A PRESSURE-RECORDING GUIDE-WIRE FOR MEASUREMENTS OF TRANS-STENOTIC GRADIENTS IN ARTERIES - IN-VITRO VALIDATION

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 i n vitro are evaluated. METHODS. Static and dynamic tests were performe d with five guide wires. Dynamic tests (step response and recordings o f phase and frequency response) were performed with a pressure generat or connected to a recording system and a spectrum analyzer. RESULTS. Z ero drift at 3 hours ranged from -1.9 to 2.2 mmHg/hour. Sensitivity dr ift 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 ch anged sensitivity and zero pressure recordings in all guide wires. Dyn amic recordings showed a slight undershoot and no oscillation. CONCLUS ION. 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, m ake this pressure wire a promising device for recording trans-stenotic pressure gradients in arteries.