Carotid Filters

Abstract

A lthough percutaneous, catheter-based treatment for atherosclerotic arterial obstruction began in the peripheral circulation, usage became widespread only after coronary application. The procedure's abilities to relieve angina and either spontaneous or provoked myocardial ischemia and to achieve prompt reperfusion in myocardial infarction are well-documented. 1 Even selected patients with advanced, multivessel coronary disease can expect outcomes similar to those provided by the more invasive bypass surgery. [2][3][4] Now, enthusiasm for catheter revascularization is circling back to arteries beyond the coronary circulation. See p 12Among these new targets are the carotid arteries, which are well recognized as sources for cerebral emboli, a major cause of stroke. Surgical endarterectomy is performed for severe, symptom-related carotid atherosclerosis and, in selected asymptomatic patients, it seems superior to medical treatment alone in preventing stroke. [5][6][7] Using approaches and techniques developed from coronary intervention, clinicianinvestigators have demonstrated that balloon angioplasty and stent deployment are feasible for narrowings involving the internal and external carotid and its bifurcation. Initial observational results are encouraging to the point where a direct comparison of catheter-based therapy to carotid endarterectomy has begun in the form of a large, multicenter, randomized, clinical trial. 8 Distal embolization of atherosclerotic debris as a consequence of balloon angioplasty has been an issue of concern since the inception of the procedure. Fearful of emboli, Andreas Gruentzig drained, filtered, and examined blood from the coronary sinus when he first performed coronary balloon angioplasty in man (Andreas Gruentzig, MD, personal communication, August 1978). With the exception of degenerated saphenous aortocoronary vein grafts and native arteries with substantial intracoronary thrombus, however, clinically significant embolization resulting from balloon angioplasty alone or with stent deployment is not a major concern in the coronary circulation.Such may not be the case with carotid intervention. Strokes, both major and minor, are acknowledged complications of carotid stenting, and the mechanism now seems to be embolic, rather than the acute occlusion or dissection that was observed during the early balloon angioplasty experience. 9 Of special note are the success and complication rates of carotid artery stenting that have been observed with the development of the technique. As reported by Roubin et al, 10 success rates of 98% are now achievable, and the incidence of minor strokes seems to be declining. What does not seem to be declining, however, is the incidence of procedure-related major stroke. Thus, in the first year of their experience, the major stroke rate was 1%; the rate was 1.2% in their fifth year. This issue is one of substantial concern given the grave consequences of major stroke, the low rate observed with alternative therapy, and recognition that avoidance of stroke...

Cerebral Protection During Carotid Artery Stenting

“…However, we could not exclude the development of a stroke even in the setting of distal protection. 25 In a recently published article, Roubin et al 2 reported the important reduction of periprocedural complication rate over 5 years of experience from 9.3% in the first year to 4.3% in the fifth year. This was probably due to refinement of stenting techniques and newly developed equipment.…”

“…Furthermore, particles of vasoactive substances contained within plaque or thrombus could cause intense, prolonged vasospasm and subsequent cerebral infarction. 25 The histopathologic analysis showed that retrieved material consists of dislocated debris featuring atheroembolism as a consequence of atheromatous plaque squeezing and rupture occurring during carotid stent implantation. This result confirms the data of previously reported studies evaluating different emboli protection devices during percutaneous intravascular interventions.…”