Stroke in atrial fibrillation and improving the identification of 'high-risk' patients: the crossroads of immunity and thrombosis

Leukocyte indicators and variations predict worse outcomes after intravenous thrombolysis in patients with acute ischemic stroke

Leukocytes are systematic inflammation indicators related to stroke prognosis and can exhibit large dynamic waves before and after recombinant tissue plasminogen activator (r-tPA) therapy. However, additional evidence is needed to determine the prognostic significance of various leukocytes including both static and dynamic data among patients who underwent r-tPA therapy. A total of 251 patients treated with r-tPA were included; their leukocyte data were collected at two time points, and patients were followed up for three months. Analysis revealed the following findings. (i) Patients with hemorrhagic transformation (HT) and unfavorable outcomes had a higher level of leukocytes after r-tPA therapy (leukocyte count (adjusted OR (aOR) 1.191 for HT and 1.184 for unfavorable outcomes), neutrophil count (aOR 1.215 and 1.214), neutrophil-to-lymphocyte ratio (NLR; aOR 1.084 and 1.091)) and larger dynamic leukocyte changes. (ii)Among all leukocytes, the NLR after r-tPA administration demonstrated the strongest correlation with HT and unfavorable outcomes. (iii) Patients with an NLR ≥ 3.322 had a 3.492-fold increased risk for HT, and those with an NLR ≥ 5.511 had a 3.024-fold increased risk for functional outcomes. Overall, this study shows that leukocytes, especially leukocyte count, neutrophil count and the NLR, are independently associated with HT and functional outcomes in stroke patients.

Neutrophil dynamics and inflammaging in acute ischemic stroke: A transcriptomic review

Stroke is among the leading causes of death and disability worldwide. Restoring blood flow through recanalization is currently the only acute treatment for cerebral ischemia. Unfortunately, many patients that achieve a complete recanalization fail to regain functional independence. Recent studies indicate that activation of peripheral immune cells, particularly neutrophils, may contribute to microcirculatory failure and futile recanalization. Stroke primarily affects the elderly population, and mortality after endovascular therapies is associated with advanced age. Previous analyses of differential gene expression across injury status and age identify ischemic stroke as a complex age-related disease. It also suggests robust interactions between stroke injury, aging, and inflammation on a cellular and molecular level. Understanding such interactions is crucial in developing effective protective treatments. The global stroke burden will continue to increase with a rapidly aging human population. Unfortunately, the mechanisms of age-dependent vulnerability are poorly defined. In this review, we will discuss how neutrophil-specific gene expression patterns may contribute to poor treatment responses in stroke patients. We will also discuss age-related transcriptional changes that may contribute to poor clinical outcomes and greater susceptibility to cerebrovascular diseases.

A nomogram for predicting atrial fibrillation detected after acute ischemic stroke

Background

Atrial fibrillation detected after stroke (AFDAS) is associated with an increased risk of ischemic stroke (IS) recurrence and death. Early diagnosis can help identify strategies for secondary prevention and improve prognosis. However, there are no validated predictive tools to assess the population at risk for AFDAS. Therefore, this study aimed to develop and validate a predictive model for assessing the incidence of AFDAS after acute ischemic stroke (AIS).

Methods

This study was a multicenter retrospective study. We collected clinical data from 5332 patients with AIS at two hospitals between 2014.01 and 2021.12 and divided the development and validation of clinical prediction models into a training cohort (n = 3173) and a validation cohort (n = 2159). Characteristic variables were selected from the training cohort using the least absolute shrinkage and selection operator (LASSO) algorithm and multivariable logistic regression analysis. A nomogram model was developed, and its performance was evaluated regarding calibration, discrimination, and clinical utility.

Results

We found the best subset of risk factors based on clinical characteristics and laboratory variables, including age, congestive heart failure (CHF), previous AIS/transient ischemia attack (TIA), national institutes of health stroke scale (NIHSS) score, C-reactive protein (CRP), and B-type natriuretic peptide (BNP). A predictive model was developed. The model showed good calibration and discrimination, with calibration values of Hosmer-Lemeshow χ² = 4.813, P = 0.732 and Hosmer-Lemeshow χ² = 4.248, P = 0.834 in the training and validation cohorts, respectively. The area under the ROC curve (AUC) was 0.815, 95% CI (0.777–0.853) and 0.808, 95% CI (0.770–0.847). The inclusion of neuroimaging variables significantly improved the performance of the integrated model in both the training cohort (AUC. 0.846 (0.811–0.882) vs. 0.815 (0.777–0.853), P = 0.001) and the validation cohort (AUC: 0.841 (0.804–0.877) vs. 0.808 (0.770–0.847), P = 0.001). The decision curves showed that the integrated model added more net benefit in predicting the incidence of AFDAS.

Conclusion

Predictive models based on clinical characteristics, laboratory variables, and neuroimaging variables showed good calibration and high net clinical benefit, informing clinical decision-making in diagnosing and treating patients with AFDAS.

