EDITORIAL

 

Vascular access: where are we heading? An answer from our neighbours: an important statement

 

Pedro Vieira¹, Ramon Roca Tey², Jose Ibeas-Lo pez³

¹ Department of Nephrology, Hospital Central do Funchal, Portugal

² Department of Nephrology, Hospital de Mollet, Mollet del Vallès, Barcelona, Spain

³ Department of Nephrology, Parc Taulí Sabadell, Hospital Universitari, Universitat Autò noma de Barcelona, Sabadell, Barcelona, Spain.

 

Correspondence to:

 

Vascular access (VA) plays a central role in the treatment of haemodialysis (HD) patients mainly for two reasons: first, as the key factor in enabling dialysis adequacy, and second, as a major cause of morbidity and mortality, as well as associated costs.

Weighing all this up, the arteriovenous fistula (AVF) is generally accepted as the VA of choice in HD patients¹. But considering an increasing prevalence of comorbidities, such as vascular disease and diabetes mellitus, in the HD population, the creation and maintenance of a patent and well-functioning AVF has become a demanding task². In the search for the answer to this herculean mission, clinical practice guidelines^3-5 recommended preoperative evaluation including Doppler ultrasound (US) in order to allow the placement of an AVF in a higher number of patients and, after the creation of a VA, to assess its maturation process. This is followed by periodic monitoring and surveillance, as it is considered that early detection of access dysfunction and subsequent intervention would help to reduce the rate of access failure.

Observational studies focusing on preoperative vascular mapping, together with a few randomized trials bearing the same evidence in support of vascular mapping^6,7, showed that there was an increase in the total number of patients with fistulae, including distally placed fistulae, venous capital was saved for later exploration and outcomes in terms of patency and use for dialysis were improved⁸.

When considering early assessment of pathologically non-matured VA, it is also widespread opinion that prompt correction of underlying problems may salvage these VA⁹. These latter two points are mainly consensual; however, despite numerous observational studies evidencing favourable outcomes through surveillance, such as a significant decrease in access thrombosis and prolonged access life^10-12, the surveillance of VA has fallen into discredit in the light of recent findings. This is mainly driven by conflicting results from randomized controlled trials (RCT) compiled on the basis of the meta-analysis by Tonelli et al., where he highlights that although surveillance with access blood flow measurements decreases the risk of access thrombosis in AVF, it does not significantly increase secondary patency and, in the case of grafts, no surveillance method prevents access thrombosis¹³.

These findings have surely brought surveillance to a sharp and dangerous edge, leading many to doubt its value. However, apart from the commented bias of the selected trials, Tuka and Malik pointed out other non-adjusted bias as for the VA vintage and the non-assessment of haemodynamic stenosis criteria, leading to unnecessary vascular interventions in many cases¹⁴. Krivitski, on the other hand, highlights the likely low efficacy of undertaken angioplasties, which would hamper any results of prolonging assisted patency¹⁵, not to mention the significant decrease in risk of hospitalization and central venous catheterization that are known independent risk factors for morbidity and mortality in HD patients. Despite the poor-to-moderate quality of the selected RCT, some other authors’ piercing opinion¹⁶, branding the alleged low utility of surveillance, raised overwhelming challenges in an economically-driven world. This rendered surveillance rather unappealing on the other side of the Atlantic, as it is not reimbursed by Medicare and other insurance companies. While hoping for a welldesigned, adequately powered RCT to evaluate the value and benefits of surveillance as some desire¹⁷, in complete contrast, the European point of view could not be more different as monitoring/surveillance keeps gaining strength. In support of surveillance and after a considerable time gap since the previous guidelines were published, the new Spanish VA guidelines were presented in the latest Vascular Access Society Congress. These are the first guidelines to be reinforced by a true consensus, as it was produced by all five major medical groups involved in vascular access, thereby representing a true multidisciplinary approach where nephrologists, vascular surgeons, interventional radiologists, haemodialysis’ nurses and infectious diseases’ specialists come together for the first time. Sustaining a patient-centred approach, these new guidelines afford surveillance a renewed position, with US assuming a major role in multiple directions, such as mapping, surveillance and dysfunction assessment, providing multi-level grades of recommendation. Apart from some new but consensual recommendations that are taken into consideration on the basis of the latest findings, where the IDEAL study states that initiation of dialysis should be later than sooner¹⁷ and, therefore, the same trend should be followed when referring to VA construction, those issues related to VA monitoring and surveillance really come to stir the waters.

