Determination of a treatment response index

An apparatus, comprising:

• an intravascular catheter or guidewire configured to be positioned within a renal artery of a subject, wherein the intravascular catheter or guidewire comprises a sensor configured to measure a physiological parameter of the renal artery;
• and
• a controller comprising at least one of a processor, an application specific integrated circuit (ASIC), or a field-programmable gate array (FPGA), wherein the controller is configured to:
• control the intravascular catheter or guidewire to:
• obtain, with the subject under no stimulation or a first stimulation, a first measurement of the physiological parameter for the renal artery while positioned in the renal artery, wherein the no stimulation or the first stimulation is distinct from renal denervation;
• and
• obtain, with the subject under a second stimulation, a second measurement of the physiological parameter for the renal artery while positioned in the renal artery, wherein the second stimulation is distinct from the renal denervation;
• determine a ratio for the renal artery using the first measurement and the second measurement;
• generate a renal response index for the renal artery based on the ratio;
• and
• provide the renal response index to a display,
• wherein the first and second measurements are obtained, the ratio is determined, and the renal response index is generated and provided to the display before the renal denervation is performed.