VASCULAR ACCESS IN HEMODIALYSIS

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VASCULAR ACCESS IN HEMODIALYSIS

• Dr. Mohan Rajapurkar, MDDirector, Postgraduate
  Studies Research,Muljibhai Patel Urological
  HospitalNadiad-387001, Gujarat, INDIAWebsite
  www.mpuh.orgConvenor CKD registry of ISN
  Website www.ckdri.org
• THANKS TO Drs.Bhagwan Kalani Maulik Shah for
  slides preparation

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HISTORY

• 1896 Jaboulay/Briau Artery End-end
  anastomosis. Eversion of suture protection agnst
  thrombosis.
• 1924 George Haas cannulated RA CV for the 1st
  HD in human beings. Done for 15 mts. Glass
  cannulae.
• 1943 Williem Kolff Rotating drum kidney.
  Femoral vessels.
• 1960 Quinton ,Dillard, Scribner Teflon AV
  shunt.
• 9/3/1960 LANDMARK DAY IN HISTORY OF MHD.
• CLYDE SHIELDS 1st pt survived for 11
  yrs.
• 1961 Stanley Shaldon Venovenous access.
• 1966 Cimino Brescia AVF. S-S anastomosis.

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HISTORY

• 1968 Lars RohlAVF S-E.
• 1973 TW Staple Retrograde venography.
• 1977Gracz Proximal forearm (Brachial
  perforating vein) fistulas.
• Gordon Angioplasty.
• G Kronung different types of cannulation
  remodelling of venous arm of aVF.
• Barbara Daniel Color doppler assesment of AVF.
• 
  Klaus Konner NDT 2005,202629-2635

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ANGIO ACCESS CLASSIFICATION

• Location
• Conduit
• Configuration (Straight, Looped, Direct)
• 
  
  
  Drekker
  5th edition

Expected ½ life Examples
Acute VA lt90 days. Catheters /AV shunts
Bridging VA 3mths 3yrs Permacath/AVG/ Port cath
Long Term VA gt 3 yrs AVF
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• N
• ormal ven
• ous anantomy of upper limb.

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NATIVE AV FISTULA SITES

• FOREARM
• Radiocephalic snuffbox/wrist/forearm
• Ulnar Basilic forearm transposition
• Radial brachial (Saph vein reversed
  translocated RA BV)
• UPPER ARM
• Brachiocephalic (CEPHALIC/MEDIAN CUBITAL VEIN)
• Brachiobasilic
• Brachio-brachial
• Saphenous graft between Brachial art axillary
  vein
• LOWER EXTREMITY
• Saphenous vein E S femoral artery fistula
  transposition

Silva et alChap 12 Dialysis access
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VEINS PRESERVATION FOR FUTURE USE

• In patients with progressive renal failure, the
  veins of both arms must be protected,
  anticipating their possible use for vascular
  access.
• One should minimize venipunctures and placement
  of catheters into the forearm veins, especially
  the cephalic veins of either arm.
• The dorsum of the hand should be used when
  venipuncture cannot be avoided.
• Because of the risk of central vein stenosis, the
  subclavian vein should not be cannulated unless
  absolutely necessary
• Percutaneously inserted central catheter (PICC)
  lines should be avoided.

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TIMING OF AVF CREATION

• AS SOON AS POSSIBLE IF PATIENT LIKELY TO GO FOR
  MAINTENANCE HEMODIALYSIS.
• INITIATE DISCUSSION _at_ Cr 3mg/dl
• CONSTRUCT _at_ Cr 5mg/dl.

