Vascular access care .. nephrology perspective - Dr. Tamer El said MNDU 8

1. Vascular access care:
Nephrology perspective
By
Tamer ElSaid, MD

2. The Problem!
• Steady increase in no. of ESRD patients
requiring RRT (usually being Hemodialysis).
• We need an adequate vascular access (VA) to
be able to deliver this extracorporeal blood
purification treatment (HD)
• VA and it’s associated complications,
constitute the most common cause of
morbidity, hospitalization, and cost among
those patients

4. Common types of HD Vascular access
• Arteriovenous fistulae (AVF)
• Arteriovenous grafts (AVG)
• Catheters
- Temporary (non-tunneled catheters)
- Permanent (tunneled catheters)

5. AVFs

6. AVGs

7. Temporary catheter
• short term (<3 wks)
• immediate/bedside
insertion
• higher risks/non-cuffed

8. Permanent catheters
• long term
• placed in a SC tunnel (usually
under fluoroscopic guidance)
• Dacron cuff allows tissue in
growth that helps reduce the
risk of infection

9. Planning is crucial

10. Preoperative assessment
• History & physical examination
• Ultrasound
• Aniogram

11. History & physical examination
• Focus on hx of
Diabetes & PVD
• Focus on hx of
previous VA
• Focus on hx of
cardiovascular
disease!

12. Ultrasound
 Arterial/Venous Duplex
There is increasing evidence that routine
preoperative duplex scanning
ultrasound cannot only increase the
utilization of native AVF for dialysis
access but also allow proper selection of
a target vessel with adequate luminal
diameter to improve outcome

13. Ultrasound
Arterial/Venous Duplex
A minimum arterial diameter of
2 mm is associated with successful
fistula formation.
A threshold for minimal venous
diameter is difficult to establish.
Most clinical studies use a value of
2.5 mm for AVF and 4 mm for
prosthetic grafts

16. Vein mapping by Duplex US
vein diameter and depth!

17. Angiogram

18. Postoperative care
• History & physical examination
• Ultrasound
• Aniogram

19. Complications of hemodialysis
vascular access
1.Stenosis
2.Thrombosis
3.Aneurysmal formation.
4.Venous hypertension
5.Infection
6.Steal phenomenon
7.Heart failure

20. Monitoring and Surveillance of VA!
Monitoring
• This term refers to the examination and evaluation of the vascular
access by means of physical examination to detect physical signs that
would suggest the presence of pathology.
Surveillance
• This term refers to periodic evaluation of the vascular access by
means of tests, which may involve special instrumentation, for which
an abnormal test result suggests the presence of pathology.
Diagnostic Testing
• This term refers to testing that is prompted by some abnormality or
other medical indication and which is undertaken to diagnose the
presence of pathology (i.e.,angiography).

21. Prospective Diagnosis of Venous Stenosis
NKF-K/DOQI Clinical Practice Guideline 4
4.1 Physical examination (monitoring):
• Physical examination should be used to detect dysfunction in fistulae and grafts at
least monthly by a qualified individual
4.2 Surveillance of grafts:
• Techniques, not mutually exclusive, that may be used in surveillance for stenosis in
grafts include:
• 4.2.1 Preferred:
• o 4.2.1.1 Intra-access flow by using 1 of several methods that are available, using
sequential measurements with trend analysis.
• o 4.2.1.2 Directly measured or derived static venous dialysis pressure by 1 of
several methods that are available
• o 4.2.1.3 Duplex ultrasound
• 4.2.2 Acceptable:
• o 4.2.2.1 Physical findings of persistent swelling of the arm, presence of collateral
veins, prolonged bleeding after needle withdrawal, or altered characteristics of
pulse or thrill in a graft
• 4.2.3 Unacceptable:
• o 4.2.3.1 Unstandardized dynamic venous pressures should not be used.

