INFLUENCE OF ABDOMINAL AORTIC CURVATURE AND RESTING VERSUS EXERCISE CONDITIONS ON VELOCITY-FIELDS IN THE NORMAL ABDOMINAL AORTIC BIFURCATION

Local hemodynamics are considered an important atherogenetic factor in the abdominal aortic bifurcation. This study addresses the quantitati ve flow fields in a pulsatile flow model of a normal abdominal aortic bifurcation when encountering realistic upstream anatomy, realistic in let flow conditions and different physiologic flow conditions (rest vs . exercise). Two-dimensional laser Doppler anemometry measurements gav e axial as well as radial velocities. The localization and magnitude o f peak velocities, retrograde flow and secondary velocity patterns wer e found to be determined to a great extent by the curvature of the abd ominal aorta, the triphasic flow wave form and the inlet velocity prof ile. Significant changes were also seen when simulating different phys iologic flow conditions. Thus retrograde velocities were present at bo th the flow divider and the lateral vessel wall for the rest condition but not for the exercise flow conditions, and the location of low and retrograde velocities during diastole were as much determined by abdo minal aortic curvature as by the bifurcation for nearly all flow condi tions and locations. In conclusion, the anatomy and hemodynamics in th e abdominal aorta cannot be neglected when studying the hemodynamics i n the abdominal aortic bifurcation.