 

References

1. III. NKF-K/DOQI Clinical Practice Guidelines for Vascular Access: update 2000. Am J Kidney Dis 2001;37(1 Suppl 1):S137-181.         [ Links ]

2. Konner K, Hulbert-Shearon TE, Roys EC, Port FK. Tailoring the initial vascular access for dialysis patients. Kidney Int 2002;62(1):329-338.         [ Links ]

3. Ethier JH, Lindsay RM, Barre PE, Kappel JE, Carlisle EJ, Common A. Clinical practice guidelines for vascular access. Canadian Society of Nephrology. J Am Soc Nephrol 1999;10 (Suppl 13):S297-305.         [ Links ]

4. Tordoir J, Canaud B, Haage P, et al. EBPG on vascular access. Nephrol Dial Transplant 2007;22 (Suppl 2):ii88-117.         [ Links ]

5. Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis 2006;48 (Suppl 1):S176-247.         [ Links ]

6. Ferring M, Claridge M, Smith SA, Wilmink T. Routine preoperative vascular ultrasound improves patency and use of arteriovenous fistulas for hemodialysis: a randomized trial. Clin J Am Soc Nephrol 2010;5(12):2236-2244.         [ Links ]

7. Niyyar VD, Wasse H. Vascular mapping: does it help to maximize fistulae placement? Adv Chronic Kidney Dis 2009;16(5):316-320.         [ Links ]

8. Gibson KD, Caps MT, Kohler TR, et al. Assessment of a policy to reduce placement of prosthetic hemodialysis access. Kidney Int 2001;59(6):2335-2345.         [ Links ]

9. Tordoir JH, Rooyens P, Dammers R, van der Sande FM, de Haan M, Yo TI. Prospective evaluation of failure modes in autogenous radiocephalic wrist access for haemodialysis. Nephrol Dial Transplant 2003;18(2):378-383.         [ Links ]

10. Besarab A, Sullivan KL, Ross RP, Moritz MJ. Utility of intra-access pressure monitoring in detecting and correcting venous outlet stenoses prior to thrombosis. Kidney Int 1995;47(5):1364-1373.         [ Links ]

11. Cayco AV, Abu-Alfa AK, Mahnensmith RL, Perazella MA. Reduction in arteriovenous graft impairment: results of a vascular access surveillance protocol. Am J Kidney Dis 1998;32(2):302-308.         [ Links ]

12. McCarley P, Wingard RL, Shyr Y, Pettus W, Hakim RM, Ikizler TA. Vascular access blood flow monitoring reduces access morbidity and costs. Kidney Int 2001;60(3):1164-1172.         [ Links ]

13. Tonelli M, James M, Wiebe N, Jindal K, Hemmelgarn B with the Alberta Kidney Disease Network. Ultrasound monitoring to detect access stenosis in hemodialysis patients: a systematic review. Am J Kidney Dis 2008;51(4):630-640.         [ Links ]

14. Tuka V, Malik J. Vascular access surveillance: no benefit? A J Kidney Dis 2008;52(3):628.         [ Links ]

15. Krivitski N. Why vascular access trials on flow surveillance failed. J Vasc Access 2014;15 (Suppl 7):S15-19.         [ Links ]

16. Paulson WD, Work J. Controversial vascular access surveillance mandate. Semin Dial 2010;23(1):92-94.         [ Links ]

17. Cooper BA, Branley P, Bulfone L, et al. with the IDEAL Study. A randomized, controlled trial of early versus late initiation of dialysis. N Engl J Med 2010;363(7):609-619.         [ Links ]

 

Correspondence to:

Dr. Pedro Vieira

Department of Nephrology,

Hospital Central do Funchal

Avenida Luís de Camões Nº 57, 9004-514 Funchal, Portugal.

E-mail: pedro.mds.vieira@gmail.com

 

Conflict of interest statement: None declared.

 

Received for publication: 02/10/2015

Accepted: 14/10/2015