Usefulness of Neuron-Specific Enolase to Detect Silent Neuronal Ischemia After Percutaneous Coronary Intervention

'Evaluation of beta-2-microglobulin and neuron-specific enolase as prognostic factors in patients over 65 years of age with frailty syndrome hospitalized for acute coronary syndrome'

BACKGROUND

The aim of the study is to assess the value of beta-2-microglobulin (B2M) and neuron-specific enolase (NSE) as prognostic factors in the population of patients over 65 years of age with frailty hospitalized due to acute coronary syndrome (ACS).

METHODS

Patients aged ≥65 years with ACS were included. Assessment of frailty was carried out using the FRAIL scale. The measurement of NSE and B2M was carried out three times during hospitalization: (1) at the time of admission, (2) on the second day of hospitalization, (3) on the seventh day of hospitalization, or the day of discharge if it was before the seventh day. The primary endpoint was all-cause mortality, and the secondary endpoint was unscheduled rehospitalization.

RESULTS

Of the 127 patients, frailty was identified in 39.3%. Multivariate analysis of variance showed significantly higher levels of NSE (P = 0.012) and B2M (P < 0.001) in patients with frailty compared to the nonfrail group and significant changes in marker levels during hospitalization - decreased NSE (P < 0.001) and increased B2M levels (P < 0.001). Elevated B2M-1 level was an independent marker of the occurrence of frailty [odds ratio (OR), 1.98 (1.09-4.00); P = 0.044], and the optimal cutoff point for the diagnosis of frailty was 2.85 mg/l [area under the curve (AUC), 0.718 (0.632-0.795)] with sensitivity 52% and specificity 84.4% (P < 0.001). Elevated NSE-3 level was associated with all-cause mortality, and each 1 ng/ml increase in NSE-3 increased the risk of death by 1.07-fold [OR, 1.07 (1.03-1.10]). Meanwhile, elevated B2M-3 level was associated with unscheduled rehospitalization, and each 1 mg/l increase in B2M-3 increased the risk of unscheduled rehospitalization by 1.21-fold [OR, 1.21 (1.03-1.42)]. The Harrell's C-index for all-cause mortality was higher for NSE-3 [0.820 (95% confidence interval {CI}, 0.706-0.934)] compared to frailty assessed by the FRAIL scale [0.715 (95% CI, 0.580-0.850)], which means that additional NSE-3 assessment may improve the prediction of all-cause mortality. However, Uno's C-Statistic analysis showed that the difference was not statistically significant (Pr>chi-square 0.556). Harrell's C-index for unscheduled rehospitalization was higher for frailty assessed by the FRAIL scale compared to B2M-3.

CONCLUSION

Monitoring NSE and B2M marker levels in patients over 65 years of age with frailty and ACS does not provide additional benefits in terms of prognostic ability compared to tests assessing frailty. B2M, assessed upon hospital admission and monitoring NSE and B2M levels during hospitalization may be considered in the diagnosis of frailty and risk stratification in a group of patients for whom currently available frailty diagnostic tools cannot be used.

Assessment of silent brain injury in patients undergoing elective percutaneous coronary intervention due to chronic total occlusion

Objective: Silent brain infarcts (SBI) are thromboembolic complications associated with cardiac surgery, diagnostic angiography, and percutaneous interventions. Serum neuron-specific enolase (NSE) is the proven biomarker for measuring neuronal damage. This study aimed to evaluate the incidence of SBI, defined as elevated NSE after coronary chronic total occlusion (CTO) intervention and elective coronary stenting. Design: The study population consisted of two patient groups: the CTO group included consecutive patients with coronary CTO intervention, and the control group consisted of patients who underwent elective coronary intervention. NSE blood levels were measured before and 12-18 h after the procedure. NSE blood levels of >20 ng/mL were considered SBI. Results: A total of 108 patients were included in the study. Of these, 55 (50.9%) had SBI after the procedure. The SBI rate was 59.7% in the CTO group and 39.1% in the control group. Patients with SBI were more likely to have diabetes mellitus, hyperlipidemia, higher HbA1c, higher total stent length, and longer procedural time. Multivariate logistic regression analysis showed that CTO procedure (odds ratio [OR]: 3.129; 95% confidence interval [CI]: 1.246-7.858; p < 0.015) and diabetes mellitus (OR: 2.93; 95% CI: 1.185-7.291; p < 0.020) are independent predictors of SBI. Conclusion: Our data suggest that SBI occurs more frequently after CTO intervention than after non-CTO intervention. Intervention complexity and patient clinical characteristics may explain the increased incidence.