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HISTORY

• 
  
• 
  K DOQI
  GUIDELINES

Dominant arm Neg impact on QOL.
Arterial /venous catheter May damage vessel wall.
Central venous cath/ Pacemaker Central venous stenosis
Diabetes PVD
Past H/o vascular access Limited site prevent complication.
CHF Access alter hemodynamics CO.
H/O anticoagulant therapy Clotting/excessive bleeding.
H/O previous arm, neck, or chest surgery/trauma Vascular damage
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PHYSICAL EXAMINATION
ARTERIAL SYSTEM
Peri. Pulse Exmn /Dopp Adequate arterial system
Bilateral UL BP Discrepancy lt 20mmHG
VENOUS SYSTEM
Edema Venous outflow problem
Arm size comparision Inadequate veins/ venous
Collateral veins Venous obstruction
Tourniquet vein palpn Selection of ideal vein
Previous P/C catheter May affect the overall result
Previous surgery/trauma May affect the overall result
CARDIOVASCULAR
E/O CHF Acceses may alter CO
K DOQI GUIDELINES
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Allen test

1. Position the pt so that he /she is facing you
   with their arm extended with the palm turned
   upward.
2. Compress both the radial ulnar arteries at the
   wrist.
3. Creation of a fist repetitively to cause the
   palm to blanch.
4. After the blanching of hand, release the
   compression over ulnar artery watch the palm to
   determine if it becomes pink. Then all
   compression shd be released.
5. For radial artery same steps need to be repeated.

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DIAGNOSTIC EVALUATION

• Clinical assessment of intravascular volume
  status.
• Doppler ultrasound.
• Venography .
• Magnetic Resonance Imaging.
• Arteriography .

K DOQI GUIDELINES
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Venography

1. Edema.
2. Collateral vein development.
3. Differential extremity size, if that extremity is
   contemplated as an access site.
4. Current or previous subclavian catheter placement
   of any type in venous drainage of planned access.
5. Current or previous transvenous pacemaker in
   venous drainage of planned access.
6. Previous arm, neck, or chest trauma or surgery in
   venous drainage of planned access.
7. Multiple previous accesses in an extremity.

K DOQI GUIDELINES
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Preop Duplex USG Assessment

• Venous anatomy
• Venous Dia gt 2.5mm
• Patent venous segments without stenosis /
  thrombosis.
• Continuity with the deep veins of the upper arm.
• Absence of central venous stenosis.
• Straight segment.
• Within 1cm of surface.
• Arterial anatomy
• Patent palmar arch.
• Arterial inflow gt 2mm
• Symmetric UL BP discrepancy lt 20mmHG.

Michael Jaff, Preop USG Chap 10 Vascular access
65-66
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SETTINGS IN WHICH AV FISTULA CREATION IS
DIFFICULT 

• Poor vessels 
• Skill of surgeons 
• Low life expectancy 
• Diabetes (PVD)
• Elderly (calcification)
• Obesity (Depth)
• Needs further evaluation for AVF creation or
  alternate modalities of RRT

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CRITERIA FOR AVFISTULA CREATION

• Adequate, palpable veins
• Healthy arteries - Allens test or doppler
  studies to assure adequacy of flow to hand
• Good cardiac output

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ANASTOMOSIS
Art - Vein Advantages Disadvantages
Side - Side Simple,Distensibility of prox vein frm distal venous limb Venous Hypertension
End - End Limited flow prevents hyperciculation Equal diameters , risk of ischemia,extension of thrombosis,acute angles
Side - End When A V apart, no acute angle, no extn of thrombosis into artery. -
Klaus Konner JASN2003141669-16
80
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TECHNICAL POINTS

• Avoid ligation of run off vessels at fistula
  surgery, because imposssible to predict the
  future of the fistula. Can be done at 2nd
  setting.
• Higher the site of anastomosis higher the future
  blood flow for any given area of the anastomosis.
  So smaller anastomosis recommended.
• Suture technique by Tellis starts in the
  centre of the back wall of the arteriotomy
  venotomy.
• Closure of skin by subcutaneous sutures, close
  the skin by adapting the edges with tapes.

Klaus Konner JASN2003141669-16
80
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ANAESTHESIA

• Antibiotics only in Diabetics/ high risk cases
  for infection, Single dose aminoglycoside.
• Platelet inhibitors only in selected cases.
• CCBs/ ACEI Vasodilatory properties.

