Paladin System Case Studies

The patient was scheduled for carotid intervention, and a FilterWire was placed distal to the lesion in the RICA. Pre-dilation of the lesion was not performed. The lesion was successfully treated with an 8 mm x 25 mm Roadsaver stent. Post-dilation of the stent was subsequently performed using a 5.0 x 20 mm Paladin System. The patient did not experience any neurological adverse events during the procedure and stenosis of the lesion was reduced to 20%. Following the procedure, the Paladin and FilterWire filters were collected and preserved in 10% formalin. Embolic particle count and size in each filter was analyzed and reported. The distal filter (FilterWire) contained 1,171 particles and the proximal filter (Paladin) contained 2,834 particles. At discharge, the neurological examination was unremarkable and the NIHSS remained 0/42. The patient returned to the clinic for routine follow up 35 days post-intervention and reported no adverse events.

In this case of a patient with a symptomatic RICA stenosis, more embolic particles were captured in the Paladin filter (n=2,834) as compared to the mean number of embolic particles captured in 20 asymptomatic patients (n=1,288), Figure 2(a). These results are consistent with a known higher risk of embolization during post-dilation of symptomatic lesions as compared to asymptomatic lesions¹.

A further analysis of the 2,834 particles captured revealed that 2,476 (87%) particles were between 40 to 100 microns, 297 (11%) particles were between 101 to 200 microns, and 61 (2%) particles were between 201 and 400 microns. Results are shown in Figure 2(b). While this patient was treated with a mesh-covered stent, this did not appear to significantly reduce the number of embolic particles captured in the Paladin filter during post-dilation.

¹Gray, W. A., et al. (2007), The CAPTURE registry: Predictors of outcomes in carotid artery stenting with embolic protection for high surgical risk patients in the early post-approval setting. Cath. Cardiovasc. Intervent., 70: 1025–1033. doi:10.1002/ccd.21359

The patient returned with an asymptomatic carotid artery stenosis of the RICA 5 years later. The patient had a medical history of type II diabetes, peripheral vascular disease, previous PCI and CABG, hyperlipidemia and hypertension.

Angiography revealed a target lesion stenosis of approximately 90% with lesion length of 15 mm and a reference vessel diameter of 5.0 mm. A primary distal protection device, Emboshield NAV6, was placed in the pre-petrous segment of the RICA. The RICA lesion was direct-stented with a 5 mm x 15 mm XACT carotid stent. A 5.0 mm x 20 mm Paladin System was then used to successfully post-dilate the stented lesion. Residual stenosis of the lesion was 20%.

The patient underwent DW-MRI scans prior to the procedure and within 24 hours post-procedure to assess for the presence of new ischemic lesions. The pre-procedure DW-MRI was unremarkable, with no cerebral ischemia. Post-procedure DW-MRI revealed no new lesions. The patient reported no major adverse events through the 30-day follow-up.

Angiography revealed a target lesion stenosis of approximately 90% with a target lesion length of 17 mm and a reference vessel diameter of 6.0 mm. The Mo.MA proximal cerebral protection device was used and pre-dilation of the lesion was performed. The lesion was treated with a 7 mm x 25 mm Roadsaver stent. Post-dilation of the stent was performed using a 5.0 mm x 20 mm Paladin System. Residual stenosis of the lesion was 0%. No major or device-related adverse events were reported through 30-day follow-up.

Following the procedure, the Paladin filter was removed from the catheter, placed into formalin and evaluated by a histology core laboratory to identify particulate debris collected (Figure 4). In total, 2,789 particles were collected in the Paladin filter, ranging in size from 40 μm to >200 μm. The largest particle detected in the Paladin filter was 374 microns in size.

Diagnostic angiography revealed a stenosis of approximately 70% in the RICA and 70% in the LICA (Figure 5a). Visual estimation indicated a length of 20 mm and a reference vessel diameter of 5.0 mm of both target lesions. The patient first underwent intervention of the LICA, and a FilterWire EZ System was chosen as the primary distal protection device. The lesion was treated with a 9 mm x 30 mm Roadsaver stent and post-dilation was successfully performed using a 5.0 mm x 20 mm Paladin System, reducing the stenosis to 10% (Figure 5b).

The patient returned for a staged intervention to the RICA following the 30-day follow-up period. A FilterWire EZ System was again chosen as the primary distal protection device. The lesion was treated with a 9 mm x 30 mm Roadsaver stent and post-dilation was successfully performed using a 5.0 mm x 20 mm Paladin System. Residual stenosis of the lesion was 20% (Figure 5c). No major or device-related adverse events were reported through the 30-day follow-up period.

The patient had a medical history of current tobacco use, hypertension, peripheral vascular disease, valvular disease, and a previous right CEA. Angiography revealed a target lesion stenosis of approximately 80% with a length of 12 mm and a reference vessel diameter of 6.0 mm.

The patient underwent the carotid intervention of the LICA. A SpiderFX Embolic Protection Device was used for primary protection. Pre-dilation of the lesion not was performed prior to stent placement and the LICA lesion was successfully treated with an 8 mm x 30 mm PRECISE stent. Post-dilation of the stent was performed using a 5.0 mm x 20 mm Paladin System. Residual stenosis of the lesion was 20%. No adverse events were reported during the procedure through 30-day follow-up.

An Emboshield NAV6 Protection System was deployed for primary distal protection. Pre-dilation of the lesion was performed with a 2.5 mm x 20 mm balloon prior to stent placement. The lesion was then treated with an 8 mm x 30 mm XACT stent and post-dilation was performed using a 5.0 mm x 20 mm Paladin System. Residual stenosis of the lesion was 0%. No major or device-related adverse events were reported through 30-day follow-up.

FILTER PARTICLE CONTENT ANALYSIS
A quantitative particle analysis was conducted on the Paladin System filter used for post-dilation of carotid artery stents in a subset of patients‡. All interventions were performed using a primary EPD. Paladin filters and primary EPD filters were removed from the catheter, placed into formalin and evaluated by a histology core laboratory (Imaging and Analysis, LLC, Saint Paul, MN).

The preserved Paladin System and primary EPD underwent hematoxylin and eosin (H&E) stained microscopic evaluations to identify particulate debris collected (Figure 6). Filter particle count results are shown in Figure 7.

Microscopic debris was present in 100% of filters. The majority of particles (>85%) captured in the Paladin filter were 100 μm or less in size. The mean number of particles between 40 – 100 microns collected in the Paladin filter was 1,167 compared to a mean of 700 collected in the primary EPD, suggesting that the small-pore Paladin filter collects the smaller particles that could pass through the primary EPD, and may provide additional patient safety.

Available distal filter based embolic protection devices feature pore sizes of more than 100 microns, and thus are unlikely to capture a majority of embolic particles released during the post-dilation phase of carotid artery stenting. The small-pore filter on the Paladin System collects particles that could pass through the primary filter, thus providing additional patient safety during CAS during the time of highest risk of microembolization.