Proximal Embolic Protection

Safety and Efficacy of Flow Reversal in Acute and Elective Carotid Angioplasty and Stenting Using the Mo.Ma Device with Short-Term Follow-Up

Objective

To determine the safety and efficacy of flow reversal following proximal flow arrest as an embolic protection strategy for carotid angioplasty and stenting (CAS) with short-term follow-up.

Method

We performed a retrospective review of our CAS database for patients who underwent stent-supported carotid revascularization in the setting of acute/subacute stroke or TIA. We reviewed clinical and radiographic data during a 36-month period. Primary outcome was clinical evidence of ipsilateral stroke in the first 30 days. Secondary outcomes include clinical outcomes and sonographic and/or angiographic follow-up over 6 months, 6-month functional scale, and all-cause mortality.

Results

Fifty-five patients underwent CAS using flow reversal: 26 females and 29 males with a mean age of 69.7 years. Median time to treatment from index event was 3 days. 11% underwent stenting as part of hyperacute stroke therapy. Average luminal stenosis was 86%. The 9-Fr Mo.Ma device was used in combination with Penumbra aspiration in all cases. There were no ipsilateral strokes. Incidence of any ischemic event was 3.64%, but only 1 (1.82%) patient had a postoperative stroke. Clinical follow-up was available for 94.5%, while lesion follow-up was available for 73% of patients. Three patients had evidence of restenosis, but none were symptomatic. Luminal restenosis was ≤30% in all three. Median pre- and post-NIHSS were 1 and 1, respectively.

Conclusion

Flow reversal using the Mo.Ma device is a safe and effective strategy in preventing distal embolization during carotid artery revascularization.

Carotid artery stenting: Current state of evidence and future directions

Both carotid endarterectomy (CEA) and carotid artery stenting (CAS) are common treatments for carotid artery stenosis. Several randomized controlled trials (RCTs) have compared CEA to CAS in the treatment of carotid artery stenosis. These studies have suggested that CAS is more strongly associated with periprocedural stroke; however, CEA is more strongly associated with myocardial infarction. Published long-term outcomes report that CAS and CEA are similar. A reduction in complications associated with CAS has also been demonstrated over time. The symptomatic status of the patient and history of previous CEA or cervical radiotherapy are significant factors when deciding between CEA or CAS. Numerous carotid artery stents are available, varying in material, shape and design but with minimal evidence comparing stent types. The role of cerebral protection devices is unclear. Dual antiplatelet therapy is typically prescribed to prevent in-stent thrombosis, and however, evidence comparing periprocedural and postprocedural antiplatelet therapy is scarce, resulting in inconsistent guidelines. Several RCTs are underway that will aim to clarify some of these uncertainties. In this review, we summarize the development of varying techniques of CAS and studies comparing CAS to CEA as treatment options for carotid artery stenosis.

The Role of Embolic Protection in Carotid Stenting Progress in Cardiovascular Diseases (PCVD)

Embolic protection device (EPD) use has become ubiquitous and is currently mandated by the Centers for Medicare and Medicaid (CMS) for reimbursement in conjunction with carotid artery stenting (CAS). There are two classes of EPD devices: distal filter EPD (f-EPD) and proximal EPD (p-EPD). Measuring the incremental benefit of one strategy over the other remains problematic for several reasons. The first lies in the difficulty of defining an embolic event as transcranial Doppler and diffusion-weighted magnetic resonance imaging abnormalities may not correlate with clinical events. Next, f-EPD is used more frequently than p-EPD making direct comparisons challenging, as analyses to this point have been underpowered. However, there are several promising emerging techniques and technologies that warrant further investigation.

Ascertainment of any and all neurologic and myocardial damage in carotid revascularization: the key to optimization?

The majority of carotid revascularization procedures performed at present are in asymptomatic patients. Since such procedures convey no immediate benefit, but rather protect from future hazard, optimization of procedural safety is mandatory. The authors focus their discussion on the methodologies that assess periprocedural myocardial damage and brain injury, as used in past clinical trials, from the fields of perioperative medicine and neurovascular imaging, and discuss methodologies to reduce both events in carotid revascularization.