Direct transcatheter aortic valve implantation (TAVI) decreases silent cerebral infarction when compared to routine balloon valvuloplasty

PURPOSE

Silent cerebral infarctions (SCI), as determined by neuron-specific enolase (NSE) elevations, may develop after the transcatheter aortic valve implantation (TAVI) procedure. Our aim in this study was to compare the SCI rates between patients who underwent routine pre-dilatation balloon aortic valvuloplasty (pre-BAV) and patients who underwent direct TAVI without pre-BAV.

METHODS

A total of 139 consecutive patients who underwent TAVI in a single center using the self-expandable Evolut-R valve (Medtronic, Minneapolis, Minnesota, USA) were included in the study. The first 70 patients were included in the pre-BAV group, and the last 69 patients were included in the direct TAVI group. SCI was detected by serum NSE measurements performed at baseline and 12 h after the TAVI. New NSE elevations > 12 ng/mL after the procedure were counted as SCI. In addition, SCI was scanned by MRI (magnetic resonance imaging) in eligible patients.

RESULTS

TAVI procedure was successful in all of the study population. Post-dilatation rates were higher in the direct TAVI group. Post-TAVI NSE positivity (SCI) was higher in the routine pre-BAV group (55(78.6%) vs. 43(62.3%) patients, p = 0.036) and NSE levels were also higher in this group (26.8 ± 15.0 vs. 20.5 ± 14.8 ng/ml, p = 0.015). SCI with MRI was found to be significantly higher in the pre-BAV group than direct TAVI group (39(55.1%) vs. 31(44.9%) patients). The presence of atrial fibrillation and diabetes mellitus (DM), total cusp calcification volume, calcification at arcus aorta, routine pre-BAV and failure at first try of the prosthetic valve implantation were significantly higher in SCI (+) group. In the multivariate analysis, presence of DM, total cusp calcification volume, calcification at arcus aorta, routine pre-BAV and failure at first try of the prosthetic valve implantation were significantly associated with new SCI development.

CONCLUSIONS

Direct TAVI procedure without pre-dilation seems to be an effective method and avoidance of pre-dilation decreases the risk of SCI development in patients undergoing TAVI with a self-expandable valve.

Comparison of frequency of silent cerebral infarction as assessed by serum neuron specific enolase in patients with non-valvular atrial fibrillation: Warfarin versus direct oral anticoagulant

BACKGROUND

Cerebral infarction in patients with atrial fibrillation (AF) may clinically vary from being silent to catastrophic. Silent cerebral infarction (SCI) is the neuronal injury in the absence of clinically appearent stroke or transient ischaemic attack. Serum neuron specific enolase (NSE) is suggested to be a valid surrogate biomarker that allows to detect recent neuronal injury. We aimed to evaluate the incidence of recent SCI by positive NSE levels in patients with non-valvular AF (NVAF) on oral anticoagulants.

METHODS

Blood samples for NSE were collected from 197 consecutive NVAF patients. NSE levels of greater than 12 ng/ml was considered as positive and suggestive of SCI.

RESULTS

Patients were mainly female with a mean age of 69 years. Ninety-eight of them (49.7%) were taking warfarin. Mean INR level was 2.3 ± 0.9. Mean CHA₂DS₂-VASc score of the study population was 3.5 ± 1.5. Seventy-two patients (36.5%) were found to have NSE elevation. They were more likely to have history of chronic heart failure and previous stroke/TIA. Increased left atrial diameter and higher CHA₂DS₂-VASc were other factors associated with SCI. Patients on DOACs and patients taking aspirin on top of oral anticoagulant treatment were less likely to have SCI. Multivariate analysis demonstrated that increased left atrial diameter (OR: 2.5; 95% CI: 1.52-4; p < 0.001) and use of warfarin (OR: 2.8; 95% CI: 1.37-5.61; p = 0.005) were detected as independent predictors of SCI.

CONCLUSIONS

Our study revealed that DOACs were associated with significantly reduced SCIs compared with warfarin, probably due to more effective and consistent therapeutic level of anticoagulation.