22. 4.3 Surveillance in fistulae:
• Techniques, not mutually exclusive, that may be used in surveillance for
stenosis in AVFs include:
• 4.3.1 Preferred:
• o 4.3.1.1 Direct flow measurements
• o 4.3.1.2 Physical findings of persistent swelling of the arm, presence of
collateral veins, prolonged bleeding after needle withdrawal, or altered
characteristics of pulse or thrill in the outflow vein
• o 4.3.1.3 Duplex ultrasound
• 4.3.2 Acceptable:
• o 4.3.2.1 Recirculation using a non–urea-based dilutional method
• o 4.3.2.2 Static pressures, direct or derived

23. The Main Goal In Managing A Failing
VA!
“Prospective Diagnosis of Venous Stenosis”
• It is important that all hemodialysis facilities
have in place a system designed to detect
venous stenosis so that it can be diagnosed
and treated prospectively

24. http://www.esnonline.net/

25. Physical Examination
• Look
– Well-developed main venous outflow
– Collateral venous effluent vessels
– Collapses or softens when arm is raised
• Listen
– Low-pitched continuous systolic-diastolic bruit
• Feel
– Gentle thrill at the arterial anastomosis
– Should NOT be hyperpulsatile

26. Radiocephalic
Arteriovenous Fistula
(Brescia-Cimino)
Type of
stenosis
Inflow
stenosis
Feeding
artery
Artery-vein
anastomosis
Juxta-
anastomotic
Outflow
stenosis
Body
Draining
veins
Central
veins

27. Possible sites of stenosis in relation to clinical
findings & physical exam
Clinical findings Physical examination Possible sites of stenosis
High dynamic or static
venous pressure
Pulsatile AVF Outflow stenosis
Prolonged bleeding after
removal of dialysis needle
Pulsatile AVF Outflow stenosis
Upper limb swelling Swollen arm Central vein stenosis
Decreased thrill Flat AVF Inflow stenosis and body
Difficult cannulation Flat or difficult to palpate
Good thrill
Inflow stenosis and body
No stenosis, AVF too deep
for cannulation
Failure to mature Flat AVF
Multiple dilated veins
Inflow stenosis
Presence of accessory
veins or collaterals

28. Surveillance of Vascular Access
• Intra-Access Flow Determination
• Venous Pressure Measurement

29. Color Doppler ultrasound

30. Stenosis

31. TransonicTM Technique for Determining Intra-
Access Blood Flow
1. Reverse the bloodlines.
2. Attach the ultrasonic probes to the
bloodlines.
3. Adjust flow to 300 ml/min; be sure that
ultrafiltration is turned off.
4. Set Transonic© device for blood flow
measurement.
5. Administer a bolus of saline when directed
by the message on the computer screen.
6. Record the value given on the computer
screen.
7. Do test three times and take the average.

32. Intra-access Pressures
Static venous pressure: Pia/MAP at venous
outlet >0.35 (for AVF) and >0.5 (for AVG)

34. ‘Standardized’ Dynamic Venous
Pressure
Determinants of Dynamic Venous Pressure
• Pressure within the access (this is an asset)
• Pressure related to the resistance created by the
system (this is a liability)
- Venous return blood tubing
- Any constriction in the system
- Venous return needle (gauge)
- Hematocrit (viscosity of blood)
“Dynamic venous pressure: >120 (with needle
gauge 15) and >150 (with needle gauge 16)”

35. Finally ‘Test’ to evaluate!
• Angiogram
- Identifies anatomic abnormalities
- Allows for pre-emptive percutaneous
interventions (e.g. angioplasty and/or stent
placement)
- Guides surgical intervention

36. Juxta-anastomotic stenosis;
A – fistula, B – radial artery, C – anastomosis, D - area of stenosis

37. AV access salvage
• Balloon angioplasty for short segment of stenosis
(inflow, intra-access, outflow)
• Balloon angioplasty/stenting for central vein stenosis
• Mechanical thrombectomy or pharmacologic
thrombolysis
• Graft interposition for long segments of stenosis
• Ligation of side branches/stealing branches
• Covered stents or resection for aneurysms

38. Juxta-anastomotic stenosis (before
and after angioplasty)

39. Summary of clinical practice guidelines for vascular
access for haemodialysis*
1. Preferred type of vascular access (Guidelines 1.1 – 1.3)
2. Preservation of sites for native vascular access (Guidelines
2.1-2.2)
3. Timing of creation of vascular access (Guidelines 3.1-3.2)
4. Maintenance of vascular access (Guidelines 4.1-4.4)
5. Prevention of catheter related infections (Guidelines 5.1-
5.4)
6. Complications of vascular access (Guidelines 6.1-6.4)
*The Renal Association
http://www.renal.org/clinical/guidelinessection/vascularaccess.aspx

