Wei-Hsin Tien

Characterization of a Bioprosthetic Bicuspid Venous Valve Hemodynamics and Implications for Mechanism of Valve Dynamics

of CCSVI. We hypothesize that the BA effect on clinical parameters is mediated by mechanical stimulation of perivascular autonomic fibers and is independent of vascular obstruction. The purpose of this study is to describe Trans-Vascular Autonomic Modulation (TVAM) in multiple sclerosis (MS) patients as a means of improving ANS dysfunction, comparing its safety and efficacy to the traditional BA. Methods: Twenty-one MS patients who presented with symptoms of cardiovascular ANS dysfunction underwent TVAM. These patients were compared with 20 MS patients who presented with CSSVI, and who underwent traditional BA. TVAM deviated from traditional BA in that target veins, bilateral internal jugular, azygos, and left renal veins, were each dilated regardless of the presence of vascular abnormalities. This also included treatment of patients without evidence of abnormality in any of the target veins, eliminating the possibility of vascular effect. The improvement in cardiovascular ANS function was indicated by determining R-R interval variations during deep breathing (MCR, E/I ratio), valsalva maneuver (valsalva ratio), and postural changes (30:15 postural ratio). Results: The safety profile of the TVAM procedure was similar to that of the traditional BA with no adverse events occurring in either group. However, TVAM increased MCR, E/I ratio, and postural ratio more significantly than the traditional BA. Postintervention, improvements were seen in the TVAM group relative to baseline for MCR (3.34 6 0.41 vs 2.44 6 0.48; 36.4%; P 1⁄4 .08), E/I ratio (1.11 6 0.01 vs 1.09 6 0.01; 1.8%; P 1⁄4 .3), valsalva ratio (1.95 6 0.09 vs 1.74 6 0.09; 12%; P 1⁄4 .10), and postural ratio (1.36 6 0.08 vs 1.04 6 0.09; 30.7%; P 1⁄4 .027). The postural ratio response in the TVAM group relative to baseline (1.36 6 0.08 vs 1.04 6 0.09; 30.7%; P 1⁄4 .027) demonstrated the largest change relative to postintervention postural ratio in the control group (1.36 6 0.08 vs 1.167 6 0.03; 16.5%; P 1⁄4 .016). Conclusions: TVAM-mediated deposition of mechanical energy to central veins by balloon dilation, including anatomically normal veins, can improve indicators of ANS dysfunction. The observed safety and efficacy of TVAM is encouraging, paving the way for the treatment of ANS dysfunction in pathological states other than MS. Further studies should investigate the response to TVAM in larger cohort. Characterization of a Bioprosthetic Bicuspid Venous Valve Hemodynamics and Implications for Mechanism of Valve Dynamics W. Tien, H. Chen, Z. Berwick, J. Krieger, S. Chambers, D. Dabiri, G. Kassab. University of Washington, Seattle, Wash; 3DT Holdings, LLC, Indianapolis, Ind; COOK Medical, Bloomington, Ind; Indiana University School of Medicine, Indianapolis, Ind

Hemodynamic Role of Sinus on Venous Valve Performance

measurement of stenosis was compared with the adjacent nonstenotic iliofemoral veins. If more than 50% cross sectional area or diameter reduction was found via IVUS imaging, it was treated with appropriate balloon size (range, 10 40-16 60) and stent (12-24 mm diameter by 40-90 mm length). Results: A total of 233 lesions were identified, with 115 in left lower extremity (LLE) and 118 in right lower extremity (RLE). The CEAP classification score in the LLE were C1, 0; C2, 35; C3, 40; C4, 15; C5, 20; C6, 6; with the most common site being proximal common iliac vein, 37.4% (20.86% females and 16.5% males). The CEAP classification score in the RLE were C1, 0; C2, 31; C3, 42; C4, 14; C5, 23; C6, 7; while most common site was middle external iliac vein, 31.35% (20.4% females and 11.01% males). The least common site of the NIVL was noted in LLE in the distal external iliac vein, 2.6% (2.6% females and 0% males). In the RLE, the least common site of NIVL was also in the distal external iliac vein, 7.62% (5.93% females and 1.69% males). No correlation between age, laterality, gender, or CEAP score has been noted. Conclusions: This analysis gives an insight into understanding the anatomical locations of the NIVL that are an often undiagnosed cause of lower extremity venous diseases. Despite multiple questions not yet answered, it gives an insight to clinicians and researchers to guide their treatment and research.

Color-Coded Three-Dimensional Micro Particle Tracking Velocimetry and Its Applications

A color-coded three-dimensional particle image velocimetry is successfully adapted into a microscopic setup using a 10X objective lens. A three-pinhole plate, color-coded by color filters of different wavelengths, is utilized to create a triangular triple exposure pattern on the image sensor plane for each tracer particle in the flow. The 3-D physical location of the particle can then be calculated from the size of the triangle pattern with micrometer accuracy. Light sources of different wavelengths are aligned with the corresponding pinholes, and a color separation algorithm based on principal component transformation (PCT) is developed to account for the signal crosstalk issues caused by the color filters. A particle identification method modified from cascade correlation method is used to resolve the peak locations of heavily overlapped particle images, and the triplet exposures are matched to reconstruct the 3D particle locations with a calibration-based epi-polar line search method. The velocity field is resolved by a vision-based particle tracking algorithm to track the individual particle movement between the reconstructed particle fields from each image pair. The experimental uncertainties of the system verified with experiments shows that the location uncertainties are less than 0.10µm and 0.08µm for the in-plane, and less than 0.82µm for the out-of-plane components, respectively. The displacement uncertainties are 0.62 µm and 0.63µm for the in-plane, and 0.77µm for the out-of-plane components, respectively. With the ability to tack particles in higher particle densities, the experimental setup is used to image a 600 µm × 600 µm × 600 µm volume of a backward-facing step micro-channel flow. Both results of steady flow and decelerating flow are presented, ranging from Reynolds number 0.825 to 0.033.