Flow Analyses of Microvascular Bifurcation Using Laser Doppler Anemometry

Abstract

Introduction Vascular surgery affects, among other factors, vessel geometry and might result in significant flow changes. For this reason a basic understanding of flow behavior at bifurcations plays an important role for microsurgeons. The aim of the present work was to establish an experimental model that enables rheological analyses of microvascular techniques.

Methods Laser Doppler anemometer (LDA) measurements in a total of four cross-sections of a true-to-scale silicone model were performed. The model was installed in a circulatory experimental setup that simulates the physiologic human blood flow. The flow velocity data measured with the LDA system was processed and analyzed with an image-processing system.

Results The flow curve at each cross-section was recorded for sevem cycles. A physiologic flow separation at bifurcational level was seen. Maximal and minimal horizontal velocities of all measurement points were between 0.32 and −0.15 m/s. No signs of turbulentlike flow were seen in the cross-sections distal to the bifurcation. A total, centrally located backflow in the diastolic phases in all four cross-sections was registered, resembling an oscillatorylike flow.

Conclusions The LDA analysis represents a valid experimental method for rheological evaluation of microvessels. Due to its unique high spatial and temporal resolution, it represents a worthwhile alternative to other flow investigations.

Keywords

laser Doppler anemometry - rheological analyses - elastic true-to-scale model - microsurgery

