# US 10,244,951 B2 · Physiological sensor delivery device and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,244,951 B2 - Document ID: US10244951B2 - Status: Granted - Kind: B2 - Application number: 14/300,654 - Filed: 2014-06-10 - Published: 2015-12-10 - Granted: 2019-04-02 - Earliest claimed: 2014-06-10 - Assignees: ACIST Medical Systems, Inc. - Applicants: ACIST Medical Systems, Inc. - Inventors: Jason F. Hiltner - Web page: https://patentgrep.com/patent/US10244951B2 ## CPC - A61B 5/02156: {Calibration means} - A61B 5/02007: {Evaluating blood vessel condition, e.g. elasticity, compliance} - A61B 5/02158: {provided with two or more sensor elements} - A61M 25/09: Guide wires - A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors - A61B 2562/0247: Pressure sensors - A61M 2025/0004: {having two or more concentrically arranged tubes for forming a concentric catheter system} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract 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. ## Claims ### Claim 1 A method of measuring Fractional Flow Reserve (FFR) in a patient, the method comprising: advancing a guidewire through a patient's vasculature to a location of interest in a patient; advancing a guiding catheter over the guidewire to the location of interest; advancing a sensor delivery device within the guiding catheter to the location of interest, the sensor delivery device comprising a distal sleeve, a distal sensor located on the distal sleeve, a proximal sensor located on the distal sleeve and proximal to the distal sensor, a proximal portion, and a communication channel, the sensors adapted to generate signals proportional to fluid pressure; 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; generating a first distal fluid pressure signal with the distal sensor at a location outside of the guiding catheter and distal to the location of interest; generating a reference fluid pressure signal with the proximal sensor at a location inside of the guiding catheter, the reference fluid pressure signal representing a fluid pressure within the guiding catheter; calculating FFR using the first distal fluid pressure signal and the reference fluid pressure signal. ### Claim 2 (depends on 1) The method of claim 1 wherein the steps of generating the first distal fluid pressure signal with the distal sensor at the location distal to the location of interest and of generating the reference fluid pressure signal with the proximal sensor at the location inside of the guiding catheter are performed after the step of advancing only the distal portion of the distal sleeve without advancing or retracting the distal sleeve. ### Claim 3 (depends on 1) The method of claim 1 further comprising the step of normalizing the reference fluid pressure signal to an independent fluid pressure signal prior to positioning the distal sensor downstream of the location of interest. ### Claim 4 (depends on 1) The method of claim 1 wherein the FFR is calculated as a ratio of the distal fluid pressure signal to the reference fluid pressure signal. ### Claim 5 (depends on 4) The method of claim 4 further comprising making a therapy decision based on the calculated FFR being below a threshold value. ### Claim 6 (depends on 4) The method of claim 4 further comprising withdrawing the device and deploying an interventional therapy device using the same guidewire used to position the distal sensor downstream of the location of interest. ### Claim 7 (depends on 5) The method of claim 5 wherein the therapy decision comprises selecting an interventional therapy if the calculated FFR is less than about 0.75. ### Claim 8 (depends on 1) The method of claim 1 wherein the one or both of the proximal and distal sensors has a low thermal coefficient. ### Claim 9 (depends on 8) The method of claim 8 wherein only one of the proximal and distal sensors has a low thermal coefficient, further comprising: before advancing the sensor delivery device to the location of interest, calibrating the sensor having a low thermal coefficient to atmospheric pressure; and after advancing the sensor delivery device to the location of interest and before generating the distal fluid pressure signal or the reference fluid pressure signal, calibrating the sensor which does not have a low thermal coefficient to be equal to the sensor having a low thermal coefficient. ### Claim 10 (depends on 1) The method of claim 1, wherein the reference fluid pressure signal is generated while the first distal fluid pressure signal is generated. ### Claim 11 (depends on 1) The method of claim 1, wherein the sensor delivery device is configured such that a distance between the proximal sensor and the distal sensor allows the distal sensor to be positioned downstream of the location of interest while the proximal sensor remains inside of the guiding catheter. ### Claim 12 A method of measuring Fractional Flow Reserve (FFR) in a patient, the method comprising: advancing a guidewire through a patient's vasculature to a location of interest in a patient; advancing a guiding catheter over the guidewire to the location of interest; advancing a sensor delivery device within the guiding catheter to the location of interest, the sensor delivery device comprising a distal sleeve, a proximal portion, one or more sensors located on the distal sleeve and/or the proximal portion, the one or more sensors adapted to generate signals proportional to fluid pressure; generating a first distal fluid pressure signal at a location outside of the guiding catheter and distal to the location of interest; generating a reference fluid pressure signal at a location inside of the guiding catheter and proximal to the location of interest; and calculating FFR using the first distal fluid pressure signal and the reference fluid pressure signal. ### Claim 13 (depends on 12) The method of claim 12, wherein the reference fluid pressure signal and the first distal fluid pressure signal are generated at different times. ### Claim 14 (depends on 11) The method of claim 11, wherein the first distal fluid pressure signal is generated by a distal sensor located on the distal sleeve and the reference fluid pressure signal is generated by a proximal sensor located on the distal sleeve and spaced proximally from the distal sensor, and wherein the reference fluid pressure signal is generated while the first distal fluid pressure signal is generated. ### Claim 15 (depends on 14) The method of claim 14, wherein the sensor delivery device is configured such that a distance between the proximal sensor and the distal sensor allows the distal sensor to be positioned downstream of the location of interest while the proximal sensor remains inside of the guiding catheter. ### Claim 16 (depends on 14) The method of claim 14, wherein the one or both of the proximal and distal sensors has a low thermal coefficient. ### Claim 17 (depends on 16) The method of claim 16, wherein only one of the proximal and distal sensors has a low thermal coefficient, further comprising: before advancing the sensor delivery device to the location of interest, calibrating the sensor having a low thermal coefficient to atmospheric pressure; and after advancing the sensor delivery device to the location of interest and before generating the distal fluid pressure signal or the reference fluid pressure signal, calibrating the sensor which does not have a low thermal coefficient to be equal to the sensor having a low thermal coefficient. ### Claim 18 (depends on 12) The method of claim 12, further comprising the step of normalizing the reference fluid pressure signal to an independent fluid pressure signal prior to generating the first distal fluid pressure signal at the location outside of the guiding catheter and distal to the location of interest. ### Claim 19 (depends on 12) The method of claim 12, wherein the reference fluid pressure signal represents a fluid pressure within the guiding catheter.