Renal vascular resistance using intravascular blood flow and pressure and associated systems, devices, and methods
A system includes a processor circuit configured to receive a first set of data. The first set of data includes two pressure measurements and a flow measurement from the vasculature of a patient obtained while the sympathetic nervous system of the patient is not under stimulation. The processor circuit calculates a blood flow resistance value based on the first set of data. The processor circuit then receives a second set of data. The second set of data also includes two pressure measurements and a flow measurement from the vasculature of the patient obtained while the sympathetic nervous system of the patient is stimulated. The processor circuit calculates another blood resistance value based on the second set of data. The processor circuit then compares the two blood flow resistance values to determine whether a denervation procedure would be effective to mitigate the nerve system's response to stimulation. The processor circuit outputs to a screen display metrics obtained from the measurement procedure.
1 . A system comprising:
a processor circuit configured for communication with a first pressure sensor, a second pressure sensor, and a flow sensor,
wherein the processor circuit is configured to:
determine if renal denervation is recommended for a patient based on a comparison between blood flow resistance with and without stimulation of a sympathetic nervous system of the patient, wherein the blood flow resistance is calculated using a single formula incorporating pressure and flow; and
provide, to a display in communication with the processor circuit, an output based on if the renal denervation is recommended for the patient,
wherein the blood flow resistance is distinct from fractional flow reserve (FFR), instant wave free ratio (iFR), and coronary flow reserve (CFR),
wherein, to determine if the renal denervation is recommended for the patient, the processor circuit is configured to:
calculate a first value of the blood flow resistance using first pressure measurements and a first flow measurement obtained without the stimulation of the sympathetic nervous system; and
calculate a second value of the blood flow resistance using second pressure measurements and a second flow measurement obtained with the stimulation of the sympathetic nervous system,
wherein the output comprises a visual representation of the first value of the blood flow resistance and a visual representation of the second value of the blood flow resistance.
2 . The system of claim 1 , further comprising a first intravascular catheter or guidewire comprising the first pressure sensor and the flow sensor.
3 . The system of claim 2 , further comprising a second intravascular catheter or guidewire comprising the second pressure sensor.
4 . The system of claim 1 ,
further comprising an intravascular catheter or guidewire,
wherein the intravascular catheter or guidewire comprises the first pressure sensor, the second pressure sensor, and the flow sensor.
5 . The system of claim 1 ,
wherein the first pressure measurements and the second pressure measurements each comprise:
a pressure measurement obtained by the first pressure sensor;
a pressure measurement obtained by the second pressure sensor; and
wherein the first flow measurement and the second flow measurement are obtained by the flow sensor.
6 . The system of claim 5 ,
wherein the first pressure measurements and the first flow measurement are obtained simultaneously,
wherein the second pressure measurements and the second flow measurement are obtained simultaneously.
7 . The system of claim 1 , wherein the comparison between the blood flow resistance with and without the stimulation of the sympathetic nervous system comprises a comparison between the first value of the blood flow resistance and the second value of the blood flow resistance.
8 . The system of claim 7 , wherein the comparison between the blood flow resistance with and without the stimulation of the sympathetic nervous system comprises a determination of whether a difference between the first value of the blood flow resistance and the second value of the blood flow resistance exceeds a threshold difference.
9 . The system of claim 1 ,
wherein the processor circuit is configured to: determine a location for the renal denervation based on the comparison between the blood flow resistance with and without the stimulation of the sympathetic nervous system,
wherein the screen display comprises a visual representation based on the location.
10 . The system of claim 1 , wherein the single formula incorporating pressure and flow is
F=ΔP/Q,
where
F is the first value of the blood flow resistance, ΔP is a difference between the first pressure measurements, and Q is the first flow measurement, or
F is the second value of the blood flow resistance, ΔP is a difference between the second pressure measurements, and Q is the second flow measurement.
11 . The system of claim 1 , wherein the processor circuit is configured to:
receive, from a plurality of sensors, a first set of data associated with blood within a blood vessel, wherein the first set of data is obtained without the stimulation of the sympathetic nervous system, wherein the plurality of sensors comprises the first pressure sensor, the second pressure sensor, and the flow sensor, wherein the first set of data comprises the first pressure measurements and the first flow measurement; and
receive, from the plurality of sensors, a second set of data associated with the blood within the blood vessel, wherein the second set of data is obtained with the stimulation of the sympathetic nervous system, wherein the second set of data comprises the second pressure measurements and the second flow measurement.
12 . The system of claim 11 ,
wherein the blood vessel comprises a renal artery, and
wherein the nerve comprises a renal nerve.
13 . The system of claim 11 , wherein the first set of data and the second set of data are obtained while:
the first pressure sensor and the flow sensor are positioned within the blood vessel; and
the second pressure sensor is positioned outside of a body of the patient, wherein the second pressure sensor is in direct fluid communication with blood within the blood vessel.
14 . The system of claim 11 , wherein the first set of data and the second set of data are obtained while the first pressure sensor, the second pressure sensor, and the flow sensor are positioned within the blood vessel.
15 . The system of claim 11 ,
wherein the first set of data and the second set of data are obtained before the renal denervation,
wherein, after the renal denervation, the processor circuit is further configured to:
determine a third value of the blood flow resistance based on a third set of data associated with the blood within the blood vessel and a fourth value of the blood flow resistance based on a fourth set of data associated with the blood within the blood vessel; and
provide a further screen display to the display, wherein the further screen display comprises a visual representation of the third value of the blood flow resistance and the fourth value of the blood flow resistance.
16 . The system of claim 15 , wherein the processor circuit is configured to:
perform a comparison based on the third value of the blood flow resistance and the fourth value of the blood flow resistance;
determine if the renal denervation procedure was successful based on the comparison; and
wherein the further screen display comprises a visual representation based on the determination of if the renal denervation was successful.
17 . The system of claim 1 , wherein the processor circuit is configured to:
generate a visual representation of the first value of the blood flow resistance; and
generate a visual representation of the second value of the blood flow resistance.