Functional gain measurement technique and representation

1. A method for determining improvement of a physiological property after a therapeutic procedure, the method comprising:

obtaining, prior to conducting the therapeutic procedure, first pressure measurements using a pressure sensor disposed at a distal portion of an intravascular pressure-sensing guidewire positioned within a vessel of a patient;

determining, at a computer in communication with the intravascular pressure-sensing guidewire and prior to conducting the therapeutic procedure, a baseline quantity of a physiological property associated with the vessel, wherein the physiological property comprises a pressure ratio calculated using the first pressure measurements;

conducting the therapeutic procedure to treat the vessel;

obtaining, after conducting the therapeutic procedure, second pressure measurements using the pressure sensor of the intravascular pressure-sensing guidewire positioned within the vessel;

determining, at the computer and after conducting the therapeutic procedure, a post-therapy quantity of the physiological property based on the second pressure measurements;

comparing, at the computer, the post-therapy quantity to the baseline quantity;

calculating, at the computer based on the comparison of the post-therapy quantity to the baseline quantity, a functional gain of the physiological property as a result of the therapeutic procedure; and

outputting, to a display in communication with the computer, a visual representation of the comparing, wherein the visual representation of the comparing comprises displaying:

a numerical value associated with the functional gain;

at least one of a numerical value associated with the baseline quantity or a numerical value associated with the post-therapy quantity; and

a visual rendering of the vessel that includes an indication of at least one of the baseline quantity or the post-therapy quantity at a corresponding location of the visual rendering of the vessel.

2. The method of claim 1 , wherein the determining the baseline quantity and post-therapy quantity comprises measuring an amount of flow and/or pressure in the vessel.

3. The method of claim 2 , wherein the vessel is a blood vessel.

4. The method of claim 1 , wherein physiological property is selected from fractional flow reserve, instant free-wave ratio, hyperemic stenosis resistance, hyperemic microvascular resistance, index of microvascular resistance, or a combination thereof.

5. The method of claim 1 , wherein the therapeutic procedure comprises a cardiovascular procedure.

6. The method of claim 5 , wherein the cardiovascular procedure is selected from an angioplasty, a stent placement, an ablation, or a combination thereof.

7. The method of claim 1 , further comprising inserting the intravascular pressure-sensing guidewire into the vessel.

8. The method of claim 7 , further comprising guiding the intravascular pressure-sensing guidewire to a stenosis within the vessel, wherein the first pressure measurements are obtained distal to the stenosis.

9. An intravascular system, comprising:

an intravascular pressure-sensing guidewire configured for positioning within a vessel of a patient and comprising a pressure sensor disposed at a distal portion of the intravascular pressure-sensing guidewire and configured to obtain pressure measurements associated with the vessel;

a display; and

a computer in communication with the intravascular pressure-sensing guidewire and the display, wherein the computer is operable to:

determine, prior to conducting a therapeutic procedure, a baseline quantity of a physiological property associated with the vessel, wherein the physiological property comprises a pressure ratio calculated using pressure measurements obtained by the intravascular pressure-sensing guidewire while positioned within the vessel;

determine, after conducting the therapeutic procedure, a post-therapy quantity of the physiological property based on the pressure measurements obtained by the intravascular pressure-sensing guidewire positioned within the vessel;

compare the post-therapy quantity to the baseline quantity;

calculate, based on the comparison of the post-therapy quantity to the baseline quantity, a functional gain of the physiological property as a result of the therapeutic procedure; and

output, to the display, a visual representation of the comparison, wherein the visual representation of the comparison comprises displaying:

a numerical value associated with the functional gain;

at least one of a numerical value associated with the baseline quantity or a numerical value associated with the post-therapy quantity; and

a visual rendering of the vessel that includes an indication of at least one of the baseline quantity or the post-therapy quantity at a corresponding location of the visual rendering of the vessel.

10. The system of claim 9 , wherein the baseline measurement and the post-therapy measurement comprise at least one of a flow measurement or a pressure measurement.

11. The system of claim 9 , wherein the vessel comprises a blood vessel.

12. The system of claim 9 , wherein the baseline measurement and the post-therapy measurement comprise at least one of fractional flow reserve, instant free-wave ratio, hyperemic stenosis resistance, hyperemic microvascular resistance, or index of microvascular resistance.

13. The system of claim 9 , wherein the visual representation comprises at least one of a graphical representation or a textual representation.

14. The system of claim 13 , wherein the numerical value comprises at least one of a difference or a percentage change, between the post-therapy measurement and the baseline measurement.

15. The system of claim 9 , wherein the computer is further operable to:

compare a further post-therapy quantity to at least one of the baseline quantity or the post-therapy quantity; and

wherein the visual representation of the comparison comprises a numerical value associated with the further post-therapy quantity in a manner that indicates a functional improvement in the physiological property as a result of a further therapeutic procedure.