Rationale and objectives: A 0.018'' guide wire with a pressure sensor near the tip has been developed for measuring arterial trans-stenotic pressure gradients. The pressure-recording properties of this system in vitro are evaluated.
Methods: Static and dynamic tests were performed with five guide wires. Dynamic tests (step response and recordings of phase and frequency response) were performed with a pressure generator connected to a recording system and a spectrum analyzer.
Results: Zero drift at 3 hours ranged from -1.9 to 2.2 mmHg/hour. Sensitivity drift ranged from 0.3% to 2.1%/hour. Hysteresis ranged from 0.2% to 4.3% (mean 2.4%). Bending in arcs of 180 degrees with diameters < 4 cm changed sensitivity and zero pressure recordings in all guide wires. Dynamic recordings showed a slight undershoot and no oscillation.
Conclusion: Static errors exceeded those of external pressure transducers for fluid-filled catheters, indicating suboptimal recordings of absolute pressures. However, the small size, and the good dynamic properties, make this pressure wire a promising device for recording trans-stenotic pressure gradients in arteries.