The Role of Electrocardiographic Markers for Predicting Atrial Fibrillation in Patients with Acute Ischemic Stroke: Data from the BIOSIGNAL Cohort Study

BACKGROUND AND AIMS

P-wave abnormalities in the 12-lead electrocardiogram (ECG) have been associated with a higher risk of acute ischemic stroke (AIS) as well as atrial fibrillation (AF). This study aimed to assess pre-determined ECG criteria during sinus rhythm in unselected AIS patients and their value for predicting newly diagnosed atrial fibrillation (NDAF) after hospital admission.

METHODS

P-wave alterations were measured on 12-lead ECG on admission in all consecutively enrolled patients without known AF between October 2014 and 2017. The outcome of interest was NDAF, identified by prolonged electrocardiographic monitoring within one year after the index AIS. Univariable and multivariable logistic regression was applied to assess the magnitude and independence of the association between pre-selected ECG markers and NDAF. The discriminatory accuracy was evaluated with the area under the receiver operating characteristic curve (AUC), and the incremental prognostic value was estimated with the net reclassification index.

RESULTS

NDAF was detected in 87 (10%) of 856 patients during a follow-up of 365 days. Out of the pre-selected ECG parameters, advanced interatrial block (aIAB) and PR interval in lead II were independently associated with NDAF in univariable regression analysis. Only aIAB remained a significant predictor in multivariable analysis. Adding aIAB to the best-performing multivariable regression model improved the discriminatory accuracy to predict NDAF from an AUC of 0.78 (95%-CI 0.77-0.80) to 0.81 (95%-CI 0.80-0.83, p < 0.001).

CONCLUSION

aIAB is independently and highly associated with NDAF in patients with AIS, has high inter-rater reliability, and therefore may be helpful to refine diagnostic work-up to search for AF in AIS.

Serum S-100B adds incremental value for the prediction of symptomatic intracranial hemorrhage and brain edema after acute ischemic stroke

Background:

Early identification of patients developing symptomatic intracranial hemorrhage and symptomatic brain edema after acute ischemic stroke is essential for clinical decision-making. Astroglial protein S-100B is a marker of blood-brain barrier disruption, which plays an important role in the formation of intracranial hemorrhage and brain edema. In this study, we assessed the prognostic value of serum S-100B for the development of these complications.

Methods:

Serum S-100B levels were measured within 24 h from symptom onset in 1749 consecutive acute ischemic stroke patients from the prospective, observational, multicenter BIOSIGNAL cohort study (mean age 72.0 years, 58.3% male). To determine symptomatic intracranial hemorrhage or symptomatic brain edema, follow-up neuroimaging was performed in all patients receiving reperfusion therapy or experiencing clinical worsening with an NIHSS increase of ⩾4.

Results:

Forty six patients (2.6%) developed symptomatic intracranial hemorrhage and 90 patients (5.2%) developed symptomatic brain edema. After adjustment for established risk factors, log10S-100B levels remained independently associated with both symptomatic intracranial hemorrhage (OR 3.41, 95% CI 1.7–6.9, p = 0.001) and symptomatic brain edema (OR 4.08, 95% CI 2.3–7.1, p < 0.001) in multivariable logistic regression models. Adding S-100B to the clinical prediction model increased the AUC from 0.72 to 0.75 ( p = 0.001) for symptomatic intracranial hemorrhage and from 0.78 to 0.81 ( p < 0.0001) for symptomatic brain edema.

Conclusions:

Serum S-100B levels measured within 24 h after symptom onset are independently associated with the development of symptomatic intracranial hemorrhage and symptomatic brain edema in acute ischemic stroke patients. Thus, S-100B may be useful for early risk-stratification regarding stroke complications.

Impact of Seizures and Status Epilepticus on Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

We aimed to evaluate the association between seizures as divided by timing and type (seizures or status epilepticus) and outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

All consecutive patients with aSAH admitted to the neurocritical care unit of the University Hospital Zurich between 2016 and 2020 were included. Seizure type and frequency were extracted from electronic patient files.

RESULTS

Out of 245 patients, 76 experienced acute symptomatic seizures, with 39 experiencing seizures at onset, 18 experiencing acute seizures, and 19 experiencing acute nonconvulsive status epilepticus (NCSE). Multivariate analysis revealed that acute symptomatic NCSE was an independent predictor of unfavorable outcome (odds ratio 14.20, 95% confidence interval 1.74-116.17, p = 0.013) after correction for age, Hunt-Hess grade, Fisher grade, and delayed cerebral ischemia. Subgroup analysis showed a significant association of all seizures/NCSE with higher Fisher grade (p < 0.001 for acute symptomatic seizures/NCSE, p = 0.031 for remote symptomatic seizures). However, although acute seizures/NCSE (p = 0.750 and 0.060 for acute seizures/NCSE respectively) were not associated with unfavorable outcome in patients with a high Hunt-Hess grade, they were significantly associated with unfavorable outcome in patients with a low Hunt-Hess grade (p = 0.019 and p < 0.001 for acute seizures/NCSE, respectively).

CONCLUSIONS

Acute symptomatic NCSE independently predicts unfavorable outcome after aSAH. Seizures and NCSE are associated with unfavorable outcome, particularly in patients with a low Hunt-Hess grade. We propose that NCSE and the ictal or postictal reduction of Glasgow Coma Scale may hamper close clinical evaluation for signs of delayed cerebral ischemia, and thus possibly leading to delayed diagnosis and therapy thereof in patients with a low Hunt-Hess grade.

