Detecting vascular stenosis in chronic hemodialysis patients
First Claim
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1. A method of detecting an occlusion in a blood conduit of a hemodialysis patient comprising:
- inserting a velocity detector into an examined blood conduit at a selected site;
measuring velocity of the blood flow in a first region of the examined blood conduit;
moving said velocity detector to a second region of the examined blood conduit;
measuring velocity of the blood flow in at least a second region of the examined blood conduit;
and comparing the velocities measured in the different regions to obtain an indication of an occlusion in said blood conduit.
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Abstract
Stenotic regions in the vasculature of chronic hemodialysis patients are detected and monitored by blood velocity measuring.
38 Citations
45 Claims
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1. A method of detecting an occlusion in a blood conduit of a hemodialysis patient comprising:
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inserting a velocity detector into an examined blood conduit at a selected site; measuring velocity of the blood flow in a first region of the examined blood conduit; moving said velocity detector to a second region of the examined blood conduit; measuring velocity of the blood flow in at least a second region of the examined blood conduit; and comparing the velocities measured in the different regions to obtain an indication of an occlusion in said blood conduit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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11. The method of claim 10 wherein said velocity is a phasic velocity.
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12. The method of claim 10 wherein said velocity is a mean velocity averaged over at least one heart beat.
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13. The method of claim 9 further comprising controlling the orientation of said doppler transducer relative to the measured blood flow to achieve reliable velocity measurements.
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14. The method of claim 9 wherein said velocity is a phasic velocity.
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15. The method of claim 9 wherein said velocity is a mean velocity averaged over at least one heart beat.
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16. The method of claim 9 further comprising:
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moving said doppler transducer to a second region of said blood conduit; measuring a velocity of blood flow in said second region; and determining cross-sectional area of said second region based on said measured velocities.
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17. The method of claim 16 further comprising the steps of forming a profile of said blood conduit by correlating said measured cross-sectional areas and their locations.
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18. The method of claim 17 further comprising visually displaying said profile.
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19. The method of claim 1 further comprising repeating the method of claim 1 at a later date and comparing the velocity measurement provided by the method of claim 1 at an earlier date with that at a later date.
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20. A system for detecting a partial occlusion in a blood conduit of a hemodialysis patient comprising:
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a velocity detector insertable into different regions of an examined blood conduit at a selected site used for hemodialysis access, said velocity detector constructed to provide velocity signals representative of velocity of the blood flow at said different regions; and a processor constructed to receive said velocity signals from said detector and arranged to compare said velocity signals measured at different regions of the examined blood conduit to create a velocity profile. - View Dependent Claims (21, 22, 23)
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24. A method of detecting an occlusion in a blood conduit of a hemodialysis patient including,
inserting a velocity sensing device into said conduit to provide a velocity signal representative of the velocity of blood flow in said conduit at the location of said device in said conduit and a position signal representative of said location, moving said velocity sensing device through said conduit, and sensing a significant change in said velocity signal and the position signal when said significant change occurs to provide an indication of the location of an occlusion in said blood conduit.
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26. Apparatus for detecting an occlusion in a blood conduit of a hemodialysis patient comprising,
a velocity sensing device in said conduit constructed and arranged to provide a velocity signal representative of the velocity of blood flow in said conduit at the location of said device in said conduit and a position signal representative of said location, said velocity sensing device being movable through said conduit, and a detector constructed and arranged to sense a significant change in said velocity signal and the position signal when said significant change occurs to provide an indication of the location of an occlusion in said blood conduit.
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28. A method of detecting an occlusion in a blood conduit of a hemodialysis patient comprising the steps of:
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locating a section of blood flow conduit having a zone of a known cross-sectional area; substantially all blood passing through said zone also flowing in the examined blood conduit; measuring a velocity of the blood flow in said zone; measuring a velocity of the blood flow in a region of the examined blood conduit; and determining a cross-sectional area of said region based on said velocities. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A system for detecting a stenosis in a blood conduit of a hemodialysis patient comprising:
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a detector constructed and arranged to provide velocity signals representative of velocity of the blood flow; a blood flow conduit having a zone of a known cross-sectional area that intercepts substantially all blood flowing in said blood conduit; and a processor constructed and arranged to receive velocity signals from said detector and provide an area signal representative of a cross-sectional area of a region of said blood conduit. - View Dependent Claims (41, 42, 43, 44, 45)
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Specification