Читать книгу Interventional Cardiology - Группа авторов - Страница 169

Caution is required to ensure there is no damping of the pressure signal after coronary engagement. Catheter‐induced damping can cause ischemia but will also compromise pressure‐wire readings by artificially exaggerating a proximal stenosis. Catheters with side‐holes should be avoided; although the side‐hole can improve the appearance of the pressure trace, there remains a relative ostial obstruction which will alter the measured physiology. Furthermore, there is a risk that the pressure wire may pass out of the catheter through a side‐hole.

A better solution would be to disengage the guiding catheter, and to “normalize” or “equalize” the coronary pressure wire within the aorta. The wire can then be withdrawn into the guiding catheter before re‐engagement with the coronary ostia. Once the pressure wire is positioned distally, the guiding catheter can be disengaged to relieve the damping. An alternative approach would be to use a “buddy wire” which can be placed within a secondary vessel, such as the circumflex when interrogating the LAD. This enables the guiding catheter to be held out of the left main stem before delivering the pressure wire. A major limitation of guide disengagement is that delivery of using intracoronary vasodilators or injectants particularly challenging.