Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 7  |  Issue : 3  |  Page : 222-224

Arteriovenous graft patency outcomes and prognostic factors: A single-center study


Department of Vascular and Endovascular Surgery, MS Ramaiah Medical College and Hospital, Bengaluru, Karnataka, India

Date of Submission15-Sep-2019
Date of Acceptance21-Oct-2019
Date of Web Publication12-Sep-2020

Correspondence Address:
Ranjith Kumar Anandasu
Department of Vascular and Endovascular Surgery, MS Ramaiah Medical College and Hospital, Bengaluru, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijves.ijves_72_19

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  Abstract 


Aim/Purpose: Functional, long-lasting vascular access is essential for maintaining effective long-term hemodialysis. Various factors including demographics and comorbid conditions have influenced the patency rates. As per the KDOQI reports, vascular access-related complications account for 15%–20% of hospitalizations in end-stage renal disease (ESRD) cases. This study aims to analyze various factors and to study the patency rates and complications of brachioaxillary arteriovenous (AV) prosthetic grafts for dialysis access at a single center. Materials and Methods: This was a single-center prospective study, which was conducted in Ramaiah Medical College Hospital, Bengaluru. All patients who underwent brachioaxillary AV prosthetic graft surgery for dialysis access over a period of 5 years from July 2012 to June 2017 were included. Follow-up of cases was done up to 2 years, and any complications encountered during the study period were recorded. Results: A total of 408 patients were included, in which 77% were male, with a mean age of 60.1 years. The most common comorbidity associated was hypertension (68%) followed by diabetes (36%), and the mean axillary vein diameter was 5.2 mm. The primary patency rates at the end of 1 and 2 years were 61.5% and 49%, respectively, and the secondary patency rates at the end of 1 and 2 years were 70% and 59%, respectively. Conclusions: In ESRD patients, in whom an autogenous fistula is not possible, prosthetic AV grafts are a suitable choice for vascular access and provide satisfactory patency rates for hemodialysis access. Thrombosis, secondary to venous intimal hyperplasia, is the most common complication and generally occurs by the 3rd month. Interventions will improve long-term patency rates and should consist of thrombectomy and thrombolysis in addition to balloon angioplasty. However, complications will still be encountered and their early recognition with aggressive surveillance and appropriate management is necessary to prolong overall graft survival.

Keywords: Arteriovenous fistula, arteriovenous graft, end-stage renal disease, ePTFE (polytetrafluoroethylene)


How to cite this article:
Basavanthappa RP, Anandasu RK, Gangadharan AN, Luthra L, Vardhan J P, Ramswamy CA, Desai SC, Maruthu Pandian AK. Arteriovenous graft patency outcomes and prognostic factors: A single-center study. Indian J Vasc Endovasc Surg 2020;7:222-4

How to cite this URL:
Basavanthappa RP, Anandasu RK, Gangadharan AN, Luthra L, Vardhan J P, Ramswamy CA, Desai SC, Maruthu Pandian AK. Arteriovenous graft patency outcomes and prognostic factors: A single-center study. Indian J Vasc Endovasc Surg [serial online] 2020 [cited 2020 Sep 28];7:222-4. Available from: http://www.indjvascsurg.org/text.asp?2020/7/3/222/294911




  Introduction Top


Arteriovenous graft (AVG) is an option for hemodialysis (HD) only after arteriovenous fistula (AVF). Rise in chronic kidney disease patients and exhaustion of access sites and small-caliber veins unsuitable for AVF creation are few reasons for increased AVG[1] creation. Herein, a prosthetic graft made of ePTFE (polytetrafluoroethylene) is used to connect brachial artery and axillary vein. Fistula first initiative is recommended as per revised KDOQI guidelines. Upper limb AVG creation is preferred in patients with failed AVF and exhausted autogenous venous conduits. The AVG is a major financial burden on health-care systems and it is associated with high morbidity and mortality.[2] However, AVG creation has more complication than AVF.[3] This study aims to analyze various factors and to study the patency rates and complications of brachioaxillary AV prosthetic grafts for dialysis access at a single center.