Local Simple Edema infection Spasms
Regional Skilled No Spasms,can change site from wrist to forearm.
General Skilled Comorbid condition, More proximal site.
Klaus Konner JASN 2003141669-1680
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ORDER OF PREFERENCE FOR AV ACCESS

• Radio-cephalic primary AV fistula
• Brachio-cephalic primary AV fistula
• Transposed brachial-basilic vein fistula
  (or sapheno-femoral)
• PTFE graft/saphenous graft
• All preferred in non-dominant hand

2006 NKF-K/DOQI Clinical Practice Guidelines
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MATURATION PROCESS

• Hemodynamic, anatomic, molecular, and functional
  maturation.
• The single most important determinant Response
  of both the feeding artery and the draining vein
  to the increase in shear stress that occurs after
  the creation of an arteriovenous anastomosis
• An increase in blood flow and consequently shear
  stress (because shear is directly proportional to
  flow), after the creation of an AVF, result in
  attempts to decrease the shear stress applied to
  the vessel wall.
• Because blood viscosity is difficult to alter, an
  increase in shear stress invariably results in
  vascular dilation .
• This flow-mediated (shear stress) dilation
  increases vessel diameter consequently brings
  the shear stress back to the prearteriovenous
  anastomosis.

Arif Asif cJASN 2006332-339
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MATURATION PROCESS

• At a biologic level, high shear stress rates
  (e.g., those seen in the arterial circulation)
  result in endothelial cell survival quiescence,
  alignment of endothelial cells in the direction
  of flow, secretion of substances such as NO
  prostacyclin that promote vasodilation inhibit
  thrombosis platelet aggregation .
• In marked contrast, low shear stress rates result
  in endothelial activation secretion of
  prothrombotic vasoconstrictive substances TXA.
• Multiple studies clearly demonstrate that an
  increase in arterial flow rate shear stress
  secondary to the creation of a distal AVF results
  in vascular dilation regression of neointimal
  hyperplasia.
• Increased expression of nitric oxide.
• Inhibition of nitric oxide/MMP/ TGF-ß PDGF / bFGF
  results in a diminution of the vasodilation that
  occurs after an increase in flow shear stress
• 
  Arif Asif cJASN
  2006332-339

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MATURATION PROCESS

• Regardless of the exact biologic mediators
  involved, the vascular response to changes in
  shear stress is mediated through the endothelium,
  in that endothelial denudation abrogates this
  response .

Arif Asif cJASN 2006332-339
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MATURATION PROCESS

• Whereas numerous histologic studies have
  demonstrated medial hypertrophy in the venous
  limb of the AVF, there are almost no hard
  scientific data on the temporal pattern of
  vascular dilation that occurs in the vein in
  response to a flow-mediated increase in shear
  stress.
• It also should be noted that the medial
  hypertrophy that occurs in the draining vein in
  this setting would in fact reduce the vascular
  diameter increase shear stress rather than
  reduce it back toward the pre-AVF level.
• This raises the question as to whether there are
  two competing mechanisms that are operative after
  the creation of an arteriovenous anastomosis.
• Flow-mediated venous dilation brings the shear
  stress rate back toward its pre-AVF level,
  pressure-mediated medial hypertrophy is
  completely independent of any shear
  stressmediated changes.

Arif Asif cJASN 2006332-339
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Enhancement of AVF maturation

1. Fistula hand-arm exercise (eg, squeezing a rubber
   ball with or without a lightly applied
   tourniquet) will increase blood flow speed
   maturation of a new native AVF.
2. Selective obliteration of major venous side
   branches will speed maturation of a slowly
   maturing AV fistula. (o)
3. When a new native AV fistula is infiltrated (ie,
   presence of hematoma with associated induration
   and edema), it should be rested until swelling is
   resolved
4. Persistence of swelling that does not respond to
   arm elevation or persists beyond 2 weeks after
   dialysis AV access placement Venogram or other
   noncontrast study to evaluate central veins

K DOQI GUIDELINES
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TIME TO USE

• DOQI recommendations wait for 3-4 months.
• Minimum 1 month.
• Duration is not as important as is the judgement
  about maturation for usage of AVF.

