Abstract: Apparatus and method to perform therapeutic treatment and diagnosis of a patient's vasculature through the use of an intravascular device having an optical fiber disposed therein. In an embodiment of this invention, the apparatus includes a therapeutic guidewire and at least one optical fiber disposed through the therapeutic guidewire, the optical fiber capable of providing diagnostic information before, during, and after the therapeutic treatment. In an embodiment, diagnostic information includes vessel and blood characteristics such as hemodynamic characteristics, hematological parameters related to blood and blood components, and thermal parameters of the vasculature.

Abstract: A technique is disclosed for determining blood flow in a living body by changing the thermal energy level in the venous blood flow path and determining temperatures in both the venous and arterial blood flow paths. Blood flow is calculated as a function of the change in energy level and the temperature differences in the venous and arterial blood flow paths.

Abstract: The present invention provides an implantable modular AV shunt device, which is capable of monitoring and reporting its own patency, and which comprises a plurality of modular components that may be assembled and adjusted by the vascular surgeon during the implantation procedure, using well-known surgical techniques, in order to provide a custom fit and arrangement for the particular patient involved. The device comprises an arterial anastomotic valve that permits blood flowing through an artery to pass into the shunt device, a venous anastomotic valve that permits blood flowing through the shunt device to pass into a vein, a medial flow control unit, a first flexible shunt that carries blood from the arterial anastomotic valve to the medial flow control unit, a second flexible shunt that carries blood from the medial flow control unit to the venous anastomotic valve, and a valve control system.

Abstract: Analysis of metabolic gases by an implantable medical device allows the assessment of the status of a congestive heart failure patient by providing for the assessment of cardiac output. The present invention is directed to an implanted medical device configured to measure concentrations of metabolic gases in the blood to determine cardiac output of a patient. The device is also configured to measure changes in the cardiac output of a patient. The present invention is also directed to a method of measuring cardiac output by an implanted medical device. Further, the detection of changes in cardiac output utilizing an implanted medical device as disclosed herein is useful in a method of detecting exacerbation of congestive heart failure. The implanted medical device can also be used to pace a heart to modify cardiac output in a patient.

Abstract: A catheter has a plurality of sensors and electrodes, wherein the sensors are arranged alternately and spaced apart from each other. A system for continuous measurement and mapping of physiological data may use such a catheter with a coupling unit for insulated coupling of the plurality of sensors with a measurement unit and a mapping unit for mapping values received from the sensors to a predefined matrix.

Abstract: The present invention provides implantable systems that communicate wirelessly with each other using a unique format that enables devices configurations and applications heretofore not possible. Embodiments of the present invention provide communication apparatuses and methods for exchanging information with implantable medical devices. In some embodiments, two implantable devices communicate with each other using quasi-electrostatic signal transmission in a long wavelength/low frequency electromagnetic band, with the patient's body acting as a conductive medium.

Abstract: An apparatus includes an endoluminal implant, a RF coupling coil coupled to the endoluminal implant and a therapeutic transducer electrically coupled to the RF coupling coil and physically coupled to the endoluminal implant. The RF coupling coil supplies electrical power to the therapeutic transducer. The therapeutic transducer has a capability for delivering therapeutic energy to a lumen disposed within the endoluminal implant in response to signals coupled via the RF coupling coil.

Abstract: An improved method and apparatus for measuring changes in blood flow, particularly in the context of an automatic arrhythmia treatment device. The invention may employ a flow sensor which is activated in response to detection of a tachyarrhythmia or in response to delivery of an anti-tachyarrhythmia therapy. If activated in response to detection of tachyarrhythmia, the flow sensor may be employed to determine whether a substantial drop in cardiac output has or has not occurred, in order to select an appropriate therapy, in particular to avoid unnecessary delivery of high level shocks. If activated in response to delivery of an anti-tachyarrhythmia therapy, the flow sensor may be employed to determine whether the therapy was or was not successful in correcting a low cardiac output or whether a reduced cardiac output followed delivery of the therapy.

