A description of the angioscopy device and catheter is outlined in Fig. 5.1a, b. The physician operates the fiber and probe catheters, while a 2nd operator flushes low molecular weight dextran through the manifold.

The probing catheter requires rinsing with saline solution. The outer and inner catheters are then separated and rinsed using a 10 ml syringe which is also effective in removing residual air. The probe catheter is rinsed in a tray (it is important to ensure that the catheter does not dry out). The catheter should be carefully rinsed to ensure that no residual air remains (residual air bubbles in the tip of the probing catheter will result in interference of the field of imaging). The inner catheter is placed within the outer catheter while immersed in saline solution. As the catheter is relatively thin, the use of a small tray may affect the ability to insert the catheter effectively, and excessive force may result in damage to the catheter. The catheter is easily inserted in a straight position, and should resistance be encountered, it may be effective to pre-insert the guidewire in the inner catheter prior to insertion into the outer catheter (Fig. 5.4). If there is residual air inside the catheter, air bubbles or ST elevation on the electrocardiograph is observed during the procedure; a 20–30 ml syringe of saline solution should be used to repetitively flush the coronary arteries and wash out any air post procedure. When the probing catheter in the angioscopy catheter set cannot cross over severe stenosis, an aspiration catheter (>7Fr) for thrombectomy can be used instead of the original probing catheter.

In order to align the focus of the angioscopy catheter, the tip should be placed close to a dry gauze in order to confirm the imaging. The image should be focused to align either the 2 × 2 or 3 × 3 markers (Fig. 5.5). The focusing dial should be adjusted carefully and the focus confirmed. Following repetitive use, the tip should be cleaned with damp gauze and the focus readjusted. When protein becomes attached to the tip, the image may become unfocused. When large particles are observed on the image, it may be resultant from particles contained within the connection rather than the catheter tip. The connection should be wiped with either gauze or cotton swab or the “white balance” button reset.

Similar to other catheters, the fiber catheter is easily damaged under excessive bending. When the fiber is broken, sufficient light is unable to reach the catheter tip. When product is not in use, it is recommended to place a cover over the fiber when stored. The probing catheter is inserted beyond the target location. Care should be given that the guiding catheter does not become disengaged when the probing catheter is inserted into tortuous vasculature (the guiding catheter should ideally be coaxially positioned). It might be impossible to advance the fiber catheter when the guiding catheter is bent. When the catheter is placed in position, the inner catheter and guidewire are removed (quickly removing product may result in the introduction of air). Use a 2.5 ml syringe to remove any residual air, and confirm the backflow of blood. When reverse blood flow is not observed, the catheter may have become wedged in a smaller vessel diameter, and under minimal negative pressure, the catheter should be pulled slightly proximal. Not correcting this issue may result in an ST elevation.