• Cannulation of AVFs lt2 weeks old should be
  avoided.
• Cannulation between 2 and 4 weeks should be
  performed only if the AVF is deemed mature by the
  treating nephrologist (by means of both a
  thorough clinical appraisal and objective
  quantitative criteria as a working hypothesis, a
  brachial artery Qb  500 ml/min) and under close
  supervision, electively never as an
  emergency.
• It is probably safe to cannulate an AVF 4 weeks
  after creation. Furthermore, as a working
  hypothesis, a brachial artery Qb lt500 ml/min at
  day 28 may be proposed as a cut-off point at
  which to implement a policy of closer monitoring
  of AVFs, even before starting dialysis. In other
  words, a brachial artery Qb lt500 ml/min at day 28
  should alert the attending nephrologist to early
  investigation and intervention.

Rajiv Saran2005 NDT 20(4)688-690
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CRITICAL SHUNT FLOW VOLUME IN AVF

• Minimum 350 400 ml/mt.
• lt 300 ml/mt Recirculation.
• lt 200 ml/mt Clotting problems

Blood Flow Recirculation
Radiocephalic 600/- 300 lt 5
Brachiocephalic 1200/- 300 lt 5
Thigh 1200/- 300 lt 5
PTFE 900 lt 5
Thomas 900 lt 5
K DOQI GUIDELINES
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Relation of blood flow access survival

RC AVF Q gt700 ml/mt Q lt 700 ml/mt
Carlo Basile NDT(2004) 19 1231-1236
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PUNCTURE TECHNIQUES
1.Rope ladder Entire Length Progressive diln along entire lt.
2.Area puncture Limited Area Prone for aneurysms.
3.Button hole Exactly Identical spot Displaces thrombus prevent orgn.
Klaus Konner JASN 2003141669-1680
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UPPER ARM FISTULAE
BRACHIOCEPHALIC BRACHIOBASILIC
Small dia cephalic vein Basilic vein larger
Easy access for venipuncture Less accessible so, less phlebitis less thrombosis.
Anterolateral incision cosmetically not better. Median incsn cosmetic better
Long length Short
- Steal syndrome(large dia)
Less dissection. More dissection.
Allow future BBAVF. Cant do future BCAVF.
1st Choice 2nd choice.
EQUAL PATENCY RATES AT 1 2 YRS 60-80 EQUAL PATENCY RATES AT 1 2 YRS 60-80
ASCHER et al Chap 14 Hemodialysis access
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MONITORING OF AVF

• Regular assessment of physical findings
  (Monitoring) may supplement enhance an
  organized surveillance program to detect access
  dysfunction.
• Specific findings predictive of venous stenoses
  
• Edema of the access extremity,
• Prolonged bleeding postvenipuncture (in the
  absence of excessive anticoagulation),
• Changes in the physical characteristics of the
  pulse or thrill in the graft .
• Conversion of thrill to pulse indicates lower
  flows. Intensification of bruit (higher pitch)
  indicates a stenosis.

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Question the Patient About the Following

• Bleeding
• Swelling
• Bruising
• Redness
• Drainage
• Pain
• Change in thrill or pulse

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Observation of the Skin Includes

• Skin is clean and intact-no evidence of cuts,
  scratches, excoriations, rashes.
• Presence of drainage note onset, color and
  amount nurse to culture and notify MD.
• Healing of previous needle insertion sites do
  not disturb scabs if present.
• Presence of skin erosion over the vessel(s) of
  the access.

Observation for Temperature and Color Includes

• Skin over access in warm-not hot
• Fingers are same as opposite hand not cool or
  cold
• Normal skin tones no discoloration, bruising

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SURVEILLANCE OF AVF

• A. Intra-access flow (E)
• B. Static venous dialysis pressure
• C. Dynamic venous pressures
• D. Measurement of access recirculation using urea
  concentrations
• E. Measurement of recirculation using dilution
  techniques (nonurea-based)
• F. Unexplained decreases in the measured amount
  of hemodialysis delivered (URR, Kt/V)
• Persistent abnormalities in any of these
  parameters should prompt referral for venography.
  (E)

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INTRA-ACCESS FLOW

• Sequential timely repetitive measurement of
  access flow Preferred method for surveillance
  of AVF.
• Doppler flow , ultrasound dilution, MRA have
  been the most extensively evaluated.
• Although Doppler studies can be predictive of
  access stenosis and the likelihood for failure,
  frequency of measurement may be limited by
  expense, inter-observer variability, variation in
  Doppler flow measurements performed by machines
  produced by different manufacturers.
• MRA is accurate but expensive.
• Both Doppler MRA are difficult to perform
  during dialysis.
• In contrast, flow measurements performed by
  ultrasound velocity other techniques using
  blood dilution are reliable and valid can be
  done on-line during dialysis, thereby providing
  rapid feedback.  

