Carotid artery stents: Benefits and challenges John J. Ricotta, MD

Cardiology Review® Online, September 2004, Volume 21, Issue 9

Carotid angioplasty and stenting is an emerging technology under investigation for the treatment of carotid bifurcation stenosis. Advocates point to its minimally invasive nature and studies showing results comparable to some published surgical series. Detractors emphasize that carotid angioplasty and stenting is an evolving technology whose purpose is to supplant an established, highly scrutinized and safe operation that has excellent results and low morbidity. All agree, but may not admit, that issues of turf, economics, and marketing have assumed dominance over patient safety in the current environment.

The Achilles’ heel of carotid angioplasty and stenting, similar to carotid endarterectomy, is periprocedural neurologic events. Neuroprotective devices have been developed to address this issue, and have reduced clinically apparent neurology deficits after carotid angioplasty and stenting.1 However, these devices have limitations, as shown by Schofer and Tübler (page 41). Emboli can occur during manipulations in the aortic arch, cannulation of the carotid artery, dilation of the stenotic lesion, and passage and retrieval of the protection device. The contralateral lesions seen on magnetic resonance imaging (MRI) reported by Schofer and Tübler most likely resulted from manipulation of the aorta and arch vessels rather than from the carotid angioplasty and stenting itself. Furthermore, distal neuroprotective devices do not trap all particles. Conceptually, the technique of flow reversal as described by Ohki and colleagues may offer the best protection from embolization during carotid angioplasty and stenting.2

Diffusion-weighted MRI is the most sensitive technology currently available for detecting cerebral ischemia, and lesions are often asymptomatic. The long-term implications of these asymptomatic lesions are unpredictable at the present time; however, they raise concerns, particularly in patients with asymptomatic stenosis. Data on diffusion MRI after carotid endarterectomy are scarce, so comparisons are difficult.

Carotid angioplasty and stenting will remain a technique indicated in some patients with carotid bifurcation disease. Its clearest indications are in patients with difficult carotid anatomy (high lesion) or a “hostile neck,” and in neurologically symptomatic patients with severe cardiac comorbidities. There are also clear situations in which carotid angioplasty and stenting is associated with increased technical difficulties and morbidity; most relate to problems with femoral access, evidence of aortic arch atheroma and tortuous arch vessels, and unstable or highly echolucent plaque. The role of carotid angioplasty and stenting in asymptomatic carotid stenosis, currently the primary indication for intervention in most series, remains to be established by prospective randomized trials. It cannot be extrapolated from data on carotid endarterectomy. However, it is likely that both techniques will be effective in a large number of patients.

Conclusion

As physicians dedicated to the care of patients with cerebrovascular disease, we are obligated to adapt the treatment to the patient, rather than the patient to the treatment, or to our own prejudices and abilities. Proper studies comparing carotid angioplasty and stenting to carotid endarterectomy, employing patient stratification on the basis of vascular anatomy, plaque character, and patient characteristics are needed to preserve the patient’s best interest.