Plaque Contact Surface Area and Flow Lumen Volume Predict Stroke Risk in Extracranial Carotid Artery Stenosis

The standard indication for intervention in asymptomatic disease is currently percent stenosis in the internal carotid artery as measured by the NASCET method, which remains limited in discriminating power. CT angiography (CTA) is widely used to calculate NASCET stenosis but also offers the opportunity to analyze carotid artery plaques from a morphological perspective that has not been widely utilized. We aim to improve stroke risk stratification of patients with carotid artery stenosis using plaque 3D modeling and image analysis. Patients with CTAs appropriate for 3D reconstruction were identified from an NIH designated stroke center database, and carotid arteries were segmented and analyzed using software algorithms to calculate contact surface area between the plaque and blood flow (CSA), and volume of the flow lumen within the region of the plaque (FLV). These novel parameters factor in the 3D morphometry inherent to each carotid plaque. A total of 134 carotid arteries were analyzed, 33 of which were associated with an ipsilateral stroke. Plaques associated with stroke demonstrated statistically significant increases in average CSA and FLV when compared to those not associated with stroke. When compared to NASCET percent stenosis, CSA and FLV both demonstrated a larger area under the receiver operating characteristics curve (AUC) in predicting stroke risk in patients with carotid stenosis. The data presented here demonstrate morphological features of carotid plaques that are independent of NASCET criteria stratification and may present an improved method in assessing stroke risk in patients with carotid artery stenosis

Interferon-producing Cells Fail to Induce Proliferation of Naive T Cells but Can Promote Expansion and T Helper 1 Differentiation of Antigen-experienced Unpolarized T Cells

Interferon-producing cells (IPCs) secrete high levels of type I interferon in response to certain viruses. The lack of lineage markers, the expression of major histocompatibility complex (MHC) class II and the capacity to stimulate allogeneic T cells have led these cells to be classified as a subset of dendritic cells (DCs), called plasmacytoid DCs (PDCs). However, the role of IPCs/PDCs in initiating primary immune responses remains elusive. Here we examined the antigen presenting capacity of murine IPCs in antigen specific systems. While CD8α+ and CD11b+ DCs induced logarithmic expansion of naive CD4 and CD8 T cells, without conferring T helper commitment at a first encounter, primary IPCs lacked the ability to stimulate naive T cells. However, when antigen-experienced, nonpolarized T cells expanded by classical DC subsets, were restimulated by IPCs, they proliferated and produced high amounts of IFN-γ. These data indicate that IPCs can effectively stimulate preactivated or memory-type T cells and exert an immune-regulatory role. They also suggest that expansion of naive T cells and acquisition of effector function during antigen-specific T cell responses may involve different antigen-presenting cell (APC) types. Independent and coordinated control of T cell proliferation and differentiation would provide the immune system with greater flexibility in regulating immune responses

Left subclavian artery coverage during thoracic endovascular aortic repair and risk of perioperative stroke or death

IntroductionLeft subclavian artery (LSA) coverage during thoracic endovascular aortic repair (TEVAR) is often necessary due to anatomic factors and is performed in to up to 40% of procedures. Despite the frequency of LSA coverage during TEVAR, reported associations with risk of periprocedural stroke or death are inconsistent in reported literature. We examined the 2005-2008 American College of Surgeons National Surgical Quality Improvement Program Participant Use Data file to determine associations between LSA coverage during TEVAR and risk of perioperative stroke or death.MethodsCurrent procedural terminology (CPT) codes were used to identify patients undergoing TEVAR, LSA coverage, and subclavian revascularization. Patients undergoing coronary bypass, ascending aortic repair, abdominal aortic aneurysm repair, or nonvascular intra-abdominal procedures during the same operation were excluded. Perioperative stroke and mortality associations with LSA coverage were examined using logistic regression models for each outcome. Significance was assessed at α = 0.05, with univariable P < .05 required for multivariable model entry.ResultsEight hundred forty-five TEVAR procedures were identified, of which 52 patients were excluded due to additional major procedures performed with TEVAR. Seven hundred thirty-three of the remaining 793 procedures included CPT codes indicating primary placement of an initial thoracic endograft and form the basis of this analysis. LSA coverage occurred in 279 procedures (38%). Thirty-day stroke and mortality rates were 5.7% and 7.0%, respectively. LSA coverage was associated with increased 30-day risk of stroke in multivariable modeling (odds ratio [OR], 2.17 95% confidence interval [CI], 1.13-4.14; P = .019). Other significant multivariable risk factors for stroke included proximal aortic cuff placement during TEVAR (OR, 2.58; 95% CI, 1.30-5.16; P = .007) and emergency procedure status (OR, 3.60; 95% CI, 1.87-6.94; P < .001). No significant association between LSA coverage and perioperative mortality was identified (univariable OR, 1.70; 95% CI, 0.98-2.93; P = .0578).ConclusionLSA coverage during thoracic endovascular repair is associated with increased risk of perioperative stroke following TEVAR. Further evidence is needed to determine whether procedural modifications, including LSA revascularization, reduce the incidence of stroke associated with TEVAR

Characterization of resident surgeon participation during carotid endarterectomy and impact on perioperative outcomes

IntroductionThe impact of resident surgeon participation during vascular procedures on postoperative outcomes is incompletely understood. We characterized resident physician participation during carotid endarterectomy (CEA) procedures within the 2005-2009 American College of Surgeons National Surgical Quality Improvement Participant Use Datafile and evaluated associations with procedural characteristics and perioperative adverse events.MethodsCEAs were identified using primary current procedural terminology codes; those performed simultaneously with other major procedures or unknown resident participation status were excluded. Group-wise comparisons based on resident participation status were performed using χ2 or Fisher's exact test for categorical variables and t tests or nonparametric methods for continuous variables. Associations with perioperative adverse events (major = stroke, death, myocardial infarction, or cardiac arrest; minor = peripheral nerve injury, bleeding requiring transfusion, surgical site infection, or wound disruption) were assessed using multivariable logistic regression models adjusting for other known risk factors.ResultsA total of 25,280 CEA procedures were analyzed, of which residents participated in 13,705 (54.2%), while residents were absent in 11,575 (45.8%). Among CEAs with resident physician participation, resident level was categorized as junior (postgraduate year [PGY] 1-2) in 21.9%, senior (PGY 3-5) in 52.7%, and fellow (PGY ≥6) in 25.3%. Major adverse event rates with and without resident participation were 1.9% versus 2.1%, and minor adverse event rates with and without resident participation were 0.9% versus 1.0%, respectively. In multivariable models, resident physician participation was not associated with perioperative risk for major adverse events (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.75-1.08) or minor adverse events (OR, 0.93; 95% CI, 0.72-1.21).ConclusionsResident surgeon participation during CEA is not associated with risk of adverse perioperative events

Internal Mammary Arterial Injury from Lead Extraction: A Clinically Subtle yet Important Complication of Implantable Device Removal

Percutaneous implantable device extraction has increased in recent years and is associated with small but significant risk. Arteriovenous fistula formation is an uncommon complication of this procedure. We report two cases where lead extraction was complicated by an arteriovenous fistula between the left internal mammary artery and the left brachiocephalic vein. In both cases, the patients were asymptomatic and the presence of a continuous murmur in the left subclavicular region led to the appropriate diagnosis. These were successfully treated with coil embolization. Auscultation around prior extraction sites should be routinely done to aid in the diagnosis of this potentially harmful complication