CARDIOVASCULAR VESSEL ELASTICITY MONITORING

• US 20110028801A1
• Filed: 07/29/2009
• Published: 02/03/2011
• Est. Priority Date: 07/29/2009
• Status: Abandoned Application

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Koh, Steve
• Application Number:
  US12/511,484
• Publication Number:
  US 20110028801A1
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02152 specially adapted for venous pressure

Abstract

Elasticity of a cardiovascular vessel of a patient is monitored to provide an indication of whether the patient'"'"'s health is changing. In some aspects the elasticity of a cardiovascular vessel is determined irrespective of the current blood pressure level of the patient at the time the elasticity is determined. For example, vessel elasticity may be determined based on a defined set of data that maps vessel elasticity with reflectance times for different blood pressure levels. In some implementations, this set of data corresponds to a set of iso-pressure lines.

Claims

1. An implantable medical monitoring apparatus, comprising:

a reflectance time detector configured to determine reflectance time of a pressure wave in a cardiovascular system of a patient;

a blood pressure detector configured to determine blood pressure of the cardiovascular system; and

a cardiovascular vessel elasticity detector configured to determine elasticity of a vessel of the cardiovascular system based on the determined blood pressure, the determined reflectance time, and a data set that correlates different blood pressure values and different pressure wave reflectance time values to different vessel elasticity values.

2. The apparatus of claim 1, wherein the data set comprises a set of iso-pressure lines that map reflectance time to elasticity.

3. The apparatus of claim 1, further comprising a photoplethysmography sensor configured to generate signals indicative of changes in blood flow in the cardiovascular system, wherein the reflectance time detector is further configured to process the generated signals to determine the reflectance time.

4. The apparatus of claim 3, wherein the blood pressure detector is further configured to process the generated signals to determine the blood pressure.

5. The apparatus of claim 1, wherein the cardiovascular vessel elasticity detector is further configured to determine a trend indicative of changes in elasticity of the vessel based on the determined elasticity.

6. The apparatus of claim 5, further comprising a therapy module configured to identify at least one condition associated with the patient based on the trend.

7. The apparatus of claim 6, wherein the at least one condition relates to at least one of the group consisting of:

an indication of heart failure, an indication of hypertension, an indication of neurohormonal insult leading to wall stiffness, medical regimen compliance, and salt intake compliance.

8. The apparatus of claim 1, wherein:

the data set comprises a set of iso-pressure lines; and

the cardiovascular vessel elasticity detector is further configured to determine a trend indicative of changes in elasticity of the vessel based on the determined elasticity.

9. The apparatus of claim 8, further comprising a photoplethysmography sensor configured to generate signals indicative of changes in blood flow in the cardiovascular system, wherein:

the reflectance time detector is further configured to process the generated signals to determine the reflectance time; and

the blood pressure detector is further configured to process the generated signals to determine the blood pressure.

10. A method of monitoring vessel elasticity, comprising:

determining reflectance time of a pressure wave in a cardiovascular system of a patient;

determining blood pressure of the cardiovascular system; and

determining elasticity of a vessel of the cardiovascular system based on the determined blood pressure, the determined reflectance time, and a data set that correlates different blood pressure values and different pressure wave reflectance time values to different vessel elasticity values.

11. The method of claim 10, wherein the data set comprises a set of iso-pressure lines that map reflectance time to elasticity.

12. The method of claim 10, wherein the determination of the reflectance time comprises using photoplethysmography to detect the pressure wave.

13. The method of claim 12, wherein the determination of the blood pressure comprises using photoplethysmography to detect blood velocity in the cardiovascular system.

14. The method of claim 10, further comprising:

determining a trend indicative of changes in elasticity of the vessel based on the determined elasticity; and

identifying at least one condition associated with the patient based on the trend.

15. The method of claim 14, wherein the at least one condition relates to at least one of the group consisting of:

an indication of heart failure, an indication of hypertension, an indication of neurohormonal insult leading to wall stiffness, medical regimen compliance, and salt intake compliance.

16. The method of claim 10, wherein the data set comprises a set of iso-pressure lines, the method further comprising:

determining a trend indicative of changes in elasticity of the vessel based on the determined elasticity; and

predicting heart failure or hypertension based on the trend.

17. The method of claim 16, wherein:

the determination of the reflectance time comprises using photoplethysmography to measure changes in blood flow associated with the pressure wave; and

the determination of the blood pressure comprises using photoplethysmography to measure changes in blood flow in the cardiovascular system and estimating the blood pressure based on the changes in blood flow in the cardiovascular system.

18. The method of claim 10, wherein the blood pressure and the reflectance time are determined by an implantable medical device.