A-V Fistula in Heamodialysis

Techniques and Complications

Dr- Saeed Al-ShomimiKing Faisal University Saudi Arabia

2003

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

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

Introduction

Fistula vs GraftMaturation

• Fistula 4 -8 weeks• Graft 2- 4 weeks

InfectionBlockage (thrombosis)Other complications:

• Psudoaneurysm• Venous hypertension

Cosmotic

Introduction

Grafts:VeinArtificial:

• Gortex• Teflon

Straight looped

Anatomy

Anatomy

GENERAL PRINCIPLES OF ACCESS SURGERY

General Principles

1. Preferable to use the arm vessels rather than the leg vessels

When possible the non-dominant arm

2. 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.

General Principles

4. The chosen site should allow for ease of access for cannulation and should be positioned so that patient comfort is assured during heamodialysis.

5. Technical precision and gentle tissue handling is mandatory.

6. 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.

General Principles

7. 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.

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 arteryCephalic and cubital fossa veins

• So these vessels should be preserved by avoidance of:Venipuncture Intravenous cannulation Invasive monitoring lines

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 graftUpper arm AV fistula (brachial basilic)

Procedure choices

• Third choice:Forearm AV graft to brachial vein

• Straight : radiobrachial• Loop : brachiobrachial

• Forth choice:Femorosaphenous graftFemorofemoral graft

• Others:Axilloaxillary graft Illiac-femoral graftmiscellaneous

Surgical Techniques

Surgical Techniques

• Four different anastomotic connections of artery and vein are in common use and each has its advantages and disadvantages

1. Side to side anastomosis:• Technically is the easiest anastomosis• Highest fistula flow

2. End to side (artery to vein):• Minimize turbulence and distal steal• Slightly lower fistula flow • Twisting of the artery during construction

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

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

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

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

– 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

Complications

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)DMerythropoietin

• 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 sizeCacification of the arterial wall

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

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

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

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

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

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

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

Thank

you