Diagnosis of and treatment for symptomatic carotid stenosis: an updated review

Carotid stenoses of ≥50% account for about 15-20% of strokes. Their degree may be moderate (50-69%) or severe (70-99%). Current diagnostic methods include ultrasound, MR- or CT-angiography. Stenosis severity, irregular plaque surface, and presence of microembolic signals detected by transcranial Doppler predict the early recurrence risk, which may be as high as 20%. Initial therapy comprises antiplatelets and statins. Benefit of revascularization is greater in men, in older patients, and in severe stenosis; patients with moderate stenoses may also profit particularly if the plaque has an irregular aspect. An intervention should be performed within <2 weeks. In large randomized studies comparing endarterectomy and stenting, endovascular therapy was associated with a higher risk of periprocedural stroke, yet in some studies, with a lower risk of myocardial infarction and of cranial neuropathy. These trials support endarterectomy as the first choice treatment. Risk factors for each of the two therapies have been indentified: coronary artery disease, neck radiation, contralateral laryngeal nerve palsy for endarterectomy, and, elderly patients (>70 years), arch vessel tortuosity and plaques with low echogenicity on ultrasound for carotid stenting. Lastly, in direct comparisons, a contralateral occlusion increases the risk of periprocedural complications in both types of treatment.

Advances in the management of carotid artery disease: focus on recent evidence and guidelines

Recent landmark randomized trials and society guidelines have significantly revised the management of carotid artery disease. Duplex ultrasonography is the recommended initial diagnostic test for the assessment of extracranial carotid artery stenosis. Carotid artery imaging is reasonable in select patients scheduled for coronary artery bypass graft (CABG) surgery. Carotid revascularization can be achieved safely and effectively with carotid endarterectomy or carotid artery stenting. Because each procedure has a different risk/benefit profile, the optimal approach is to match the particular patient to the intervention that maximizes outcome benefit. Carotid revascularization is recommended in patients scheduled for CABG surgery when the carotid artery stenosis is symptomatic and/or bilateral. Further trials are required to guide the management of asymptomatic unilateral carotid artery stenosis in patients undergoing CABG surgery. Aggressive medical therapy remains the gold standard for intracranial carotid artery disease because landmark trials have shown no outcome improvement with vascular bypass or percutaneous angioplasty and stenting. A large recent trial showed that local anesthesia, as compared with general anesthesia, for carotid endarterectomy has no major clinical outcome advantage. Although carotid artery stenting is associated with a reduced risk of myocardial ischemia, it still has important risks of stroke and hemodynamic instability that significantly affect clinical outcome. The timing and choice of carotid revascularization technique ultimately depends on multiple clinical factors.

The PROFI study (Prevention of Cerebral Embolization by Proximal Balloon Occlusion Compared to Filter Protection During Carotid Artery Stenting): a prospective randomized trial

OBJECTIVES

The objective of this study was to compare the cerebral embolic load of filter-protected versus proximal balloon-protected carotid artery stenting (CAS).

BACKGROUND

Randomized trials comparing filter-protected CAS with carotid endarterectomy revealed a higher periprocedural stroke rate after CAS. Proximal balloon occlusion may be more effective in preventing cerebral embolization during CAS than filters.

METHODS

Patients undergoing CAS with cerebral embolic protection for internal carotid artery stenosis were randomly assigned to proximal balloon occlusion or filter protection. The primary endpoint was the incidence of new cerebral ischemic lesions assessed by diffusion-weighted magnetic resonance imaging. Secondary endpoints were the number and volume of new ischemic lesions and major adverse cardiovascular and cerebral events (MACCE).

RESULTS

Sixty-two consecutive patients (mean age: 71.7 years, 76.4% male) were randomized. Compared with filter protection (n = 31), proximal balloon occlusion (n = 31) resulted in a significant reduction in the incidence of new cerebral ischemic lesions (45.2% vs. 87.1%, p = 0.001). The number (median [range]: 2 [0 to 13] vs. 0 [0 to 4], p = 0.0001) and the volume (0.47 [0 to 2.4] cm(3) vs. 0 [0 to 0.84] cm(3), p = 0.0001) of new cerebral ischemic lesions were significantly reduced by proximal balloon occlusion. Lesions in the contralateral hemisphere were found in 29.0% and 6.5% of patients (filter vs. balloon occlusion, respectively, p = 0.047). The 30-day MACCE rate was 3.2% and 0% for filter versus balloon occlusion, respectively (p = NS).

CONCLUSIONS

In this randomized trial of patients undergoing CAS, proximal balloon occlusion as compared with filter protection significantly reduced the embolic load to the brain.

Carotid artery stent placement

In the past 3 years, there have been significant developments in the field of carotid revascularization, including: 1) the results of a large primary stroke prevention trial; 2) the emergence of novel platforms for emboli protection; 3) improved characterization of the high-risk carotid artery stent (CAS) patient; 4) completion of several very large post-market surveillance (PMS) trials of CAS in high-surgical-risk patients; and 5) the completion of 4 large randomized controlled trials comparing CAS with carotid endarterectomy in average-risk patients. The purpose of this review is to update the current status of revascularization therapies to reduce stroke in patients with extracranial carotid artery disease with a focus on the most recent developments regarding the role of CAS.