Ultrasonic sensors for monitoring the condition of flow through a cardiac valve
First Claim
1. A band adapted to be applied externally around a cardiac vessel in a vicinity of a cardiac valve to monitor a condition of the cardiac valve that controls blood flow through the cardiac vessel in a patient'"'"'s body, comprising:
- (a) a biocompatible material that is sufficiently elastomeric to be wrapped around said cardiac vessel, forming a cuff;
(b) a first transducer disposed within the wall of the cuff, said first transducer producing a signal indicative of a parameter of the blood flowing through the cardiac vessel, and thus, indicative of a condition of the cardiac valve; and
(c) a coil coupled to the first transducer for conveying the signal to a point external to the patient'"'"'s body, for use in evaluating a condition of the cardiac valve, as a function of the parameter of the blood flowing through the cardiac vessel.
3 Assignments
0 Petitions
Accused Products
Abstract
A parameter indicative of the condition of a cardiac valve is determined by monitoring blood flow and/or velocity in a vessel that is coupled to the cardiac valve or in a chamber adjacent to an artificial cardiac valve. One or more ultrasonic transducers are provided either in a wall or a cuff disposed about a cardiac vessel to monitor the parameter in regard to a natural or artificial cardiac valve, or in a support sewing ring of an artificial cardiac valve. A conformal array transducer or a tilted element is used to monitor fluid flow or velocity based on the effect of the blood on ultrasonic waves produced by the transducers. The conformal array transducer comprises a plurality of elements that are excited with an input signal provided by an implantable electronics circuit, producing ultrasonic waves. Transit time or Doppler measurements are made using an appropriate number of these transducers to determine either blood volumetric flow or velocity. Various implantable electronic circuits are disclosed that enable a transducer to be driven and to receive an ultrasonic signal indicative of the status of blood flow and thus, the condition of the cardiac valve. A radio frequency (RF) coil is coupled to an external coil. The external coil is connected to a power supply and monitoring console, conveying power to the ultrasonic transducers and receiving data signals that enable the condition of the cardiac valve to be determined.
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Citations
64 Claims
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1. A band adapted to be applied externally around a cardiac vessel in a vicinity of a cardiac valve to monitor a condition of the cardiac valve that controls blood flow through the cardiac vessel in a patient'"'"'s body, comprising:
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(a) a biocompatible material that is sufficiently elastomeric to be wrapped around said cardiac vessel, forming a cuff;
(b) a first transducer disposed within the wall of the cuff, said first transducer producing a signal indicative of a parameter of the blood flowing through the cardiac vessel, and thus, indicative of a condition of the cardiac valve; and
(c) a coil coupled to the first transducer for conveying the signal to a point external to the patient'"'"'s body, for use in evaluating a condition of the cardiac valve, as a function of the parameter of the blood flowing through the cardiac vessel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for monitoring a parameter indicative of a condition of a cardiac valve, said system comprising:
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(a) a carrier band that is adapted to couple about a cardiac vessel through which blood flows either to or from the cardiac valve, so that the carrier band is in close proximity to at least one side of the cardiac vessel;
(b) a first transducer having at least one conformal element disposed on the carrier band, said at least one conformal element being sufficiently flexible and shaped so that it is adapted to curve about the cardiac vessel, conforming to its shape, said first transducer being adapted to couple to a radio frequency signal and producing ultrasonic waves when excited by the radio frequency signal, said ultrasonic waves being emitted from said at least one conformal element and being directed into an interior of the cardiac vessel; and
(c) a receiver disposed to receive the ultrasonic waves after they have propagated at least partially through the cardiac vessel, said receiver producing a signal indicative of an effect on the ultrasonic waves due to the blood in the cardiac vessel and thus, indicative of a parameter relating to a flow of the blood through the cardiac vessel and of a condition of the cardiac valve. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for remotely determining a condition of a cardiac valve within a patient'"'"'s body, for an extended period of time, comprising the steps of:
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(a) providing a first transducer that includes a plurality of elements for producing ultrasonic waves, carried on a band fitted about an exterior surface of the cardiac vessel, said plurality of elements being sufficiently flexible to conform to a curved shape of the cardiac vessel and being spaced apart along one side of the band;
(b) producing ultrasonic waves with the first transducer that are directed into the cardiac vessel, blood within the cardiac vessel affecting the ultrasonic waves;
(c) receiving the ultrasonic waves after they have been affected by the blood in the cardiac vessel, and producing a signal in response thereto that is indicative of a parameter related to the flow of the blood through the cardiac vessel;
(d) transmitting the signal to a point outside the patient'"'"'s body; and
(e) producing an indication of the parameter and thus of the condition of the cardiac valve, as a function of the signal. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
(a) providing a second transducer that includes a plurality of elements for producing ultrasonic waves, carried on the band, said plurality of elements being sufficiently flexible to conform to the curved shape of the wall and being spaced apart along a side of the band;
(b) receiving the ultrasonic waves with the second transducer; and
(c) producing the signal in response to the ultrasonic waves that are received with the second transducer.
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43. The method of claim 42, wherein the first and second transducers are disposed on a common side of the band, spaced apart from each other.
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44. The method of claim 43, wherein the first and the second transducers each emit pulses of ultrasonic waves and each receive reflected pulses of the ultrasonic waves back from the blood, further comprising the step of correlating signals produced in response to the reflected pulses to determine the parameter.