Neurovascular Unit as a Source of Ischemic Stroke Biomarkers-Limitations of Experimental Studies and Perspectives for Clinical Application

Cerebral stroke, which is one of the most frequent causes of mortality and leading cause of disability in developed countries, often leads to devastating and irreversible brain damage. Neurological and neuroradiological diagnosis of stroke, especially in its acute phase, is frequently uncertain or inconclusive. This results in difficulties in identification of patients with poor prognosis or being at high risk for complications. It also makes difficult identification of these stroke patients who could benefit from more aggressive therapies. In contrary to the cardiovascular disease, no single biomarker is available for the ischemic stroke, addressing the abovementioned issues. This justifies the need for identifying of effective diagnostic measures characterized by high specificity and sensitivity. One of the promising avenues in this area is studies on the panels of biomarkers characteristic for processes which occur in different types and phases of ischemic stroke and represent all morphological constituents of the brains' neurovascular unit (NVU). In this review, we present the current state of knowledge concerning already-used or potentially applicable biomarkers of the ischemic stroke. We also discuss the perspectives for identification of biomarkers representative for different types and phases of the ischemic stroke, as well as for different constituents of NVU, which concentration levels correlate with extent of brain damage and patients' neurological status. Finally, a critical analysis of perspectives on further improvement of the ischemic stroke diagnosis is presented.

Silent cerebral infarction after percutaneous coronary intervention of chronic total occlusions (CTO) and non-CTOs

Silent cerebral infarctions (SCI) determined by neuron specific enolase (NSE) elevation may develop more during chronic total occlusion (CTO) percutaneous coronary interventions (PCI) than non-CTO interventions. Our aim was to examine CTO and non-CTO PCIs for SCI development. 100 consecutive CTO and 100 non-CTO PCI patients were enrolled. SCI was detected by serum NSE measurements performed at baseline and 12 h after the interventions. New NSE elevations > 12 ng/mL after the procedure were counted as SCI. Post-procedural NSE levels were found to be significantly higher in the CTO PCI group and NSE positivity was more prevalent in the CTO PCI group (56 (56%) vs. 31 (31%), p < 0.001), but PCI of CTOs did not independently increase risk of SCI (OR: 2.39 (0.85-6.73), p: 0.10). Patients who developed SCI after PCI had the characteristics of tough PCI interventions. In the multivariate analysis, two parameters were found to be independently associated with SCI development, namely more contrast volume (OR: 1.014 (1.005-1.023), p: 0.003) and longer procedural time (OR: 1.030 (1.010-1.051), p: 0.003). It has been firstly demonstrated in the literature that CTO PCIs, by its nature, have increased rates of SCI when compared to non-CTO PCIs but presence of a CTO was not an independent predictor of SCI. Mainly, procedural characteristics of the PCIs, especially longer procedural times and more contrast consumption, observed more in CTO PCIs, have been found to be independently associated with elevations of plasma NSE levels.

Relationship between silent cerebral infarcts and quality of anticoagulation in patients with prosthetic mitral valves

OBJECTIVE

Although patients with prosthetic heart valves have an increased risk of clinically overt cerebrovascular events, evidence for the risk of silent cerebral infarction (SCI) is scarce. Serum neuron-specific enolase (NSE) is suggested to be a valid biomarker that allows for the quantification of the degree of neuronal injury. We aimed to assess whether NSE is elevated as a marker of recent SCI in patients with a prosthetic mitral valve.

METHODS

We measured the NSE levels in 103 patients with a prosthetic mitral valve (PMV), admitted to our outpatient clinics for routine evaluation. International normalized ratio (INR) and time in target therapeutic range (TTR) were noted as anticoagulation quality measures.

RESULTS

Most of the patients were females (58%), and a mean age was 65 years. NSE values of >12 ng/mL, suggesting a recent SCI, was detected in 25 patients (24%). NSE was negatively correlated with admission INR (r=-0.307, p=0.002). Multivariate analyses demonstrated subtherapeutic INR (INR <2.5) and suboptimal TTR as independent predictors of SCI [odds ratio (OR) 5.420; 95% confidence interval (CI) 1.589 to 18.483; p=0.007, and OR 4.149; 95% CI 1.019 to 16.949; p=0.047, respectively]. Being a current smoker (OR 10.798; 95% CI 2.520 to 46.272; p=0.001), large left atrium (OR 6.763; 95% CI 2.253 to 20.302; p=0.001), and not using aspirin (OR 10.526; 95% CI 1.298 to 83.333; p=0.027) were other independent predictors.