  Materials and Methods Top


This was a single-center prospective study, which was conducted in Ramaiah Medical College Hospital, Bengaluru. Four hundred and eight patients with end-stage renal disease (ESRD) who underwent brachioaxillary AV prosthetic graft surgery for dialysis access over a period of 5 years from July 2012 to June 2017 were included. Follow-up of cases was done up to 2 years, and any complications encountered during the study period were recorded. All patients below 18 years and other than brachioaxillary AV prosthetic graft were excluded. We reviewed outpatient clinic and electronic medical follow-up records for graft event information and complications associated with it.

Data collection and follow-up

During the initial assessment for surgery, all patients' demographic data and comorbid conditions were evaluated and recorded. Preoperative duplex imaging of the upper limb veins and artery was done, and the suitable upper limb with good caliber artery and vein was taken for surgery. All patients preoperatively underwent cardiac evaluation with ECG and two-dimensional echo. Baseline blood investigations and preoperative heparin-free HD were done. This was followed by complete blood count, electrolytes, prothrombin time, activated partial thromboplastin time, international normalized ratio 4 hours post-HD. We proceeded with surgery under regional anesthesia after obtaining a pre-anesthetic evaluation and explaining the complications including steal phenomenon.

All details of surgery were recorded and stored. This included the size of vein and artery, back bleed and forward bleed from the artery; type of suture material, hypotension during surgery. All procedures were done as elective cases and none as emergency. All patients received anticoagulation in the form of low molecular weight heparin (LMWH) postsurgery for at least 3 days with intravenous antibiotics. Postoperative antiplatelets for a minimum of 3 months.

Follow-up was done initially after 2 weeks of surgery during which suture removal was done and the patients were allowed to undergo dialysis through AVG after 3 weeks from the time of surgery. Primary patency at the end of 1 year and 2 years and secondary patency at the end of 1 year and 2 years were primary outcomes. Complications were recorded and noted during the follow-up.

Vast majority of access failure is caused by thrombosis, secondary to intimal hyperplasia at venous outflow end. The mechanism of which is incompletely understood. However, possible factors include flow turbulence, vascular inflammation and prothrombotic milieu resulting in endothelial damage leading to stenotic lesions.

Primary patency[4] is defined as per previous literature as continuously patent without any actions to maintain graft patency which reflects durability. Secondary patency is defined as the interval from time of access placement to access abandonment including intrervening interventions (surgical or endovascular interventions).

Statistical analyses

For descriptive analyses, continuous variables were summarized as median and interquartile range. Statistical analysis was performed using SPSS software (version 18.0; SPSS Inc., Chicago, Illinois, USA).


  Results Top


Four hundred and eight patients with ESRD who underwent brachioaxillary AV prosthetic graft surgery for dialysis access over a period of 5 years from July 2012 to June 2017 were included. Baseline characteristics are shown in [Table 1]. In this study, 77% were male with a mean age of 60.1 years. Patient comorbidities included hypertension (68%) and diabetes mellitus (36%) depicted in [Figure 1]. The mean follow-up is for 2 years postsurgery.
Table 1: Demographic data

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Figure 1: Demographics

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Patency rates and prognostic factors

During the follow-up period, 136 patients required interventions. Of which, 98 patients underwent graft thrombectomy + access angioplasty, 34 underwent graft explantation, two patients underwent patch plasty at venous anastomotic end, and the remaining two underwent interposition graft placement. Complication rates observed in this study are depicted in [Table 2] and [Figure 2]. The primary graft patency rates at the end of 1 year and 2 years were 61.5 and 49%, respectively. The secondary patency rates at 1 year and 2 years were 70% and 59%, respectively, depicted in [Figure 3].
Table 2: Complication rates

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Figure 2: Complications

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Figure 3: Patency rates

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  Discussion Top


Even though the guidelines suggest that AVF is the first choice for HD access in ESRD patients, in patients with multiple AV access failure and poor caliber veins unsuitable for AVF, another option for HD is AVG.

