When are embolic protection devices (EPDs) recommended for use?

Embolic Protection Devices in Carotid Artery Stenting

Embolic protection devices (EPDs) should be used during carotid artery stenting (CAS) procedures when the risk of vascular injury is low, as they can reduce the risk of periprocedural stroke despite conflicting evidence about their efficacy. 1

Types of Embolic Protection Devices

There are three main types of EPDs used during CAS:

1. Distal filter devices - Most commonly used, capture embolic debris while maintaining blood flow
2. Distal occlusion balloons - Temporarily occlude the vessel distal to the stenosis
3. Proximal occlusion systems - Create flow reversal or stasis in the target vessel

Evidence Supporting EPD Use

The evidence regarding EPD use during CAS shows mixed results:

• Two systematic reviews demonstrated a reduction in neurological events with protected CAS 1
• A large-scale prospective registry showed an in-hospital death or stroke rate of 2.1% with EPDs versus 4.9% without EPDs 1
• EPDs were identified as an independent protective factor for adverse outcomes in multivariable analysis 1
• The best results for CAS in randomized trials have been obtained in studies that mandated embolic protection with a single device and properly trained operators (SAPPHIRE and CREST trials) 1

Evidence Against EPD Use

Some studies have shown no benefit or even potential harm:

• Two small randomized studies failed to demonstrate improved clinical outcomes with EPDs 1
• Secondary analyses from the SPACE trial showed 30-day ipsilateral stroke or death rates of 8.3% with EPDs versus 6.5% without EPDs 1
• In an ICSS sub-study, new diffusion-weighted MRI lesions were more common with EPDs (68%) than without (35%) 1
• A 2017 retrospective study of 166 patients undergoing CAS without EPDs reported no 24-hour or 30-day TIAs, intracranial hemorrhage, or ischemic strokes 2

Clinical Recommendations for EPD Use

EPDs are generally recommended during CAS in the following situations:

1. Standard recommendation: Class IIa recommendation - EPD deployment during CAS can be beneficial to reduce stroke risk when the risk of vascular injury is low 1

2. Operator experience: EPDs are most effective when used by operators experienced with the specific device 1. In unfamiliar hands, EPDs may be associated with worse clinical outcomes 1

3. Patient selection: CAS with EPDs is particularly beneficial for:

   • Patients at high surgical risk for carotid endarterectomy (CEA) 1
   • Patients with unfavorable neck anatomy 1
   • Cases of restenosis after CEA 1
   • Prior neck dissection or radiation therapy 1
   • High internal carotid or low common carotid artery lesions 1

Technical Considerations

When using EPDs, clinicians should consider:

• The complication rate associated with EPD use is generally low (<1%) 1
• Proper sizing of EPDs is critical - undersizing allows passage of debris, while oversizing can cause endothelial damage or vasospasm 1
• Dual protection (combining flow reversal with distal filter) with blood aspiration may provide more effective protection 3
• Proximal occlusion systems may offer advantages in embolic protection 1

Potential Complications of EPDs

• Inability to deliver the device due to large profile or reduced steerability 1
• Ischemia if the device becomes overloaded with embolic material 1
• Vessel injury during deployment or retrieval 1
• Device malfunction (rare, <1% of procedures) 1

Conclusion

Despite some conflicting evidence, current guidelines and the majority of evidence support the use of EPDs during CAS procedures to reduce the risk of periprocedural stroke, particularly when used by experienced operators familiar with the specific device. The decision to use an EPD should consider the patient's anatomy, the operator's experience, and the specific characteristics of the carotid lesion.