Pressure-sensing apparatus includes a sensor die, which is configured for percutaneous insertion through a wall of a blood vessel of a patient so as to generate an electrical signal that is responsive to a pressure in the blood vessel. A wire has a first end connected to the sensor die and a second end connected to an electronics package, which is configured for subcutaneous implantation and is connected via the wire to receive and process the electrical signal that is generated by the sensor die in order to provide an output that is indicative of the pressure.