In a study conducted by Hurlbert et al.,[5] the primary and secondary patency rates were 47% and 87%, respectively. In a study conducted by Cinat et al.,[6] the primary and secondary patency rates were 43% and 66%, respectively. In a study conducted by Park et al.,[7] the primary and secondary patency rates were 42% and 85%, respectively, and our study has better primary patency than other studies and comparable secondary patency rates.

Primary patency was markedly affected by surgical factors and elective creations than emergent. Hence, timely referral is critical. Adjuvant medications such as LMWH in the immediate postoperative period and antiplatelets[8] provide sufficient evidence on better graft patency, but did not prevent recurrent thrombosis and need for surgical thrombectomy.


  Conclusions and Future Perspective Top


Vascular access is essential for any ESRD patients on HD, AVF or AVG. Still research is going on in identifying the pathophysiology of neointimal hyperplasia[9] and its progression to result in loss of vascular access. Timely follow-up and assessment with flow rates, duration of dialysis, bleeding after dialysis is stopped should be assessed and recorded. Guidelines for graft surveillance and patient compliance will improve the patency rates. Novel treatment in arresting the neointimal hyperplasia by understanding molecular biology[10] and genetics is on its way. Still, further studies are required and newer agents which can aid in arresting the neointimal hyperplasia and promote access patency.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
III. NKF-K/DOQI clinical practice guidelines for vascular access: Update 2000. Am J Kidney Dis 2001;37:S137-81.  Back to cited text no. 1
    
2.
Pisoni RL, Arrington CJ, Albert JM, Ethier J, Kimata N, Krishnan M, et al. Facility hemodialysis vascular access use and mortality in countries participating in DOPPS: An instrumental variable analysis. Am J Kidney Dis 2009;53:475-91.  Back to cited text no. 2
    
3.
Akoh JA. Prosthetic arteriovenous grafts for hemodialysis. J Vasc Access 2009;10:137-47.  Back to cited text no. 3
    
4.
Sidawy AN, Gray R, Besarab A, Henry M, Ascher E, Silva M Jr, et al. Recommended standards for reports dealing with arteriovenous hemodialysis accesses. J Vasc Surg 2002;35:603-10.  Back to cited text no. 4
    
5.
Hurlbert SN, Mattos MA, Henretta JP, Ramsey DE, Barkmeier LD, Hodgson KJ, et al. Long-term patency rates, complications and cost-effectiveness of polytetrafluoroethylene (PTFE) grafts for hemodialysis access: A prospective study that compares impra versus gore-tex grafts. Cardiovasc Surg 1998;6:652-6.  Back to cited text no. 5
    
6.
Cinat ME, Hopkins J, Wilson SE. A prospective evaluation of PTFE graft patency and surveillance techniques in hemodialysis access. Ann Vasc Surg 1999;13:191-8.  Back to cited text no. 6
    
7.
Park J, Kim J, Hwang S, Lee MK, Jang HR, Eun Lee J, et al. Arteriovenous graft patency outcomes and prognostic factors. Vascular 2019;27:128-34.  Back to cited text no. 7
    
8.
Yeh CH, Huang TS, Wang YC, Huang PF, Huang TY, Chen TP, et al. Effects of antiplatelet medication on arteriovenous fistula patency after surgical thrombectomy. Curr Vasc Pharmacol 2016;14:353-9.  Back to cited text no. 8
    
9.
Collins MJ, Li X, Lv W, Yang C, Protack CD, Muto A, et al. Therapeutic strategies to combat neointimal hyperplasia in vascular grafts. Expert Rev Cardiovasc Ther 2012;10:635-47.  Back to cited text no. 9
    
10.
Li L, Terry CM, Shiu YT, Cheung AK. Neointimal hyperplasia associated with synthetic hemodialysis grafts. Kidney Int 2008;74:1247-61.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2]



 

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