Safety and Feasibility Using a Fluid-Filled Wire to Avoid Hydrostatic Errors in Physiological Intracoronary Measurements

Background. Using a fluid-filled wire with a pressure sensor outside the patient compared to a conventional pressure wire may avoid the systematic error introduced by the hydrostatic pressure within the coronary circulation. Aims. To assess the safety and effectiveness of the novel fluid-filled wire, Wirecath (Cavis Technologies, Uppsala, Sweden), as well as its ability to avoid the hydrostatic pressure error. Methods and Results. The Wirecath pressure wire was used in 45 eligible patients who underwent invasive coronary angiography and had a clinical indication for invasive coronary pressure measurement at Sahlgrenska University Hospital, Gothenburg, Sweden. In 29 patients, a simultaneous measurement was performed with a conventional coronary pressure wire (PressureWire X, Abbott Medical, Plymouth, MN, USA), and in 19 patients, the vertical height difference between the tip of the guide catheter and the wire measure point was measured in a 90-degree lateral angiographic projection. No adverse events caused by the pressure wires were reported. The mean Pd/Pa and mean FFR using the fluid-filled wire and the sensor-tipped wire differed significantly; however, after correcting for the hydrostatic effect, the sensor-tipped wire pressure correlated well with the fluid-filled wire pressure (R = 0.74 vs. R = 0.89 at rest and R = 0.89 vs. R = 0.98 at hyperemia). Conclusion. Hydrostatic errors in physiologic measurements can be avoided by using the fluid-filled Wirecath wire, which was safe to use in the present study. This trial is registered with NCT04776577 and NCT04802681.