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45. The method of claim 43, further comprising the step of providing a reflector disposed on an opposite side of the band from that along which the first and the second transducers are disposed, wherein the second transducer receives the ultrasonic waves produced by the first transducer that have passed through the cardiac vessel, been reflected by the reflector, and passed back through the cardiac vessel.
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46. The method of claim 44, wherein the second transducer is disposed on an opposite side of the band from the first transducer, said second transducer receiving the ultrasonic waves produced by the first transducer and producing the signal which varies as a function of a transit time through the cardiac vessel.
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47. The method of claim 39, wherein the step of transmitting comprises the step of electromagnetically coupling the signal from a coil implanted within the patient'"'"'s body to an external coil disposed outside the patient'"'"'s body.
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48. The method of claim 47, further comprising the step of electromagnetically coupling electrical energy from an external power source that is connected to the external coil to the coil implanted within the patient'"'"'s body, to supply electrical power to at least the first transducer.
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49. The method of claim 39, wherein the band is formed as a cylinder, further comprising the steps of cutting the band;
- wrapping the band around the cardiac vessel; and
reconnecting ends of the band so that the band substantially encircles the cardiac vessel.
- wrapping the band around the cardiac vessel; and
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50. The method of claim 39, wherein the parameter comprises at least one of a volumetric flow of blood, and a velocity of blood flowing through the cardiac vessel.
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51. The method of claim 39, further comprising the steps of cutting the cardiac vessel;
- slipping the band over the cut cardiac vessel, and reconnecting cut ends of the cardiac vessel.
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52. The method of claim 39, further comprising the step of remotely monitoring the condition of the cardiac valve while a patient in which it is disposed is ambulatory.
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53. An artificial cardiac valve that monitors blood flow therethrough to determine a condition of said cardiac valve after it is mounted in a patient'"'"'s heart, comprising:
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(a) a movable valve element, which in a first position, enables blood to flow in a desired direction through the artificial cardiac valve, but in a second position, blocks blood flow therethrough in an opposite direction;
(b) a generally annular support for the valve element;
(c) a flow transducer disposed within the support and oriented to monitor flow through the artificial cardiac valve within a portion of a chamber in a patient'"'"'s heart after the artificial cardiac valve is mounted in said heart, said flow transducer producing a signal indicative of blood flow through the artificial cardiac valve during a cardiac cycle, said signal being indicative of a condition of the artificial cardiac valve and being adapted to couple through a radio link to an external monitoring site that is outside the patient'"'"'s body to enable the condition of the artificial cardiac valve to be monitored at least from time to time;
(d) an additional flow transducer disposed within the support and oriented to monitor flow through the artificial cardiac valve within a different portion of said chamber, producing an additional signal that is adapted to couple with the external monitoring device through the radio link and which is further indicative of blood flow through the artificial cardiac valve, to better determine said blood flow and thereby, to better determine the condition of the artificial cardiac valve; and
(e) a multiplexer that is coupled to the flow transducer and to the additional flow transducer, said multiplexer being adapted to selectively alternatively couple the flow transducer and the additional flow transducer to the radio link. - View Dependent Claims (54, 55, 56, 57, 58)
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59. A method for monitoring blood flow through an artificial cardiac valve to determine a condition of said valve, comprising the steps of:
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(a) providing an artificial cardiac valve that includes at least one flow transducer disposed therein;
(b) mounting the artificial cardiac valve within a patient'"'"'s heart;
(c) with said at least one flow transducer, producing ultrasonic pulses directed into a cardiac chamber adjacent to the artificial cardiac valve;
(d) monitoring blood flow through the cardiac valve with said at least one flow transducer, producing a flow signal; and
(e) transmitting the flow signal to an external receiver over a radio link, said flow signal indicating the blood flow through the artificial cardiac valve, enabling a condition of the artificial cardiac valve to be determined. - View Dependent Claims (60, 61, 62, 63)
(a) providing an antenna coil that is coupled to said at least one flow transducer;
(b) transmitting the flow signal to the external receiver via the antenna coil; and
(c) receiving electrical power to energize said at least one flow transducer from an external transmitter through the antenna coil.
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61. The method of claim 60, wherein the antenna coil is disposed in the artificial cardiac valve.
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62. The method of claim 61, further comprising the step of processing the ultrasonic pulses as a plurality of range-gated Doppler pulses.
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63. The method of claim 62, further comprising the step of using the range-gated Doppler pulses to monitor blood flow velocity through the artificial cardiac valve, for use in determining a condition of the artificial cardiac valve.
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64. A band adapted to be applied externally around a tubular passage in a patient'"'"'s body to monitor a fluid flow through the tubular passage, comprising:
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(a) a biocompatible material that is sufficiently elastomeric to be wrapped around the tubular passage, forming a cuff;
(b) a first transducer disposed within the wall of the cuff, said first transducer producing a signal indicative of a parameter of the fluid flowing through the tubular passage; and
(c) a coil coupled to the first transducer for conveying the signal to a point external to the patient'"'"'s body, for use in evaluating a condition of the patient'"'"'s body, as a function of the parameter of the fluid flowing through the tubular passage.
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Specification