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Capri

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Capri

  1. 1. Shear stress imaging and palpography Frank Gijsen, Jolanda Wentzel, Attila Thury, Frits Mastik, Johannes Schaar, Johan Schuurbiers, Pim de Feyter, Ton van der Steen, Patrick Serruys, and Cornelis Slager Thoraxcenter, Erasmus MC
  2. 2. Shear stress and atherosclerosis Shear stress has a strong impact on endothelial function. In the presence of risk factors, low shear stress is one of the key factors in localizing early atherosclerosis. Shear stress regulated compensatory remodelling prevents plaque protrusion into the lumen in early atherosclerosis. Vanderlaan, ATVB 2004
  3. 3. Shear stress and atherosclerosis cap lipid core high shear stress low shear stress flow
  4. 4. Slager et al., Nature Clinical Practice, accepted for publication
  5. 5. Shear stress and atherosclerosisShear stress and atherosclerosis Aim: Investigate, in coronary arteries of patients, the relationship between shear stress and plaque vulnerability. Working hypothesis: Early atherosclerosis: low shear stress is one of the localizing factors of the disease and high shear stress acts protective. Advanced atherosclerosis: high shear stress might enhance plaque vulnerability.
  6. 6. ANGUS  3D wall thickness ANGUS + CFD  3D shear stress ANGUS + palpo  3D strain data high low
  7. 7. midcap upstream shoulder shoulder downstream flow Scoring system for shear stress and strain: 1: high 0: average -1: low MethodsMethods
  8. 8. Results: shear stressResults: shear stress 1 0 -1 downstream 15 1 0 -1 shoulders 15 15 1 0 -1 midcap 11 5 1 1 0 -1 upstream 1 87 u s m d 0.38 0.64 0.59 -1.00
  9. 9. Results: shear stressResults: shear stress 0.31 0.55 0.12 -0.47 u s m d 1 0 -1 downstream 9 42 1 0 -1 shoulders 12 10 1 0 -1 upstream 8 5 3 1 0 -1 midcap 4 11 2
  10. 10. ResultsResults u s m d meanstrain p < 0.01 p < 0.01 meanshearstress 0.38 0.64 0.59 -1.00 p = 0.07 0.31 0.55 0.12 -0.47
  11. 11. ResultsResults NS p < 0.01 meanstrain shear stress -1 0 1 0.47 0.19 -0.41
  12. 12. Discussion and conclusions Low shear stress downstream of a plaque relates to low strain. High shear stress and high strain occur at shoulders, midcap and upstream part of the plaque. High shear stress predicts the location of high strain spots. Follow-up data have to reveal if this relationship is confirmed.
  13. 13. Methods: matchingMethods: matching Volcano data CVIS data
  14. 14. MethodsMethods Shear stress: 3D lumen and wall info from ANGUS (biplane ANGiography and IVUS) combined with Computational Fluid Dynamics. Strain data: IVUS based data palpography data render radial strain map at lumen wall. Challenge: match ANGUS (CVIS) with palpography data (Volcano) using anatomical landmarks.
  15. 15. MethodsMethods Patients: Sub-population from the IBIS trial (n=10) Segments: We analyzed 21 segments (average length 18.6 mm), 4 contained no plaques, the remaining 17 segments rendered 22 plaques that could be analyzed. Average plaque data: wall thickness: WT = 0.76 ± 0.20 mm shear stress: SS= 1.83 ± 0.81 Pa strain: STR= 0.56 ± % at 3 mmHg
  16. 16. Results: strainResults: strain 1 0 -1 midcap 4 11 2 1 0 -1 upstream 8 5 3 1 0 -1 shoulders 12 10 1 0 -1 downstream 9 42

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