System for determining endothelial dependent vasoactivity

• US 20080200820A1
• Filed: 04/25/2008
• Published: 08/21/2008
• Est. Priority Date: 12/09/2002
• Status: Active Grant

• Current Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Original Assignee: Ramot at Tel Aviv University Limited (Tel Aviv University)
• Inventors: Einav, Shmuel, Peleg, Eran, Amitzur, Giora, Zimerman, Elya
• Granted Patent: US 8,187,196 B2
• Time in Patent Office: Days
• US Class Current: 600/485
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02133 by using induced vibration of the blood vessel
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/416 the spleen
• CPC Class Codes: A61B 5/726 using Wavelet transforms

Abstract

A method of determining endothelial dependent vasoactivity of a subject, the method is effected by recording pressure-related signals of a plurality of locations adjacent to at least one blood vessel; extracting at least one parameter from the pressure-related signals; and using the at least one parameter to determine a change of at least one characteristic of the at least one blood vessel, the change being representative of endothelial functioning; thereby determining the endothelial dependent vasoactivity of the subject.

Claims

1-55. -55. (canceled)

56. A method of determining endothelial dependent vasoactivity of a subject, the method comprising:

recording pressure-related signals of a plurality of locations adjacent to at least one blood vessel;

extracting time variability of at least one of

amplitude of said pressure-related signals;

elapsed time between two peaks of said pressure related signals; and

elapsed time between a peak of said pressure related signals and a peak of electrocardiogram signal recorded simultaneously with recording said pressure-related signals

using said time variability to determine a change of at least one characteristic of said at least one blood vessel, said change being representative of endothelial functioning;

determining the endothelial dependent vasoactivity of the subject; and

displaying at least an indication of said endothelial dependent vasoactivity.

57. A method according to claim 56, wherein using said time variability comprises obtaining a frequency decomposition of said time variability.

58. A method according to claim 56, wherein said time variability is of elapsed time between two peaks of said pressure related signals.

59. A method according to claim 56, wherein said elapsed time is between two peaks of signals recorded at two different locations.

60. A method according to claim 59, wherein said two different locations are near same blood vessels.

61. A method according to claim 59, wherein said two different locations are near different blood vessels.

62. A method according to claim 56, wherein the subject is sitting during recording.

63. A method according to claim 56, comprising, walking the subject before recording.

64. A method according to claim 63, wherein walking is for 2 minutes of moderate walk.

65. A method according to claim 56, wherein said peak of an electrocardiogram signal is a peak of an R-wave.

72. A method according to claim 56, further comprising stimulating said at least one blood vessel.

73. A method according to claim 56, further comprising determining an autonomic nervous system activity of the subject.

74. The method of claim 72, wherein said stimulating of said at least one blood vessel is effected by a procedure selected from the group consisting of a mechanical stimulation, a thermal stimulation a chemical stimulation, an electrical stimulation a mental stress stimulation and a physical exercise stimulation.

75. The method of claim 72, wherein said stimulating of said at least one blood vessel is by applying external pressure on said at least one blood vessel.

76. The method of claim 72, wherein said stimulating of said at least one blood vessel is by reducing a temperature of said at least one blood vessel.

77. The method of claim 56, wherein said at least one blood vessel is selected from the group consisting of a brachial artery, a radial artery and a carotid artery.

79. The method of claim 73, further comprising correlating said endothelial functioning and said autonomic nervous system activity, so as to obtain a correlation function, and using said correlation function to at least preliminarily determine the endothelial dependent vasoactivity of the subject.

80. The method of claim 73, wherein said determining of said autonomic nervous system activity is by heart rate variability analysis of said pressure-related signals.

81. The method of claim 73, wherein said determining of said autonomic nervous system activity comprises recording electrocardiogram signals of a chest of the subject and performing heart rate variability analysis of said electrocardiogram signals, thereby determining said autonomic nervous system activity.

82. The method of claim 81, further comprising determining a pre-ejection period and valve-artery period.

83. The method of claim 82, wherein said valve of said valve-artery period is an aortic valve and said artery of said valve-artery period is a carotid artery.

84. The method of claim 82, wherein said determination of said pre-ejection period and said valve-artery period, comprises determining an elapsed time between peaks of said electrocardiogram signals and peaks of said pressure-related signals.

85. The method of claim 56, wherein said at least one characteristic of said at least one blood vessel is selected from the group consisting of a radius of said at least one blood vessel and an elastic modulus of said at least one blood vessel.