Systemic Immune-Inflammation Index Predicts 3-Month Functional Outcome in Acute Ischemic Stroke Patients Treated with Intravenous Thrombolysis

Background and Purpose

Systemic immune-inflammation index (SII), a novel inflammation index derived from counts of circulating platelets, neutrophils and lymphocytes, has been studied in developing incident cancer. However, the clinical value of SII in acute ischemic stroke (AIS) patients had not been further investigated. Therefore, we aimed to explore the association between SII and severity of stroke as well as 3-month outcome of AIS patients.

Methods

A total of 216 AIS patients receiving intravenous thrombolysis (IVT) and 875 healthy controls (HCs) were retrospectively recruited. Blood samples were collected within 24h after admission. Severity of stroke was assessed by the National Institute of Health stroke scale (NIHSS) scores on admission and poor 3-month functional outcome was defined as Modified Rankin Scale (mRS) > 2.

Results

SII levels in AIS patients were higher than in HCs. The cut-off value of SII is 545.14×10⁹/L. Patients with SII > 545.14×10⁹/L had higher NIHSS scores (median: 5 vs 9, p < 0.001), a positive correlation between SII and NIHSS was observed (rs = 0.305, p < 0.001). Multivariate logistic regression analyses showed that high SII was one of the independent risk factors for poor prognosis at 3 months of AIS patients (OR = 3.953, 95% CI = 1.702-9.179, p = 0.001). The addition of SII to the conventional prognostic model improved the reclassification (but not discrimination) of the functional outcome (net reclassification index 39.3%, p = 0.007).

Conclusion

SII is correlated with stroke severity at admission and can be a novel prognostic biomarker for AIS patients treated with IVT.

A high neutrophil-to-lymphocyte ratio predicts hemorrhagic transformation of large atherosclerotic infarction in patients with acute ischemic stroke

Increasing evidence suggests that inflammation is associated with the development of acute ischemic stroke (AIS). The neutrophil-to-lymphocyte ratio (N/L) is an important marker of inflammation and is highly correlated with mortality in stroke patients in recent studies. The N/L of patients who experience hemorrhagic transformation (HT) after AIS is know, but any relationship between N/L and large artery atherosclerosis (LAA) remains unclear, this is our present topic. We enrolled 185 patients with LAA-type HT in the development cohort from a prospective, consecutive, hospital-based stroke registry to this end. We matched these patients to 213 LAA patients who did not develop HT as controls. The incidence of HT after LAA was significantly greater (P<0.01) in patients with higher N/L. We developed a predictive nomogram (incorporating age, systolic blood pressure, the National Institutes of Health Stroke Scale, and the N/L) for LAA patients. The predictive power was good (area under the curve, AUC: 0.832, 95%CI: 0.791–0.872). Our findings were further validated in a validation cohort of 202 patients with AIS attributable to LAA (AUC:0.836, 95%CI:0.781–0.891). In summary, a high N/L is associated with an increased risk for HT after LAA.

Atrial Fibrillation Known Before or Detected After Stroke Share Similar Risk of Ischemic Stroke Recurrence and Death

Background and Purpose- We aim to compare the risk of 1-year ischemic stroke recurrence and death for atrial fibrillation diagnosed after stroke (AFDAS), atrial fibrillation known before stroke (KAF), and sinus rhythm (SR). Methods- From June 2012 to January 2013, 19 604 patients with acute ischemic stroke were admitted to 219 urban hospitals in the China National Stroke Registry II. Based on heart rhythm assessed during admission, we classified patients as AFDAS, KAF, or SR. We explored the relationship between heart rhythm groups and 1-year ischemic stroke recurrence or death by using Cox regression adjusted for multiple covariates. Considering that death is a competing risk for stroke recurrence, we used the competing risks analysis of Fine and Gray and subdistribution Cox proportional hazards to test the association between heart rhythm and 1-year outcomes. Results- Among 19 604 ischemic stroke patients, 17 727 had SR, 495 AFDAS, and 1382 KAF. At 1 year, 54 (10.9%) patients with AFDAS, 182 (13.2%) with KAF, and 1008 (5.7%) with SR had recurrent ischemic strokes ( P<0.0001). Mortality was 22.0% in patients with AFDAS, 22.1% in patients with KAF, and 7.0% in patients with SR ( P<0.0001). AFDAS-related ischemic stroke recurrence adjusted risk was higher than that of SR (adjusted subdistribution hazard ratios, 1.61; 95% CI, 1.29-2.01) but not different from that of KAF (adjusted subdistribution hazard ratio, 1.12; 95% CI, 0.87-1.45]). The adjusted risk of 1-year death for AFDAS was also higher than that of SR (hazard ratio, 1.70; 95% CI, 1.37-2.12) and not different from that of KAF (hazard ratio, 1.10; 95% CI, 0.86-1.41). Conclusions- This study showed that AFDAS had similar risk of 1-year ischemic stroke recurrence and mortality when compared with KAF and higher risk when compared with SR. The potential risk of AFDAS should be given more emphasis, and appropriate treatment is needed to achieve reduction in the incidence of stroke recurrence and mortality.