• References

• 1 Hayhurst JW, O'Brien BM. An experimental study of microvascular technique, patency rates and related factors. Br J Plast Surg 1975; 28 (2) 128-132
• 2 Chen KT, Mardini S, Chuang DC , et al. Timing of presentation of the first signs of vascular compromise dictates the salvage outcome of free flap transfers. Plast Reconstr Surg 2007; 120 (1) 187-195
• 3 Bui DT, Cordeiro PG, Hu QY, Disa JJ, Pusic A, Mehrara BJ. Free flap reexploration: indications, treatment, and outcomes in 1193 free flaps. Plast Reconstr Surg 2007; 119 (7) 2092-2100
• 4 Chien S. Effects of disturbed flow on endothelial cells. Ann Biomed Eng 2008; 36 (4) 554-562
• 5 Chiu JJ, Chien S. Effects of disturbed flow on vascular endothelium: pathophysiological basis and clinical perspectives. Physiol Rev 2011; 91 (1) 327-387
• 6 Zhang L, Moskovitz M, Piscatelli S, Longaker MT, Siebert JW. Hemodynamic study of different angled end-to-side anastomoses. Microsurgery 1995; 16 (2) 114-117
• 7 Rao VK, Morrison WA, Angus JA, O'Brien BM. Comparison of vascular hemodynamics in experimental models of microvascular anastomoses. Plast Reconstr Surg 1983; 71 (2) 241-247
• 8 Nam DA, Roberts III TL, Acland RD. An experimental study of end-to-side microvascular anastomosis. Surg Gynecol Obstet 1978; 147 (3) 339-342
• 9 Neville RF, Elkins CJ, Alley MT, Wicker RB. Hemodynamic Comparison of Differing Anastomotic Geometries Using Magnetic Resonance Velocimetry. J Surg Res 2011; 169 (2) 311-318
• 10 Migliavacca F, Dubini G. Computational modeling of vascular anastomoses. Biomech Model Mechanobiol 2005; 3 (4) 235-250
• 11 Holm C, Mayr M, Höfter E, Dornseifer U, Ninkovic M. Assessment of the patency of microvascular anastomoses using microscope-integrated near-infrared angiography: a preliminary study. Microsurgery 2009; 29 (7) 509-514
• 12 Liepsch D, Poll A, Strigberger J, Sabbah HN, Stein PD. Flow visualization studies in a mold of the normal human aorta and renal arteries. J Biomech Eng 1989; 111 (3) 222-227
• 13 Levesque MJ, Liepsch D, Moravec S, Nerem RM. Correlation of endothelial cell shape and wall shear stress in a stenosed dog aorta. Arteriosclerosis 1986; 6 (2) 220-229
• 14 Pevec WC, L'Italien GJ, Megerman J, Cambria RP, Abbott WM. Abnormal wall strain at distal end-to-side anastomoses. Ann Vasc Surg 1993; 7 (1) 14-20
• 15 Pries AR, Neuhaus D, Gaehtgens P. Blood viscosity in tube flow: dependence on diameter and hematocrit. Am J Physiol 1992; 263 (6 Pt 2) H1770-H1778
• 16 Liepsch D, Thurston G, Lee M. Studies of fluids simulating blood-like rheological properties and applications in models of arterial branches. Biorheology 1991; 28 (1-2) 39-52
• 17 Liepsch D, Moravec S, Baumgart R. Some flow visualization and laser-Doppler-velocity measurements in a true-to-scale elastic model of a human aortic arch—a new model technique. Biorheology 1992; 29 (5-6) 563-580
• 18 Dorn F, Niedermeyer F, Balasso A, Liepsch D, Liebig T. The effect of stents on intra-aneurysmal hemodynamics: in vitro evaluation of a pulsatile sidewall aneurysm using laser Doppler anemometry. Neuroradiology 2011; 53 (4) 267-272
• 19 Liepsch D, Pflugbeil G, Matsuo T, Lesniak B. Flow visualization and 1- and 3-D laser-Doppler-anemometer measurements in models of human carotid arteries. Clin Hemorheol Microcirc 1998; 18 (1) 1-30
• 20 Chien S. Mechanotransduction and endothelial cell homeostasis: the wisdom of the cell. Am J Physiol Heart Circ Physiol 2007; 292 (3) H1209-H1224
• 21 Zarins CK, Giddens DP, Bharadvaj BK, Sottiurai VS, Mabon RF, Glagov S. Carotid bifurcation atherosclerosis. Quantitative correlation of plaque localization with flow velocity profiles and wall shear stress. Circ Res 1983; 53 (4) 502-514
• 22 Chiu JJ, Usami S, Chien S. Vascular endothelial responses to altered shear stress: pathologic implications for atherosclerosis. Ann Med 2009; 41 (1) 19-28
• 23 Liepsch D. Biofluid mechanical studies in models of blood vessels and some applications. Journal of Engineering Physics and Therrnophysics 1996; 69 (3) 316-328
• 24 Zhao SZ, Papathanasopoulou P, Long Q, Marshall I, Xu XY. Comparative study of magnetic resonance imaging and image-based computational fluid dynamics for quantification of pulsatile flow in a carotid bifurcation phantom. Ann Biomed Eng 2003; 31 (8) 962-971
• 25 Botnar R, Rappitsch G, Scheidegger MB, Liepsch D, Perktold K, Boesiger P. Hemodynamics in the carotid artery bifurcation: a comparison between numerical simulations and in vitro MRI measurements. J Biomech 2000; 33 (2) 137-144
• 26 Vera N, Steinman DA, Ethier CR, Johnston KW, Cobbold RS. Visualization of complex flow fields, with application to the interpretation of colour flow Doppler images. Ultrasound Med Biol 1992; 18 (1) 1-9
• 27 Picot PA, Rickey DW, Mitchell R, Rankin RN, Fenster A. Three-dimensional colour Doppler imaging. Ultrasound Med Biol 1993; 19 (2) 95-104
• 28 Harloff A, Albrecht F, Spreer J , et al. 3D blood flow characteristics in the carotid artery bifurcation assessed by flow-sensitive 4D MRI at 3T. Magn Reson Med 2009; 61 (1) 65-74
• 29 Maniatis TA, Cobbold RS, Johnston KW. Two-dimensional velocity reconstruction strategies for color flow Doppler ultrasound images. Ultrasound Med Biol 1994; 20 (2) 137-145
• 30 Faik I, Mongrain R, Leask RL, Rodes-Cabau J, Larose E, Bertrand O. Time-dependent 3D simulations of the hemodynamics in a stented coronary artery. Biomed Mater 2007; 2 (1) S28-S37
• 31 Ku DN, Liepsch D. The effects of non-Newtonian viscoelasticity and wall elasticity on flow at a 90 degrees bifurcation. Biorheology 1986; 23 (4) 359-370
• 32 Mücke T, Wolff KD, Wagenpfeil S, Hölzle F, Scholz M. Reliability of near-infrared angiography and micro-Doppler sonography for evaluating microvascular anastomoses. Plast Reconstr Surg 2010; 126 (5) 1506-1514
• 33 Zhang F, Sones WD, Lineaweaver WC. Microsurgical flap models in the rat. J Reconstr Microsurg 2001; 17 (3) 211-221