Impact of Carotid Endarterectomy on Medical Secondary Prevention After a Stroke or a Transient Ischemic Attack

Regional Molecular Signature of the Symptomatic Atherosclerotic Carotid Plaque

BACKGROUND

Many studies have explored molecular markers of carotid plaque development and vulnerability to rupture, usually having examined whole carotid plaques. However, there are regional differences in plaque morphology and known shear-related mechanisms in areas surrounding the lipid core.

OBJECTIVE

To determine whether there are regional differences in protein expression along the long axis of the carotid plaque and how that might produce gaps in our understanding of the carotid plaque molecular signature.

METHODS

Levels of 7 inflammatory cytokines (IL-1β, IL-6, IL-8, IL-10, IL-12 p70, IFN-γ, and TNF-α) and caspase-3 were analyzed in prebifurcation, bifurcation, and postbifurcation segments of internal carotid plaques surgically removed from symptomatic and asymptomatic patients. Expression profiles of miRNAs and mRNAs were determined with microarrays for the rupture-prone postbifurcation segment for comparison with published whole plaque results.

RESULTS

Expression levels of all proteins examined, except IL-10, were lowest in the prebifurcation segment and significantly higher in the postbifurcation segment. Patient group differences in protein expression were observed for the prebifurcation segment; however, no significant differences were observed in the postbifurcation segment between symptomatic and asymptomatic patients. Expression profiles from postbifurcation carotid plaques identified 4 novel high priority miRNAs differentially expressed between patient groups (miR-214, miR-484, miR-942, and miR-1287) and 3 high-confidence miRNA:mRNA targets, including miR-214:APOD, miR-484:DACH1, and miR-942:GPR56.

CONCLUSION

The results demonstrate regional differences in protein expression for the first time and show that focus on the rupture-prone postbifurcation region leads to prioritization for further study of novel miRNA gene regulation mechanisms.

Secreted proteins from carotid endarterectomy: an untargeted approach to disclose molecular clues of plaque progression

BACKGROUND

Atherosclerosis is the main cause of morbidity and mortality in Western countries and carotid plaque rupture is associated to acute events and responsible of 15-20% of all ischemic strokes. Several proteomics approaches have been up to now used to elucidate the molecular mechanisms involved in plaque formation as well as to identify markers of pathology severity for early diagnosis or target of therapy. The aim of this study was to characterize the plaque secretome. The advantage of this approach is that secretome mimics the in vivo condition and implies a reduced complexity compared to the whole tissue proteomics allowing the detection of under-represented potential biomarkers.

METHODS

Secretomes from carotid endarterectomy specimens of 14 patients were analyzed by a liquid chromatography approach coupled with label free mass spectrometry. Differential expression of proteins released from plaques and from their downstream distal side segments were evaluated in each specimen. Results were validated by Western blot analysis and ELISA assays. Histology and immunohistochemistry were performed to characterize plaques and to localise the molecular factors highlighted by proteomics.

RESULTS

A total of 463 proteins were identified and 31 proteins resulted differentially secreted from plaques and corresponding downstream segments. A clear-cut distinction in the distribution of cellular- and extracellular-derived proteins, evidently related to the higher cellularity of distal side segments, was observed along the longitudinal axis of carotid endarterectomy samples. The expressions of thrombospondin-1, vitamin D binding protein, and vinculin, as examples of extracellular and intracellular proteins, were immunohistologically compared between adjacent segments and validated by antibody assays. ELISA assays of plasma samples from 34 patients and 10 healthy volunteers confirmed a significantly higher concentration of thrombospondin-1 and vitamin D binding protein in atherosclerotic subjects.

CONCLUSIONS

Taking advantage of the optimized workflow, a detailed protein profile related to carotid plaque secretome has been produced which may assist and improve biomarker discovery of molecular factors in blood. Distinctive signatures of proteins secreted by adjacent segments of carotid plaques were evidenced and they may help discriminating markers of plaque complication from those of plaque growth.

Ischemic stroke predicts myocardial injury after carotid endarterectomy for symptomatic severe carotid artery stenosis

Myocardial injury following carotid endarterectomy (CEA) is a common cause of morbidity and mortality, and its risk varies depending on the severity and extent of disease. However, when patients with sympotomatic severe carotid stenosis undergo CEA, the frequency and potential predictors of myocardial injury remain unknown. A total of 40 patients (32 men and 8 women) who underwent successful standard CEA were observed. Cardiac troponin I (cTnI) concentrations were assessed before surgery and on postoperative days 1, 2, and 3 in all patients. Myocardial injury was defined as the peak cTnI concentration > 0.04 ng/mL. In all, 42.5% patients had postoperative myocardial injury. Previous ischemic stroke and abnormal ST-segment changes were the preoperative predictors of myocardial injury after CEA, with odds ratios of 4.1 (95% confidence interval, 1.1-16.1; P = .04) and 5.9 (95% confidence interval, 1.3-27.7; P = .04), respectively. Sympotomatic patients with those conditions should receive more attention to myocardial injury, when presented for CEA.

Inclusion of stroke in cardiovascular risk prediction instruments: a statement for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

Current US guideline statements regarding primary and secondary cardiovascular risk prediction and prevention use absolute risk estimates to identify patients who are at high risk for vascular disease events and who may benefit from specific preventive interventions. These guidelines do not explicitly include patients with stroke, however. This statement provides an overview of evidence and arguments supporting (1) the inclusion of patients with stroke, and atherosclerotic stroke in particular, among those considered to be at high absolute risk of cardiovascular disease and (2) the inclusion of stroke as part of the outcome cluster in risk prediction instruments for vascular disease.

