current procjects the effect of avf size and position on distal perfusion focus: alter diameter,...
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CURRENT PROCJECTSThe Effect of AVF Size and Position on Distal Perfusion
Focus: Alter diameter, length and position of fistula and monitor changes in hemodynamics of system
CFD (Computational Fluid Dynamics) ModelingFocus: Alteration of fistula diameter and the resulting changes in flow patterns
FUTURE PROJECTS The Hemodynamics of AVF and DRIL Bypass Focus: Understand hemodynamics of system with AVF and DRIL, study hemodynamics of DRIL and optimal treatment for ischemic steal.
Mean Aortic Flow: 4.2 L/min
Hollow Tygon tubingFeatures: Tubing length and thickness match vessel compliance and anatomy and includes venous return
Glycerin and WaterFeatures: Match blood viscosity
Connectors with fabricated pressure tapsFeatures: Non- Compliant tubing, capable of acquiring pressure measurements at each junction through pressure transducers, one-way valve included in venous return
Hand compliance chamberFeatures: Column of water below column of pressurized air, accurately mimics compliance and resistance of hand capillary bed
Heart SimulatorFeatures: Ventricular and Venous Compliance chamber, ventricular and buffing chamber, two artificial valves, driven by Servo motor, outputs pulsatile flow
Complete in Vitro Model of the Pulsatile Upper Extremity Arteriovenous Circulation: a Platform for Hemodynamic Testing and Modeling
Ankur Chandra, MD1, Nicole A. Varble, BS2, Dan B. Phillips, Ph.D.2, Steven W. Day, Ph.D.2, Karl Schwarz, M.D.1, Karl A. Illig, M.D.1. 1University of Rochester Medical Center, Rochester, NY, USA, 2Rochester Institute of Technology, Rochester, NY, USA.
Introduction Results Conclusions
Methods and Materials
Current and Future Work
Venous Compliance Chamber
Ventricular Compliance Chamber
Valve Viewing Chamber
Buffing Chamber
Ventricular Chamber
Intersection of Arm
Vasculature
Subclavian A.
Aorta
Axillary A.
Brachial
Ulnar
Radial
Compliance Chamber
Distal Arm V.
One-Way Check Valve
Axillary V.
Subclavian V.
Body Resistance
Collateral
The experimental study of pulsatile arterial and venous hemodynamics is challenging. Mathematical modeling struggles to accurately represent the capillary bed/venous circulation while in vivo animal models are expensive and labor intensive.
We hypothesized that an in vitro, physiologic model of the extremity arteriovenous (AV) circulation could be created as a platform for hemodynamic modeling and testing.
In vitro upper extremity vascular simulator with pressure waveforms at specified locations
Physiologically representative, in vitro, fluid model of the extremity AV circulation which incorporates:• Vessel wall compliance• Blood viscosity• Capillary bed physiology• Variation of all aspects of input hemodynamics (B.P., C.O., and SV) with
heart simulator Applications:Ideal tool to study complex hemodynamics of dialysis access and steal physiology, device testing, surgical simulation
1004.58 L/min
1310 mL/min
1317 mL/min
1260 mL/min
1280 mL/min
29 mL/min
29 mL/min
39 mL/min-20 mL/min
65 mL/min
136 mL/min
1375 mL/min
1410 mL/min
1260 mL/min84 mL/min
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65
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47
35
28
Mean Flows and Pressures are labeled at the appropriate vessels and connectors
above. Pressures [mmHg] are indicated by balloons: #
0 0.5 1 1.5 2 2.5 30
20
40
60
80
100
120
140
time
mm
Hg
P2- Subclavian Artery
0 0.5 1 1.5 2 2.5 30
20
40
60
80
100
120
140
time
mm
Hg
P7: Radial- Ulnar Bifurcation
0 0.5 1 1.5 2 2.5 30
20
40
60
80
100
120
140
time
mm
Hg
P12- Venous Return
0 0.5 1 1.5 2 2.5 30
20
40
60
80
100
120
140
time
mm
Hg
P14- Venous Return
Retrograde Flow
Brachial A.: 121/54 mmHg (91.92 mmHg)
SC V.: 17.63 mmHg
Distal Venous Return: 41.30 mmHg
SC A.: 125/55 mmHg (90.47 mmHg)
CFD Model of brachial artery bifurcated with AVF