Multicenter study of the feasibility and safety of using the Memotherm carotid arterial stent for extracranial carotid artery stenosis

Abstract

Object. Carotid artery (CA) angioplasty with stent placement has been proposed as an alternative technique for revascularization in cases of CA stenosis. In this report the authors review the results of a multicenter Phase I study in which they evaluated the safety and feasibility of using a new self-expanding nitinol stent, the Bard Memotherm, to treat CA stenosis. Methods. Enrollment was limited to patients in whom there was either 50% or greater symptomatic or 70% or greater asymptomatic stenosis of the internal CA. The primary endpoint was a technically successful implantation procedure (delivery of the stent to the target site and retrieval of the delivery device), resulting in less than 30% residual stenosis demonstrated on immediate postprocedure (control) angiograms, and no incidence of mortality, ipsilateral stroke, Q-wave myocardial infarction, or other major cardiovascular events immediately after or within 30 days following the procedure. Stent placement was attempted for 73 lesions in 71 patients (mean age 71.3 ± 8.5 years), 43 (61%) of whom were men. The mean degree of stenosis was 82.6 ± 9%. The stenosis was symptomatic in 27 (37%) and asymptomatic in 46 (63%) of 73 lesions. In four procedures the stent could not be delivered or released. The mean residual stenosis observed on angiograms was 3.8 ± 6.9% in the 69 lesions treated with the Bard Memotherm stent; residual stenosis was greater than 30% in one of the 69 procedures. The primary endpoint was achieved in 65 (89%) of the 73 procedures. One patient experienced a major ischemic stroke and another patient died of intracerebral hemorrhage. The overall 1-month stroke rate was 2.7% for 73 attempted procedures. One patient died of pneumonia and acute respiratory distress syndrome, which occurred 3 weeks after the stent procedure and was unrelated to the procedure. Conclusions. The Memotherm stent can be used to treat patients with CA stenosis and is associated with a low periprocedure complication rate. Long-term follow-up studies are underway to determine the impact of stent placement on the risk of ipsilateral ischemic events.