14 (10) 11 (8) 20 (14) 16 (11) 36 (25) 10 (7) 6 (4) 6 (4) 27 (18)
6 (8) 5 (7) 10 (14) 8 (11) 18 (25) 7 (10) 1 (1) 6 (8) 11 (15)
8 (11) 6 (8) 10 (14) 8 (11) 18 (24) 3 (4) 5 (7) 0 (0) 16 (22)
0.17
Data are presented as n and (%), unless otherwise specified.
SD=standard deviation; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year); Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year); AVF=arteriovenous fistula; AVG=arteriovenous graft; ASA=American society of anaesthesiologists 21; SVS-ISCVS=the Society of Vascular Surgery/North American Chapter, International Society of Cardiovascular surgery 18-20.
vascular surgeons, nephrologists, interventional radiologists, the ultrasound technicians and dialyse nurses participated and assessed the medical records and dialysis charts of these patients in a structured standardized manner using a pre-fixed individual patient work sheet. The purpose of this protocol was (1) to optimize and standardize pre-operative work-up with emphasis on access site selection (2) to optimize postopera- tive surveillance in order to detect and treat potential access graft failure early (3) to optimize communication among all specialist involved in treatment of vascular access graft patients.
Preoperative work-up
Preoperative standardised work-up included careful assessment of the vascular anato- my. Arterial examination included pulse assessment, performance of the Allen test, and bilateral upper extremity blood pressure measurement. Venous examination included inspection and palpation of the cephalic vein at the wrist and upper arm and the basilica vein at the elbow, with a tourniquet in place. Both arms were evaluated with DUE by an experienced sonographer. The diameter of the radial artery at the wrist and the brachial artery immediately above the antecubital fossa were determined. Veins were assessed on the adequacy of the superficial vein, on ease of compressibility, thickness continuity and depth below the skin. The evaluation of stenosis or occlusion of the deep venous system (axillary and subclavian veins) was registered. The minimum acceptable thresh- old for internal diameters for arteries and veins were set at ≥ 2.0 mm according to the guidelines of NKF-DOQI 2-4, the Vascular Access Society 22, 23 and overall HD literature 6, 7,
24. Measurements of vein diameter were recorded at representative sites, including wrist, distal forearm, mid-forearm, proximal forearm, antecubital fossa, distal upper arm, mid- upper arm and proximal upper arm. In case of a suspected inflow stenosis or occlusion, contrast angiography was used to optimize preoperative work-up. Venography was per- formed selectively if no suitable vein was identified at DUE. There was more thorough pre-operative evaluation concerning standardized DUE and angioplasty. The protocol we used for access site and type is autogenous before prosthetic and distal arm before proximal to conserve sites. If technically possible, the non-dominant extremity was used for construction of the AVF/AVG, however the final decision was ultimately determined according to size and quality of the vessels, it was made on the basis of results of clinical examination and DUE.
Important to be mentioned about the later period is the fact that there was no timelier referral. Patients were not referred earlier for HD access in their disease course, and the waiting time from referral to operation was the same.
Arteriovenous haemodialysis access surgery
The AVF procedures were autogenous radial-cephalic direct wrist access, brachial- cephalic direct access and brachial-basilic transpositions. An end-to-side anastomosis was made with a running 6-0 or 7-0 monofilament suture between the vein and artery.
The AVG procedures were brachial-cephalic looped transposition (polytetrafluoroeth- yleen, PTFE). Also ProCol® shunts were used. All operations were performed by or under the supervision of a vascular surgeon. There was no change in surgeons or quality of surgeons during the study period. A surgical revision of a failed AVF/AVG could be a thrombectomy, a segmental access replacement, a surgical PTA, a correction of a postoperative haemorrhage or aneurysm. A PTA could also be an endovascular revision performed by the interventional radiologist. Percutaneous thrombectomy, stenting or placement of stent grafts were not part of the protocol, however all thrombectomies were performed surgically. All operations were performed under local, regional or gen- eral anaesthesia. AVFs were allowed at least 6 weeks to develop before venepuncture for haemodialysis. An AVF was considered to have matured when the diameter of the vein was sufficient to provide adequate dialysis. Data of the surgical interventions are listed in Table III. Because of the fact that the same experienced vascular surgeons operated in both periods, the quality of surgeons and executed operations did not change during this study period. The same holds for the interventional radiologists and the quality of their expertise. Also no differences existed in type of referral patterns, operation room facilities, reimbursement patterns.
