Detection of aortic coarctation using photoplethysmography

• US 10,376,154 B2
• Filed: 03/12/2015
• Issued: 08/13/2019
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: The Feinstein Institutes For Medical Research
• Original Assignee: The Feinstein Institute for Medical Research (Northwell Health, Inc.)
• Inventors: Koppel, Robert, Nitzan, Meir
• Primary Examiner(s): Stice, Paula J
• Application Number:
  US15/125,203
• Publication Number:
  US 20170164842A1
• Time in Patent Office: 1,615 Days
• CPC Class Codes: A61B 2503/04 Babies, e.g. for SIDS detection
• CPC Class Codes: A61B 2503/045 Newborns, e.g. premature baby monitoring
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/6825 Hand
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

Methods and systems are described for detecting the likelihood of an aortic coarctation in an infant using photoplethysmographic pulse signals obtained from the hand and foot of the infant.

Claims

1. A method for detecting an aortic coarctation in an infant comprising:

a) obtaining photoplethysmographic (PPG) signals from a right hand and from a foot of the infant using a photoplethysmograph of at least two channels;

b) selecting a section of the PPG signals without movement noise for analysis, low-pass filtering the PPG signals to reduce high frequency noise, and smoothing the PPG signals using a moving average filter;

c) identifying end-diastolic maxima and minima of systolic decrease for hand PPG pulses and for the foot PPG pulses from the PPG signals, and using the end-diastolic maxima and minima of systolic decrease to determine one or both of the following;

c1) time delay (TD) between the end-diastolic maxima for the hand PPG pulses and the end-diastolic maxima for the foot PPG pulses (f-hTD), and/or

c2) PPG pulse amplitude (AM) between the end-diastolic maxima and minima of systolic decrease for the hand PPG pulses and for the foot PPG pulses;

d) if PPG pulse amplitude (AM) is determined, determining a relative pulse amplitude (rAM) by dividing the AM by the minima of systolic decrease to obtain a rAM for the foot (rAM-F) PPG pulses and a rAM for the hand (rAM-H) PPG pulses;

e) calculating mean and standard deviation (SD) of f-hTD, and/or rAM for the foot (rAM-F) and rAM for the hand (rAM-H) for the PPG pulses in a selected section of PPG pulses, and discarding values deviating from the mean by 2 standard deviations or more from the calculation of the mean;

f) if mean foot rAM-F and mean hand rAM-H are calculated, determining a ratio F/H between mean foot rAM-F and mean hand rAM-H, and/or determining a ratio H/F between mean hand rAM-H and mean foot rAM-F; and

optionally, obtaining a multiplication product of H/F times f-hTD and/or a multiplication product of F/H times f-hTD; and

g) detecting the aortic coarctation in the infant if one or more of;

the f-hTD is elevated above normal, or

the ratio F/H is decreased below normal, or

the ratio H/F is increased above normal, or

the product H/F times f-hTD is increased above normal.

2. The method of claim 1, wherein an aortic coarctation is determined using f-hTD.

3. The method of claim 1, wherein an aortic coarctation is determined using ratio F/H.

4. The method of claim 1, wherein an aortic coarctation is determined using f-hTD and ratio F/H.

5. The method of claim 1, wherein an aortic coarctation is determined using the product H/F times f-hTD.

6. The method of claim 1, wherein the f-hTD values for normal infants have a range of 15-50 milliseconds (ms) and a mean of 35 ms.

7. The method of claim 1, wherein the f-hTD value equal to or higher than a predetermined value in a range of 50-60 ms is indicative that the infant has an aortic coarctation.

8. The method of claim 1, wherein the f-hTD value of 50 ms or more is indicative that the infant has an aortic coarctation.

9. The method of claim 1, wherein the f-hTD value of 55 ms or more is indicative that the infant has an aortic coarctation.

10. The method of claim 1, wherein the f-hTD value of 60 ms or more is indicative that the infant has an aortic coarctation.

11. The method of claim 1, wherein infants without an aortic coarctation have a mean ratio F/H of 0.9.

12. The method of claim 1, wherein the ratio F/H equal to or less than a predetermined value in a range of 0.4-0.6 is indicative that the infant has an aortic coarctation.

13. The method of claim 1, wherein the ratio F/H of 0.6 or less is indicative that the infant has an aortic coarctation.

14. The method of claim 1, wherein the ratio F/H of 0.5 or less is indicative that the infant has an aortic coarctation.

15. The method of claim 1, wherein the ratio F/H of 0.4 or less is indicative that the infant has an aortic coarctation.

16. The method of claim 1, wherein infants without an aortic coarctation have a mean product of ratio H/F times f-hTD of 45.

17. The method of claim 1, wherein a product of ratio H/F times the f-hTD equal to or higher than a predetermined value in a range of 80-100 is indicative that the infant has an aortic coarctation.

