disclosure recognition and diagnosis of high-flow ... · recognition and diagnosis of high-flow...

Recognition and Diagnosis of High-Flow Autogenous Accesses

Dirk Hentschel, MDDirector, Interventional Nephrology

Brigham and Women’s Hospital

ASDIN 9th Annual Scientific MeetingWashington, DC, February 17, 2013

Disclosure

• Proteon Therapeutics

What is a High-Flow Autogenous Access? What is a High-Flow Autogenous Access?

• KDOQI Vascular Access (2006)★ No definition★ single mention in context of AVF aneurysm formation

What is a High-Flow Autogenous Access?

• KDOQI Vascular Access (2006)★ No definition★ single mention in context of AVF aneurysm formation

• EBPG on Vascular Access (2007) ★ “High flow access” := brachial-cubital/cephalic/basilic (upper

arm) autogenous accesses★ no blood flow range

#1

flow 1400ml/min @blood pressure 146/65

#1


#1


#1


#1DMII, HTN, CAD, PVD

“STEAL”

#2 flow 1300ml/min @blood pressure 119/78

#2



#2


#2

decompensatedheart failure

over course of 6 months

#3



#3



#3



#3

inflow-outflow mismatch


#4


#4

Aug-2011 Mar-2011


#4

Aug-2011 Mar-2011

time horizon


#4

Aug-2011 Mar-2011

time horizon

#5



#5

decreased URR/elevated venous pressures - cardiopulmonary

recirculation

type of high flow Steal CV strain inflow-outflow mismatch

Time Horizon(URR)

pulsatility any normal or increased

increased normal

thrill presentjuxta-anastomotic

present only systolic present

bruit continuous continuous pronounced systolic

continuous

augmentation any moderate-strong

moderate-strong

moderate

collapse with gravity

yes yes no yes

Physical exam of high-flow accesses


Time Horizon(URR)


increased normal




continuous


moderate-strong

moderate


yes yes no yes



Time Horizon(URR)


increased normal




continuous


moderate-strong

moderate


yes yes no yes



Time Horizon(URR)


increased normal




continuous


moderate-strong

moderate


yes yes no yes



Time Horizon(URR)


increased normal




continuous


moderate-strong

moderate


yes yes no yes



Time Horizon(URR)


increased normal




continuous


moderate-strong

moderate


yes yes no yes


High-Flow Autogenous Accesses

• High for artery (1400ml/min) - Steal

• High for pump (1300ml/min) - Cardiovascular compromise, heart failure

• High for access (1700ml/min) - inflow-outflow mismatch, enlarging aneurysms

• High for time-considerations (2500ml/min) - transplant patients, “young” dialysis patients

Flow considerations 1


2xR L Δ P η Φ2 1 40 2.6 479.88

2.5 1 40 2.6 1171.5823 1 40 2.6 2429.3934 1 40 2.6 7678.084 1 20 2.6 3839.044 1 10 2.6 1919.52

diameter length pressure gradient at anastomosis

blood viscosity

FLOW ml/min


2xR L Δ P η Φ2 1 40 2.6 479.88

2.5 1 40 2.6 1171.5823 1 40 2.6 2429.3934 1 40 2.6 7678.084 1 20 2.6 3839.044 1 10 2.6 1919.52

diameter length pressure gradient at anastomosis

blood viscosity

FLOW ml/min

arteries adjust to higher flow with increase in diameter to reach 10-25 dyn/cm2 optimum shear stress

higher flow := higher pressure if outflow stenosis

higher pressures := enlargement and calcification


arteries adjust to higher flow with increase in diameter to reach 10-25 dyn/cm2 optimum shear stress

higher flow := higher pressure if outflow stenosis

higher pressures := enlargement and calcification


upper arm access := anastomosis is flow limiting resistor

forearm access := calcified inflow artery may be limiting

f/u #1

Tx x 13 years10mm anastomosis @ brachial artery

f/u #1flow 4200ml/min @blood pressure 125/52

Tx x 13 years10mm anastomosis @ brachial artery

f/u #2 f/u #2

flow 700ml/min @blood pressure

124/85

f/u #2

• apparent lack of systemic vascular disease

• young age

• Access flow >2000; low URR despite large access; high venous pressures

Recognition of “high flow” High Flow Accesses

Patient Characteristics

• apparent lack of systemic vascular disease

• young age

• Access flow >2000; low URR despite large access; high venous pressures

Surgical and Angiographic Characteristics

• location/diameter of inflow artery

• diameter of anastomosis (>3-4mm?)

• velocity of contrast and/or its dilution

• MEASURE... (flow, artery, anastomosis)

Recognition of “high flow” High Flow Accesses

Patient Characteristics• steal - banding, DRIL, proximalization; inflow stenosis

• cardiovascular compromise - banding, ligation

• inflow-outflow mismatch - fix outflow +/- banding

• decreasing URR, chronically elevated venous pressures

Summary

High flow because of symptoms

• steal - banding, DRIL, proximalization; inflow stenosis

• cardiovascular compromise - banding, ligation

• inflow-outflow mismatch - fix outflow +/- banding

• decreasing URR, chronically elevated venous pressures

Summary

High flow because of symptoms

• “Normal” flows: forearm 850 ml/min (n=11); upper arm brachial-cephalic 1580ml/min (n=56) - depends on local surgeons...

• Think about high flow state if flows >1500ml/min, access pulsatile and without collapse after angioplasty

High flow because of potential complications

disclosure recognition and diagnosis of high-flow ... · recognition and diagnosis of high-flow...

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