Postoperative surveillance
As listed in Figure 1, a more intensive use of surveillance occurred in the new OCP study period. The first postoperative visit was at the dialysis centre for examination, suture removal, and patient education after one week. The patient underwent directed physi- cal examination for signs of impending thrombosis or lack of maturation, during regular visits at the dialysis centre three times a week. The problems that would initiate an urgent assessment were: (1) high venous pressures (> 250 mmHg at a 400 mL/min pump speed); (2) difficult cannulation; and (3) an AVF flow rate < 400-500 mL/min or an AVG flow rate < 600 mL/min, (4) minimal thrill with low flow suspected, (5) minimal increase in vein dilatation, (6) increasing arm edema, (7) barely audible or highly pitched bruit or (8) physical signs of suspected stenosis after careful palpation of the entire length of the AVF/AVG.
In case of susceptive AVF/AVG failure, as mentioned above, DUE was performed to evaluate stenosis before occlusion, and the AVF/AVG was automatically according OCP earlier re-introduced at the multidisciplinary meeting for a possible surgical or endovas-
cular revision. The duplex results were not validated by fistulography in all cases as per protocol. Criteria for a hemodynamically significant stenosis (≥50% reduction in luminal diameter) were based on guidelines of previously published reports 13, 24, 25. If stenosis in case of maturation failure, conduit stenosis and native arterial stenosis, in the region of the venous anastomosis or anywhere along the draining vein or the central veins was detected, PTA was the treatment of choice. It was performed with a 5-8 mm diameter balloon catheter.
Figure 1. Flow chart, multidisciplinary meeting and follow-up of arteriovenous haemodialysis access (AVF/AVG).
patient with ESRD / w aiting for kidney transplant primary AVF/AVG
pre-operative evaluation nephrologists
- complete the initial medical evaluation
- responsible for management of the comorbid conditions ultrasound technicians (duplex scanning results) - diameter of the artery
- adequacy of the superficial vein
- evaluation of stenosis or occlusion of the deep venous system - velocity of the bloodflow
operation: AVF/AVG location
- non-dominant extremity, if technically possible - from distal to proximal, to preserve proximal sites - minimum vein diameter required 2 mm or higher conduit
- AVF: autogenous (preferably) - AVG: PTFE graft maturation AVF - 6 w eeks maturation AVG
- directly after patient education and suture removal
dialysis centre: detection of AVF/AVG problems dialyse nurses / nephrologists / vascular surgeon - high venous pressures (> 250 mmHg at a 400 mL/min pump
speed) - difficult cannulation
- AVF flow rate < 400-500 mL/min or an AVG flow rate < 600 mL/min
- minimall thrill w ith low flow suspected - minimal increase in vein dilatation - increasing arm edema
- barely audible or highly pitched bruit
- physical signs of suspected stenosis after careful palpation of the antire length of the AVF/AVG
adverse event ultrasound technicians (duplex scanning results) - diameter of the artery
- adequacy of the superficial vein
- evaluation of stenosis or occlusion of the deep venous system - velocity of the bloodflow
multidisciplinary meeting vascular surgeons
- surgical revision or new AVF/AVG nephrologists
interventional radiologist - angiography
in case of evaluation AVF/AVG
- stenosis (>50% reduction in luminal diameter) w ithout thrombosis w as detected in the region of the venous anastomosis or anyw here along the draining vein or the central veins => PTA
ultrasound technicians (duplex scanning results) dialyse nurses
revision AVF/AVG
AVF=arteriovenous fistula; AVG=arteriovenous graft; PTA=percutaneous transluminal angioplasty.
Definitions of patency and success of the AVF/AVG
Definitions of patency were those recommended by the Committee on Reporting Stan- dards for Arteriovenous Access of the Society for Vascular Surgery and the American Association for Vascular Surgery 18-20. Technical success was defined as the presence of a thrill on palpation or bruit on auscultation 24-h post operatively. The primary patency (PP) and secondary patency (SP) rates (including initial failure to mature in 6 weeks) were determined at regular intervals: 1 month, 3 months, 6 months, 9 months and 12 months.