METHODS AND RESULTS

Writing group members were nominated by the committee co-chairs on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council's Scientific Statements Oversight Committee and the AHA Manuscript Oversight Committee. The writers used systematic literature reviews (covering the period from January 1980 to March 2010), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and, when appropriate, formulate recommendations using standard AHA criteria. All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. The guideline underwent extensive AHA internal peer review, Stroke Council leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the AHA Science Advisory and Coordinating Committee. There are several reasons to consider stroke patients, and particularly patients with atherosclerotic stroke, among the groups of patients at high absolute risk of coronary and cardiovascular disease. First, evidence suggests that patients with ischemic stroke are at high absolute risk of fatal or nonfatal myocardial infarction or sudden death, approximating the ≥20% absolute risk over 10 years that has been used in some guidelines to define coronary risk equivalents. Second, inclusion of atherosclerotic stroke would be consistent with the reasons for inclusion of diabetes mellitus, peripheral vascular disease, chronic kidney disease, and other atherosclerotic disorders despite an absence of uniformity of evidence of elevated risks across all populations or patients. Third, the large-vessel atherosclerotic subtype of ischemic stroke shares pathophysiological mechanisms with these other disorders. Inclusion of stroke as a high-risk condition could result in an expansion of ≈10% in the number of patients considered to be at high risk. However, because of the heterogeneity of stroke, it is uncertain whether other stroke subtypes, including hemorrhagic and nonatherosclerotic ischemic stroke subtypes, should be considered to be at the same high levels of risk, and further research is needed. Inclusion of stroke with myocardial infarction and sudden death among the outcome cluster of cardiovascular events in risk prediction instruments, moreover, is appropriate because of the impact of stroke on morbidity and mortality, the similarity of many approaches to prevention of stroke and these other forms of vascular disease, and the importance of stroke relative to coronary disease in some subpopulations. Non-US guidelines often include stroke patients among others at high cardiovascular risk and include stroke as a relevant outcome along with cardiac end points.

CONCLUSIONS

Patients with atherosclerotic stroke should be included among those deemed to be at high risk (≥20% over 10 years) of further atherosclerotic coronary events. Inclusion of nonatherosclerotic stroke subtypes remains less certain. For the purposes of primary prevention, ischemic stroke should be included among cardiovascular disease outcomes in absolute risk assessment algorithms. The inclusion of atherosclerotic ischemic stroke as a high-risk condition and the inclusion of ischemic stroke more broadly as an outcome will likely have important implications for prevention of cardiovascular disease, because the number of patients considered to be at high risk would grow substantially.

Post-operative risk factor control following internal carotid artery intervention

BACKGROUND

Patients who undergo carotid surgical interventions remain at significant risk of further vascular events post-operatively. This study evaluates the level of risk factor monitoring and control being achieved post-operatively for patients who undergo carotid surgical interventions within Southern Health and investigates the significance of patient education and patient insight in this context.

METHODS

The study included all patients who underwent successful carotid endarterectomy (CEA) or carotid angioplasty within Southern Health during the 5-year study period. To ascertain the objective risk factor status of participants, the most current reported measurements for the variables of blood pressure, blood lipids and glycosylated hemoglobin were obtained from the participant's usual medical attendants. To ascertain the participant's subjective perceptions of their risk factor status, participants completed a self-administered mail-out questionnaire.

RESULTS

A high level of post-operative risk factor monitoring was demonstrated. Post-operative risk factor control was not as commendable. There was a significant discrepancy identified between patient perceptions of current post-operative risk factor status and the objective reality of current post-operative risk factor status. There was a moderate positive linear correlation between level of accurate patient insight into their disease (including their post-operative risk factor control) and the level of postoperative risk factor control being achieved (r = 0.51, P <0.001).

CONCLUSION

Future strategy targeted at achieving optimal post-CEA and carotid angioplasty with adjuvant stenting risk factor control should consider incorporating themes that increase the level of accurate patient insight into their disease (particularly their post-operative risk factor control), for instance, patient education and effective doctor-patient communication.

Endarterectomy or carotid artery stenting: the quest continues

BACKGROUND

Carotid endarterectomy (CEA) is still considered the "gold-standard" of the treatment of patients with significant carotid stenosis and has proven its value during past decades. However, endovascular techniques have recently been evolving. Carotid artery stenting (CAS) is challenging CEA for the best treatment in patients with carotid stenosis. This review presents the development of CAS according to early reports, results of recent randomized trials, and future perspectives regarding CAS.

METHODS

A literature search using the PubMed and Cochrane databases identified articles focusing on the key issues of CEA and CAS.

RESULTS

Early nonrandomized reports of CAS showed variable results, and the Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy trial led to United States Food and Drug Administration approval of CAS for the treatment of patients with symptomatic carotid stenosis. In contrast, recent trials, such as the Stent-Protected Angioplasty Versus Carotid Endarterectomy trial and the Endarterectomy Versus Stenting in Patients with Symptomatic Severe Carotid Stenosis trial, (re)fuelled the debate between CAS and CEA. In the Stent-Protected Angioplasty Versus Carotid Endarterectomy trial, the complication rate of ipsilateral stroke or death at 30 days was 6.8% for CAS versus 6.3% for CEA and showed that CAS failed the noninferiority test. Analysis of the Endarterectomy Versus Stenting in Patients With Symptomatic Severe Carotid Stenosis trial showed a significant higher risk for death or any stroke at 30 days for endovascular treatment (9.6%) compared with CEA (3.9%). Other aspects-such as evolving best medical treatment, timely intervention, interventionalists' experience, and analysis of plaque composition-may have important influences on the future treatment of patients with carotid artery stenosis.

CONCLUSIONS

CAS performed with or without embolic-protection devices can be an effective treatment for patients with carotid artery stenosis. However, presently there is no evidence that CAS provides better results in the prevention of stroke compared with CEA.