Copeptin: a new and promising diagnostic and prognostic marker

The study conducted by Seligman and coworkers included in the previous issue of Critical Care demonstrates that copeptin is a promising marker to predict outcome in patients with ventilator-associated pneumonia. In recent years, copeptin has emerged as a new prognostic marker in a variety of diseases, such as sepsis, community-acquired pneumonia, chronic obstructive pulmonary failure, heart failure and myocardial infarction. What is the pathophysiological basis for these findings? Copeptin together with vasopressin is co-secreted from the posterior pituitary and therefore mirrors the amount of vasopressin in the circulation. Vaso-pressin is a main secretagogue of the hypothalamo–pituitary–adrenal axis, thereby mirroring the individual stress level. Furthermore, vasopressin is an important hormone in salt and volume regulation. In this context, copeptin is also a diagnostic marker in patients with diabetes insipidus and in patients with disordered water states

Aetiology, secondary prevention strategies and outcomes of ischaemic stroke despite oral anticoagulant therapy in patients with atrial fibrillation

OBJECTIVE To investigate the aetiology, subsequent preventive strategies and outcomes of stroke despite anticoagulation in patients with atrial fibrillation (AF). METHODS We analysed consecutive patients with AF with an index imaging-proven ischaemic stroke despite vitamin K-antagonist (VKA) or direct oral anticoagulant (DOAC) treatment across 11 stroke centres. We classified stroke aetiology as: (i) competing stroke mechanism other than AF-related cardioembolism; (ii) insufficient anticoagulation (non-adherence or low anticoagulant activity measured with drug-specific assays); or, (iii) AF-related cardioembolism despite sufficient anticoagulation. We investigated subsequent preventive strategies with regard to the primary (composite of recurrent ischaemic stroke, intracranial haemorrhage, death) and secondary endpoint (recurrent ischaemic stroke) within 3 months after index stroke. RESULTS Among 2946 patients (median age 81 years; 48% women; 43% VKA, 57% DOAC), stroke aetiology was competing mechanism in 713 patients (24%), insufficient anticoagulation in 934 (32%) and cardioembolism despite sufficient anticoagulation in 1299 (44%). We found high rates of the primary (27% of patients; completeness 91.6%) and secondary endpoint (4.6%; completeness 88.5%). Only DOAC (vs VKA) treatment after index stroke showed lower odds for both endpoints (primary: adjusted OR (aOR) (95% CI) 0.49 (0.32 to 0.73); secondary: 0.44 (0.24 to 0.80)), but not switching between different DOAC types. Adding antiplatelets showed higher odds for both endpoints (primary: aOR (95% CI) 1.99 (1.25 to 3.15); secondary: 2.66 (1.40 to 5.04)). Only few patients (1%) received left atrial appendage occlusion as additional preventive strategy. CONCLUSIONS Stroke despite anticoagulation comprises heterogeneous aetiologies and cardioembolism despite sufficient anticoagulation is most common. While DOAC were associated with better outcomes than VKA, adding antiplatelets was linked to worse outcomes in these high-risk patients. Our findings indicate that individualised and novel preventive strategies beyond the currently available anticoagulants are needed. TRIAL REGISTRATION NUMBER ISRCTN48292829

Procalcitonin and midregional proatrial natriuretic peptide as biomarkers of subclinical cerebrovascular damage: the northern manhattan study

BACKGROUND AND PURPOSE: Chronic infections and cardiac dysfunction are risk factors for stroke. We hypothesized that blood biomarkers of infection (procalcitonin) and cardiac dysfunction (midregional proatrial natriuretic peptide [MR-proANP]), previously associated with small vessel stroke and cardioembolic stroke are also associated with subclinical cerebrovascular damage, including silent brain infarcts and white matter hyperintensity volume. METHODS: The NOMAS (Northern Manhattan Study) was designed to assess risk factors for incident vascular disease in a multiethnic cohort. A subsample underwent brain magnetic resonance imaging and had blood samples available for biomarker measurement (n=1178). We used logistic regression models to estimate the odds ratios and 95% confidence intervals (95% CIs) for the association of these biomarkers with silent brain infarcts after adjusting for demographic, behavioral, and medical risk factors. We used linear regression to assess associations with log-white matter hyperintensity volume. RESULTS: Mean age was 70±9 years; 60% were women, 66% Hispanic, 17% black, and 15% were white. After adjusting for risk factors, subjects with procalcitonin or MR-proANP in the top quartile, compared with the lowest quartile were more likely to have silent brain infarcts (adjusted odds ratio for procalcitonin, 2.2; 95% CI, 1.3-3.7 and for MR-proANP, 3.3; 95% CI, 1.7-6.3) and increased white matter hyperintensity volume (adjusted mean change in log-white matter hyperintensity volume for procalcitonin, 0.29; 95% CI, 0.13-0.44 and for MR-proANP, 0.18; 95% CI, 0.004-0.36). CONCLUSIONS: Higher concentrations of procalcitonin, a marker of infection, and MR-proANP, a marker of cardiac dysfunction, are independently associated with subclinical cerebrovascular damage. If further studies demonstrate an incremental value for risk stratification, biomarker-guided primary prevention studies may lead to new approaches to prevent cerebrovascular disease

