Surgery – Diagnostic testing – Cardiovascular
Reexamination Certificate
2003-02-24
2004-09-28
Nasser, Robert L. (Department: 3736)
Surgery
Diagnostic testing
Cardiovascular
C600S485000
Reexamination Certificate
active
06796946
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an arteriostenosis inspecting apparatus which inspects presence or absence of arteriostenosis of a living person, and an ankle-blood-pressure measuring apparatus which measures a blood-pressure of an ankle of a living subject.
2. Related Art Statement
Atherosclerosis as a sort of arteriosclerosis is a disease that lipid, in particular, cholesterol deposits on walls of arteries and thereby thickens the arterial walls. Since atherosclerosis generates stenosis of an artery and thereby decreases its diameter, it is also called arteriostenosis or arteriosclerosis obliterans. There is known an inferior-and-superior-limb-blood-pressure-index measuring apparatus which can be used for inspecting arteriostenosis, by utilizing a fact that blood pressure lowers on a distal side of a body portion having arteriostenosis. The measuring apparatus is disclosed in, e.g., Japanese Patent No. 3,140,007 or its corresponding U.S. Pat. No. 6,355,000. The disclosed measuring apparatus includes a cuff worn on an inferior limb to measure a blood pressure of the inferior limb, and a cuff worn on a superior limb to measure a blood pressure of the superior limb, calculates an inferior-and-superior-limb blood-pressure index as a ratio of one of the inferior-limb blood pressure and the superior-limb blood pressure to the other, and inspects presence or absence of arteriosclerosis based on the thus calculated index.
For example, in the case where arteriosclerosis obliterans is inspected based on an inferior-and-superior-limb blood-pressure index, the index is calculated by dividing an inferior-limb systolic blood pressure by a superior-limb systolic blood pressure and, if the thus calculated index is greater than 0.9, it is judged that arteriostenosis is absent and, if the index is not greater than 0.9, it is judged that arteriostenosis is suspected.
In the above-indicated inferior-and-superior-limb-blood-pressure-index measuring apparatus, generally, an ankle is selected as the inferior limb and a cuff is worn on the ankle. Meanwhile, an ankle has two thick arteries, i.e., an anterior tibial artery and a posterior tibial artery. There are known some cases where one of the two arteries has stenosis but the other artery does not. As explained above, blood pressure lowers on a distal side of a stenotic portion. Since, however, an ankle has two thick arteries, if only one of the two arteries has stenosis and accordingly a blood pressure of the other artery free of stenosis does not lower, the blood pressure of the other artery is measured as a blood pressure of the ankle. Thus, even if one of the two arteries may have stenosis, a measured blood pressure of the ankle may be normal, and an inferior-and-superior-limb blood-pressure index calculated based on the measured ankle blood pressure may be normal. In this case, the inferior-and-superior-limb blood-pressure index cannot be used for finding arteriostenosis.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an ankle-blood-pressure measuring apparatus which can measure an ankle blood pressure that can be used for calculating an inferior-and-superior-limb blood-pressure index that can be used for accurately inspecting presence or absence of arteriostenosis of an inferior limb of a living person, and an arteriostenosis inspecting apparatus which can accurately inspect presence or absence of arteriostenosis of an inferior limb of a living person.
The above object has been achieved according to a first aspect of the present invention. According to the first aspect, there is provided an ankle-blood-pressure measuring apparatus for measuring a blood pressure of an ankle of a living subject, comprising an inflatable cuff which is adapted to be worn on the ankle of the subject; a cuff-pressure changing device which decreases a pressure in the cuff from a pressure higher than a systolic blood pressure of the ankle; a distal-pulse-wave detecting device which is adapted to be worn on a distal portion of the subject that is located on a distal side of the ankle and detects a distal pulse wave produced from the distal portion; an increasing-point detecting means for detecting at least one increasing point where a magnitude of the distal pulse wave continuously detected by the distal-pulse-wave detecting device when the pressure of the cuff is decreased by the cuff-pressure changing device, significantly increases; and an ankle-blood-pressure determining device which determines a pressure of the cuff when the increasing-point detecting means detects the second increasing point, as a systolic blood pressure of one of a plurality of tibial arteries of the ankle of the subject that has stenosis.
According to this aspect, when the pressure of the cuff worn on the ankle is decreased, the distal-pulse-wave detecting device worn on the distal portion located on the distal side of the ankle continuously detects the distal pulse wave produced from the distal portion, and the increasing-point detecting means detects the increasing point where the magnitude of the distal pulse wave significantly increases. In the case where only one of anterior and posterior tibial arteries has stenosis, a pressure of the cuff when flow of blood resumes in the stenotic tibial artery is lower than a pressure of the cuff when flow of blood resumes in the non-stenotic tibial artery. Therefore, in the distal portion on the distal side of the cuff, amount of flow of blood significantly largely increases twice. Thus, in this case, the increasing-point detecting means detects two increasing points and accordingly the ankle-blood-pressure determining device determines the pressure of the cuff when the increasing-point detecting means detects the second increasing point, as the systolic blood pressure of the stenotic tibial artery.
The above object has been achieved according to a second aspect of the present invention. According to the second aspect, there is provided an arteriostenosis inspecting apparatus, comprising an ankle-blood-pressure measuring apparatus according to the first aspect; a superior-limb-blood-pressure measuring device which measures a systolic blood pressure of a superior limb of the subject; and an inferior-and-superior-limb-blood-pressure-index determining means for determining an inferior-and-superior-limb blood-pressure index of the subject, based on the systolic blood pressure of the ankle measured by the ankle-blood-pressure measuring apparatus and the systolic blood pressure of the superior limb measured by the superior-limb-blood-pressure measuring device.
If an inferior-and-superior-limb blood-pressure index is determined based on the systolic blood pressure of the stenotic tibial artery, measured by the ankle-blood-pressure measuring apparatus, and presence or absence of arteriostenosis is judged based on the thus determined index, the presence or absence of arteriostenosis can be accurately judged by a living person such as a medical person or the subject. According to this aspect, the inferior-and-superior-limb-blood-pressure-index determining means determines the inferior-and-superior-limb blood-pressure index based on the systolic blood pressure of the stenotic tibial artery, measured by the ankle-blood-pressure measuring apparatus. Therefore, if presence or absence of arteriostenosis is judged based on the thus determined index, it is possible to accurately judge the presence or absence of arteriostenosis.
The above object has been achieved according to a third aspect of the present invention. According to the third aspect, there is provided an arteriostenosis inspecting apparatus, comprising an inflatable cuff which is adapted to be worn on an ankle of a living subject; a cuff-pressure changing device which decreases a pressure in the cuff from a pressure higher than a systolic blood pressure of the ankle; a distal-pulse-wave detecting device which is adapted to be worn on a distal portion of the subject that is located on a distal side of the ankle
Narimatsu Kiyoyuki
Ogura Toshihiko
Colin Medical Technology Corporation
Nasser Robert L.
Oliff & Berridg,e PLC
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