AbstractsMedical & Health Science

In 2005, Centers for Medicare and Medicaid Services (CMS) expanded eligibility criteria for patients to receive carotid artery stenting (CAS) as an alternative to carotid endarterectomy (CEA). The goal of this study is to examine the outcomes of wider utilization of CAS and the sustainability of favorable outcomes reported in pre-marketing FDA approval trials. A cohort of 169 patients undergoing either CEA or CAS, at two institutions with CMS approval, and experience in both procedures was retrospectively analyzed for outcomes and their determinants. From 2007 to 2012, patients underwent either CEA (n = 70) or CAS (n = 99) at one of two institutions selected for study. The two groups had similar baseline characteristics with the exception of more symptomatic patients in the CEA group (55.7% CEA vs. 17.2 % CAS; p < 0.001) and previous stroke or transient ischemic attack (TIA) (72.5% CEA vs. 39.4%; p < 0.001). Lesion characteristics between the two groups differed in terms of the presence of a thrombus (16.0% CEA vs. 2.02% CAS; p = 0.002), stenosis 2: 80% (69.6% CEA vs. 95.0% CAS; p < 0.001) and length of lesion 2: 2cm (70.6% CEA vs. 24.4% CAS; p < 0.001). Major adverse events within 30-days of the procedure were higher in the CAS group (0% CEA vs. 5.05% CAS; p = 0.077), but not statistically significant. Three of the five patients who suffered a major adverse event had a stroke; all three patients were 2:80 years old, asymptomatic, and had 2: 80% stenosis. Acute neurologic events, including strokes and TIAs, were higher in the CAS group (1.4% CEA vs. 12.1% CAS; p = 0.016). No myocardial infarction occurred in either group. Minor adverse events occurred in 49.5% of CAS and 7.1% of CEA patients (p < 0.001). When total minor adverse events were subdivided by event type and analyzed, only hemodynamic instability was significantly different between the CEA and CAS group (1.4% CEA versus 41.4% CAS; p < 0.001). Asymptomatic CAS patients with high-grade stenosis (2: 80%) had more hemodynamic instability (p < 0.001) compared to matched CEA patients. Hemodynamic instability in CAS procedures correlated with embolic protection device performance issues (p = 0.004), successful stent placement (p = 0.018), and post-stenting dilation (p < 0.001). Post-market, real-world utilization of CAS results in higher rates of neurologic events and hemodynamic instability. However, overall stroke rate was comparable to that reported in pre-marketing FDA approval trials. CEA or CAS can be offered with a stroke rate ≤3% at institutions with large experience. CEA should remain the procedure of choice for asymptomatic carotid stenosis, particularly in elderly patients. Hemodynamic instability is a minor, but important, adverse event associated with CAS and should be further investigated.