Method and apparatus for detecting the onset and relative degree of atherosclerosis in humans
First Claim
1. An apparatus for detecting the onset of atherosclerosis comprising:
- means for changing blood flow through an artery with the application of differing amounts of induced pressure thereat;
means for sensing an arterial blood volume differential while said artery is placed under said differing amounts of induced pressure and generating a representative signal;
means for determining whether a function of said volume differential representative signal at said differing amounts of induced pressure defines a waveform peak; and
,means, coupled to said means for determining, for generating an atherosclerosis indicator signal in the absence of said waveform peak.
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Accused Products
Abstract
The present invention relates to a method for detecting the onset of atherosclerosis and for detecting the degree of atherosclerosis. Accordingly, one aspect of the present invention correlates data obtained from arteries having a measured amount of stenosis with actual arterial data (blood volume change vs. cuff pressure) obtained from a patient which is converted into data relating to the patient'"'"'s arterial peak compliance. Another aspect of the present invention detects the onset and the degree of atherosclerosis by classifying the shape of a curve obtained by relating arterial blood volume change with cuff pressure. Two devices can be used, an electrical impedance plethysmograph and a volume plethysmograph.
77 Citations
23 Claims
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1. An apparatus for detecting the onset of atherosclerosis comprising:
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means for changing blood flow through an artery with the application of differing amounts of induced pressure thereat; means for sensing an arterial blood volume differential while said artery is placed under said differing amounts of induced pressure and generating a representative signal; means for determining whether a function of said volume differential representative signal at said differing amounts of induced pressure defines a waveform peak; and
,means, coupled to said means for determining, for generating an atherosclerosis indicator signal in the absence of said waveform peak. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for detecting the degree of atherosclerosis in an artery comprising:
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means for changing blood flow through an artery with the application of differing amounts of induced pressure thereat; means for sensing an arterial blood volume differential while said artery is placed under said differing amounts of induced pressure and generating representative data; means for relating said volume differential representative data to data representing said differing amounts of induced pressure; means, coupled to said means for relating, for correlating the volume differential-induced pressure relationship with one of a plurality of predetermined waveform shapes; and
,means for generating one of a plurality of atherosclerosis indicator signals based upon the waveform correlation wherein each indicator signal indicates a different degree of atherosclerosis. - View Dependent Claims (9, 10, 11)
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12. An apparatus for non-invasively detecting the relative degree of atherosclerosis in a patient comprising:
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means for changing blood flow through an artery by placing relatively discrete levels of pressure on a portion of said artery; means for non-invasively sensing blood volume as an impedance pulse in said artery at various induced pressure levels and generating an impedance pulse signal representative thereof, and obtaining a representative signal of a tissue impedance near said artery; means for calculating an arterial blood volume differential from said impedance pulse signal and the tissue impedance signal; means for sensing and calculating a blood pressure differential of the patient; means for obtaining a peak compliance value by determining a maximal ratio of the blood volume differential and blood pressure differential by repeatedly obtaining the arterial blood volume differential at different induced levels of arterial pressures; means for providing a target value related to at least one factor of factors from the group consisting of a chronological age of said patient, said representative signal of said tissue impedance, said target value being based upon a quantitative analysis of arteries possessing different degrees of atherosclerosis; means for determining and indicating the relative degree of atherosclerosis by comparing said target value with a patient specific value that is computed using a predetermined correlation incorporating said peak compliance value and at least one characteristic value from the group consisting of a detected systolic pressure, a detected diastolic pressure, an ascertained cholesterol level and the patient'"'"'s chronological age, all obtained from said patient. - View Dependent Claims (13, 14)
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15. A non-invasive apparatus for detecting atherosclerosis of a patient comprising:
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means for changing blood flow through an artery with the application of discrete levels of induced pressure thereat; means for obtaining an arterial blood volume differential by non-invasively sensing pulsatile blood flow through said artery while said artery is placed under said discrete levels of induced pressure; means for sensing and calculating a pressure differential of the pulsatile blood flow passing through an arterial system that includes said artery; means for obtaining a peak compliance value by determining a maximal ratio of the blood volume differential and the pressure differential; means for providing a target value for said patient using a first predetermined correlation incorporating at least one from the group consisting of a patient'"'"'s chronological age factor, a tissue factor characteristic of said patient, a diastolic pressure, a systolic pressure, and a cholesterol level, said first predetermined correlation derived from a quantitative analysis of arteries possessing different degrees of atherosclerosis; means for calculating and indicating the relative degree of atherosclerosis by comparing said target value with a patient specific value that is computed using a second predetermined correlation with said peak compliance value and at least one characteristic value from the group consisting of a detected systolic pressure, a detected diastolic pressure, an ascertained cholesterol level and the patient'"'"'s chronological age, all obtained from said patient. - View Dependent Claims (16, 17)
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18. An apparatus for detecting the degree of atherosclerosis of a patient under study comprising:
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means for changing blood flow through an artery with the application of discrete levels of induced pressure thereat; means for obtaining an arterial blood volume differential from said artery while said artery is placed under said discrete levels of induced pressure; means for obtaining the patient'"'"'s blood pressure differential from said artery while said artery is placed under said discrete levels of induced pressure; means for calculating a peak arterial compliance value by selecting the maximal ratio of said volume differential and said pressure differential; means for providing a target value for said patient using a first predetermined correlation incorporating at least one from the group consisting of a patient'"'"'s chronological age factor, a patient'"'"'s tissue factor, a diastolic pressure, a systolic pressure, and a cholesterol level, said first predetermined correlation derived from a quantitative analysis of arteries possessing different degrees of atherosclerosis; means for determining and indicating the relative degree of atherosclerosis by comparing said target value with a patient specific value from a second predetermined correlation incorporating said peak compliance value and at least one characteristic value from the group consisting of a detected systolic pressure, a detected diastolic pressure, an ascertained cholesterol level and the patient'"'"'s chronological age, all obtained from said patient. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification