A v fistula in heamodialysis

1. A-V Fistula in Heamodialysis Techniques and Complications Dr- Saeed Al-Shomimi King Faisal University Saudi Arabia 2003

2. Introduction Definition Abnormal connection between artery and vein which bypasses capillary bed Aetiology congenital acquired: - surgically created for haemodialysis - penetrating trauma - iatrogenic eg following surgical dissection of artery, cannulation of artery or vein

3. Introduction The advent of hemodialysis in the early 1960 has provided longevity for many patients with CRF Quinton and his associates → external A-V shunt 1963 , Shaldon → femoral vien catheter

4. Introduction Fistula vs Graft Maturation Fistula 4 -8 weeks Graft 2- 4 weeks Infection Blockage (thrombosis) Other complications: Psudoaneurysm Venous hypertension Cosmotic

5. Introduction Grafts: Vein Artificial: Gortex Teflon Straight looped

6. Anatomy

7. Anatomy

8. GENERAL PRINCIPLES OF ACCESS SURGERY

9. General Principles Preferable to use the arm vessels rather than the leg vessels When possible the non-dominant arm Access site should be placed as distally as practical in the limb , so that proximal sites will be available for subsequent procedures. 3. Inadequate or atherosclerotic arteries should be avoided , and a long section of patent vein is required to accommodate multiple cannulation site.

10. General Principles The chosen site should allow for ease of access for cannulation and should be positioned so that patient comfort is assured during heamodialysis. Technical precision and gentle tissue handling is mandatory. A temporary access procedure , such as : Rt Internal jagular Subclavian or femoral catheter External shunt Peritoneal catheter required during the time that the permanent access are maturing prior to use.

11. General Principles Anticoagulation is not necessary during routine access operations , except for graft thrombectomy and revision procedures, or patients who do not have the usual hypocoagulable state of chronic renal failure. 8. Prophylactic antibiotics are used for all cases involving insertion of prosthetic material.

12. Preservation of access vessels The autogenenous AV fistula at the wrist is the procedure of choice Most second choice procedures also make use of the forearm , with the principle access vessels being the : Radial – brachial artery Cephalic and cubital fossa veins So these vessels should be preserved by avoidance of: Venipuncture Intravenous cannulation Invasive monitoring lines

13. Procedure choices in vascular access surgery First choice: Radiocephalic direct AV fistula Brescia-Cimino (wrist) Snuff-box (base of the thumb) Second choice: Forearm AV graft bridge fistula Straight : radial artery → largest superficial vein of the cubital fossa Loop : brachial artery → largest superficial vein of the cubital fossa Brachioaxillary graft Upper arm AV fistula (brachial basilic)

14. Procedure choices Third choice: Forearm AV graft to brachial vein Straight : radiobrachial Loop : brachiobrachial Forth choice: Femorosaphenous graft Femorofemoral graft Others: Axilloaxillary graft Illiac-femoral graft miscellaneous

15. Surgical Techniques

16. Surgical Techniques Four different anastomotic connections of artery and vein are in common use and each has its advantages and disadvantages Side to side anastomosis: Technically is the easiest anastomosis Highest fistula flow End to side (artery to vein): Minimize turbulence and distal steal Slightly lower fistula flow Twisting of the artery during construction

17. Surgical Techniques 3. End to side (vein to artery): Decrease turbulence Highest venous flow Minimal venous hypertension More difficult than side to side 4. End to end: Least arterial steal and venous hypertension Lowest flow of the four configurations

18. Procedures Side to side radiocephalic fistula: Oblique or longitudinal incision is made overlaying the selected anastomotic site. Cephalic vein is located and isolated from the surrounding subcutanious tissue Venous tributaries are ligated and divided to improve mobility of the vein Incision is made in the deep fascia of the forearm and the radial artery exposed carfully Radial artery carefully mobilized , ligating the muscular branches and isolating it from the surruondhig tissue Adequately mobilized length of both vessels are necessary so that they rest side by side without tension

19. Procedures Side to side brachiocephalic fistula: When construction of fistula at the wrist is not possible , anastomosis of the cephalic vein to the brachial artery immediately proximal to the cubital fossa will provide satisfactory access A transverse incision is made proximal to the cubital fossa The brachial artery is mobilized untill it reaches the bifurcation at the level of bicipital tendon The median nerve lies medial and posterior to the artery and should be carefully protected The anastomosis is similar to the radiocephalic but the veenotomy and arteriotomy should be limited to about 5 – 7 mm to minimize the incidence of steal syndrome

20. Procedures Basilic vein – radial artery fistula: Mobilization of the basilic vein in the forearm and anastomosis of its end to the radial artery also may be used to provide access for heamodialysis The basilic vein is mobilized along the ulner border of the forearm to about the middle of the forearm. A subcutanious tunnel is prepared between the vein and the radial artery These vessels are then anastomosed attaching the vein end to either the end or the side of the artery

21. This technique of fistula formation may be used in patients who have an obliterated cephalic vein or distal radial artery It is possible to anastomose the basilic vein to the ulner artery, however if there has been a previous radiocephalic fistula in that arm , there is a danger that circulation in the hand will be compromized

22. Complications

23. complications Failure: The most frequently complication is that of early failure Reported incidence of up to 27% Such a complication may be a result of : Thrombosis: (more in) DM erythropoietin Failure to mature and achieve an adequate flow rate to maintain dialysis: Techniqal problems in constructing the anastomosis A sclerotic vein segment in the forearm because of previous venisection Inadequate venous size Cacification of the arterial wall

24. complications So when thrombosis is suspected by clinical evaluation , further assessment can be made by : Angiogram US Surgical thrombectomy is done by making a small venotomy and using a fogarty balloon catheter to remove the thrombus

25. complications Aneurysm: Pseudoaneurysm formation may occur at puncture sites following dialysis However , the incidence is much lower than that of prosthetic grafts True aneurysm are much rare but have also been reported in few occasions in the vein distal to the anastomosis These can be treated with resection and either end to end anastomosis Placement of short segment graft

26. complications Infection: Infection of autogenous fistula are rare compared to prosthetic graft They present with: Fever Erythema Tenderness And complications (such as thrombosis and aneurysm ) The most common infecting organism is staph aureus Managed by systemic antibiotics , drainage and revision as necessary

27. complications Ischemic changes: Steal symptoms may occur in around 4% of patients with autogenous fistula The incidence is higher in : Diabetic patients Atherosclerotic patients And in anticubital fistulas The symptoms may only manifested during dialysis and as such may be managed by observation and by using low flow rate At its worst , gangrene may occur requiring amputation To avoid the problem of retrograde flow through the palmar arch in wrist fistula , ligation of the radial artery distal to the anastomosiscan be performed . Alternatively an end to end anastomosis can be constructed

28. complications Venous hypertension: Another vascular complication is the development of venous hypertension syndrome , where the hand distal to the fistula become swollen and uncomfortable with thickning of the skin and hyperpigmentation Venous hypertension may be avoided by forming an end to end anastomosis Or to ligate the enlarged venous tributaries causing the hypertension of the distal digits , so preserving the fistula

29. complications Cardiovascular complication: High output cardiac failure is a rare complication which may occurs particularly in patients displaying a combination of low heamatocrit, cardiomyopathy from diabetes and the presence of high flow fistula Treatment usually involves sacrificing the fistula

30. Care of A-V Fistula Keep the fistula arm raised on a pillow to reduce swelling. The dressing should remain intact and dry at all times. As soon as post operative pain has subsided, start arm exercises Do not allow blood pressure, blood taking or intravenous administration on the fistula arm. Check for thrill

31. Thank you