Primary patency was described as the interval from the time of access placement until the first intervention designed to maintain or re-establish patency, access thrombosis, or the time of measurement of patency. Secondary patency was described as the interval from the time of access placement until access abandonment, thrombosis, or the time of patency measurement including intervening manipulations (surgical or endovascular interventions) designed to re-establish functionality in thrombosed access. Inadequate maturation was defined as insufficient access flow to maintain dialysis or the unavail- ability to cannulate an AVF, if required, at 6 weeks after surgery. AVFs that never matured were included in the patency rates.
Registration and statistical analysis
By using Access (Office XP from Microsoft) patient information was entered on a spe- cifically designed computerized analysis program for haemodialysis patients. Statistical analyses were performed through a computerized software package, using Excel (Office XP from Microsoft) and SPSS 12.01 for Windows. Follow-up was complete in all patients (mean 12 months). Using the Fisher’s exact test, Student’s T-test or Chi-square test as- sessed differences between both groups for a given parameter. The postoperative revi- sions were analysed with the Mann-Whitney U-Test. The Kaplan-Meier survival method was used to calculate the time curve of the cumulative primary and secondary patency at 1-, 3-, 6-, 9- and 12-months after AVF/AVG creation. The log-rank test was used for comparison of the primary - and secondary patency rates. For all statistical analyses, a P-value <0.05 was considered to be statistically significant.
RESULTS
Patient demographic characteristics, AVFs and AVGs
The HD population at the Haga Hospital at any time totals approximately 80 patients.
During the two study periods, 146 primary access procedures, primary AVFs (n=91, 62%)
and AVGs (n=55, 38%) were performed (male n=82, 56% and female n=64, 44%) and 111 additional revisions. Fifty-six of all AVFs (62%) were created in women. There were no significant differences with regard to ASA-classification, comorbidity and causes of renal failure. Most of these patients (56%) were 70 years of age or older. In the study group (group II) patients were significantly more likely to be older than 80 years. Table 1 shows comparisons of demographics, comorbidity and primary renal disease. No patients were lost to follow-up.
Group I: historical control group
This historical control group consisted of 72 access procedures (49%), AVFs (n=41, 57%) and AVGs (n=31, 43%), performed between January 2001 and December 2002 (follow- up till 2003). Twenty-one of all AVFs (51%) were created in women. A total of 60 surgical revisions (95%) and 3 radiological PTAs (5%) were carried out to maintain function in 46 AVFs/AVGs (64%). This resulted in a total revision percentage of 88. Twenty-six AVFs/
AVGs (36%) never underwent a revision by a surgeon or an interventional radiologist.
The cumulative primary patency rates, obtained by Kaplan-Meier analysis, of all AVFs/
AVGs at 1-, 3-, 6-, 9- and 12-months were 69%, 50%, 40%, 36% and 36% respectively.
The cumulative secondary patency rates of all AVFs/AVGs were 76%, 61%, 54%, 53% and 47% respectively. The summary of the AVFs/AVGs, postoperative revisions, cumulative primary - and secondary patency results are listed in Table 2-4 and outlined in Figure 3 and 4.
Group II: study group
This study group consisted of 74 access procedures (51%), AVFs (n=50, 68%) and AVGs (n=24, 32%), performed between January 2004 and December 2005 (follow-up till 2006).
Thirty-five of all AVFs (70%) were created in women. A total of 23 surgical revisions (48%) and 25 radiological PTAs (52%) were carried out to maintain function in 38 AVFs/AVGs (50%). This resulted in a total revision percentage of 63. Thirty-eight AVFs/AVGs (50%) never underwent a revision by a surgeon or an intervention radiologist. The cumulative primary patency rates, obtained by Kaplan-Meier analysis, of all AVFs/AVGs at 1-, 3-, 6-, 9- and 12-months were 89%, 74%, 61%, 54% and 49% respectively. The cumulative secondary patency rates of all AVFs/AVGs were 92%, 82%, 77%, 74% and 70% respec- tively. The summary of the AVFs/AVGs, postoperative revisions, cumulative primary - and secondary patency results are listed in Table 2-4 and outlined in Figure 3 and 4.
Table 2. Summary of all AVFs (n=146): Group I (n=72) and Group II (n=74).
