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Saudi Journal of Kidney Diseases and Transplantation
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Table of Contents   
ORIGINAL ARTICLE  
Year : 2019  |  Volume : 30  |  Issue : 1  |  Page : 39-44
Vascular access outcome with a dedicated vascular team based approach


1 King Abdullah Hemodialysis Center, South Riyadh, Riyadh, Saudi Arabia
2 King Abdul Aziz Medical City, Riyadh, Saudi Arabia
3 King Abdul Aziz Medical City; Department of Medicine, King Saud Bin Abdul-Aziz University for Health Sciences, Riyadh, Saudi Arabia

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Date of Submission17-Sep-2018
Date of Acceptance17-Sep-2018
Date of Web Publication26-Feb-2019
 

   Abstract 


The objective of this study is to determine the impact of a dedicated vascular team in the early detection of complications and improvement of vascular access patency. A dedicated vascular access team comprised four dialysis nurses, a vascular access coordinator and led by a physician. They were assigned for the surveillance and care of all vascular accesses. The team presented problematic cases in the regular quality meeting with documentation of access blood flow, dynamic venous pressure, findings of hematoma, prolonged bleeding, swelling, low arterial pressures, steal syndrome, recirculation studies and dialysis adequacy. In case of failed recirculation or persistently elevated dynamic venous pressure, further evaluation was done either a fistulogram or review by a vascular surgeon. A total of 226 problematic vascular access cases were detected during the study (January 2014 to October 2017). The majority were in 41–70 years age group. A total of 248 referrals were given. Two hundred cases were referred for fistulogram, but it was performed in 188 patients. Vascular access stenosis was detected in 153 patients (81.3%) and angioplasty was performed in 137 (89.5%) of these patients. Fifteen (9.8%) patients were managed conservatively and one patient refused angioplasty. The 15 cases managed conservatively continued to work normally. One patient who refused to angioplasty later clotted his fistula during the follow-up period. Out of 41 cases who were totally noncompliant to referral, nine (22%) clotted their fistula during the follow-up period. In 12 cases in whom fistulogram was requested, but the request was declined by the primary hospital, five patients (41.6%) clotted their fistulas. Subgroup analysis showed that in patients who had both failed recirculation and high venous pressure, the prevalence of stenosis was 90% and angioplasty was performed in 94.4%. In patients who had failed recirculation and low arterial pressure, stenosis was detected in 85.7% and angioplasty was performed in 100% of cases. A dedicated vascular team approach for the care of dialysis vascular access helps in early identification of complications and improve vascular access outcome.

How to cite this article:
Raza H, Hashmi M N, Dianne V, Hamza M, Hejaili F, A-Sayyari A. Vascular access outcome with a dedicated vascular team based approach. Saudi J Kidney Dis Transpl 2019;30:39-44

How to cite this URL:
Raza H, Hashmi M N, Dianne V, Hamza M, Hejaili F, A-Sayyari A. Vascular access outcome with a dedicated vascular team based approach. Saudi J Kidney Dis Transpl [serial online] 2019 [cited 2019 Mar 23];30:39-44. Available from: http://www.sjkdt.org/text.asp?2019/30/1/39/252931



   Introduction Top


Vascular access is the dialysis patient's lifeline. Currently, arteriovenous fistula (AVF) and arteriovenous graft are common forms of permanent dialysis vascular access. The maintenance of vascular access is a challenging task. The vascular accesses are prone to thrombosis, infection and other complications which can decrease the adequacy of dialysis treatment leading to under dialysis and increased hospitalizations.[1] To ensure the patency of AV access and decrease complications, regular monitoring, and surveillance is mandatory. Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines enlist some techniques for monitoring and surveillance of AV access.[2] These include physical examination of access, duplex ultrasound, blood flow monitoring, intra-access static pressure, and access recirculation. A study done by Campos et al[3] using physical examination as a monitoring technique to detect vascular access stenosis in AV fistula comparing to Doppler ultrasound and angiography showed the sensitivity of 96% and specificity of 76%.


   Materials and Methods Top


This is a prospective study on our dialysis patients from January 2014 to October 2017 at King Abdullah Hemodialysis Center, South Riyadh. A dedicated vascular access team was assigned for monitoring and surveillance of all permanent dialysis accesses in patients enrolled for dialysis at our center.