Selection bias in clinical stroke trials depending on ability to consent

BACKGROUND Clinical trials are the hallmark of evidence-based medicine, but recruitment is often challenging, especially in stroke trials investigating patients not being able to give informed consent. In some nations, ethics committees will not approve of inclusion in a clinical study via consent of a legal representative. The ethical dilemma of including or excluding those patients has not been properly addressed, as there is little data on the effect of stroke characteristics on the ability to give informed consent. METHODS To examine differences between patients able and unable to consent at inclusion to an acute stroke trial, we conducted a post-hoc analysis of monitoring records from a multicentric interventional trial. These records listed patients who gave informed consent by themselves and those who needed a legal representative to do so. This exemplary STRAWINSKI trial aimed at improving stroke outcome by biomarker-guided antibiotic treatment of stroke associated pneumonia and included patients within 40 h after stroke onset, suffering from MCA infarctions with an NIHSS score > 9 at admission. Standard descriptive and associative statistics were calculated to compare baseline characteristics and outcome measures between patients who were able to consent and those who were not. RESULTS We identified the person giving consent in 228 out of 229 subjects. Patients with inability to consent were older (p < 0.01), suffered from more left-hemispheric (p < 0.01) and more severe strokes (NIHSS, p < 0.01), were more likely to die during hospitalisation (p < 0.01) or have unfavourable outcome at discharge (mRS, p < 0.01), to develop fever (p < 0.01) and tended to be more susceptible to infections (p = 0.06) during the acute course of the disorder. CONCLUSIONS Demographics, stroke characteristics and outcomes significantly affect stroke patients in their ability to consent. Where selection criteria and primary outcome measures of a trial are significantly affected by ability to consent, excluding patients unable to consent might be unethical. TRIAL REGISTRATION URL http://www.clinicaltrials.gov . Unique identifier: NCT01264549

Mannose-Binding Lectin Deficiency Is Associated With Smaller Infarction Size and Favorable Outcome in Ischemic Stroke Patients

BACKGROUND: The Mannose-binding lectin (MBL) pathway of complement plays a pivotal role in the pathogenesis of ischemia/reperfusion (I/R) injury after experimental ischemic stroke. As comparable data in human ischemic stroke are limited, we investigated in more detail the association of MBL deficiency with infarction volume and functional outcome in a large cohort of patients receiving intravenous thrombolysis or conservative treatment. METHODOLOGY/PRINCIPAL FINDINGS: In a post hoc analysis of a prospective cohort study, admission MBL concentrations were determined in 353 consecutive patients with an acute ischemic stroke of whom 287 and 66 patients received conservative and thrombolytic treatment, respectively. Stroke severity, infarction volume, and functional outcome were studied in relation to MBL concentrations at presentation to the emergency department. MBL levels on admission were not influenced by the time from symptom onset to presentation (p = 0.53). In the conservative treatment group patients with mild strokes at presentation, small infarction volumes or favorable outcomes after three months demonstrated 1.5 to 2.6-fold lower median MBL levels (p = 0.025, p = 0.0027 and p = 0.046, respectively) compared to patients with more severe strokes. Moreover, MBL deficient patients (>100 ng/ml) were subject to a considerably decreased risk of an unfavorable outcome three months after ischemic stroke (adjusted odds ratio 0.38, p>0.05) and showed smaller lesion volumes (mean size 0.6 vs. 18.4 ml, p = 0.0025). In contrast, no association of MBL concentration with infarction volume or functional outcome was found in the thrombolysis group. However, the small sample size limits the significance of this observation. CONCLUSIONS: MBL deficiency is associated with smaller cerebral infarcts and favorable outcome in patients receiving conservative treatment. Our data suggest an important role of the lectin pathway in the pathophysiology of cerebral I/R injury and might pave the way for new therapeutic interventions

Serum circulating sirtuin 6 as a novel predictor of mortality after acute ischemic stroke

In a murine model of acute ischemic stroke, SIRT6 knockdown resulted in larger cerebral infarct size, worse neurological outcome, and higher mortality, indicating a possible neuro-protective role of SIRT6. In this study, we aimed at evaluating the prognostic value of serum SIRT6 levels in patients with acute ischemic stroke (AIS). Serum levels of SIRT6, collected within 72 h from symptom-onset, were measured in 317 consecutively enrolled AIS patients from the COSMOS cohort. The primary endpoint of this analysis was 90-day mortality. The independent prognostic value of SIRT6 was assessed with multivariate logistic and Cox proportional regression models. 35 patients (11%) deceased within 90-day follow-up. After adjustment for established risk factors (age, NIHSS, heart failure, atrial fibrillation, and C reactive protein), SIRT6 levels were negatively associated with mortality. The optimal cut-off for survival was 634 pg/mL. Patients with SIRT6 levels below this threshold had a higher risk of death in multivariable Cox regression. In this pilot study, SIRT6 levels were significantly associated with 90-day mortality after AIS; these results build on previous molecular and causal observations made in animal models. Should this association be confirmed, SIRT6 could be a potential prognostic predictor and therapeutic target in AIS

Copeptin is associated with mortality and outcome in patients with acute intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) accounts for a high mortality and morbidity. Early prediction of outcome is crucial for optimized care and treatment decision. Copeptin, the C-terminal part of provasopressin, has emerged as a new prognostic marker in a variety of diseases, but its prognostic value in ICH is unknown