Access surgery Total
n = 146
Group I n = 72
Group II n = 74
P-value
Arteriouvenous haemodialysis access AVF
Brachial-cephalic upper arm direct access Brachial-basilic upper arm transposition Radial-cephalic direct wrist access (brescia-cimino) AVG
Brachial-cephalic looped transposition ProCol® shunt
Material used in AVFs/AVGs PTFE
ProCol® Autogenous
2 (1) 6 (4) 83 (57)
53 (36) 2 (1)
53 (36) 2 (1) 91 (62)
0 (0) 0 (0) 41 (57)
30 (42) 1 (1)
30 (42) 1 (1) 41 (57)
2 (3) 6 (8) 42 (57)
23 (31) 1 (1)
23 (31) 1 (1) 50 (68)
0.06
0.41
Data are presented as n and (%), unless otherwise specified.
AVF=arteriovenous fistula; AVG=arteriovenous graft; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year).
Table 3. Total revisions (n=111) of AVFs in Group I (n=63) and Group II (n=48).
Revisions Total
n = 111
Group I n = 63
Group II n = 48
P-value
Revisions surgical (by surgeon) Thrombectomy
Segmental access replacement Balloon angioplasty
Bleeding Aneurysm Total
Revisions endovascular (by intervention radiologist) Balloon angioplasty Total revisions
36 (0,0,4) 18 (0,0,4) 25 (0,0,4) 1 (0,0,1) 3 (0,0,2) 83 (0,0,9)
28 (0,0,5) 111 (0,0,9)
25 (0,0,4) 15 (0,0,4) 16 (0,0,4) 1 (0,0,1) 3 (0,0,2) 60 (0,0,9)
3 (0,0,2) 63 (0,0,9)
11 (0,0,3) 3 (0,0,2) 9 (0,0,3) 0 (0,0,0) 0 (0,0,0) 23 (0,0,6)
25 (0,0,5) 48 (0,0,6)
0.08 0.03 0.26 0.31 0.15 0.02
0.01 0.89 Data are presented as n (median, minimum, maximum), unless otherwise specified. AVF=arteriovenous fistula; AVG=arteriovenous graft; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year).
Table 4. Cumulative life-table primary - and secondary patency rates of all AVFs and AVGs (n=146) in Group I (n=72) and group II (n=74), subdivided in: radial-cephalic direct wrist access (brescia- cimino) AVFs (n=83) in group I (n=41) and Group II (n=42) and all brachial-cephalic forearm looped transposition AVGs (n=53) in Group I (n=30) and Group II (n=23).
1 month 3 months 6 months 9 months 12 months All AVFs and AVGs (n=146)
Primary patency All
Group I Group II
Secondary patency All
Group I Group II
146 (79) 72 (69) 74 (89)
146 (84) 72 (76) 74 (92)
116 (62) 50 (50) 66 (74)
123 (72) 55 (61) 68 (82)
91 (51) 36 (40) 55 (61)
105 (66) 44 (54) 61 (77)
74 (45) 29 (36) 45 (54)
96 (64) 39 (53) 57 (74)
66 (42) 26 (36) 40 (49)
93 (59) 38 (47) 55 (70) AVF: radial-cephalic direct wrist
access, brescia-cimino (n=83) Primary patency
All Group I Group II
Secondary patency All
Group I Group II
83 (74) 41 (63) 42 (83)
83 (76) 41 (66) 42 (86)
61 (57) 26 (44) 35 (69)
63 (59) 27 (46) 36 (72)
47 (45) 18 (34) 29 (55)
49 (51) 19 (37) 30 (64)
37 (41) 14 (32) 23 (50)
42 (49) 15 (37) 27 (62)
34 (37) 13 (32) 21 (43)
41 (46) 15 (37) 26 (55) AVG: brachial-cephalic forearm
looped transposition (n=53) Primary patency
All Group I Group II
Secondary patency All
Group I Group II
53 (87) 30 (80) 23 (96)
53 (94) 30 (90) 23 (100)
46 (68) 24 (60) 22 (78)
50 (87) 27 (80) 23 (96)
36 (59) 18 (50) 18 (70)
46 (85) 24 (77) 22 (96)
31 (49) 15 (43) 16 (57)
45 (81) 23 (73) 22 (91)
26 (49) 13 (43) 13 (57)
43 (74) 22 (60) 21 (91) Data are presented as n, at risk and (%), unless otherwise specified.
