18-04-16 The BEST Hemodialysis Vascular Access Fistula failure how - - PDF document

18-04-16 1 Fistula failure – how to use risk scores and algorithms

Charmaine Lok, MD Professor of Medicine, University of Toronto UCSF Vascular Symposium 2018 April 19, 2018 San Francisco

The BEST Hemodialysis Vascular Access A functioning FISTULA!

Fistula is 35 years old, 1 intervention no complications

Problem: Fistula Failure

• “Suitability Failure” or “Failure to Mature”
• Early thrombosis
• Failure of vessel dilatation and maturation (stenosis, collaterols)
• Difficulties with cannulation: infiltration injury

Would we recommend a fistula is these patients?

• Multiple previously failed fistula?
• Deemed “marginal” by the surgeon
• Multiple comorbidities
• Elder age e.g. >75?
• Limited life expectancy
• O’Hare, A, et al., Kidney Int, 2007
• pts >85 yrs would have 5:1 unneccessary

to necessary procedures

• Richardson, et.al, J Vasc Access, 2009
• Pts >70 yrs →50% 18 mo survival
• Fistula survival: 39% at 12 mos
• Only 35% accessed their fistulas

FTM Risk Score

Variable Points Score

Baseline

+3 +3

Age >=65

+ 2

PVD

+ 3

CAD

+ 2.5

Caucasian

• 3

Total

Score <2 2-3 3.1-7.9 >8.0

Lok et al, JASN, 2006

ü

Discrimmination

ü

Calibration

ü

External validation

Risk of Fistula Failure to Mature

Potential Uses of Score

• Patient Education
• Identifies high risk patients
• Stratify post op for need of close follow-up (e.g. look for change in blood

flow, diameter size) +/- intervention

• Consider high risk patients for a graft
• A tool that may assist in decision of choice of access along

with other evaluations

18-04-16 2

HOW WELL DO SURGEONS PREDICT? What are “other” evaluations?

Great! This Patient Comes to See You

• 68 years old, active
• Non-caucasian
• Longstanding HTN
• DM II, poorly controlled;

had BKA

• Already has 2 failed

forearm fistulas, eGFR 15 ml/min, ACR 3 mg/mmol

• Patient strongly dislike needles,

“okay” with continual CVC use

• PD not an option

Application to Our Patient

Variable Points Score for Our Patient

Baseline +3

+3

Age >=65 + 2 +2 PVD + 3 +3 CAD + 2.5 Caucasian

• 3

Total 8 = Very High Risk

Nb: High risk if Caucasian (score=5)

Implementation Considerations

Critical Data to Consider for Access Creation

• Patient’s CKD status + timelines
• Predialysis or long-term dialysis?
• Timeframe for fistula creation and maturation
• Patient’s overall status
• Patient survival should be at least equivalent to access

survival

• Risk of fistula failure → should consider:
• History of prior access failure
• Vessel quality as per surgeon evaluation +/- vessel mapping
• Clinical factors (+/- with help of Score)

Tangri KFRE and our case

18-04-16 3 KFRE Results Results

Clinical Thinking & Risk Stratification

Allon & Lok, CJASN, 2010

The Graft

A Patient’s Access Trajectory….. can harmoniously include Grafts and Fistulae

Don’t Forget about Secondary AVF

18-04-16 4 Practical Considerations for Graft

• Prevalent dialysis patients
• Suffered multiple prior fistula failures
• Has high – very high FTM risk score
• Incident patients
• Expected to start HD in 2-3 weeks + high –very high FTM

risk score - ↑likelihood CVC

• In such cases, emphasis= temporary in preparation for

secondary AVF fistula once graft becomes problematic

• Advantages: start HD without CVC & avoid complications;

improve bloodflow and vessel calibre for fistula Highlights need for timely and appropriate vascular access care

Points about Prediction Models

AGE

Vessel integrity Comorbidity Impact of prior access Functional status

Flow Calcification Venipuncture/ PICCs etc Size CHF DM PVD CAD Stenosis Mobility Cognition Nutrition Interventions Available access Sites Reasons for loss CVD Surgeon Factors

FTM Risk Score

• Needs an UPDATE!
• Patients and

practice patterns have changed

• Generalizability to

YOUR patient population

Tangri KFRE

• Has not been tested/

validated for clinical use for VA planning

• ? Pts who went on for

VA surgery vs not

• Competing risk of death

Summary: Use of Risk Scores & Algorithms

§ Fistulas continue to have high rates of FTM /non- suitability for dialysis § Risk scores are tools that may support a clinician/surgeon’s decision making

§ Multiple variables must be considered in deciding on hemodialysis AVF creation – patient age, comorbidity, vessel characteristics, timing +more

§ Tangri KFRE may be used in help priorize urgency for decision making and planning for AVF creation and use § FTM Score is one tool that may assist in determining risk of fistula failure § Fistulas remain the preferred vascular access for dialysis if they mature and are usable § Grafts are a reasonable alternative and better than a catheter whenever a fistula is not feasible or appropriate

THANK YOU!