History and current status of endovascular management for the extracranial carotid and supra-aortic vessels

The development of carotid stent material

Endovascular angioplasty with stenting is a promising option for treating carotid artery stenosis. There exist a rapidly increasing number of different stent types with different materials. The bare-metal stent is the most commonly used stent with acceptable results, but it leaves us with the problems of thrombosis and restenosis. The drug-eluting stent is a breakthrough as it has the ability to reduce the restenosis rate, but the problem of late thrombosis still has to be addressed. The biodegradable stent disappears after having served its function. However, restenosis and degradation rates remain to be studied. In this article, we review every stent material with its characteristics, clinical results and complications and point out the standards of an ideal carotid stent.

Protection Filter–Related Events in Extracranial Carotid Artery Stenting:A Single-Center Experience

PURPOSE

To report the complications, rescue procedures, and consequences related to the use of an embolus protection filter during carotid artery stenting (CAS).

METHODS

A retrospective review was undertaken of 72 patients (58 men; mean age 70.0+/-8.2 years, range 56-87) with extracranial atherosclerotic carotid stenosis who underwent 77 CAS procedures under filter protection. Filter-related events and rescue procedures according to each procedural step were retrospectively evaluated on CAS angiograms. In addition, neurological events and outcomes were also assessed.

RESULTS

CAS using a filter was successful in 99% of cases, and the overall rate of minor stroke (n=1), major stroke (0), or mortality (n=1) was 2.6% at 30 days. Filter placement was successful in all cases. However, arterial tortuosity made it difficult for a filter to pass through the stenosis in 1 case; this was overcome with an additional supportive wire (0.018-inch). Filter-related events were flow impairment in 6 (7.8%), filter wedging in the catheter tip in 4 (5.2%), vasospasm >50% narrowing in 7 (9.1%), filling defects within the filter membrane in 5 (6.5%), retrieval failure with the provided retriever in 3 (3.9%), and insecure retrieval without filter collapse in 2 (2.6%). Flow impairment caused drowsy mentality and impaired verbal response in 4, which resolved after prompt filter retrieval. All the cases of filter wedging were resolved with a catheter pulled down into the stented segment to separate the filter element from the catheter tip. Significant vasospasm and filling defects were spontaneously resolved in all cases after filter retrieval. Inability to pass a retriever catheter through a stent was overcome with curved 5-F catheter manipulation in all 3 cases.

CONCLUSION

The use of a filter during CAS may induce various angiographic or technical events at each step. For a severely stenotic and tortuous carotid lesion with difficult access, a filter may become trapped or irretrievable during flow arrest. Physicians should be aware of the preventive and rescue maneuvers to counter filter-related events, perhaps even considering another type of protection mechanism or carotid endarterectomy.

Rationale and design of a multidisciplinary national real-world registry on carotid stenting: the Italian Registry for Carotid Stenting (RISC)

The Registro Italiano per lo Stenting Carotideo (RISC, Italian Registry for Carotid Stenting) has been organized by Italian specialists from different disciplines directly involved in the prevention of stroke due to carotid plaques through stenting of carotid lesions. The Registry has been endorsed by the national societies of 4 different specialties: vascular surgery, interventional cardiology, radiology, and neuroradiology. Each society contributed in the planning stage. The basis for the registry is to collect data on carotid stenting procedures performed by different specialists with different techniques in a "real-world" setting without the limitations of a randomized clinical trial. The Registry was funded to enroll at least 1200 patients over a minimum period of 36 months. The results will be analyzed using the intention-to-treat principle and are anticipated in late 2006. Primary endpoints of the registry are the 30-day combined death and stroke rate and the occurrence of restenosis and ipsilateral neurological deficit at 12 and 24 months. Considerable attention has been paid to the registry's quality control program to ensure scientific validation. An online database facilitates the collection of data with speed and accuracy.

Filter-Protected Carotid Stenting Via a Minimal Cervical Access With Transitory Aspirated Reversed Flow During Initial Passage of the Target Lesion

PURPOSE

To evaluate the preliminary results of filter-protected carotid artery stenting (CAS) via a minimal cervical access, with temporary common carotid artery (CCA) occlusion and aspiration in selected high-risk candidates for carotid endarterectomy.

METHODS

Since February 2002, 26 patients (17 men; mean age 73.7 years, range 54-98) at high surgical risk according to the SAPPHIRE eligibility criteria underwent 29 transcervical CAS procedures under filter protection. Under general anesthesia, a 6-F short introducer sheath was directly mounted in the CCA through a small (2-4 cm) laterocervical cutdown. The CCA was briefly clamped, and blood was aspirated while the filter device was positioned above the target lesion. With the filter in place and the clamp released, nitinol stents were deployed under filter protection. Hemostasis was achieved by direct suture.

RESULTS

Twenty-eight (96%) interventions were technically successful; 1 complex lesion could not be crossed and was converted to surgery. Mean clamping time was 1.7 (range 1.0-3.5) minutes. Combined 30-day stroke/mortality was 0%. Ultrasound surveillance demonstrated a < 60% asymptomatic in-stent restenosis in 1 (4%) patient with radiation-induced arteritis after 28 months. During a mean follow-up of 11.6 months (range 3-38), 1 (4%) minor ipsilateral stroke was noted at 6 months in a patient whose antiplatelet therapy was transitorily interrupted.

CONCLUSION

Our preliminary observations from this small early experience suggest that this variant CAS technique is feasible and probably diminishes the neuroembolic risk during initial navigation of the ICA target stenosis.

Carotid stenting done exclusively by vascular surgeons: first 175 cases

BACKGROUND

Percutaneous CAS may well replace CEA as standard of care. CAS has been performed largely by interventional cardiologists; however, with recent Food and Drug Administration approval, vascular surgeons are now hurriedly attempting to obtain the requisite endovascular skills. Reported are our 30-day and midterm outcomes of CAS.

METHODS

Retrospective review of 175 cervical carotid stenoses treated with elective CAS from April 2001 to February 2005. All procedures were performed under local anesthesia via percutaneous femoral access in an operating room angiosuite. Mechanical cerebral protection was used in 90% of cases. Data analysis includes demographics, procedural records, and duplex exams over a mean follow-up of 21 months.

RESULTS

Mean age is 70 years (74% men and 26% women). Preprocedural neurologic symptoms were present in 32%. Intraoperative complications included 2 seizures (1.1%) and 4 asystolic arrests (2.3%), all managed medically without sequelae. Over the 30-day follow-up there were no deaths, no myocardial infarctions (MIs), 2 major strokes (1.1%), 2 minor strokes (1.1%), 3 transient ischemic attacks (TIAs) (1.7%), and 1 major access-site complication (0.6%). At late follow-up, 3 cases (1.7%) of restenosis occurred; all were treated with repeat angioplasty and remain patent. One (0.6%) asymptomatic occlusion was detected at 6-month follow-up. There have been no late carotid-related complications or deaths.

CONCLUSIONS

Vascular surgeons possessing advanced catheter-based skills can safely perform CAS and achieve perioperative results comparable to CEA. Such skills are crucial to those surgeons intent on the future management of carotid occlusive disease.