18. The method of claim 1, wherein a product of ratio H/F times the f-hTD of 80 or more is indicative that the infant has an aortic coarctation.

19. The method of claim 1, wherein a product of ratio H/F times the f-hTD of 90 or more is indicative that the infant has an aortic coarctation.

20. The method of claim 1, wherein a product of ratio H/F times the f-hTD of 100 or more is indicative that the infant has an aortic coarctation.

21. The method of claim 1, wherein the f-hTD value equal to or higher than a predetermined value in a range of 50-60 ms and a ratio F/H equal to or less than a predetermined value in a range of 0.4-0.6 is indicative that the infant has an aortic coarctation.

22. A system for detecting an aortic coarctation in an infant comprising a photoplethysmograph of at least two channels, a computing device comprising a processor operably connected to the photoplethysmograph and a computer-readable storage medium operably connected to the processor, and a display device operably connected to the photoplethysmograph and to the processor, where the computer-readable storage medium includes computer-readable code that is read by the processor to perform a method comprising the steps of:

a) accessing photoplethysmographic (PPG) signals from a right hand and from a foot of the infant;

b) identifying end-diastolic maxima and minima of systolic decrease for hand PPG pulses and for foot PPG pulses from the PPG signals, and using the end-diastolic maxima and minima of systolic decrease to determine one or both of the following;

b1) time delay (TD) between the end-diastolic maxima for the hand PPG pulses and the end-diastolic maxima for the foot PPG pulses (f-hTD), and/or

b2) PPG pulse amplitude (AM) between the end-diastolic maxima and minima of systolic decrease for the hand PPG pulses and for the foot PPG pulses;

c) if PPG pulse amplitude (AM) is determined, determining a relative pulse amplitude (rAM) by dividing the AM by the minima of systolic decrease to obtain a rAM for the foot (rAM-F) PPG pulses and a rAM for the hand (rAM-H) PPG pulses;

d) calculating mean and standard deviation (SD) of f-hTD, and/or rAM for the foot (rAM-F) and rAM for the hand (rAM-H) for the PPG pulses in the selected section, and discarding values deviating from the mean by 2 standard deviations or more from the calculation of the mean;

e) if mean foot rAM-F and mean hand rAM-H are calculated, determining a ratio F/H between mean foot rAM-F and mean hand rAM-H, and/or determining a ratio H/F between mean hand rAM-H and mean foot rAM-F; and

optionally, obtaining a multiplication product of H/F times f-hTD and/or a multiplication product of F/H times f-hTD; and

f) outputting to the display device one or more of f-hTD, ratio F/H, ratio H/F, f-hTD and ratio F/H, the product H/F times f-hTD, and the product F/H times f-hTD.

23. A method for treating an infant with an aortic coarctation, the method comprising

performing or having performed a method for detecting the aortic coarctation in an infant, and

treating the infant so identified with aortic coarctation using surgical intervention;

wherein the method for detecting the aortic coarctation in the infant comprises the steps of

a) obtaining photoplethysmographic (PPG) signals from a right hand and from a foot of the infant using a photoplethysmograph of at least two channels;

b) selecting a section of the PPG signals without movement noise for analysis, low-pass filtering the PPG signals to reduce high frequency noise, and smoothing the PPG signals using a moving average filter;

c) identifying end-diastolic maxima and minima of systolic decrease for hand PPG pulses and for foot PPG pulses from the PPG signals, and using the end-diastolic maxima and minima of systolic decrease to determine one or both of the following;

c1) time delay (TD) between the end-diastolic maxima for the hand PPG pulses and the end-diastolic maxima for the foot PPG pulses (f-hTD), and/or

c2) PPG pulse amplitude (AM) between the end-diastolic maxima and minima of systolic decrease for the hand PPG pulses and for the foot PPG pulses;

d) if PPG pulse amplitude (AM) is determined, determining a relative pulse amplitude (rAM) by dividing the AM by the minima of systolic decrease to obtain a rAM for the foot (rAM-F) PPG pulses and a rAM for the hand (rAM-H) PPG pulses;

e) calculating mean and standard deviation (SD) of f-hTD, and/or rAM for the foot (rAM-F) and rAM for the hand (rAM-H) for the PPG pulses in a selected section of PPG pulses, and discarding values deviating from the mean by 2 standard deviations or more from the calculation of the mean;

f) if mean foot rAM-F and mean hand rAM-H are calculated, determining a ratio F/H between mean foot rAM-F and mean hand rAM-H, and/or determining a ratio H/F between mean hand rAM-H and mean foot rAM-F, and optionally, obtaining a multiplication product of H/F times f-hTD and/or a multiplication product of F/H times f-hTD, and

g) detecting the aortic coarctation in the infant if one or more of;

the f-hTD is elevated above normal, or

the ratio F/H is decreased below normal, or

the ratio H/F is increased above normal, or

the product H/F times f-hTD is increased above normal.