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VENOUS DIALYSIS PRESSURE

• Prospective Surveillance using dynamic or static
  venous dialysis pressures detects outflow
  stenoses.
• Both methods have acceptable sensitivity
  specificity, are inexpensive.
• Validated in prospective trials are recommended
  weekly. Venous pressures (dynamic) while less
  predictive than flow measurements, have been
  validated should continue to be used until flow
  measurements are widely available. Shortcomings
  of dynamic venous pressure techniques are the
  need to standardize for blood tubing, needle
  size, HD machine.
• Surveillance protocols that use static venous
  dialysis pressure (ie, venous dialysis pressure
  at zero blood pump flow)are strongly predictive
  of outflow stenoses than dynamic pressure
  measurements.

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DYNAMIC VENOUS PRESSURE
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STATIC VENOUS PRESSURE

• Turn the blood pump off and clamp tubing between
  the dialyzer and the venous drip chamber.
• Make static measurement (P) from venous
  transducer exactly 30 s after stopping blood
  flow.
• Determine in centimeters the height difference
  between the arm of the chair and blood in the
  venous drip chamber (H).
• Calculate estimated intra-access pressure eIAP
  P (0.35 x H 3.4)
• Measure mean arterial pressure (MAP).
• Calculate eIAP/MAP (absolute eIAP/MAP gt0.5 or a
  progressive rise on repeated measurements
  indicates a stenosis/thrombosis beyond the venous
  needle site in AV grafts).

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SLOW FLOW VENOUS PRESSURE MEASUREMENT PROTOCOL

• Measure venous pressure from machine transducer
  at a blood flow of 50 ml/min during first 15 min
  of dialysis.
• Measure MAP.
• Calculate ratio of various pressures and MAP.
• Investigate any venous pressure/MAP ratio gt0.6.

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INFECTION CONTROL MEASURES

• Staff pt education should include instruction
  on infection control measures for all
  hemodialysis access sites. (O)  
• In hemodialysis patients, poor personal hygiene
  is a risk factor for vascular access site
  infections. Therefore, HD patients with poor
  personal hygiene habits should be taught how to
  improve maintain their personal hygiene.
• Higher rate of infection in HD pts when new or
  inexperienced dialysis staff manipulate the
  patient's vascular access . So,all dialysis staff
  should be trained in infection control procedures
  .
• Documenting educational materials objectives
  must be part of the patient's records staff
  orientation records. Tracking the occurrence of
  infections can help identify the source allow
  corrective action to be taken.  

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AVF
Local infection Without bacteremia
Bacteremia
Uncomplicated
Complicated
IV Ab 2-4 wks
Septic Thrombosis Endocarditis Osteomyelitis
Abscess Septic arthritis
IV Ab 4 wks
Persistent infection Surgical revsn AVF
Drain abscess IV Ab 4-6 wks
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AVF FAILURE

• Early failure AVF that is never usable for
  dialysis or fails within three months of initial
  use is classified as an early failure.
• Late failure Late AVF failure is defined as
  failure that occurs after three months of use.
  Lesions typical of early failure are also
  commonly seen during this later period.

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CAUSES OF EARLY AVF FAILURE

• INFLOW
• Preexisting Arterial anomaly( Small,
  atherosclerotic) Preventable.
• Acquired JAS (Juxta Anastomotic Stenosis)

• OUTFLOW
• Preexisting accesory vein,small vein, fibrotic
  vein.

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LATE FISTULA FAILURE - CAUSES

• Acquired venous stenosis
• Acquired arterial stenoses.
• These lesions are manifest as pathological
  changes in the AVF from increased pressure and
  decreased flow, leading to inadequate dialysis
  and eventually thrombosis.

