An eavesdropping system comprising: a receiver configured to receive both (i) a signal representing a measured aortic blood pressure value measured by an aortic pressure sensor, and (ii) a signal representing a measured distal blood pressure value measured by a distal pressure sensor of a sensor guide wire, the receiver is configured to analyze the signal representing a measured aortic blood pressure value and the signal representing a measured distal blood pressure value, and thereafter display data calculated based on said signals, said data indicating an extent of a stenosis in a blood vessel; wherein the system further comprises a sensor guide wire connector configured to (i) receive a signal representing the measured distal blood pressure value via a connection between the distal pressure sensor and the sensor guide wire connector, and (ii) send a signal representing the measured distal blood pressure value to the receiver via a wired connection between the sensor guide wire connector and the receiver; characterized in that the system further comprises: a communication interface configured to (i) eavesdrop on a signal representing the measured aortic blood pressure value received from the aortic pressure sensor via a high impedance input connected to a wired channel between the aortic pressure sensor and a central monitor for monitoring the measured aortic pressure, and (ii) send a signal representing the measured aortic blood pressure value to the receiver via a wireless connection between the communication interface and the receiver, without altering the measured aortic blood pressure value. a receiver configured to receive both (i) a signal representing a measured aortic blood pressure value measured by an aortic pressure sensor, and (ii) a signal representing a measured distal blood pressure value measured by a distal pressure sensor of a sensor guide wire, the receiver is configured to analyze the signal representing a measured aortic blood pressure value and the signal representing a measured distal blood pressure value, and thereafter display data calculated based on said signals, said data indicating an extent of a stenosis in a blood vessel; wherein the system further comprises a sensor guide wire connector configured to (i) receive a signal representing the measured distal blood pressure value via a connection between the distal pressure sensor and the sensor guide wire connector, and (ii) send a signal representing the measured distal blood pressure value to the receiver via a wired connection between the sensor guide wire connector and the receiver; characterized in that the system further comprises: a communication interface configured to (i) eavesdrop on a signal representing the measured aortic blood pressure value received from the aortic pressure sensor via a high impedance input connected to a wired channel between the aortic pressure sensor and a central monitor for monitoring the measured aortic pressure, and (ii) send a signal representing the measured aortic blood pressure value to the receiver via a wireless connection between the communication interface and the receiver, without altering the measured aortic blood pressure value.