87. The method of claim 56, wherein said extracting of said at least one parameter comprises:

(a) scanning pressure-related signals recorded of a first location and detecting a first peak;

(b) scanning pressure-related signals recorded of a second location and detecting a second peak corresponding to said first peak;

(c) measuring an elapsed time between said first peak and said second peak; and

(d) repeating said steps (a)-(c) at least once.

66. A method of determining endothelial dependent vasoactivity of a subject, the method comprising:

recording pressure-related signals of a plurality of locations adjacent to at least one blood vessel, said locations being in at least one organ;

cooling an organ other than any of said at least one organ;

extracting at least one parameter from said at least one pressure related;

using said at least one parameter to determine a change of at least one characteristic of said at least one blood vessel, said change being representative of endothelial functioning;

determining the endothelial dependent vasoactivity of the subject; and

displaying at least an indication of said endothelial dependent vasoactivity.

67. A method according to claim 66, wherein said cooling is simultaneous with said recording.

68. A method according to claim 66, wherein cooling comprises submerging in cold water.

69. A method according to claim 66, wherein the subject is sitting during recording.

70. A method according to claim 66, comprising, walking the subject before recording.

71. A method according to claim 70, wherein walking is for 2 minutes of moderate walk.

78. The method of claim 66, wherein said at least one blood vessel is selected from the group consisting of a brachial artery, a radial artery and a carotid artery.

86. The method of claim 66, wherein said at least one characteristic of said at least one blood vessel is selected from the group consisting of a radius of said at least one blood vessel and an elastic modulus of said at least one blood vessel.

88. A system for determining endothelial dependent vasoactivity of a subject, the system comprising:

an arrangement of sensors for recording pressure-related signals of a plurality of locations adjacent to at least one blood vessel, said at least one blood vessel being in at least one organ of said subject;

a processing unit configured to receive and process said pressure-related signals;

said processing unit being configured to extract at least one parameter from said pressure-related signals, and to use said at least one parameter to determine a change of at least one characteristic of said at least one blood vessel, said change being representative of endothelial functioning, wherein said at least one parameter comprises a parameter selected from the group consisting of elapsed time between two successive peaks of one or more of said pressure-related signals, and amplitude of one or more of said pressure-related signals.

89. The system of claim 88, further comprising electronic-calculation functionality for determining an autonomic nervous system activity of the subject.

90. The system of claim 88, further comprising a mechanism for stimulating said at least one blood vessel.

91. The system of claim 90, wherein said mechanism for stimulating said at least one blood vessel is selected from the group consisting of a mechanical mechanism, a thermal mechanism, a chemical mechanism an electrical mechanism, a mechanism for generating mental stress and a device for allowing the subject to perform physical exercise.

92. The system of claim 90, wherein said mechanism is configured to apply external pressure on said at least one blood vessel.

93. The system of claim 92, wherein said mechanism comprises a sphingomanometer.

94. The system of claim 90, wherein said mechanism is configured to reduce a temperature of said at least one blood vessel.

95. The system of claim 88, comprising a mechanism configured to reduce a temperature of an organ other than any of said at least one argan.

96. The system of claim 94, wherein said mechanism selected from the group consisting of a bath of fluid and a cuff of fluid, said fluid being at a predetermined temperature.

97. The system of claim 95, wherein said mechanism selected from the group consisting of a bath of fluid and a cuff of fluid, said fluid being at a predetermined temperature.

98. The system of claim 88, wherein said at least one blood vessel is selected from the group consisting of a brachial artery, a radial artery and a carotid artery.

99. The system of claim 89, wherein said processing unit is configured to calculate heart rate variability from said pressure-related signals thereby to determine said autonomic nervous system activity.

100. The system of claim 89, further comprising at least one electrocardiogram lead.

101. The system of claim 100, wherein said processing unit is operable to calculate heart rate variability from electrocardiogram signals sensed by said at least one electrocardiogram lead, thereby to determine said autonomic nervous system activity.

102. The system of claim 88, further comprising a spectral analyzer for analyzing said at least one parameter and obtaining a frequency decomposition of said at least one parameter, said frequency decomposition being representative of the endothelial dependent vasoactivity of the subject.

103. The system of claim 100, wherein said at least one parameter is selected from the group consisting of an amplitude of said pressure-related signals, a width of said pressure-related signals, an elapsed time between two peaks of said pressure-related signals and an elapsed time between peaks of electrocardiogram signals and peaks of said pressure-related signals.

104. The system of claim 88, wherein said at least one characteristic of said at least one blood vessel is selected from the group consisting of a radius of said at least one blood vessel and an elastic modulus of said at least one blood vessel.