The team comprised four trained dialysis nurses with good needling skills, a vascular access coordinator and was headed by a physician. The team was responsible for the initiation of needling of newly created accesses and also if an old access developed a complication. All problems with vascular access were reported to the team by the assigned nurses. The team reviewed the patient and necessary corrective action was taken. Problematic cases were defined as, difficulty in access needling, access hematoma, failed recirculation, development of aneurysm, failed adequacy parameters, prolonged bleeding posthemodialysis (HD), access arm swelling, high-dynamic venous pressure, and inadequate access blood flow. All such cases were discussed with the nephrologist. The vascular access team collected data on all vascular access. Recirculation studies by urea dilution method were performed quarterly during the study period. In case of failed recirculation >10% the test was repeated on two consecutive dialysis sessions and if results matched, further evaluation of access was planned. This was done to avoid error due to possible variability in calculated recirculation by urea dilution method.[4] Persistently elevated dynamic venous pressure in excess of 150 mm Hg at 200 mL/min blood flow on three HD session were evaluated by further investigations.

The vascular team presented all data on a monthly basis in the quality meetings. Special emphasis was given to the problematic cases, and a correction plan was devised in each case including the need for special investigations such as duplex ultrasound or fistulogram/ graftogram. When indicated, referral for vascular surgeon opinion was given. Records were kept of all the referrals and their outcome.


   Results Top


A total of 226 problematic vascular access cases were recorded during the study period, 115 males, and 111 females. Majority patients were in 41–70 years age group [Table 1].
Table 1: Demographic data.

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Most of the patients had major comorbidities of diabetes and hypertension [Table 2]. There was low incidence of smoking in study population.
Table 2: Associated comorbidities.

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In 226 patients, a total of 248 (91.1%) referrals were given. Of those referred, 41 missed their appointments and seven were lost to follow-up. The most common indication for referral was “failed recirculation” in 90 cases (39.8%). In 81 cases (35.7%), there was more than one abnormal parameter necessitating the referral [Table 3].
Table 3: Reasons for referral, procedure done and outcome.

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Fistulogram was considered in 200 patients and performed in 188 patients (in 12 cases primary hospital declined the request to perform fistulogram). The most frequent indication for doing a fistulogram was failed recirculation test (64 cases) More than one indication was seen in 77 cases [Table 3]. Overall vascular access stenosis was detected in 153 patients (81.4%). Of 153 cases with stenosis, angioplasty was performed in 137 patients (89.5%). The remaining 15 (9.8%) were managed conservatively and one patient refused angioplasty procedure [Table 3]. The 15 AVFs with stenosis who were managed conservatively continued to function adequately during the study period. The one patient who refused to have angioplasty clotted his AVF during the follow-up period [Table 4].
Table 4: Access clotting rate in noncompliant patients.

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Forty-one patients were noted to have abnormities and referred for further evaluation by the vascular surgeon but did not attend the appointments despite repeated requests. In this group of patients, the AVF clotting rate was 22.0% [Table 4]. Twelve patients were referred by the nephrologist for a fistulogram, but the requests were rejected. In this group of patients, the AVF clotting rate was 41.7% [Table 4]. Fifteen patients with stenosis were managed conservatively. In this group of patients, no AVF clotting was observed over the observation period. The one patient who refused angioplasty had his AVF clotted. The overall rate of clotting in this group of the patient was 21.7%.


   Discussion Top


Functioning vascular access is a lifeline of dialysis patient. Vascular access maintenance is a challenging task and involves a substantial cost as highlighted in the KDOQI guidelines.[5] As per DOPPS study 24.8% of HD hospitalizations are vascular access related.[6] Loss of patency and poor access blood flow leads to extended treatment times, under dialysis and frequent hospitalizations in dialysis patients.[1] To achieve the target of the highest patency rates a regular monitoring and surveillance program needs to be developed in each dialysis unit.[2] It is a common observation that vascular access dysfunction occurs mostly due to underlying stenosis.[7],[8] If not corrected in time it eventually leads to reduction in blood flow and is a precursor for access thrombosis.[7],[8] Several different techniques have been developed for regular monitoring and surveillance of vascular access with an aim to catch the developing stenosis in time before access failure.[2] Access flow measurement,[2],[9],[10] Doppler ultrasound,[11],[12] and static venous pressure monitoring[13],[14] are few of the surveillance tools reported in the literature.

