Читать книгу Interventional Cardiology - Группа авторов - Страница 173

The pressure wire should be positioned distal to the coronary stenosis being investigated under fluoroscopic guidance. The sensor should be at least two to three vessel diameters away from the stenosis to reduce the impact of pressure recovery phenomena. Fluroscopic documentation of wire position is recommended and can be done without contrast. If contrast is used, then the catheter should be thoroughly flushed and time should be allowed for the effect on the pressure trace to subside.

Before any measurement is made, a long saline flush should be performed to clear the guiding catheter of contrast. Contrast is viscous and can impact pressure tracing. If the vessel had been challenging to wire, a repeat dose of intracoronary nitrates can alleviate any epicardial spasm. Measurements should be made with the needle‐introducer fully removed and the port closed to avoid minor pressure drift. Resting indices can be repeated readily until a steady value has been achieved. If there is marked variability, then the wire position should be adjusted. For optimal resting assessment, additional contrast injections should be avoided just prior to measurement of the index. If a contrast injection is necessary, it would be appropriate to wait 20 seconds to allow the impact of submaximal hyperemia to subside.,

If using hyperemic measures, this can be used induced either with intravenous infusion or with intracoronary boluses. Hyperemic measurements should be made during a steady and a careful review of the pressure traces is required to ensure validity of the measurement. It is best practice to avoid handling the wire during recording static readings.