Method for non-evasively determining an endothelial function and a device for carrying out said method
First Claim
1. A method for noninvasive assessment of endothelial function in a patient, which method comprises:
- a. lowering a transmural pressure in an artery in an extremity by means of a pressure generating cuff;
b. measuring, via a monitoring channel, an amplitude of a plethysmographic signal at various transmural pressures generated in step (a);
c. determining a pressure in the pressure generating cuff at which the amplitude of the plethysmographic signal is maximal;
d. lowering the pressure in the pressure generating cuff to 50% of the pressure at which said maximal amplitude occurs;
e. when the pressure in the pressure generating cuff is 50% of the pressure at which said maximal amplitude occurs, running an occlusion test;
wherein running an occlusion test comprises generating a pressure in the pressure generating cuff on an observed region of the extremity which exceeds a measured systolic pressure by at least 50 mmHg for at least 5 minutes;
f. lowering the pressure in the pressure generating cuff to zero;
g. measuring an amplitude of the plethysmographic signal for at least 3 minutes and simultaneously measuring, via a reference channel, an amplitude of a plethysmographic signal detected from an artery in a second extremity where the occlusion test has not been performed;
h. using amplitudal and timely analyses to compare data collected through the reference and monitoring channels; and
i. providing an assessment of the patient'"'"'s endothelial function based on the amplitudal and timely analyses.
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Accused Products
Abstract
The invention relates to medicine. The inventive method for non-evasively determining an endothelial function consists in reducing a transmural pressure in a limb, recording the amplitude of plethysmographic signals at different pressures, determining the pressure of a maximum plethysmographic signal amplitude, reducing the pressure to a value corresponding to the specified percentage of the maximum amplitude, carrying out an occlusion sample in the course of which a pressure higher by at least 50 mm Hg than the systolic pressure of a tested patient is produced in a cuff arranged proximally to the located limb area, wherein the occlusion is carried out during at least 5 minutes. The inventive device for carrying out said method comprises a sensory unit, a pressure producing unit, an electronic unit constructed in such a way that it makes it possible to measure the cuff pressure corresponding to the maximum plethysmographic signal amplitude and a unit for controlling the pressure producing unit in such a way that the cuff pressure corresponding to the amplitude of a plethysmographic signal, which represents a specified percentage of the maximum amplitude, is attained. The sensory unit is connected to the electronic unit to the output of which the pressure producing unit is connected.
231 Citations
11 Claims
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1. A method for noninvasive assessment of endothelial function in a patient, which method comprises:
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a. lowering a transmural pressure in an artery in an extremity by means of a pressure generating cuff; b. measuring, via a monitoring channel, an amplitude of a plethysmographic signal at various transmural pressures generated in step (a); c. determining a pressure in the pressure generating cuff at which the amplitude of the plethysmographic signal is maximal; d. lowering the pressure in the pressure generating cuff to 50% of the pressure at which said maximal amplitude occurs; e. when the pressure in the pressure generating cuff is 50% of the pressure at which said maximal amplitude occurs, running an occlusion test;
wherein running an occlusion test comprises generating a pressure in the pressure generating cuff on an observed region of the extremity which exceeds a measured systolic pressure by at least 50 mmHg for at least 5 minutes;f. lowering the pressure in the pressure generating cuff to zero; g. measuring an amplitude of the plethysmographic signal for at least 3 minutes and simultaneously measuring, via a reference channel, an amplitude of a plethysmographic signal detected from an artery in a second extremity where the occlusion test has not been performed; h. using amplitudal and timely analyses to compare data collected through the reference and monitoring channels; and i. providing an assessment of the patient'"'"'s endothelial function based on the amplitudal and timely analyses. - View Dependent Claims (2, 3)
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4. An apparatus for noninvasive assessment of endothelial function comprising a double-channeled sensor unit, capable of detecting pulse wave signals from peripheral arteries, a pneumatic unit capable of creating gradually increasing pressure in a pressure generating cuff, a pressure sensor configured to detect a blood pressure of a patient;
- and an electronic block configured to perform at least the following steps;
a. lowering a transmural pressure in an artery in an extremity by means of a pressure generating cuff; b. measuring, via a monitoring channel, an amplitude of a plethysmographic signal at various transmural pressures generated in step (a); c. determining a pressure in the pressure generating cuff at which the amplitude of the plethysmographic signal is maximal; d. lowering the pressure in the pressure generating cuff to 50% of the pressure at which said maximal amplitude occurs; e. when the pressure in the pressure generating cuff is 50% of the pressure at which said maximal amplitude occurs, running an occlusion test wherein running an occlusion test comprises generating a pressure in the pressure generating cuff on an observed region of the extremity which exceeds a measured systolic pressure by at least 50 mmHg for at least 5 minutes; f. lowering the pressure in the pressure generating cuff to zero; g. measuring an amplitude of the plethysmographic signal for at least 3 minutes and simultaneously measuring, via a reference channel, an amplitude of a plethysmographic signal detected from an artery in a second extremity where the occlusion test has not been performed; and h. using amplitudal and timely analyses to compare data collected through the reference and monitoring channels; wherein the double-channeled sensor unit is connected to the electronic block, which is in turn linked through an outlet to the pneumatic unit. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
- and an electronic block configured to perform at least the following steps;
Specification