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Doran Mix1
Joseph Featherall2
University of Rochester School of Medicine and Dentistry1
Rochester Institute of Technology2
Disclosure:None
Objectives:Model physiologic pulsatile blood flow in a
Brachial-Cephalic arterovenous fistula Observe retrograde blood flow in the arterial
segment distal to AVF as a surrogate of access related distal ischemia (ARI)
Observe effect of capacitance and resistance produced by the Distal Revascularization-Interval Ligation procedure (DRIL)
Hypothesis:Pulsatile retrograde blood flow in the arterial
segment distal to the AVF is a function of arterial collateral resistance and capacitance.
Distal Revascularization will promote retrograde blood flow to the distal limb by decreasing collateral resistance and increasing capacitance.
Interval Ligation is needed to prevent retrograde blood flow.
Clinical ApplicationMay 2009: 179,113 patients used AVF for
hemodialysis52.6% of RRT populationRate of Distal Ischemia after fistula creation
~1.6-8%Future reimbursement
based on outcomes
Limitations:Retrograde blood flow in the arterial
segment distal to the AVF is neither necessary nor sufficient for ARI.
Method:Convert pulsatile arterial blood flow into an
electric circuit diagram of an upper arm AVFPressure VoltageFlow CurrentVessel Radius and Length ResistanceVessel Volume CapacitanceFluid Inertia Inductance
Change resistance and capacitance of collaters Hemodynamics in segment distal to AVF
Arterial Windkessel Model
Bridge: Hemodynamic Circuit
Ohms Law: P = Q * R
Poiseuille’s Equation :
Vessel Capacitance:
Fluid Inertia:
The Wheatstone Bridge:
The Wheatstone Bridge
Balancing the Bridge
Anterograde:
No Flow:
Retrograde:
DRILing the BridgeAnterograde:
No Flow:
Retrograde:
Objective#1: Circuit Model
Objective #1: Pulsatile
Objective#2: Distal Flow
Objective#3: DRIL Effect CollateralPressure (mmHg)
Flow In (cc/min)
CollateralRadius (cm)
Rcollateral
Ccollateral
Flow Distal(cc/min)
95/28 860.243 0.16 0.1210 0.0001 -1.20523
95/28 860.47 0.18 0.0728 0.0001 -89.1715
95/28 860.51 0.14 0.1989 0.0001 95.4482
Anterograde:
No Flow:
Retrograde:
Conclusion:Retrograde flow is promoted by Distal
Revascularization: decreasing collateral resistance
Anterograde flow is promoted by Distal Revascularization: decreasing resistance of proximal segment
Interval Ligation removes the distal conduit and effectively removes retrograde flow
Collateral ligation supports anterograde flow
Objectives:Model physiologic pulsatile blood flow in a
Brachial-Cephalic AVFObserve retrograde blood flow in the arterial
segment distal to AVF as a surrogate of access related distal ischemia (ARI)
Observe effect of capacitance and resistance produced by the Distal Revascularization-Interval Ligation procedure