Measurement of dynamic venous pressure as in our study is considered a monitoring strategy rather than a surveillance tool. Its utility in detecting developing stenosis at blood flow of 200 mL/min is limited as it is affected by some confounding factors.[15] A single measurement of access flow or pressures is not very helpful;[16] rather repetitive measurements are considered essential.[17],[18] It has been noted that primary patency rates are better after elective angioplasty rather than angioplasty after thrombosis (70%–85%) versus (37%–63%, respectively), especially in AV graft.[19] Recirculation phenomenon occurs when dialyzed blood travels back to the dialyzer without adequate mixing with the systemic circuit. It can be measured by ultrasound dilution or differential conductivity techniques; however, specialized equipment is required to achieve this goal.[20] Calculation of recirculation by urea dilution technique for surveillance of developing stenosis has been used in AV grafts in the past and is still considered reasonable in patients with native AV fistulas.[20] Specialized access monitoring equipment recording ultrasound dilution methods may not be available in all HD units globally.

In our study, we relied on the development of a vascular access team comprising dialysis nurses with good needling skills and supervised by a physician. All new or problematic vascular access were needled by this team. Dynamic venous pressure and arterial pressure were recorded in each HD session. Recirculation studies by urea dilution method were undertaken quarterly for all vascular accesses. An abnormal result was verified on two further occasions so as to minimize the possibility of result variability due to calculated recirculation. Persistently, high venous pressure spanning more than three sessions, recurrent arterial alarm or patients who persistently failed recirculation studies were referred for fistulogram/graftogram. Inpatients on whom despite abnormal parameters the primary hospital declined the request to perform fistulogram/ graftogram 41.6% clotted over the study period in addition one patient who refused angioplasty also clotted subsequently, suggesting that there was a high probability of stenosis present in these patients. In a study done by Schwab et al it has been demonstrated that 50%–80% of AVF thrombosis occur on previous stenosis and most of them end up in thrombosis if no action is taken.[21] Patients who had low-grade stenosis on fistulogram and were managed conservatively all continued to function well during the study period.

An interesting observation is that the incidence of stenosis on fistulogram was the highest (90%) in failed recirculation and high venous pressure subgroup. Whereas, it was 85.7% in patients with high recirculation and low-arterial pressure. This can most likely be explained by the hemodynamic changes which occur in a vascular access depending on the site of developing vascular stenosis. Out-Flow stenosis is more likely to cause high venous pressure and access recirculation. On the other hand in case of inflow stenosis, access recirculation may be effected less due to compromised blood flow. It is also our observation that patients had a high level of noncompliance with referrals and many patients needed more than one referral during the study period. In one 5 years follow-up a prospective study where a multidisciplinary team managed vascular access related complications it was reported that the AVF survival rate was 89%, 85%, and 83% at 1-, 2-, 3-years, respectively. Survival was less in PTFE graft 83%, 67%, and 51% at 1-, 2-, 3-years, respectively. The study concluded that the monitoring of vascular access by a multidisciplinary team achieved a lower rate of access thrombosis and a lower rate of hospitalization and need of catheter insertions.[22]

Limitations of our study include the use of relatively insensitive urea dilution method for determining vascular access recirculation and monitoring of dynamic venous pressure. This was due to nonavailability of specialized equipment at our facility.

In conclusion, we can say that a dedicated team approach to monitoring the vascular access in dialysis patients can help in earlier identification of developing complications and by appropriate, timely intervention one can ensure better vascular access patency rates in patients on HD. This aspect is of particular importance in satellite HD centers setting, as it can minimize hospitalization and decrease morbidity in dialysis-dependent patient population.



 
   References Top

1.
Besarab A, Asif A, Roy-Chaudhury P, Spergel LM, Ravani P. The native arteriovenous fistula in 2007. Surveillance and monitoring. J Nephrol 2007;20:656-67.  Back to cited text no. 1
    
2.
Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis 2006;48 Suppl 1:S176-247.  Back to cited text no. 2
    
3.
Campos RP, Chula DC, Perreto S, Riella MC, do Nascimento MM. Accuracy of physical examination and intra-access pressure in the detection of stenosis in hemodialysis arteriovenous fistula. Semin Dial 2008;21:269-73.  Back to cited text no. 3
    