Lipoprotein(a) is associated with large artery atherosclerosis stroke aetiology and stroke recurrence among patients below the age of 60 years: results from the BIOSIGNAL study

AIMS

Lipoprotein(a) [Lp(a)] is a recognized causal risk factor for atherosclerotic cardiovascular disease but its role for acute ischaemic stroke (AIS) is controversial. In this study, we evaluated the association of Lp(a) with large artery atherosclerosis (LAA) stroke and risk of recurrent cerebrovascular events in AIS patients.

METHODS AND RESULTS

For this analysis of the prospective, observational, multicentre BIOSIGNAL cohort study we measured Lp(a) levels in plasma samples of 1733 primarily Caucasian (98.6%) AIS patients, collected within 24 h after symptom onset. Primary outcomes were LAA stroke aetiology and recurrent cerebrovascular events (ischaemic stroke or transient ischaemic attack) within 1 year. We showed that Lp(a) levels are independently associated with LAA stroke aetiology [adjusted odds ratio 1.48, 95% confidence interval (CI) 1.14-1.90, per unit log10Lp(a) increase] and identified age as a potent effect modifier (Pinteraction =0.031) of this association. The adjusted odds ratio for LAA stroke in patients aged <60 years was 3.64 (95% CI 1.76-7.52) per unit log10Lp(a) increase and 4.04 (95% CI 1.73-9.43) using the established cut-off ≥100 nmol/l. For 152 recurrent cerebrovascular events, we did not find a significant association in the whole cohort. However, Lp(a) levels ≥100 nmol/l were associated with an increased risk for recurrent events among patients who were either <60 years [adjusted hazard ratio (HR) 2.40, 95% CI 1.05-5.47], had evident LAA stroke aetiology (adjusted HR 2.18, 95% CI 1.08-4.40), or had no known atrial fibrillation (adjusted HR 1.60, 95% CI 1.03-2.48).

CONCLUSION

Elevated Lp(a) was independently associated with LAA stroke aetiology and risk of recurrent cerebrovascular events among primarily Caucasian individuals aged <60 years or with evident arteriosclerotic disease.

SAA (Serum Amyloid A): A Novel Predictor of Stroke-Associated Infections

BACKGROUND AND PURPOSE

The aim of this study was to evaluate and independently validate SAA (serum amyloid A)-a recently discovered blood biomarker-to predict poststroke infections.

METHODS

The derivation cohort (A) was composed of 283 acute ischemic stroke patients and the independent validation cohort (B), of 367 patients. The primary outcome measure was any stroke-associated infection, defined by the criteria of the US Centers for Disease Control and Prevention, occurring during hospitalization. To determine the association of SAA levels on admission with the development of infections, logistic regression models were calculated. The discriminatory ability of SAA was assessed, by calculating the area under the receiver operating characteristic curve.

RESULTS

After adjusting for all predictors that were significantly associated with any infection in the univariate analysis, SAA remained an independent predictor in study A (adjusted odds ratio, 1.44 [95% CI, 1.16-1.79]; P=0.001) and in study B (adjusted odds ratio, 1.52 [1.05-2.22]; P=0.028). Adding SAA to the best regression model without the biomarker, the discriminatory accuracy improved from 0.76 (0.69-0.83) to 0.79 (0.72-0.86; P<0.001; likelihood ratio test) in study A. These results were externally validated in study B with an improvement in the area under the receiver operating characteristic curve, from 0.75 (0.70-0.81) to 0.76 (0.71-0.82; P<0.038).

CONCLUSIONS

Among patients with ischemic stroke, blood SAA measured on admission is a novel independent predictor of infection after stroke. SAA improved the discrimination between patients who developed an infection compared with those who did not in both derivation and validation cohorts. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00390962.

Additional external electromagnetic fields for laser microprocessing of metals

Ultra-short pulsed laser processing is a potent tool for microstructuring of a lot of materials. At certain laser parameters, particular periodical and/or quasi-periodical µm-size surface structures evolve apparently during processing. With extended plasmonics theory, it is possible to predict the structure formation, and a systematic technology can be derived to alter the surface for laser processing. In this work, we have demonstrated the modification of the laser processing with applying tailored dynamic surface electro-magnetic fields. Possible improvement in applications is seen in the fields of process efficiency of laser ablation and a superior control of the surface topography.

Peripheral effects of thyroid hormones: alteration of intracellular Na-concentration, ouabain-sensitive Na-transport, and Na-Li countertransport in human red blood cells

To investigate the effect of thyroid hormones on erythrocyte cation transport systems and intracellular electrolyte content we have measured the activity of Na-K ATPase, Na-Li countertransport, as well as red cell sodium and potassium contents in patients with hyperthyroidism and in euthyroid controls. Intracellular Na- and K-concentrations were determined in erythrocytes washed three times in isotonic MgCl2 solution. Ouabain-sensitive Na-transport was estimated as the increase of Na before and after addition of ouabain in an erythrocyte suspension in isotonic Na-free medium. Na-Li countertransport was measured according to the method described by Canessa et al. [2]. The patients with hyperthyroidism exhibited a significantly elevated intracellular sodium content as well as a highly increased Na-K ATPase activity. Intracellular potassium content was not altered in the hyperthyroid subjects, but Na-Li countertransport was markedly decreased as compared to the controls. The results indicate that different ion transport systems of the erythrocyte membrane are influenced by thyroid hormones. We suggest that the elevation of Na-K ATPase activity might be due to the increased intracellular sodium concentration which is caused by the diminished countertransport pathway. Furthermore, the activity of Na-K ATPase, Na-Li countertransport, and intracellular sodium content in erythrocytes might be a useful peripheral indicator of thyroid hormone excess.