Sensor delivery devices and methods of measuring Fractional Flow Reserve in a patient are disclosed. One sensor delivery device includes a distal sleeve, a proximal portion, and a pressure sensor. The distal sleeve is configured to be advanced through a patient's vasculature over a guidewire. The pressure sensor is located on the distal sleeve or the proximal portion. The pressure sensor is adapted to generate a signal proportional to fluid pressure. The pressure sensor includes a material having a low thermal coefficient of pressure.

A measurement system may comprise a sensor wire and a transceiver unit. The sensor wire may comprise an insertable portion configured to be inserted in a blood vessel of a patient's body and two sensors disposed within the insertable portion at a distal end of the sensor wire. The sensors are configured to measure a parameter when inserted inside the patient. The transceiver unit may comprise: a housing adapted to be connected to a proximal end of the sensor wire; and a first communication module within the housing adapted to wirelessly communicate by a communication signal with an external second communication module in order to transfer information to the external second communication module.

An eavesdropping arrangement for acquiring a measured physiological variable of an individual includes a receiver and a communication interface in a housing separate from the receiver. The communication interface is positioned along a communication link between a first sensor, which is configured to measure aortic blood pressure and to provide a signal representing measured aortic blood pressure, and a central monitoring device configured to monitor the measured aortic blood pressure. The communication interface includes a connection to the communication link that permits the communication interface to eavesdrop on the signal representing measured aortic blood pressure such that information representing measured aortic blood pressure is sent to the receiver while allowing the central monitoring device to receive and use the signal representing measured aortic blood pressure.

Methods of measuring Fractional Flow Reserve (FFR) including advancing a sensor delivery device within a guiding catheter to a location of interest, the sensor delivery device comprising a distal sleeve including a distal sensor and a proximal sensor, advancing only a distal portion of the distal sleeve outside of the guiding catheter such that the distal sensor is outside of the guiding catheter and downstream of the location of interest and the proximal sensor is inside of the guiding catheter, measuring a distal fluid pressure with the distal sensor distal to the location of interest, measuring a reference fluid pressure with the proximal sensor inside of the guiding catheter, and calculating FFR. One or both of the proximal and distal sensor may be comprised of a material having a low thermal coefficient.

A blood pressure analysis system/method allowing conversion from an analog sensor input to a standardized analog output interface is disclosed. In some preferred embodiments the system/method permits a fiber optic pressure sensor to be interfaced to a standard patient care monitor (PCM) system using standardized Wheatstone Bridge analog interface inputs. Within this context the Wheatstone Bridge sensed output is defined by stimulus from the PCM and modulation of bridge element values by the conditioned output of an analog pressure sensor. The use of analog-to-digital-to-analog conversion in this blood pressure analysis permits retrofitting of PCM devices having analog Wheatstone Bridge inputs with advanced patient monitoring sensors without the need for specialized modifications to the baseline PCM data collection framework. Methods disclosed herein include techniques to connect arbitrary types/numbers of analog sensors to traditional PCM systems without the need for PCM system hardware/software modifications.

A method, apparatus and computer program wherein the method comprises: identifying a plurality of extrema points in a detected biosignal; comparing the identified extrema points with a plurality of sets of reference points wherein different sets of reference points correspond to different frequencies of the biosignal; and identifying the set of reference points that most closely fit the identified extrema points to determine a frequency of the biosignal.

Devices, systems, and methods for evaluating a physiological condition of a vessel are disclosed. In an embodiment, a medical system is disclosed. One embodiment of the medical system comprises a medical processing unit in communication with a first pressure sensor, a second pressure sensor, and a radiographic imaging source configured to obtain radiographic images of at least one intravascular instrument positioned within a body lumen. The medical processing unit is configured to: receive the radiographic images obtained by the radiographic imaging source; detect, using the radiographic images, when the first pressure sensor is in a pre-determined orientation with respect to the second pressure sensor; and automatically initiate normalization of the first pressure sensor and the second pressure sensor in response to detecting that the first pressure sensor is in the pre-determined orientation with respect to the second pressure sensor.

Apparatus and methods are described, including apparatus that includes an antenna (34), configured to, by drawing energy from a magnetic field, provide a main supply voltage. The apparatus further includes operational circuitry (46, 22) configured to operate only if a derived supply voltage, derived from the main supply voltage and supplied to the operational circuitry, is greater than a threshold value, and modulating circuitry (36, 40, 42), configured to modulate a load of the antenna by alternatingly (i) connecting current-drawing circuitry to the main supply voltage, thus causing the main supply voltage to drop below the threshold value, and (ii) disconnecting the current-drawing circuitry from the main supply voltage without disconnecting the operational circuitry from the main supply voltage. Other embodiments are also described.

Disclosed is an apparatus, system, and method for compensating for hydrostatic pressure offset in transducer-based pressure measurements. The system may comprise: a measurement pressure transducer to measure an apparent fluid pressure at a measurement site, a reference pressure transducer to measure a hydrostatic pressure caused by a level difference between the measurement pressure transducer and the measurement site, and a controller to generate a corrected fluid pressure measurement based on the apparent fluid pressure and the hydrostatic pressure, wherein the measurement pressure transducer and the reference pressure transducer are placed at a same first level, and the measurement site and an end of a fluid-filled tube connected to the reference pressure transducer are at a same second level.

A controller is provided for calibrating an implantable pressure sensor. The controller includes an implantable pressure sensor configured to obtain characteristics of interest related to a patient, one or more processors, and a memory coupled to the one or more processors, wherein the memory stores program instructions. The program instructions are executable by the one or more processors to determine an implantable pressure sensor parameter in real time based on the characteristics of interest related to the patient and provide a drift threshold related to the implantable pressure sensor parameter. The one or more processors are also configured to determine whether the drift threshold has been exceeded based on the implantable pressure sensor parameter and communicate an alert in response to determining the drift threshold has been exceeded.