Patients Undergoing Carotid Revascularization Research Articles

The Argument to Support Broader Application of Extracranial Carotid Artery Stent Technology

As new technology becomes available, the stent technique for the extracranial carotid artery continues to evolve into a safer, more effective therapy for stroke prevention. With the availability of embolic protection, improved stent designs, and added endovascular physician experience, outcomes for carotid artery stenting (CAS) now consistently parallel those for carotid endarterectomy (CEA). Although carotid endarterectomy was established as the gold standard for carotid revascularization, the available scientific evidence must continue to be interpreted in the context of further advancements in nearly all related areas of medicine. One multicenter randomized trial and several nonrandomized registries have successfully established the CAS indications for patients with high surgical risk and have provided evidence to support the use of CAS techniques in patients with low surgical risk. Clinicians must continue to improve their understanding of patient-specific factors and conduct research that will refine indications while optimizing current medical therapy and that will integrate CAS and carotid endarterectomy as complementary treatments. Response by LoGerfo p 1610 The outcomes for CAS have been improving over the past 10 years and now appear nearly equivalent to those for CEA. In fact, many historical similarities are seen in the development of these 2 techniques. Although CEA was established as the gold standard for extracranial carotid revascularization, the available scientific evidence must continue to be interpreted in the context of further advancements in nearly all related areas of medicine. The current research comparing CAS and CEA has not shown a clinically robust and statistically significant difference between the 2 treatments. When differences do exist, clinicians must continue to refine patient-specific indications and to conduct further research to understand these complex risk-benefit analyses in the context of advanced medical treatments and complementary revascularization techniques. The following review details the argument to support implementation of CAS technology for athero-occlusive carotid …

Decrease in Internal Jugular Endothelin Levels After Carotid Cross-Clamping During Human Carotid Revascularization Procedures

Endothelin-1 (ETL-1), a peptide recently isolated from vascular endothelial cells, acts in cerebral arteries in vitro as a potent and long-lasting vasoconstrictor and has been implicated in the development of cerebral vasospasm. To ascertain whether this new vasoconstrictor has any effect on regulation of the cerebral circulation, we measured plasma ETL-1 concentrations in patients undergoing carotid revascularization and attempted to correlate the variations of venous and arterial plasma ETL-1 with the characteristics of the procedure, including cerebral vasospasm. We prospectively studied 11 patients undergoing a total of 14 carotid surgical revascularization procedures (12 endarterectomies, 2 polytetrafluoroethylene bypass grafts from the common to the internal carotid arteries). Before carotid cross-clamping, blood samples were drawn from the internal jugular vein and the healthy common carotid artery proximal to the occlusive lesion to be treated. After endarterectomy, blood samples were withdrawn from the internal, external, and common carotid arteries. After the release of the last clamp, a final aliquot of blood was withdrawn from the internal jugular vein. After plasma extraction on a C2-ethyl microcolumn, plasma endothelin-like immunoreactivity was measured by means of radioimmunoassay with a polyclonal antibody. In 9 of the 11 patients, internal jugular vein ETL-1 concentration decreased statistically significantly after carotid artery cross-clamping (4.2 +/- 1.4 pg/ml vs. 3.9 +/- 1.1 pg/ml; p < 0.05). In the 2 patients in whom ETL-1 levels failed to drop, a shunt was used during the procedure in 1, and the other was the only patient who had an ipsilateral ischemic postoperative stroke. The decrease in internal jugular vein ETL-1 concentration failed to correlate with any of the cross-clamping times. The level of arterial blood ETL-1 remained steady in the common carotid artery before and after cross-clamping (4.5 +/- 1.5 pg/ml vs. 4.6 +/- 0.9 pg/ml). A small, nonsignificant decrease in ETL-1 level was noted in the external and internal carotid arteries after cross-clamping. The decrease in internal jugular vein ETL-1 levels may in part reflect a compensatory response to carotid artery cross-clamping, which could limit the reduction of local cerebral blood flow.

Bilateral asymptomatic carotid stenosis increases risk of stroke: Analysis by the CHAT classification

Since the 2004 approval by the United States Food and Drug Administration of carotid artery stenting (CAS), there have been two seminal publications about CAS reimbursement (Centers for Medicare and Medicaid Services guidelines; 2008) and clinical outcomes (Carotid Revascularization Endarterectomy versus Stent Trial [CREST]; 2010). We explored the association between these publications and national trends in CAS use among high-risk symptomatic patients.The most recent congruent data sets of the Nationwide Inpatient Sample (NIS) were queried for patients undergoing carotid revascularization. The sample was limited to include only patients who were defined as “high-risk” if they had a Charlson Comorbidity Score of ≥3.0. Subgroup analyses were performed of high-risk patients with symptomatic carotid stenosis. Utilization proportions of CAS were calculated quarterly from 2005 to 2011 for NIS. Three time intervals related to Centers for Medicare and Medicaid Services guidelines and CREST publication were selected: 2005 to 2008, 2008 to 2010, and after 2010. Logistic regression with piecewise linear trend for time was used to estimate different trends in CAS use for the overall high-risk sample and for neurologically asymptomatic and symptomatic cases. Multivariate logistic regression was used to compare odds of postoperative mortality and stroke between these two procedures at different time intervals independent of confounding variables.During the study period, 20,079 carotid endarterectomies (CEAs) and 3447 CAS procedures were performed in high-risk patients in the NIS database. CAS utilization constituted 20.5% of carotid revascularization procedures among high-risk symptomatic patients, with a significant increase from 18.6% to 24.4% during the study period (P < .001). There was an initial increase during 2005 to 2008 in the rate of CAS compared with CEA, CAS utilization significantly decreased during 2008 to 2010 by a 3.3% decline in the odds ratio (OR) of CAS per quarter (OR, 0.967; 95% confidence interval [CI], 0.943-0.993; P = .002), and after CREST (after 2010), CAS utilization continued to increase significantly from the prepublication to the postpublication time interval. The odds of in-hospital mortality (OR, 2.56; 95% CI, 1.17-5.62; P = .019) and postoperative in-hospital stroke (OR, 1.53; 95% CI, 1.09-3.68; P = .024) were independently and significantly higher for CAS patients in the overall sample.The use of CAS for carotid revascularization in a high-risk cohort of patients has significantly increased from 2005 to 2011. Compared with CEA, CAS independently increased the odds of perioperative in-hospital stroke in all high-risk patients and of in-hospital mortality in symptomatic high-risk patients.