Long Term Mortality Rate in Patients Treated with Carotid Endarterectomy.

OBJECTIVE: Carotid endarterectomy (CEA) is an effective surgical method for stroke prevention in selected patients with carotid stenosis. Few contemporary studies report on the long term mortality rate in CEA treated patients, despite continuous changes in medication, diagnostics, and patient selection. Here, the long term mortality rate is described in a well characterised cohort of asymptomatic and symptomatic CEA patients, sex differences evaluated, and mortality ratio compared with the general population. METHODS: This was a two centre, non-randomised, observational study evaluating all cause, long term mortality in CEA patients from Stockholm, Sweden between 1998 and 2017. Death and comorbidities were extracted from national registries and medical records. Cox regression was adapted to analyse associations between clinical characteristics and outcome. Sex differences and standardised mortality ratio (SMR, age and sex matched) were studied. RESULTS: A total of 1 033 patients were followed for 6.6 ± 4.8 years. Of those, 349 patients died during follow up where the overall mortality rate was similar in asymptomatic and symptomatic patients (34.2% vs. 33.7%, p = .89). Symptomatic disease did not influence the mortality risk (adjusted HR 1.14, 95% CI 0.81 - 1.62). Women had lower crude mortality rate than men in the first 10 years (20.8% vs. 27.6%, p = .019). In women, cardiac disease was associated with increased mortality (adjusted HR 3.55, 95% CI 2.18 - 5.79), while in men, lipid lowering medication was protective (adjusted HR 0.61, 95% CI 0.39 - 0.96). Within the first five years after surgery, SMR was increased for all patients (men 1.50, 95% CI 1.21 - 1.86; women 2.41, 95% CI 1.74 - 3.35), as well as in patients < 80 years (SMR 1.46, 95% CI 1.23 - 1.73). CONCLUSION: Symptomatic and asymptomatic carotid patients have similar long term mortality rates after CEA, but men had worse outcome than women. Sex, age, and time after surgery were shown to influence SMR. These results highlight the need for targeted secondary prevention, to alter the long term adverse effects in CEA patients.

Clinical risk scores for stroke correlate with molecular signatures of vulnerability in symptomatic carotid patients.

Unstable carotid stenosis is an important cause of ischemic stroke, yet the basis of disease pathophysiology remains largely unknown. We hypothesized that integrated analyses of symptomatic carotid stenosis patients at increased stroke risk stratified by clinical scores, CAR and ABCD2, with transcriptomic and clinical data could improve identification of molecular pathways and targets for instability. We show that high CAR score reflects plaque instability processes related to intra-plaque hemorrhage, angiogenesis, inflammation, and foam cell differentiation, whereas ABCD2 associates with neutrophil-mediated immunity, foam cell differentiation, cholesterol transport, and coagulation. Repressed processes in plaques from high-risk patients were ossification, chondrocyte differentiation, SMC migration, and ECM organization. ABCB5 gene was found as the top upregulated in high-risk patient's plaques, localized to macrophages in areas with neovascularization and intra-plaque hemorrhage. The link between ABCB5 and intra-plaque hemorrhage suggests its key role for plaque instability that warrants further exploration.

Plaque Evaluation by Ultrasound and Transcriptomics Reveals BCLAF1 as a Regulator of Smooth Muscle Cell Lipid Transdifferentiation in Atherosclerosis.

BACKGROUND: Understanding the processes behind carotid plaque instability is necessary to develop methods for identification of patients and lesions with stroke risk. Here, we investigated molecular signatures in human plaques stratified by echogenicity as assessed by duplex ultrasound. METHODS: Lesion echogenicity was correlated to microarray gene expression profiles from carotid endarterectomies (n=96). The findings were extended into studies of human and mouse atherosclerotic lesions in situ, followed by functional investigations in vitro in human carotid smooth muscle cells (SMCs). RESULTS: Pathway analyses highlighted muscle differentiation, iron homeostasis, calcification, matrix organization, cell survival balance, and BCLAF1 (BCL2 [B-cell lymphoma 2]-associated transcription factor 1) as the most significant signatures. BCLAF1 was downregulated in echolucent plaques, positively correlated to proliferation and negatively to apoptosis. By immunohistochemistry, BCLAF1 was found in normal medial SMCs. It was repressed early during atherogenesis but reappeared in CD68+ cells in advanced plaques and interacted with BCL2 by proximity ligation assay. In cultured SMCs, BCLAF1 was induced by differentiation factors and mitogens and suppressed by macrophage-conditioned medium. BCLAF1 silencing led to downregulation of BCL2 and SMC markers, reduced proliferation, and increased apoptosis. Transdifferentiation of SMCs by oxLDL (oxidized low-denisty lipoprotein) was accompanied by upregulation of BCLAF1, CD36, and CD68, while oxLDL exposure with BCLAF1 silencing preserved MYH (myosin heavy chain) 11 expression and prevented transdifferentiation. BCLAF1 was associated with expression of cell differentiation, contractility, viability, and inflammatory genes, as well as the scavenger receptors CD36 and CD68. BCLAF1 expression in CD68+/BCL2+ cells of SMC origin was verified in plaques from MYH11 lineage-tracing atherosclerotic mice. Moreover, BCLAF1 downregulation associated with vulnerability parameters and cardiovascular risk in patients with carotid atherosclerosis. CONCLUSIONS: Plaque echogenicity correlated with enrichment of distinct molecular pathways and identified BCLAF1, previously not described in atherosclerosis, as the most significant gene. Functionally, BCLAF1 seems necessary for survival and transdifferentiation of SMCs into a macrophage-like phenotype. The role of BCLAF1 in plaque vulnerability should be further evaluated.