AVF=arteriovenous fistula; AVG=arteriovenous graft; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year).
Figure 2. Summary of revisions in Group I (n=63, 57%) and Group II (n=48, 43%).
Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year); PTA=percutaneous transluminal angioplasty.
0 10 20 30 40 50 60 70 80 90 100
group I group II
P<0.09 P<0.03 P<0.26 P<0.01
P<0.02
segmental access replacements
surgical PTA
endovascular PTA thrombectomy
P<0.89
total revisions
total surgical revisions
%
Figure 3. Kaplan-Meier curve of the cumulative secondary patency rates of all radial-cephalic direct wrist access (brescia-cimino) AVFs (n=83) in Group I (n=41) and Group II (n=42).
Group II: SP 26 (55)
Group I: SP 15 (37) P<0.01
Data are presented as n, at risk and (%), unless otherwise specified.
SP=secondary patency; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year).
Comparison group I and group II
No significantly differences were found between the two groups regarding sort of AVFs/
AVGs (P<0.06) and material used in AVFs/AVGs (P<0.41), as listed in Table 2. Regarding to surgical revisions, as listed in Figure 2, there was a statistically significant difference in segmental access replacements (P<0.03) in favour of group II. This resulted in a decrease of the total of surgical revisions (P<0.02) and an increase of endovascular PTAs per- formed by the interventional radiologist (P<0.01). A significant difference was achieved in primary patency rates of all AVFs/AVGs (group I: 36% versus group II: 49%, P<0.01), the radial-cephalic direct wrist access AVFs (group I: 32% versus group II: 43%, P<0.01) and the brachial-cephalic looped transposition AVGs (group I: 43% and group II: 57%, P<0.01) after one year follow-up. Concerning the secondary patency rates, a significant difference was achieved in all AVFs/AVGs (group I: 47% versus group II: 70%, P<0.01), the radial-cephalic direct wrist access AVFs (group I: 37% versus group II: 55%, P<0.01) and the brachial-cephalic looped transposition AVGs (group I: 60% and group II: 91%, P<0.01) after one year follow-up, as listed in Table 2-4 and outlined in Figure 3 and 4.
Figure 4. Kaplan-Meier curve of the cumulative secondary patency rates of all brachial-cephalic forearm looped transposition AVGs (n=53) in Group I (n=30) and Group II (n=23).
Group II: SP 21 (91)
Group I: SP 22 (60) P<0.01
Data are presented as n, at risk and (%), unless otherwise specified.
SP=secondary patency; Group I=admissions because of treatment with a primary AVF/AVG in the year 2001 and 2002 (follow-up 2001 till 2003: mean 1 year). Group II=admissions because of treatment with a primary AVF/AVG in the year 2004 and 2005 (follow-up 2004 till 2006: mean 1 year).
DISCUSSION
Arteriovenous haemodialysis access surgery is complex. The multidisciplinary nature, preoperative work up of the patient, timing of the operation, selection of the vascular access site, surgical technique, postoperative monitoring and early detection of AVF/
AVG failure are all important aspects to assure an uninterrupted haemodialysis access and a good long-term survival. In this study, the effect of newly introduced protocol outlined in a regular bimonthly multidisciplinary meeting on the long-term patency of AVFs/AVGs was assessed. After the initiation of this protocol in January 2004, all patients with an indication of vascular access placement or with undercurrent complications or access problems were discussed according to a new protocol outlined in this meet- ing attended by the vascular surgeons, nephrologists, interventional radiologists, the ultrasound technicians and dialysis nurses. To achieve the best outcome for every indi- vidual patient, the team agreed on a set of goals, collaborate closely and maintain good communication. The medical records and dialysis charts registered in a standardised manner were discussed and policy was made. This protocol ensured that every patient was analysed in the most optimal way with the best interpretation of medical history, physical examination and additional diagnostic imaging.
