1. Arteriovenous Fistulas Types, Trends, Physical Examination & Treatment
B. Karenko, DO
January 25, 2014

2. I have no disclosures

3. Objectives Identify types of vascular access
Evaluate trends of vascular access
Physical examination of AV Fistulas
Normal
When to refer
Treatment

4. Type of Hemodialysis Access
Synthetic AV Graft
Central Venous Catheter
AV Fistula

5. Radiocephalic Fistula
Radial Artery to Cephalic Vein
Forearm
Preferential

6. Brachiocephalic Fistula
Brachial Artery to Cephalic Vein
Antecubital Fossa

7. Brachiobasilic Fistula
Brachial Artery to Basilic Vein
Upper Arm
+/- transposition

8. AV Fistula Advantages Disadvantages Long Maturation Time
Smaller Surgery
Decreased Infection
Decreased Thrombosis
Longer Lifespan
68% AVF
49% AVG
Long Maturation Time
More Difficult Cannulation
High Primary Failure with Difficult Vasculature
Infections: times less infections than AV Graft
Thrombosis: times less procedures for thrombus clearing than AV Grafts
Lifespan: 1 year patency 68% AVF 49% AVG
Allon & Robbin, Kidney Int. 62: , 2002.
Nassar & Ayus. Kidney Int. 60:1-13, 2001
Pisoni RL, et al., Kidney Int. 61: , 2002

9. Best to Worst
AVF
AVG
CVC

10. Prospective Observational Study >300 Hemodialysis Sites
Vascular Access Use & Outcomes; An International Perspective from the Dialysis Outcomes & Practice Patterns Study
Prospective Observational Study
>300 Hemodialysis Sites
12 Countries
>35,000 patients
Nephrol Dial Transplant Oct; 23(10);

11. AV Fistula Use
Since 2005; there has been >65% AVF use in Japan, Italy, Germany, France, Spain, UK, Australia and New Zeeland,
From , the use of AVF doubled from 24 to 47% in the USA
Concomitantly, graft use fell by 50% from 58% in 1996 to 28% in 2007
Nephrol Dial Transplant Oct; 23(10);

12. Referral Timeframe Nephrol Dial Transplant. 2008 Oct; 23(10);3219-26.
Patient’s were significantly less likely to start HD with an AVF in a country that had a longer duration of time from the initiation of the referral to vascular evaluation, and from evaluation to the creation of an AVF
Nephrol Dial Transplant Oct; 23(10);

13. Creation to Cannulation
Patients were less likely to start HD with an AVF in countries with a longer time from access creation to first cannulation
Nephrol Dial Transplant Oct; 23(10);

14. Successful Fistula Adequate Vessels Good Pump >0.4 cm
If the blood vessels are >0.4cm in diameter, 89% will be adequate for hemodialysis
>0.4 cm
Robbins Radiology 225; 59-64, 2002

15. Monitoring/Surveillance
New AVF
Established AVF
Identify 1° Failures
Plan for Early Interventions
Plan for Surgical Revision
Early Detection
Thrombosis
Inadequate Flow

16. Physical Examination
Look
Listen
Feel

17. Look
Radiocephalic
Brachiobasilic (transposed)
Brachiocephalic

18. Look
Early diagnosis of infection (rash, buttonhole erythema/edema, drainage) can prevent bacteremia and sepsis

19. Aneurysm & Hematoma
As aneurysm's increase in size, the risk of rupture increases. Thinning of the skin over the aneurysm (shiny) suggests the aneurysm is unstable and may need to be resected.