40. 1. Preferred type of vascular access (Guidelines
1.1 – 1.3)
Guideline 1.1 – Incident patient vascular access
• We recommend that any individual who
commences hemodialysis should do so with
an arteriovenous fistula as first choice, an
arteriovenous graft as second choice, a
tunneled venous catheter as third choice and
a non tunneled catheter as an option of
necessity. (1B)

41. Guideline 1.2 – Prevalent patient vascular
access
• We suggest that any patients on long term
hemodialysis should have vascular access
monitored and maintained to minimize failure
to allow timely planning for subsequent
replacement of optimal vascular (or PD)
access and avoid the need for emergency
access. (2B)

42. Guideline 1.3 – Complications related to
vascular access
• We recommend that any patients on long
term haemodialysis should have the risk of
complications, especially infection, related to
vascular access minimized by appropriate
interventions. (1B)

43. 2. Preservation of sites for native vascular access
(Guidelines 2.1-2.2)
Guideline 2.1 – Preservation of peripheral veins
for vascular access
• We suggest that all patients that may require
renal replacement therapy should have
education on forearm vein preservation. (2D)

44. Guideline 2.2 – Preservation of peripheral veins
for vascular access
• We suggest that healthcare workers should
avoid unnecessary venepunctures and
peripheral venous access in the upper limb
intended for creation of vascular access. (2C)

45. 3. Timing of creation of vascular access
(Guidelines 3.1-3.2)
Guideline 3.1- Planning of vascular access
• We suggest that planning for access should
commence when patients enter CKD stage 4.
(2C)

46. Guideline 3.2 – Creation of vascular access
• We recommend that the exact timing of
placement of vascular access will be
determined by rate of decline of renal
function, co-morbidities and by the surgical
pathway. (1C)

47. 4. Maintenance of vascular access (Guidelines
4.1-4.4)
Guideline 4.1 – Pharmacological treatment
• We suggest that there are no proven long
term pharmacological interventions that have
shown to improve access survival. (2C)

48. Guideline 4.2 – Needling technique
• We suggest that buttonhole is the preferred
needling technique. (2B)

49. Guideline 4.3 – Vascular access surveillance
• We suggest that systematic observation and
advanced surveillance should be employed to
predict and prevent access failure. (2C)

50. Guideline 4.4 – Intervention for failing vascular
access
• We recommend that a local standard
operating policy for intervention should be
developed. (1C)

51. 5. Prevention of catheter related infections
(Guidelines 5.1-5.4)
Guideline 5.1 – Minimize the use of venous
catheters
• We recommend that venous catheters should
be employed as a method of last resort for
longer term vascular access to reduce the
overall risk of infectious complications in
hemodialysis patients. (1B)

52. Guideline 5.2 – Minimizing the risk of catheter
related infection
• We suggest that aseptic technique should be
mandatory at every manipulation of central
venous dialysis catheters. (2C)

53. Guideline 5.3 – Minimizing the risk of catheter
related infection
• We recommend that the catheter exit site
should be cleaned with Chlorhexidine 2%. (1B)

54. Guideline 5.4 – Minimizing the risk of catheter
related infection
• We suggest that an antimicrobial or antibiotic
lock solution be used to reduce catheter
related bacteremia and other infections. (2B)

55. 6. Complications of vascular access (Guidelines
6.1-6.4)
Guideline 6.1 – Treatment of access infection
and related bacteremia
• We recommend that venous catheters should
be removed in all seriously ill hemodialysis
patients with catheter related bacteremia
unless no alternative vascular access can be
achieved. (1B)

56. Guideline 6.2 – Prevention of arteriovenous
aneurysmal formation
• We suggest that prevention of aneurysmal
formation with good needling technique is
appropriate and is the cornerstone for
preserving arteriovenous fistulae. (2C)

57. Guideline 6.3 – Treatment of ischemia related
to arteriovenous fistulae or grafts
• We suggest that the development of
peripheral ischemia related to arteriovenous
fistulae or grafts requires early review by the
vascular access surgeon to allow proactive
intervention to prevent the onset of gangrene
or need for amputation. (2B)

58. Guideline 6.4 – Prevention and treatment of
central venous catheter occlusion
• We suggest that catheter occlusion may be
prevented by the use of an antithrombotic
lock solution and catheter occlusion should be
managed by using thrombolytic agents
(urokinase or t-PA) before catheter guide
wire exchange or replacement. (2C)