Abstract: A low-power compact computer comprises a processor having relatively low-power consumption, a supporting chipset having conventional power consumption, and a conventional random access memory storage circuit.

Abstract: Disclosed herein, among other things, are intravascular flow sensors and related methods. In an embodiment, the invention includes an intravascular flow sensor including a strain gauge and a positioning element configured to be expandable from a first diameter to a second diameter. In an embodiment, the invention includes an intravascular flow sensor including a deflection member configured to be positioned within a lumen defined by a tissue wall, the deflection member including a flexible shaft and a shaft tip; and a positioning member configured to prevent the shaft tip from contacting the tissue wall. In an embodiment, the invention includes an implantable medical device including a pulse generator and an intravascular flow sensor in communication with the pulse generator, the intravascular flow sensor including a strain gauge. Other aspects and embodiments are provided herein.

Abstract: According to this technique of packaging a sensor device implantable in a living body so as to provide protection of the sensor device and to the living body itself, an electrical conductor of the sensor device is sealed in an insulating substrate extending between proximal and distal ends. The distal end of the electrical conductor is externally connected to an external sensor on the sensor device and the proximal end of the electrical conductor is externally connected to a distal end of a lead wire extending proximally to a pulse generator and these connections are embedded in an insulative sheath. The external sensor, substrate, and insulative sheath are encapsulated in a thin film of hermetic material without interference with the lead wire. In another embodiment, a layer of insulating material may underlie the hermetic material to encapsulate the external sensor and the substrate.

Abstract: The invention relates to a method for measuring the speed of a particle such as a red blood cell moving inside a flow such as a flow of the blood, using a light scanning microscope. The inventive method comprises the following steps: acquisition of an image by x and y light scanning on a plane containing the object; detection on the plane (x, y) of a mark on the plane (x, y); estimation of the speed vg of the object from the gradient thus determined.

Abstract: The smart textile vascular graft is used with an electrical control unit. The vascular graft includes a tube structure formed of a textile material. At least one active fiber is incorporated in the textile material. The active fiber provides electrical coupling thereof to the electrical control unit to provide for transmission of a control signal between the active fiber and control unit. The active fiber has at least one physical characteristic which is variable and corresponds to the control signal to provide communication between the active fiber and electrical control unit relating to the physical characteristic.

Abstract: Microwave apparatus for measuring the blood flow rate in a patient's blood vessel includes an intravascular catheter having proximal and distal ends and containing an inner coaxial cable forming a first antenna and an outer cable coaxial with the inner cable and forming a second antenna, the first antenna extending axially beyond the second antenna a selected distance. The apparatus also includes a control unit including a microwave transmitter, a microwave receiver and a processor controlling the transmitter and receiver. A diplexer is connected between the first and second antenna and the control unit to couple signals from the transmitter to the second antenna but not to the receiver and to couple signals from the first antenna to the receiver but not to the transmitter. The transmitter transmits microwave pulses to the first antenna which heat blood around that antenna. When the heated blood volume flows to the second antenna this is detected at the receiver which produces a detect signal.

Abstract: In a method for determining the effectiveness of a therapy for alleviating a constriction in a blood vessel, the functioning of collateral vessels naturally formed at the constriction is analyzed. The analysis takes place by making a blood flow measurement at the vessel in which the constriction is present, or at a complementary vessel, with the patient experiencing two different stress conditions. The flow measurement can ensue by magnetic resonance or using ultrasound. Comparison of the stress-dependent blood flow to a reference is then undertaken to determine whether the collateral vessels are functioning effectively, and thus whether the treatment for alleviating the constriction is effective.

Abstract: A vascular coupler adapted to be fixed into position upon a blood vessel and there retain and position a matable sensing device. In a preferred embodiment, the vascular coupler is an anastomotic coupler and the sensing device comprises an ultrasonic Doppler probe.