CONCLUSION

Our data suggest that silent brain infarcts are very prevalent among patients with a PMV, as one fourth of them had the event during their routine outpatient visit. Poor quality of anticoagulation partly explains the increased prevalence.

Relation of Acute Decompensated Heart Failure to Silent Cerebral Infarcts in Patients With Reduced Left Ventricular Ejection Fraction

Heart failure (HF) is a prothrombotic state with increased rate of thromboembolic events. Magnetic resonance imaging studies demonstrated increased rate of silent cerebral infarcts (SCI) in this patient group and SCIs were shown lead to dementia, cognitive decline, and depression. We aimed to show acute decompensated phase is associated with increased rate of recent SCI in reduced ejection fraction HF patients. HF patients with sinus rhythm hospitalized for acute decompensation were studied. Neuron specific enolase (NSE), a sensitive neuronal ischemia marker, was used to detect recent SCI. Decompensated and compensated phase blood samples for NSE were collected on the day of admission and on the third day of compensation, respectively. One hundred and forty seven patients with mean age of 72 were studied. There were significantly more patients with positive NSE levels at decompensated state (29% vs 4%, p <0.001). Multivariate predictors for recent SCI were smoking, new onset atrial fibrillation, spontaneous echo contrast of left ventricle, and aneurysmatic apex. Statin use was found to be protective against NSE elevation. In conclusion, our data reveal that decompensated HF is significantly associated with increased levels of NSE suggestive for silent neuronal injury.

Comparison of Frequency of Silent Cerebral Infarction After Coronary Angiography and Stenting With Transradial Versus Transfemoral Approaches

Silent cerebral infarction (SCI) can be seen after coronary procedures. We investigated whether vascular access sites have an impact on the risk of SCI. A total of 255 consecutive patients who underwent diagnostic or interventional coronary procedures through transfemoral (n = 126 patients) or transradial (n = 129 patients) approach were evaluated. Neuron-specific enolase (NSE) levels were studied before and 12 hours after the procedure. Elevation of greater than 12 ng/ml was considered as SCI. Patients were mainly men (60%) with a mean age of 62 years. SCI was observed in 74 of 255 patients (29%). It was significantly more prevalent among transradial group. Elevation of NSE was observed in 36% of transradial group (n = 47) and 21% of the transfemoral group (n = 27) (p = 0.008). Patients with SCI were more likely to have male sexuality, hyperlipidemia, history of smoking, and previous myocardial infarction. Multivariate analysis demonstrated that patients who underwent coronary procedures through transradial approach were 2.1 times more likely to have an SCI than patients with transfemoral approach (95% confidence interval [CI] 1.205 to 3.666; p = 0.008). Other independent predictors of NSE elevation were previous myocardial infarction (odds ratio 8.6; 95% CI 4.209 to 17.572; p <0.001) and smoking history (odds ratio 7.251; 95% CI 3.855 to 13.639; p <0.001). The present study suggests that transradial coronary procedures carry higher risk of SCI when compared with transfemoral route.

New Insights into the Role of Neuron-Specific Enolase in Neuro-Inflammation, Neurodegeneration, and Neuroprotection

Neurodegeneration is a complex process that leads to irreversible neuronal damage and death in spinal cord injury (SCI) and various neurodegenerative diseases, which are serious, debilitating conditions. Despite exhaustive research, the cause of neuronal damage in these degenerative disorders is not completely understood. Elevation of cell surface α-enolase activates various inflammatory pathways, including the production of pro-inflammatory cytokines, chemokines, and some growth factors that are detrimental to neuronal cells. While α-enolase is present in all neurological tissues, it can also be converted to neuron specific enolase (NSE). NSE is a glycolytic enzyme found in neuronal and neuroendocrine tissues that may play a dual role in promoting both neuroinflammation and neuroprotection in SCI and other neurodegenerative events. Elevated NSE can promote ECM degradation, inflammatory glial cell proliferation, and actin remodeling, thereby affecting migration of activated macrophages and microglia to the injury site and promoting neuronal cell death. Thus, NSE could be a reliable, quantitative, and specific marker of neuronal injury. Depending on the injury, disease, and microenvironment, NSE may also show neurotrophic function as it controls neuronal survival, differentiation, and neurite regeneration via activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways. This review discusses possible implications of NSE expression and activity in neuroinflammation, neurodegeneration, and neuroprotection in SCI and various neurodegenerative diseases for prognostic and therapeutic potential.