The complexity of atrial fibrillation newly diagnosed after ischemic stroke and transient ischemic attack: advances and uncertainties

Purpose of review

Atrial fibrillation is being increasingly diagnosed after ischemic stroke and transient ischemic attack (TIA). Patient characteristics, frequency and duration of paroxysms, and the risk of recurrent ischemic stroke associated with atrial fibrillation detected after stroke and TIA (AFDAS) may differ from atrial fibrillation already known before stroke occurrence. We aim to summarize major recent advances in the field, in the context of prior evidence, and to identify areas of uncertainty to be addressed in future research.

Recent findings

Half of all atrial fibrillations in ischemic stroke and TIA patients are AFDAS, and most of them are asymptomatic. Over 50% of AFDAS paroxysms last less than 30 s. The rapid initiation of cardiac monitoring and its duration are crucial for its timely and effective detection. AFDAS comprises a heterogeneous mix of atrial fibrillation, possibly including cardiogenic and neurogenic types, and a mix of both. Over 25 single markers and at least 10 scores have been proposed as predictors of AFDAS. However, there are considerable inconsistencies across studies. The role of AFDAS burden and its associated risk of stroke recurrence have not yet been investigated.

Summary

AFDAS may differ from atrial fibrillation known before stroke in several clinical dimensions, which are important for optimal patient care strategies. Many questions remain unanswered. Neurogenic and cardiogenic AFDAS need to be characterized, as it may be possible to avoid some neurogenic cases by initiating timely preventive treatments. AFDAS burden may differ in ischemic stroke and TIA patients, with distinctive diagnostic and treatment implications. The prognosis of AFDAS and its risk of recurrent stroke are still unknown; therefore, it is uncertain whether AFDAS patients should be treated with oral anticoagulants.

Neutrophil extracellular traps are increased in patients with acute ischemic stroke: prognostic significance

Neutrophil extracellular traps (NETs) are networks of DNA, histones, and proteolytic enzymes produced by activated neutrophils through different mechanisms. NET formation is promoted by activated platelets and can in turn activate platelets, thus favoring thrombotic processes. NETs have been detected in venous and arterial thrombosis, but data in stroke are scarce. The aim of this study was to evaluate NETs in the plasma of patients with acute ischemic stroke and their potential association with baseline clinical characteristics, stroke severity, and one-year clinical outcomes. The study included 243 patients with acute ischemic stroke. Clinical and demographic data and scores of stroke severity (NIHSS and mRs) at onset and discharge were recorded. Markers of NETs (cell-free DNA, nucleosomes, and citrullinated histone 3 (citH3)), were determined in plasma. Patients were followed-up for 12 months after the ischemic event. NETs were significantly elevated in the plasma of patients with acute ischemic stroke when compared to healthy subjects. NETs were increased in patients who were over 65 years of age and in those with a history of atrial fibrillation (AF), cardioembolic stroke, high glucose levels, and severe stroke scores at admission and discharge. In multivariate analysis, elevated levels of citH3, the most specific marker of NETs, at onset were independently associated with AF and all-cause mortality at oneyear follow-up. NETs play a role in the pathophysiology of stroke and are associated with severity and mortality. In conclusion, citH3 may constitute a useful prognostic marker and therapeutic target in patients with acute stroke.

Dynamic change of neutrophil to lymphocyte ratio and hemorrhagic transformation after thrombolysis in stroke

Background

The neutrophil to lymphocyte ratio (NLR) has been shown to predict short- and long-term outcomes in ischemic stroke patients. We sought to explore the temporal profile of the plasma NLR in stroke patients treated with intravenous thrombolysis (IVT) and its relationship with intracranial bleeding complications after thrombolysis.

Methods

A total of 189 ischemic stroke patients were prospectively enrolled. Blood samples for leukocyte, neutrophil, and lymphocyte counts were obtained at admission and at 3–6, 12–18, and 36–48 h after IVT. Head CT was performed on admission and repeated after 36–48 h, and a CT scan was done immediately in case of clinical worsening. Hemorrhagic events were categorized as symptomatic intracranial hemorrhage (sICH) and parenchymal hematomas (PH) according to previously published criteria.

Results

An increasing trend in the NLR was observed after stroke, and the NLR was higher in patients who developed PH or sICH at 3–6, 12–18, and 36–48 h after IVT (P < 0.01) than in those without PH or sICH. The optimal cutoff value for the serum NLR as an indicator for auxiliary diagnosis of PH and sICH was 10.59 at 12–18 h. Furthermore, the NLR obtained at 12–18-h post-treatment was independently associated with PH (adjusted odds ratio [OR] 1.14) and sICH (adjusted OR 1.14). In addition, patients with a NLR ≥10.59 had an 8.50-fold greater risk for PH (95 % confidence interval [CI] 2.69–26.89) and a 7.93-fold greater risk for sICH (95 % CI 2.25–27.99) than patients with a NLR <10.59.

Conclusions

NLR is a dynamic variable, and its variation is associated with HT after thrombolysis in stroke patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0680-x) contains supplementary material, which is available to authorized users.