Abstract: Doppler Velocimetry is a widely used method for estimating stroke volume (SV). The accuracy and reliability of its measurement however, is dependant on a) the correct assessment of the aortic valve cross-sectional area (CSA), and b) the maximal systolic velocity integral (SVI). The invention avoids the conventional assessment of aortic valve CSA by using a calibration method: a reference stroke volume SVREF is determined by a method different from Doppler velocimetry, e.g. by thoracic electrical bioimpedance (TEB), or thoracic electrical bioadmittance, measured via surface thorax electrodes (transthoracic approach) or via electrodes located directly on an esophageal catheter/probe (esophageal approach). In the latter case, if esophageal Doppler velocimetry is used, the same catheter can be used for the placement of the electrodes and for an ultrasound transducer.

Abstract: A pump system includes an implantable pump including a motor having a rotor and a stator. The stator includes a plurality of stator windings, and a motor controller is coupled to the motor to energize the windings so as cause the rotor to turn. A time-based system parameter of the pump is sampled and the system parameter is analyzed to calculate a suction probability index that provides an indication of the imminence of ventricle collapse.

Abstract: Multi-channel blind system identification is utilized to identify a patient's cardiac functions without catheterization. The approach is adaptive to each patient's cardiovascular system variations. The cardiac functions can be determined by formulating an auto-regression moving average model utilizing either finite impulse response systems or a group of infinite impulse response systems. Both of these models identify the system functions by solving a set of linear equations using the least-squares method. The system input is then identified by deconvolving the system output and the estimated impulse response of each channel. These models can be augmented to obtain an estimate of the maximum order of the cardiac functions when they are unknown a priori. The approach can also be modified to obtain the cardiac functions by first resolving the distinct dynamics associated with each channel, then determining the common dynamics and ultimately determining the system input.

Abstract: A method and apparatus for determining an initial flow rate in a conduit is disclosed. A known change is made to the flow to be measured, resulting changes (or values corresponding to these changes), or relative changes in the flow to be measured are monitored and the initial flow in the conduit is calculated from the value of the known change and monitored changes. Devices to practice the method include catheters having one or two sensors and one or two sites for introducing the volume change.

Abstract: A catheter for retrograde orientation in a blood flow is used to determine the blood flow rate by thermodilution measurements. The determination of the blood flow rate accommodates injectate induced thermal influences on a dilution thermal sensor, wherein the thermal influences can occur prior to introduction of the injectate into the blood flow.

Abstract: The segment volume of a cardiac chamber or blood vessel of a patient is determined by injecting a first indicator in the blood stream of a patient, which influences the conductance of the blood. The electrical conductance in the cardiac chamber or blood vessel is measured. An injected quantity of indicator is determined and the development of the concentration of this indicator in the blood is measured wherein the cardiac output is calculated from the injected quantity of indicator and the development of the concentration in the blood. Subsequently, the segment volume and electrical parallel conductance of a cardiac chamber or blood vessel are calculated from the calculated cardiac output, the injected quantity of conductance indicator and the measured conductance.

Abstract: A delivery system for delivering a sensor to a body cavity includes a catheter and sheath slidably or rotatably coupled to the catheter. The sheath may be retractable and peelable. The delivery device may include an expandable balloon or a crushable material capable of moving the sensor laterally away from the catheter, to the target site. One embodiment of the delivery system includes a deployment device comprising a cord operably engaged with a pulley, and attached at the distal end to a cap engaged with the sensor. Another embodiment of the delivery system comprises a catheter having a chamber that can accommodate the sensor, and a sheath slidably coupled to the exterior of the catheter, and covering the chamber when the sheath is in the closed position. Further included is a method of delivering a sensor to a body cavity using any of the embodiments of the delivery system.

