Technical Complications Associated with Embolic Protection Device During Carotid Artery Stenting: Incidence, Risk Factors, Clinical Implications, and Rescue Maneuvers

Figure 1. Flow chart of patients included in study. CAS: carotid artery stenting; EPD: embolic protection device; ICA: internal carotid artery; MCA: middle cerebral artery.

Figure 2. (a) Right common carotid angiogram showing focal severe stenosis at the proximal cervical internal carotid artery. (b) After carotid stenting with angioplasty, residual mild stenosis was observed. (c,d) Anterior–posterior and lateral fluoroscopic images during the procedure show that the retrieval sheath could not advance through the stenotic portion. The retrieval sheath advanced toward the anterolateral wall of the internal carotid artery and was prevented from advancing by the stent strut. (e) By advancing the guiding catheter with a curved tip, the direction of the retrieval sheath was changed and it could then pass through the stent (arrow).

Figure 3. (a) Pre-treatment left common carotid angiography showing focal severe stenosis in the proximal cervical internal carotid artery (ICA). (b) Carotid angioplasty and stenting were performed under the protection of a 5 mm Emboshield NAV™ embolic protection device (EPD, Abbott Vascular, Santa Clara, CA, USA) in the distal cervical ICA. (c) However, the retrieval sheath could not pass through the stent-placed ICA where the filter wire approximated the stent struts presumed to protrude into the lumen of the vessel (arrow). (d) A 6 × 30 mm Sterling balloon catheter (Boston Scientific, Natick, MA, USA) was placed in the mid-segment of the stent. (e,f) After rescue angioplasty, the balloon catheter was left with suboptimal inflation to eliminate the gap between the filter wire and the lumen of the guiding catheter. A guiding catheter was smoothly advanced over the partially inflated balloon catheter. (g) After complete bypass of the guiding catheter over the stent-placed carotid bulb, the EPD could be easily and safely removed with the provided retrieval sheath.

Figure 4. A schematic diagram of a rescue technique with a guiding catheter advanced over a partially inflated balloon catheter. (a) Emboshield NAV™ retrieval sheaths are frequently stuck in the intraluminally protruded stent strut at the proximal ICA. (b) After placing a balloon catheter in the problematic segment, rescue angioplasty is performed to push a stent strut. Subsequently, the balloon is maintained at a suboptimal pressure of less than 2 atm. (c–e) If partially inflated, the balloon moves the filter wire away from the stent and eliminates the gap between the inner lumen of the guiding catheter and the filter wire; the guiding catheter can then pass over the problematic segment. After bypassing the stent with the guiding catheter, the retrieval sheath can easily remove the filter.

Figure 5. (a) Pre-treatment right common carotid artery angiography shows an atherosclerotic ulcerative plaque with focal severe stenosis at the proximal cervical internal carotid artery. (b) After carotid angioplasty and stenting, residual mild stenosis occurred due to the calcified plaque. (c) The retrieval sheath could not advance over the filter wire at the proximal tip of the stent (arrow). (d) A 5 Fr curved-tip angiocatheter was used instead of a retrieval sheath. We created a side hole with a 22-gauge needle at the angiocatheter to advance the angiocatheter in the monorail system of the 190 cm EPD filter wire (arrow). (e) We inserted a 0.035-inch buddy wire (arrow) into the angiocatheter to navigate the angiocatheter pass through the stent. (f) The EPD was successfully removed into the angiocatheter.