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SURVEILLANCE OF AVF

• A. Intra-access flow (E)
• B. Static venous dialysis pressure
• C. Dynamic venous pressures
• D. Measurement of access recirculation using urea
  concentrations
• E. Measurement of recirculation using dilution
  techniques (nonurea-based)
• F. Unexplained decreases in the measured amount
  of hemodialysis delivered (URR, Kt/V)
• Persistent/Worsening abnormalities in any of
  these parameters should prompt referral for
  further evaluation

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PERMCATH INSERTION
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Angiographic evaluation of failing AV
(arteriovenous) hemodialysis fistula  

• DURUGKAR S, HEGDE U,GOHEL K, GANG S , RAJAPURKAR
  M
• MULJIBHAI PATEL UROLOGICAL HOSPITAL
• NADIAD, GUJARAT

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AIM

• To assess the role of angiography in assessment
  of malfunctioning AV hemodialysis fistulas and
  its management

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MATERIAL METHODS

• Case records of 37 patients who underwent
  fistulograms between Jan 2000 to June 2005 at our
  institute were reviewed.
• Indications for doing fistulograms were-
• Poor flow
• Primary non function
• High venous pressure

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MATERIAL METHODS

• Fistulograms were analyzed for the site and type
  of lesion -
• Lesions were classified as early
  (lt3mths) and late (gt3mths) depending on the time
  of failure from the date of construction.
• The type of interventions their outcome were
  also analyzed.

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Demographics
Demographics No
Fistulograms 38
Gender M-23F-14
Period Jan 2000-June 2005
Average age 44.3110.1years
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Causes of ESRD
Cause of ESRD Number
Diabetic Nephropathy 14
CGN 07
CTID 05
Undetermined 05
HT Nephrosclerosis 02
Graft loss 02
Cystic renal disease 02
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Comorbid conditions
Comorbid conditions Number
Diabetes 14
IHD 5
PVD 3
Smokers 3
CVA 1
60
TYPE OF AVF ANASTOMOSIS
RC AVF 30 Side to Side
anastomosis-28 End to Side anastomosis-2
BC AVF 8 Side to Side
anastomosis-6 End to Side anastomosis -2
61
Indications for Fistulography
Indications Number
Poor flow 22
Primary non function 13
No flow 1
High venous pressure 1
Aneurysm 1
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EARLY FAILURES
VENOUS STENOSIS VENOUS STENOSIS VENOUS STENOSIS ARTERIAL STENOSIS OTHERS
JUXTA ANASTOMOTIC PROXIMAL CENTRAL
RC-13 2 4 1 2 Aneurysm-1 No lesion-2 V.thrombosis-2 No opinion-1
BC-3 0 2 1 0 0
63
LATE FAILURES
VENOUS STENOSIS VENOUS STENOSIS VENOUS STENOSIS ARTERIAL STENOSIS OTHERS
JUXTA ANASTOMOTIC PROXIMAL CENTRAL
RC-17 6 8 0 1 Non dev-1 V.thrombosis-3
BC-5 0 3 3 0 No lesion-2
64
INTERVENTION

• RADIOLOGICAL
• PLASTY 7 Primary failure -3
• PLASTY STENT 2
• SURGICAL INTERVENTION ON SAME SIDE
• HIGHER UP 8
• NO INETRVENTION - 23

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SALVAGED AVFs

• RADILOGICAL - 6
• PLASTY 4
• PLASTY STENT 2
• SURGICAL (Higher up anastomosis on same side) 8
  

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Results of fistuloplasty/stenting
Patency rate
(6)
(5)
(5)
(5)

• Failed on table 3
• Stent thrombosis - 1

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Results of surgical salvage
100
87.5
(8)
(7)
PATENCY RATE
75
75
(6)
(6)
68
Complication

• Stent thrombosis - 1

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A N G I O P L A S T Y S T E N T
Stent
70
Proximal venous stenosis plasty
71
Brachiocephalic AVF with venous Stenosis
central stenosis
72
SUMMARY

• Angiographic evaluation of failing AVF is useful
  tool to determine the cause of fistula failure
  and planning its treatment.
• Significant number of these stenosed fistulae
  can be salvaged by early intervention.

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