Abstract: A biological optical measuring instrument comprising a measuring probe (101) for collecting light from a plurality of portions of a subject (214) transmitted through the subject (214) by means of an optical fiber (108) by guiding light emitted from a light source (102) by an optical fiber (107), and irradiating the light to the subject (214) so as to create a living body transmitted light intensity image of the subject (214) from the transmitted and collected light. The measuring probe (101) further comprises optical fiber fixing members (201, 210, 211) for fixing the optical fibers (107, 108) at a predetermined interval and support members (202, 204, 205) for rockably supporting the optical fiber fixing members. Thus, it is possible to provide a technique of performing living body optical measurement while the living body lies in lateral decubitus.

Abstract: A sensor is disclosed, for implantation within a blood vessel to monitor an analyte in blood. In one embodiment, the analyte is glucose. A signal indicative of glucose level is transmitted to an external receiver. The signal may also be used to drive an internal or externally worn insulin pump. Methods are also disclosed.

Abstract: A apparatus and method for cleaning a sensor tip of an implantable sensor includes a flush sleeve directed towards the sensor tip, a fluid conduit in fluid communication with the flush sleeve, where fluid injected into a first end of a flush sleeve surrounding the sensor sprays off the sensor tip through at least one orifice located at the second end of the flush sleeve. The first end of the flush sleeve contains a fluid conduit and a septum, where a needle is used to pierce the septum to inject the fluid into the fluid conduit.

Abstract: A blood flow measuring apparatus has a measuring electrode and a counter-electrode adapted to be brought into contact with the blood of a patient. A measuring unit measures a voltage or a current between the measuring electrode and the counter-electrode and determines the flow of blood therefrom. The measuring electrode is ring-shaped and sized to fit within a blood vessel in the body of the patient. An inner surface of the ring-shaped electrode forms an active measuring electrode surface. The blood flow measuring apparatus is suitable for use in a cardiac pacemaker.

Abstract: A method for the measurement of post arteriolar pressure in a patient which is determined from information regarding the blood pressure (BP), systemic vascular resistance (R) and cardiac output (CO) by plotting the regression line for the equation BP=R×Q+c where c is the post arteriolar pressure, and determining the value of c from the regression line.

Abstract: A method and a device for measuring features in a fluid such as pressure, flow rate, and temperature measurements is disclosed. The sensing device includes at least two sensing elements, all of which are mounted and/or fabricated on a chip and connected to a chip circuit, and a power supply and measuring circuit placed outside the chip and connected to the chip circuit. According to the invention the power supply and measuring circuit is controllable to feed at least two different kinds of signaling to the chip circuit. Furthermore the sensing elements are connected to each other and to the power supply and measuring circuit such that at least one of the sensing elements, controllable by the signaling from the power supply, can be individually measured. The chip is adapted to be mounted on a catheter or a guide wire.

Abstract: An inverted sensor module for sensing physical and chemical fluid characteristics in a vessel in a living body. The inverted sensor module includes an inverted sensor bonded to a hollow carrier so that sensing occurs in the lumen of the inverted sensor module. An inverted sensor module comprising one or more inverted sensors is implantable and allows fluid to flow through, thereby allowing for measurements of acute and chronic conditions. The inverted sensor module may be used in series with other inverted sensor modules to assess trends such as pressure gradients along a bloodstream.

Abstract: A technique for determining blood flow in a living body by changing the thermal energy level by a predetermined amount at a site in a blood flow path and detecting temperatures at locations upstream and downstream of the site. The temperature difference at such locations is determined and the blood flow is calculated as a function of the change in energy level and of the temperature differences measured prior to and following the change in energy level.

Abstract: A sensor is disclosed, for implantation within a blood vessel to monitor an analyte in blood. In one embodiment, the analyte is glucose. A signal indicative of glucose level is transmitted to an external receiver. The signal may also be used to drive an internal or externally worn insulin pump. Methods are also disclosed.

Abstract: A body implantable system employs a lead system having at least one electrode and at least one thermal sensor at a distal end. The lead system is implanted within a patient's heart in a coronary vein of the left ventricle. The thermal sensor can be attached to a catheter that is disposed within an open lumen of the lead system. The thermal sensor senses a coronary vein temperature. The coronary vein temperature can be measured at a detector/energy delivery system and used as an activity indicator to adaptively control pacing rate. The measured coronary vein temperature can be also used with a left ventricular flow measurement to determine hemodynamic efficiency of the heart. A detected change in hemodynamic efficiency can be used by the detector/energy delivery system to modify the delivery of electrical pulses to the lead system.

