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Carotid Artery Stenting with Proximal Endovascular Occlusion
Abstract & Commentary
By Andrew J. Boyle, MBBS, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study.
Source: Stabile E et al. Proximal endovascular occlusion for carotid artery stenting. Results from a prospective registry of 1,300 patients, J Am Coll Cardiol. 2010;55:1661-1667.
Carotid-artery stenting (CAS) has evolved significantly over recent years to become a reasonable alternative to carotid endarterectomy (CEA) for selected patients with carotid-artery disease. An important procedural aspect of CAS is embolic protection, to prevent embolic debris from causing ischemic stroke during the procedure itself. Distal protection devices must, by necessity, cross the lesion before there is protection in place and, therefore, carry some risk of embolization when they cross the lesion. Proximal occlusion of the carotid artery causes cessation of antegrade flow, thereby preventing this embolization of debris from the lesion during equipment crossing. After the procedure, debris is suctioned out of the vessel before balloon deflation and restoration of blood flow. Thus, proximal protection using PEO (proximal endovascular occlusion) has the potential to lower the rate of ipsilateral stroke during CAS. To test this, Stabile et al examined their single-center registry of patients undergoing CAS using PEO.
All patients undergoing CAS at their hospital in Italy were prospectively included in the registry. From 2004 to 2009, 1,300 patients had undergone CAS with PEO. Inclusion criteria were asymptomatic stenosis ≥ 80% or symptomatic stenosis ≥ 50%. Exclusion criteria were critical stenosis of the ipsilateral-common carotid artery, occlusion of the ipsilateral-external carotid artery (ECA), INR > 1.3, prior debilitating stroke, and contraindication to dual anti-platelet therapy. All patients received aspirin and thienopyridine prior to the procedure, then aspirin for life and thienopyridine for three months. All patients were reviewed by an independent neurologist after the procedure.
Results: The majority (72%) of patients were male, mean age was 70 years (9% were over 80 years old), and 28% were symptomatic. Significant coronary artery disease was present in 66%, and 25% were diabetic. Contralateral internal carotid artery (ICA) stenosis > 70%, or occlusion, was present in 12.5%; ipsilateral ECA stenosis > 70% was present in 7% of patients. Average procedural time was 17 ± 8 minutes. Occlusion time was 198 ± 59 seconds. Transient neurological symptoms with full resolution were encountered by 20% of patients, but only 0.3% of patients were unable to tolerate the carotid-artery occlusion.
The 30-day mortality rate was 0.61%, and the combined rate of death or stroke was 1.38%. The five in-hospital deaths were attributed to: one acute coronary syndrome, one acute pulmonary edema, one hemorrhagic stroke, one subarachnoid hemorrhage, and one acute renal failure precipitating multi-organ failure. The incidence of death or stroke was higher in symptomatic patients than in asymptomatic patients (3.0% vs. 0.8%, p < 0.01), but no difference was seen between patients with or without contralateral ICA occlusion. Multivariable analysis revealed that symptomatic status (odds ratio [OR] 4.25, p < 0.05) and hypertension (OR 3.7, p < 0.05) were independent predictors of stroke. Institutional experience increased over the time of the study, and death and stroke rate declined by approximately 70% (p < 0.01). High surgical risk features increased the total event rate, but this was not an independent predictor of death or stroke. The authors conclude that using PEO for CAS is safe and effective in an unselected population, and that anatomical and/or clinical conditions of high surgical risk were not associated with an increased rate of adverse events.
This registry has excellent procedural success rates and very low complication rates. It was performed in a center with significant experience, and their data show better results the more procedures they perform. The carotid-artery occlusion times were short, indicating the operators were very facile with the equipment. This likely contributed to their low rates of stroke. Interestingly, contralateral ICA disease did not increase the rate of events, again demonstrating that brief occlusion is well tolerated. A particular strength of the study is the use of an independent neurologist to assess the patient and adjudicate on events.
The study is limited in that there was no control group and it was a single-center study, so the results may not be generalizable to all centers. However, real-world registry data like these are important in advancing the field. While surgical CEA remains an excellent treatment option for patients with carotid stenosis, CAS using PEO appears to be a safe and effective option for some patients requiring carotid revascularization.