Abstract: Disclosed is a system and method for in-situ and instantaneous measurement of a pressure gradient by real-time localized pressure measurement with two or more pressure sensors, operating with respect to blood pressure gradient across the aortic valve, or other heart valves, and associated regurgitation of blood flow due to leakage resulting from insufficient valve closure. The system includes a multi-sensor catheter, with sensors arranged along the length of the distal segment of the catheter body, spaced apart to provide simultaneous pressure measurement on either side of the valves of the heart, in addition to one or more lumina in the core of the catheter that will provide a path for introduction of diagnostic fluids which flow out through a multitude of holes in the body of the distal segment of the catheter body.