Abstract: Methods and apparatus for guiding a guide wire through a blood vessel are described. An exemplary embodiment includes a guide wire coupled to an interferometric guidance system. The interferometric guidance system is configured to provide imaging information of the vessel. The guidance system further includes a flow detection circuit for performing Doppler shift analysis to determine the presence of neovascular channels through an obstruction in the vessel. The neovascular fow information is used by the guide wire operator to guide the guide wire through the obstruction.

Abstract: A stent graft includes a tubular prosthetic graft, a support structure expandable between contracted and enlarged conditions, and a biosensor attached thereto. The biosensor may be directly attached to an outer surface of the graft, to struts defining the support structure, or by one or more filaments configured to dispose the biosensor beyond an outer surface of the stent graft. When the biosensor is attached by one or more filaments, the stent graft is mounted in a contracted profile on a delivery apparatus with the biosensor disposed adjacent to the stent graft thereon. The stent graft is introduced into a blood vessel in the contracted profile, and advanced endolumenally until it is positioned across an aneurysm.

Abstract: Indicator dilution techniques are used to measure vascular access flow rates during routine hemodialysis.

Abstract: A delivery system for delivering a sensor to a body cavity includes a catheter and sheath slidably or rotatably coupled to the catheter. The sheath may be retractable and peelable. The delivery device may further include an expandable balloon or a crushable material capable of moving the sensor laterally away from the catheter, to the target site. One embodiment of the delivery system includes a deployment device comprising a cord operably engaged with a pulley, and attached at the distal end to a cap, the cap being engaged with the sensor to be delivered. Another embodiment of the delivery system comprises a catheter having a chamber that can accommodate the sensor, and a sheath slidably coupled to the exterior of the catheter, and covering the chamber when the sheath is in the closed position. Further included in the present invention is a method of delivering a sensor to a body cavity using any of the embodiments of the delivery system.

Abstract: A system, method and apparatus monitoring, recording and reporting physiological data includes an intravenous detection device in communication with at least one central processor. The intravenous detection device is configured to monitor at least one physiological measurement and report the measurement to the central processor via a communication medium. The central processor may store the data or immediately transmit the data to an authorized recipient. The central processor may also analyze the data to determine what further action should be taken, including immediate interventional action, such as, for example, defibrillation. The detection devices are preferably micro- or nano-level devices that are capable of flowing freely through the venous system of a host. The detection devices include a suitable transducer, an optional memory and a transceiver, and are preferably introduced into a host by injection of a fluid including a suspension of the detection devices.

Abstract: A technique is disclosed for determining blood flow in a living body by changing the thermal energy level in the venous blood flow path and determining temperatures in both the venous and arterial blood flow paths. Blood flow is calculated as a function of the change in energy level and the temperature differences in the venous and arterial blood flow paths.

Abstract: A sensor is disclosed, for implantation within a blood vessel to monitor a substance in or property of blood. In one embodiment, the sensor is retrievable. In another embodiment, the sensor has a layer that minimizes the formation of thrombus. A signal representative of the substance in or property of blood is transmitted to an external receiver. In another embodiment, the sensor detects nitric oxide or a nitric oxide metabolite and can be implanted for a period of hours, days, weeks or years. Methods are also disclosed.

Abstract: A system and method of detecting a vascular condition within a body receives vibrations emitted in response to blood flowing through a vascular structure within the body and converts the received vibrations into vibration information. The system and method generates spectral information from the vibration information, calculates a spectral parameter based on the spectral information and detects the vascular condition based on the spectral parameter.

