1. Quantitation of vascular outflow by measurement of impedance
Lewis B. Schwartz, MD, Cemil M. Purut, MD, Martin K. O'Donohoe, MB, FRCSI, Peter K. Smith, MD, Per-Otto Hagen, PhD, Richard L. McCann, MD 
Journal of Vascular Surgery 
Volume 14, Issue 3, Pages (September 1991)
DOI: / (91)90088-C
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

2. Fig. 1
Surgical procedures designed to create four distinct outflow beds for similar segments of external jugular vein in New Zealand white rabbits. A, Carotid interposition vein graft (VG); B, Linguofacial-common carotid arteriovenous fistula (AVF); C, AVF with clip applied distally (AVFobs); D, vein graft and arteriovenous fistula in series (VG/AVF). Arrows denote direction of flow.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

3. Fig. 2
Representative pressure waveforms for VG, AVF, AVFobs, and VG/AVF groups. Two consecutive beats are shown. Scales are not identical. Digital data were filtered after acquisition at 25 Hz (for display purposes).
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

4. Fig. 3
Representative flow waveforms for VG, AVF, AVFobs, and VG/AVF groups. Two consecutive beats are shown. Scales are not identical. Digital data were filtered after acquisition at 25 Hz (for display purposes).
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

5. Fig. 4
Impedance moduli and phase angles for 14 vein grafts (VG). Data points represent mean ± SEM. Zn = modulus of impedance, θn = phase angle of impedance.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

6. Fig. 5
Comparison of impedance between VG (○) and AVF (□) groups. Data points represent mean ± SEM. Zn = modulus of impedance, θn = phase angle of impedance. *p < 0.05 compared to VG.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

7. Fig. 6
Comparison of impedance between AVF (□) and AVFobs (Δ) groups. Data points represent mean ± SEM. Zn = modulus of impedance, θn = phase angle of impedance. *p < 0.05 compared to AVF.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

8. Fig. 7
Comparison of impedance between VG (○) and VG/AVF (▿) groups. Data points represent mean ± SEM. Zn = modulus of impedance, θn = phase angle of impedance. *p < 0.05 compared to VG.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

9. Fig. 8
Procedure for clamping the distal linguofacial vein to increase flow in the AVF group. CCA = common carotid artery, EJ = external jugular vein.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

10. Fig. 9
Modulus of pressure (Pn) for 7 AVF's during control periods (○) and after clamping of the distal linguofacial vein (□). Data points represent mean ± SEM. *p = compared to control.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

11. Fig. 10
Modulus of flow (Qn) for 7 AVF's during control periods (○) and after clamping of the distal linguofacial vein (□). Data points represent mean ± SEM. *p < 0.05 compared to control.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions

12. Fig. 11
Modulus of impedance (Zn) for 7 AVF's during control periods (○) and after clamping of the distal linguofacial vein (□). Data points represent mean ± SEM. There were no differences between control and clamp periods at any harmonic of frequency.
Journal of Vascular Surgery  , DOI: ( / (91)90088-C)
Copyright © 1991 Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter Terms and Conditions