Deriving Central Aortic Systolic Pressure and Analyzing Arterial Waveform Data to Derive Central Aortic Systolic Pressure Values

• US 20080306393A1
• Filed: 09/24/2007
• Published: 12/11/2008
• Est. Priority Date: 06/07/2007
• Status: Active Grant

• Current Assignee: HealthSTATS International Pte Ltd.
• Original Assignee: HealthSTATS International Pte Ltd.
• Inventors: Ting, Choon Meng, Chua, Ngak Hwee
• Granted Patent: US 8,469,895 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence

Abstract

A method of deriving central aortic systolic pressure comprises (a) creating a set having a predetermined number of blood pressure measurements, the set representative of an arterial waveform; (b) determining an integer interval value; (c) averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set; (d) storing the averaged value in a central aortic systolic pressure set; and (e) setting the central aortic systolic pressure as the highest value in the central aortic pressure set. Steps (c) and (d) are repeated with the value of f being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set.

Claims

1. A method of deriving central aortic systolic pressure comprising the steps of:

a. creating a set having a predetermined number of blood pressure measurements, the set representative of an arterial waveform;

b. determining an integer interval value;

c. averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

d. storing the averaged value in a central aortic systolic pressure set; and

e. setting the central aortic systolic pressure as the highest value in the central aortic pressure set,

wherein steps c. and d. are repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set.

2. A method of deriving central aortic systolic pressure according to claim 1, wherein the set of blood pressure measurements substantially equates to a uniform distribution of values from the arterial waveform.

3. A method of deriving central aortic systolic pressure according to claim 2, further including the step of determining the duration of the arterial waveform and where the predetermined number of blood pressure measurement is determined according to the following formula:

Predetermined number=sr×

t

where

sr=the sample rate, in Hz, of a measuring device used to record the blood pressure measurements in the set; and

t=the duration of the arterial waveform

4. A method of deriving central aortic systolic pressure according to claim 3, wherein the integer interval value is a division of the sample rate.

5. A method of deriving central aortic systolic pressure according to claim 4, wherein the integer interval value is the sample rate divided by 4.

6. A method of deriving central aortic systolic pressure according to claim 1, wherein the interger interval value is a division of the predetermined number.

7. A method of deriving central aortic systolic pressure according to claim 6, wherein the integer interval value is within a range the boundaries of which are determined as follows:

i_range=n/(t×

v)±

(n/(t×

30))

where

n is the predetermined number of blood pressure measurements in the set;

t is the duration of the waveform (in seconds); and

v is a predetermined division value.

8. A method of deriving central aortic systolic pressure according to claim 7, where v=4.

9. A method of deriving central aortic systolic pressure according to claim 1, wherein the integer interval value is equal to 60 divided by a predetermined division value.

10. A method of deriving central aortic systolic pressure according to claim 9, wherein the integer interval value is 15.

11. A method of deriving central aortic systolic pressure according to claim 1, wherein the predetermined number of blood pressure measurements in the set is equal to or greater than 15.

12. A method of deriving central aortic systolic pressure according to claim 11, wherein the predetermined number of blood pressure measurements in the set is at least 30.

13. A method of analyzing arterial waveform data to derive central aortic systolic pressure values comprising the steps of:

a) receiving an arterial waveform dataset;

b) dividing each arterial waveform in the arterial waveform dataset into a representative set of blood pressure measurements having a predetermined number;

c) determining an integer interval value for the set being processed;

d) averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

e) storing the averaged value in a central aortic systolic pressure set; and

f) storing the highest value in the central aortic pressure set in a central aortic systolic pressure value set at a position corresponding to the position the arterial waveform being processed occupies in the arterial waveform dataset,

wherein steps b. through f. are repeated for each arterial waveform in the arterial waveform dataset and, for each such repetition, steps d. and e. are further repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set being processed.

14. A method of analyzing arterial waveform data to derive central aortic systolic pressure values comprising the steps of:

a) receiving an arterial waveform dataset, where each arterial waveform in the dataset comprises a representative set of blood pressure measurements having a predetermined number;

b) determining an integer interval value for the set being processed;

c) averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

d) storing the averaged value in a central aortic systolic pressure set; and

e) storing the highest value in the central aortic pressure set in a central aortic systolic pressure value set at a position corresponding to the position the arterial waveform being processed occupies in the arterial waveform dataset,

wherein steps b. through e. are repeated for each arterial waveform in the arterial waveform dataset and, for each such repetition, steps c. and d. are further repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set being processed.

15. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 14, wherein the predetermined number of blood pressure measurements for at least one arterial waveform in the dataset differs from the predetermined number of blood pressure measurements for the other arterial waveforms in the dataset.

16. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 14, wherein the set of blood pressure measurements substantially equates to a uniform distribution of values from the arterial waveform.

17. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 16, further including the step of determining the duration of the arterial waveform, wherein the predetermined number of blood pressure measurement is determined according to the following formula:

Predetermined number=sr×

t

where

sr=the sample rate, in Hz, f a measuring device used to record the blood pressure measurements in the set; and

t=the duration of the arterial waveform

18. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 14, wherein the integer interval value is a division of the sample rate.

19. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 18, wherein the integer interval value is the sample rate divided by 4.

20. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 14, wherein the integer interval value is a division of the predetermined number.

21. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 20, wherein the integer interval value is within a range the boundaries of which are determined as follows:

i_range=n/(t×

v)±

(n/(t×

30))

where

n is the predetermined number of blood pressure measurements in the set;

t is the duration of the waveform (in seconds); and

v is a predetermined division value.

22. A method of deriving central aortic systolic pressure according to claim 21, where v=4.

25. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 14, wherein the predetermined number of blood pressure measurements in the set is equal to or greater than 15.

26. A method of analyzing arterial waveform data to derive central aortic systolic pressure values according to claim 25, wherein the predetermined number of blood pressure measurements in the set is at least 30.

23. A method of deriving central aortic systolic pressure according to clam 14, wherein the integer interval value is equal to 60 divided by a predetermined division value.

24. A method of deriving central aortic systolic pressure according to claim 23, wherein the integer interval value is 15.

27. A system for deriving central aortic systolic pressure comprising:

an arterial waveform measuring device; and

a processing unit;

wherein the arterial waveform measuring device takes a blood pressure measurement at predetermined intervals until at least one arterial waveform is represented by the set of blood pressure measurements taken, the set of blood pressure measurements representative of one arterial waveform then being communicated to the processing unit which;

a) determines an integer interval value;

b) averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

c) stories the averaged value in a central aortic systolic pressure set; and

d) sets the central aortic systolic pressure as the highest value in the central aortic pressure set,

wherein steps b. and c. are repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the number of blood pressure measurements in the set.

28. A computer readable medium having software recorded thereon to derive central aortic systolic pressure, the software including:

set means for creating a set having a predetermined number of blood pressure measurements, the set representative of an arterial waveform;

means for determining an integer interval value;

averaging means to average a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

storing means for storing the averaged value in a central aortic systolic pressure set; and

results means for setting the central aortic systolic pressure as the highest value in the central aortic pressure set;

wherein the functions of the averaging means and storing means are repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set.

29. A computer readable medium having software recorded thereon to analyze arterial waveform data to derive central aortic systolic pressure values comprising, the software including:

communication means for receiving an arterial waveform dataset;

set means for dividing each arterial waveform in the arterial waveform dataset into a representative set of blood pressure measurements having a predetermined number;

interval means for determining an integer interval value for the set being processed;

averaging means for averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

first storing means for storing the averaged value in a central aortic systolic pressure set; and

second storing means for storing the highest value in the central aortic pressure set in a central aortic systolic pressure value set at a position corresponding to the position the arterial waveform being processed occupies in the arterial waveform dataset;

wherein the functions of the set means, interval means, averaging means, first storing means and second storing means. are repeated for each arterial waveform in the arterial waveform dataset and, for each such repetition, the functions of the averaging means and first storing means are further repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set being processed.

30. A computer readable medium having software recorded thereon to analyze arterial waveform data to derive central aortic systolic pressure values, the software including:

a) communication means for receiving an arterial waveform dataset, where each arterial waveform in the dataset comprises a representative set of blood pressure measurements having a predetermined number;

b) interval means for determining an integer interval value for the set being processed;

c) averaging means for averaging a series of consecutive blood pressure measurement readings in the set equal to the integer interval value commencing from the f^th blood pressure measurement in the set;

d) first storing means for storing the averaged value in a central aortic systolic pressure set; and

e) second storing means for storing the highest value in the central aortic pressure set in a central aortic systolic pressure value set at a position corresponding to the position the arterial waveform being processed occupies in the arterial waveform dataset;

wherein the functions of the interval means, averaging means, first storing means and second storing means. are repeated for each arterial waveform in the arterial waveform dataset and, for each such repetition, the functions of the averaging means and first storing means are further repeated with the value of f commencing at 1 and being incremented by 1 each time until the value of f plus the integer interval value equals the predetermined number of blood pressure measurements in the set being processed.