20. Steal Syndrome
With steal syndrome (where to much arterial blood is diverted to the av fistula causing ischemia distal to the site), you can experience muscle wasting,

21. Central Vein Stenosis
Extremity Swelling
Collateral Veins

22. Arm Elevation Test
Elevate the arm above the head. If the fistula collapses, it means there is good venous outflow.
If only a portion collapses, the portion that remains distended is distal to the stenosis (portion that collapses is proximal to the stenosis)

23. Auscultation
Normal Bruit
High Pitched (stenosis)

24. Feel (Palpation) Inflow Assessment Outflow Assessment
Augmentation Test
Absence of Thrill
Pulsitile
Use the Augmentation test to assess inflow.
Normally a fistula is soft and is not pulsitile; easily compressible. If you artificially create a stenosis by occluding outflow with your fingers, the strength of the inflow is directly proportional to the arterial inflow pressure; weak inflow = weak pulse

25. Outflow Obstruction

26. Treatment of Stenosis Venous Anastomosis/Outlet Significant Lesions
<600 ml/min flow
>50% stenosis on angiogram
A majority of lesions are located at the venous anastomosis or venous outlet (80%)

27. Endovascular Angioplasty
First Line Treatment
7-8mm peripheral
12-14mm central
Poor long term patency
50% require repeat treatment within 6-12 months
7-8 mm balloon in the peripheral veins
12-14 mm balloon in the central veins
35-70% patency at 6 months with balloon angioplasty alone
Am. J Kidney Disease 2001; 37 (5); 1029

28. Stents Three Indications Angioplasty Failure
Rapid Recurrence of Lesion
Vessel Rupture
Failure of angioplasty to resolve the lesion to <50% stenosis
Rapid recurrence of the lesion (within 3 months of prior angioplasty
Vessel rupture with angioplasty
J. Am Coll Cardiol Interv. 2010; 3(1); 1-11

29. Patency
92%
80%
69%
35%
24%
Retrospective single center study examining the SMART SES nitinol stent
211 pts (112 AV fistula, 99 AV Graft)
Patency was higher in those who received stents;
30 days 92% vs 80%
90 days 69% vs 24%
180 days 25% vs 3% 3% 30 90
180
Clin J Am Soc Nephrol. 2008, 3(3);699

30. Surgical Revision of Stenosis
Advantage
Elimination of the lesion
Disadvantage
Frequent new lesion development
Loss of venous access sites
Post surgical pain/recovery time

31. Thrombosis
Percutaneous/Surgical Thrombectomy
Thrombolytic Agents

32. Percutaneous Thrombectomy
A sheath is placed at both the arterial inflow and venous anastamosis
Angiojet (most common) thrombectomy is performed in both directions to remove the thrombus
Balloon angioplasty is performed at the venous stenosis site
* Failure to correct the underlying outflow stenosis leads to rapid re-thrombosis
J. Am Coll Cardiol Interv. 2010; 3(1); 1-11

33. Surgical Thrombectomy
Small incision in the fistula is made
The clot/stenosis is removed via expansion of the balloon at the tip of the fogarty catheter and retraction of the catheter to the incision site
J. Am Coll Cardiol Interv. 2010; 3(1); 1-11

34. Thrombectomy Percutaneous/Surgical Thrombectomy Primary Patency
3 months: 30-60%
6 months: 10-40%
Elective Angioplasty vs Thrombectomy
Percutaneous and surgical thrombectomy are comparable in terms of primary patency
Primary patency following thrombectomy and angioplasty is 30-60% at 3 months, and 10-40% at 6 months
Patency following thrombectomy and angioplasty is worse than elective angioplasty of a patent but stenosed graft
J. Vasc. Interv. Radio. 1999; 10 (2pt1):129

35. Thrombolysis (local) Agents Contraindications Pulse Spray
Mechanical Clot Disruption
50% patent at 1 yr
Agents: Alteplase (t-PA), Urokinase most common
Contraindications: recent CVA, bleeding disorders, recent major bleeding/surgery, severe hypertension
Pulse Spray: Angiojet
Ultrasound assisted: Ekos Catheter
Mechanical Clot Disruption: Trellis Catheter

36. Major Concern Development of Clinically Significant PE
650 Thrombectomy Cases
1 Clinically Significant PE
Study out of Georgia examined 650 cases thrombectomy cases performed, only 1 clinically significant PE was noted and symptoms (hypoxia, pain) resolved within 24 hours
Kidney Int. 1994; 45(5) 1401

37. Questions?