The Neurological Morbidity of Carotid Revascularisation: Using Markers of Cellular Brain Injury to Compare CEA and CAS

AimThis comparative study attempts to evaluate the profile of S-100β and Neuron-Specific Enolase (NSE), biomarkers of brain injury, in patients undergoing carotid endarterectomy (CEA) and carotid artery stenting (CAS) and to correlate this with haemodynamic and embolic events detected using trans-cranial Doppler (TCD).Methods52 patients with internal carotid artery stenosis requiring intervention were recruited. 24 patients underwent CAS, and 28 underwent CEA. TCD was performed peri-operatively to record mean Middle Cerebral Artery (MCA) velocity and number of High Intensity Transient Signals (HITS) in the MCA of the operated side. Serum was drawn pre-operatively and at six time points in a 48 hour post-operative period, and then assayed using automated commercial equipment. Within and between group variability in markers were assessed by Generalized Estimation Equations modelling.ResultsCAS caused more HITS (p=0.028) but less haemodynamic disturbance (p=0.0001) than CEA. Treatment modality (CAS versus CEA) had no direct effect on S-100 changes (p=0.467). NSE levels declined after revascularisation in the CAS group but not after CEA (p=0.002). S-100β levels rose in patients who had higher numbers of HITS (p=0.002). S-100β and NSE were not associated with changes in MCA velocity (p>0.5). S-100β alone increased significantly at 24 hours in those patients with a post-operative neurological deficit (p=0.015).ConclusionsTrans-cranial Doppler findings suggest that the mechanisms of rise in S-100β and NSE levels may differ and may be due to increased peri-operative micro-embolisation and cerebral hypoperfusion respectively. Further studies are required to assess the clinical significance of these observed changes

Smoking and plasma fibrinogen, lipoprotein (a) and serotinin are markers for postoperative infrainguinal graft stenosis

Objectives:A number of systemic variables are associated with infrainguinal graft failure and also with experimental smooth muscle hyperplasia. Stenosis is the most common cause of infrainguinal graft thrombosis but it is not known if systemic variables are associated with stenosis.Design, materials and methods:In this study, clinical and serological factors were measured and correlated with stenosis development in 81 infrainguinal bypass grafts (52 vein, 29 PTFE; 28 with stenosis) in prospective (n = 46) and retrospective (n = 35) groups. Pre-existing stenosis was ecluded by perioperative graft assessment.Results:There was a significantly greater proportion of smokers in the patients who developed stenosis (11/18; 61%) compared with those who did not (6/28; 21%, p = 0.006; x2). Patients who developed stenosis also had significantly (Mann Whitney U-tests), higher circulating levels of [median (interquartile range)] fibrinogen (412.5 (356–484.5) vs. 339 (300–397.7) mg/100ml, p = 0.003), Lipoprotein (a) (0.20 (0.05–0.45) vs. 0.085 (0.05–0.23), g/l, p = 0.03) and 5-hydroxytryptamine (14.1 (6.6–45) vs. 4.41 (3–8.39) nmol/l, p = 0.005), than those without stenosis.By logistic regression, these associations were independent of graft material and whether grafts were studied prospectively or retrospectively.Conclusions:Smoking and plasma fibrinogen, Lp(a) and 5-hydroxytryptamine are markers for postoperative infrainguinal graft stenosis

Identification of Patient Safety Improvement Targets in Successful Vascular and Endovascular Procedures: Analysis of 251 hours of Complex Arterial Surgery

AbstractObjectivesTo investigate failures in patient safety for patients undergoing vascular and endovascular procedures to guide future quality and safety interventions.DesignSingle centre prospective observational study.Methods66 procedures (17 thoracoabdominal and 23 abdominal aortic aneurysms, 4 carotid and 22 limb procedures) were observed prospectively over a 9-month period (251 h operating time) by two trained observers. Event logs were recorded for each procedure. Two blinded experts identified and independently categorised failures into 22 types (using a validated category tool) and severity (5-point scale). Data are expressed as median (range). Statistical analysis was performed using Mann–Whitney U, Kruskal–Wallis and Spearman’s Rank tests.Results1145 failures were identified with good inter-assessor reliability (Cronbach’s alpha 0.844). The commonest failure types related to equipment (including unavailability, configuration and other failures) (269/1145 [23.5%]) and communication (240/1145 [21.0%]). A comparatively lower number of technical and psychomotor failures were identified (103 [9.0%]). The number of failures correlated with procedure duration (rho = 0.695, p < 0.001) but not anatomical site of the procedure or pathology of the disease process. Failure rate was higher in patients undergoing combined surgical/endovascular procedures compared to open surgery (median 5.7/h [IQR 4.2–8.1] vs 3.0/h [2.5–3.5]; p < 0.001). The severity of failures was similar (1.5/5 [1–2] vs 1/5 [1–2] respectively; p = 0.095). For combined procedures, failure rates were significantly higher during the endovascular phase (9.6/h [7.5–13.7]) compared to the non-endovascular phase (3.0/h [1.0–5.0]; p < 0.001).ConclusionsFailures in patient safety are common during complex arterial procedures. Few failures were severe, although minor failures during critical stages and accumulation of multiple minor failures may potentially be important. Failures occurred especially during the endovascular phase and were often related to equipment or communication aspects. Interventions to improve procedural safety and quality of care should primarily target these specific areas

Size and nature of emboli produced during carotid artery angioplasty and stenting: In vivo study

AbstractAimMicroembolization continues to be a major risk for patients undergoing carotid artery stenting (CAS) of high-grade atherosclerotic carotid stenoses. Further insight into the characteristics and significance of these embolized particles was deemed necessary. We aimed to assess the size and composition of debris captured by filters during CAS and to determine if this could be predicted using standard imaging techniques.Methods20 patients (10 symptomatic, 15 men, mean age 64.6 years) undergoing CAS for high-grade ICA stenosis were recruited. All underwent pre-operative CT angiography and calcium scoring. All underwent CAS using the same protocol. A filter-type embolic protection device (EPD) was used and retrieved post-operatively and captured particles underwent analysis using a Scanning Electron Microscope (SEM) for counting, sizing, and composition.ResultsClinical. Debris was found on 100% of filters when analysed with SEM. There were non-significant trends for CAS in asymptomatic patients to produce a greater number of smaller, calcified particles while in symptomatic patients we observed larger, lipid-rich particles. When stratified according to pre-operative calcium scores, ‘calcium-rich’ plaques produced significantly greater numbers of emboli captured on the EPD (p = 0.02).ConclusionsFilter-type EPDs collect debris of significant quantity and size during the CAS procedure as performed in our institution. The collected material was likely dislocated from the atherosclerotic plaque. CT calcium scoring allows us to predict the nature of material captured by the EPD. These data may allow the clinician to individualise care during CAS and thus reduce peri-operative risk