In this study, the overall primary and secondary 1-year patency rates improved from 36% to 49% and from 47% to 70% respectively. The primary and secondary 1-year patency rates of the radial-cephalic direct wrist access (AVF) improved from 32% to 43% and from 37% to 55% respectively. Furthermore the primary and secondary 1-year patency rates of the brachial-cephalic forearm looped transposition (AVG) improved from 43% to 57% and from 60% to 91% respectively. When comparing primary and sec- ondary 1-year patency rates (all AVFs/AVGs, AVFs and AVGs) between the two groups, a significant difference in favour of group II was seen. They are quite reasonable and meet NKF-DOQI guidelines 2-4, they are in accordance and sometimes compare favourably with the results of others 26-33.
The results of this study indicate that evaluating individual patients with vascular ac- cess indications or postoperative vascular access complications according to a new strict OCP in a regular bimonthly multidisciplinary meeting with all specialists surrounding the vascular access patient improves vascular access patency significantly. Although the total of all revisions, surgical and endovascular, did not differ significantly, a significantly decrease of all of surgical revisions and an increase of all PTAs was achieved after the implementation of this new OCP embedded in the bimonthly multidisciplinary meeting.
The greater use of PTA may reflect changes in practice and the identification of AVF/
AVG stenosis prior to thrombosis through better monitoring of access function in the dialysis centre. These changes in revisions reduce morbidity, shorten the hospitalization period, and decrease the cost of haemodialysis treatment for the individual patient and
health care in general. This is a cohort study without significant differences between both groups with regard to risk factors of AVF/AVG failure.
The improved outcome of vascular access function after the initiation of the OCP out- lined in the biweekly multidisciplinary meeting in January 2004 is presumably caused by several factors. First, a consistent analysis of the medical history and physical examina- tion of every single patient in a strict manner using a prefixed individual patient data sheet during the plenary multidisciplinary meeting ensured that no vital information was lost and that potential causes of future vascular access graft failure such as central venous thrombosis were assessed meticulously. If arterial inflow or venous outflow re- duction was suspected, additional imaging studies were conducted, ultimately striving for a complete pre-operative work-up.
Second, a careful selection of access site in patients for an AVF or AVG is of the ut- most importance. In the period after January 2004, strict minimal diameters of arterial inflow and venous outflow segments, registered by DUE in every patient preoperatively, were implemented as discussed previously. Furthermore, potential venous stenosis more downstream in the venous outflow segment was considered an absolute contra- indication for AVF placement distally.
Third, the communis opinio among the participants of the meeting was to create an arteriovenous fistula whenever possible according to the protocol described above and in Figure 1. This is in line with literature in which autogenous cephalic vein remains the superior conduit when compared with a prosthetic graft 32. The Vascular Access Work Group of the National Kidney Foundation (NKF-Dialysis Outcomes Quality Initiative, or NKF-DOQI) concluded that the proportion of primary AVFs constructed in all new patients diagnosed with ESRD entering haemodialysis should be at least 40% 2-4. Vein mapping resulted in an addition of upper arm basilic vein transposition and a slightly higher forearm AVF rate. This resulted in our dialysis unit in an increased prevalence of patients undergoing HD with an AVF during the two observational periods from 57% to 68%, surpassing the guideline mandated by the NKF-DOQI and equal to the results of study by Allon et al 34.
Fourth, the NKF-DOQI guidelines also indicate that outcomes for haemodialysis pa- tients could be significantly improved by detecting access dysfunction before access thrombosis. Consistent follow-up of haemodialysis patients with vascular access sites is the best way to diagnose problems early. The patient underwent directed physical examination for signs of impending thrombosis or lack of maturation, during regular visits at the dialysis centre three times a week. This allows the best chance of rescuing an AVF or AVG rather than creating a new one. The rescue approach reduces morbidity and decreases the cost of haemodialysis treatment. In our opinion, assessing individual patients according to this OCP outlined in a bimonthly multidisciplinary meeting with detailed analysis of decreased dialysis flow dynamics in a strict manner is paramount to
detect and treat vascular access stenosis. In this way, the incidence of acute thromboses can be reduced ultimately resulting in increased access patencies.
CONCLUSION
In this study we demonstrated significant increased primary and secondary AVF/AVG patency rates after initiation of a new OCP. Discussing patients on a regular basis in a strict manner according to a predetermined protocol resulted in significant increased endovascular revisions and significant decreased surgical revisions. Therefore, this optimised care protocol outlined in a multidisciplinary meeting with all specialists sur- rounding the vascular access patient reduces patient morbidity and is of value in order to strive for the highest possible quality of care.
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