A thin-film pressure transducer for implantable and intravascular blood pressure sensing

• Thin-film capacitive pressure transducer for space limited applications.
• Designed for intravascular and implantable devices, such as cardiovascular catheters, stents.
• Low profile transducer adds only 15 μm to the surface of the device.
• Good static sensitivity with 2.5% capacitive change over blood pressure range of 0–400 mmHg.
• Good dynamic sensitivity with flat frequency response of 500 Hz, excellent for measuring cardiovascular signals with high frequency features.

The mm-scale of micromachined pressure transducers limits numerous cardiovascular applications, including implantable pressure sensing. Here, a pressure transducer is presented which adds approximately 15 μm to the surface of an intravascular device, potentially enabling low profile implantable devices with pressure sensing functionality. The capacitive transducer consists of a polyimide diaphragm which can be transferred to an arbitrary substrate, including cardiovascular catheters, stents, or other intravascular devices. The transducer has good static and dynamic characteristics for cardiovascular applications, including pressure sensitivity of 2.5% over 400 mmHg and an estimated flat frequency response of 500 Hz. Additionally, good waveform fidelity was demonstrated in a flow loop relative to a research grade cardiovascular pressure transducer.