4.
Hester RL, Curry E, Bower J. The determination of hemodialysis blood recirculation using blood urea nitrogen measurements. Am J Kidney Dis 1992;20:598-602.  Back to cited text no. 4
    
5.
NKF-K/DOQI clinical practice guidelines for vascular access. Am J Kidney Dis 2001;37: S182-238.  Back to cited text no. 5
    
6.
Rayner HC, Pisoni RL, Bommer J, et al. Mortality and hospitalization in haemodialysis patients in five European countries: Results from the dialysis outcomes and practice patterns study (DOPPS). Nephrol Dial Transplant 2004;19:108-20.  Back to cited text no. 6
    
7.
Asif A, Gadalean FN, Merrill D, et al. Inflow stenosis in arteriovenous fistulas and grafts: A multicenter, prospective study. Kidney Int 2005;67:1986-92.  Back to cited text no. 7
    
8.
Bozof R, Kats M, Barker J, Allon M. Time to symptomatic vascular stenosis at different locations in patients with arteriovenous grafts. Semin Dial 2008;21:285-8.  Back to cited text no. 8
    
9.
Besarab A. Advances in end-stage renal diseases 2000. Access monitoring methods. Blood Purif 2000;18:255-9.  Back to cited text no. 9
    
10.
Lopot F, Nejedlý B, Sulková S, Bláha J. Comparison of different techniques of hemodialysis vascular access flow evaluation. Int J Artif Organs 2003;26:1056-63.  Back to cited text no. 10
    
11.
Bacchini G, Cappello A, La Milia V, Andrulli S, Locatelli F. Color Doppler ultrasonography imaging to guide transluminal angioplasty of venous stenosis. Kidney Int 2000;58:1810-3.  Back to cited text no. 11
    
12.
Malik J, Slavikova M, Malikova H, Maskova J. Many clinically silent access stenoses can be identified by ultrasonography. J Nephrol 2002;15:661-5.  Back to cited text no. 12
    
13.
Zasuwa G, Frinak S, Besarab A, Peterson E, Yee J. Automated intravascular access pressure surveillance reduces thrombosis rates. Semin Dial 2010;23:527-35.  Back to cited text no. 13
    
14.
Frinak S, Zasuwa G, Dunfee T, Besarab A, Yee J. Dynamic venous access pressure ratio test for hemodialysis access monitoring. Am J Kidney Dis 2002;40:760-8.  Back to cited text no. 14
    
15.
Smits JH, van der Linden J, Hagen EC, et al. Graft surveillance: Venous pressure, access flow, or the combination? Kidney Int 2001; 59:1551-8.  Back to cited text no. 15
    
16.
Besarab A, Ross R, Ai-Adel F, et al. The relation of intra access pressure to flow. J Am Soc Nephrol 1995;7:483.  Back to cited text no. 16
    
17.
White JJ, Ram SJ, Jones SA, Schwab SJ, Paulson WD. Influence of luminal diameters on flow surveillance of hemodialysis grafts: Insights from a mathematical model. Clin J Am Soc Nephrol 2006;1:972-8.  Back to cited text no. 17
    
18.
Schwab SJ, Oliver MJ, Suhocki P, McCann R. Hemodialysis arteriovenous access: Detection of stenosis and response to treatment by vascular access blood flow. Kidney Int 2001; 59:358-62.  Back to cited text no. 18
    
19.
Allon M, Robbin ML. Hemodialysis vascular access monitoring: Current concepts. Hemodial Int 2009;13:153-62.  Back to cited text no. 19
    
20.
Kumbar L, Karim J, Besarab A. Surveillance and monitoring of dialysis access. Int J Nephrol 2012;2012:649735.  Back to cited text no. 20
    
21.
Schwab SJ, Raymond JR, Saeed M, Newman GE, Dennis PA, Bollinger RR. Prevention of hemodialysis fistula thrombosis. Early detection of venous stenoses. Kidney Int 1989; 36:707-11.  Back to cited text no. 21
    
22.
Gruss E, Portolés J, Jiménez P, et al. Prospective follow-up of vascular access in hemodialysis by a multidisciplinary team. Nefrologia 2006;26:703-10.  Back to cited text no. 22
    

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Correspondence Address:
H Raza
King Abdullah Hemodialysis Center, South Riyadh, Riyadh 12799
Saudi Arabia
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PMID: 30804265

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