Abstract: Indicator dilution techniques are used to measure vascular access flow rates during routine hemodialysis. A bolus injection port is used to infuse a specific volume (Vi) of an indicator diluent, such as saline or dye, into the patient cardiovascular circuit by one of the following: 1. Needle injection of a known volume (bolus) of indicator diluent directly into the access site in the presence or absence of the hemodialysis circuit. 2. Infusion of an indicator diluent into the arterial, venous line upstream of the venous needle. 3. Turning the ultrafiltration of the dialysis delivery system from OFF to ON and OFF again over a predetermined time period. 4. In a hemodialysis circuit, turning on the hemodialysis pump and using the priming saline volume as a single saline bolus. A transdermal sensor is used to measure the percent change in a blood parameter.

Abstract: The present invention provides a method for measuring the blood flow rate within an A-V shunt via indicator dilution techniques. Unknown flow resistance within the A-V shunt are addressed by adjusting a measured flow rate to provide a flow rate within a predetermined margin of error. The calculated flow rate can be rejected based upon flow conditions of the introduced indicator. Different indicator introduction rates can be used to enhance accuracy of the measured flow. The indicator flow path can include a flow restrictor to limit the flow rate of the indicator to below a predetermined value.

Abstract: A device for introduction into an animal or human body, especially into an artery. The device is preferably positioned in an aneurysmal sac in an artery between the wall of the artery and the wall of an endoprosthesis. The device has at least a pressure sensor and transducer for wirelessly transmitting data available from the pressure sensor.

Abstract: The invention concerns a system for the measurement of cardiac (1) output. The system comprises a heating resistor (2) placed in the vena cava (6), a temperature sensor (5) placed in the pulmonary trunk (4), an isolation interface (12) for separating an isolated side (14) and a non-isolated side according to patient potential, a power source (11) which is placed on the non-isolated side and produces the energy to be supplied to the heating resistor (2), and measuring elements (18, 19, 20) for the measurement of the power supplied to the heating resistor 92). According to the invention, the power measuring (18, 19, 20) elements are disposed on the isolated side (14), allowing the effective power supplied to the heating resistor (2) to be computed as accurately as possible.

Abstract: A catheter for retrograde orientation in a blood flow is used to determine the blood flow rate by thermodilution measurements. The determination of the blood flow rate accommodates injectate induced thermal influences on a dilution thermal sensor, wherein the thermal influences can occur prior to introduction of the injectate into the blood flow.

Abstract: An insertion device that includes an insertable portion adapted to be inserted into and retained in an animal body and an ex vivo portion that is adapted to be worn while the insertable portion remains inserted. The device further includes a trocar that is adapted to insert the insertable portion into the animal body. In addition, a cavity in the ex vivo portion is adapted to accept and retain the trocar after the insertable portion is inserted and a force application device is adapted to withdraw the trocar from the animal body and place it in the cavity.

Abstract: Heat exchanger-equipped catheters and related methods that are useable for changing or maintaining at least a portion of the body of a human or veterinary patient at a desired temperature and for the measurement of cardiac output or blood flow rate within a blood vessel, without the need for introduction of saline solution or any other foreign substance into the patient's blood.

Abstract: This invention provides a method and apparatus for calculating a hemodialysis parameter, especially blood access flow rate, using multiple dialysance values. The dialysance values may be calculated based upon either sodium or urea concentrations. One dialysance value can be determined for conditions in which a patient's arterial line withdraws blood from an upstream location in a patient's fistula and treated blood is returned by a venous line to a downstream location in a patient's fistula. The second dialysance value can be determined when the lines have been reconfigured so that the arterial line withdraws blood from a downstream portion of a patient's fistula and the venous line returns treated blood to an upstream portion of a patient's fistula.

Abstract: A medical monitoring apparatus designed to be implanted in the vascular system is capable of sensing and transmitting via a telemetry link to an external monitor both pressure and temperature information. An internally or externally powered microcircuit component is supported on a stent-like structure and adapted to be placed in the vascular system. Placement in the ventricular septum permits measurement of pressure and temperature in the left ventricle without introducing thrombus generating materials in the left ventricle.