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Background and purpose: Hierarchical clustering, a common 'unsupervised' machine‐learning algorithm, is advantageous for exploring potential underlying aetiology in particularly heterogeneous diseases. We investigated potential embolic sources in embolic stroke of undetermined source (ESUS) using a data‐driven machine‐learning method, and explored variation in stroke recurrence between clusters. Methods: We used a hierarchical k‐means clustering algorithm on patients' baseline data, which assigned each individual into a unique clustering group, using a minimum‐variance method to calculate the similarity between ESUS patients based on all baseline features. Potential embolic sources were categorised into atrial cardiopathy, atrial fibrillation, arterial disease, left ventricular disease, cardiac valvulopathy, patent foramen ovale (PFO) and cancer. Results: Among 800 consecutive ESUS patients (43.3% women, median age 67 years), the optimal number of clusters was four. Left ventricular disease was most prevalent in cluster 1 (present in all patients) and perfectly associated with cluster 1. PFO was most prevalent in cluster 2 (38.9% of patients) and associated significantly with increased likelihood of cluster 2 [adjusted odds ratio: 2.69, 95% confidence interval (CI): 1.64–4.41]. Arterial disease was most prevalent in cluster 3 (57.7%) and associated with increased likelihood of cluster 3 (adjusted odds ratio: 2.21, 95% CI: 1.43–3.13). Atrial cardiopathy was most prevalent in cluster 4 (100%) and perfectly associated with cluster 4. Cluster 3 was the largest cluster involving 53.7% of patients. Atrial fibrillation was not significantly associated with any cluster. Conclusions: This data‐driven machine‐learning analysis identified four clusters of ESUS that were strongly associated with arterial disease, atrial cardiopathy, PFO and left ventricular disease, respectively. More than half of the patients were assigned to the cluster associated with arterial disease. [ABSTRACT FROM AUTHOR]

Background and purpose: The safety of early initiation of anticoagulant therapy in patients with ischaemic stroke related to atrial fibrillation (AF) is unknown. We investigated the safety of early initiation of direct oral anticoagulants (DOACs), vitamin K antagonists (VKAs) or no anticoagulation. Methods: This observational, retrospective, single‐centre study included consecutive patients with recent (<4 weeks) ischaemic stroke and AF. The primary outcome was the rate of major (intracranial and extracranial) bleeding in patients on different treatment schemes, i.e. DOACs, VKAs and not anticoagulated. We also investigated the rate of ischaemic cerebrovascular events and mortality. Results: We included 959 consecutive patients with AF and ischaemic stroke followed up for an average of 16.1 days after the index event. A total of 559 out of 959 patients (58.3%) were anticoagulated with either VKAs (n = 259) or DOACs (n = 300). Anticoagulation was started after a mean of 7 ± 9.4 days in the DOAC group and 11.9 ± 19.7 days in the VKA group. Early initiation of any anticoagulant was not associated with an increased risk of any major bleeding [odds ratio (OR), 0.49; 95% confidence intervals (CI), 0.21–1.16] and in particular of intracranial bleeding (OR, 0.47; 95% CI, 0.17–1.29; P = 0.143) compared with no anticoagulation. In contrast to VKAs (OR, 0.78; 95% CI, 0.28–2.13), treatment with DOACs (OR, 0.32; 95% CI, 0.10–0.96) reduced the rate of major bleeding compared with no anticoagulation. Early recurrences of ischaemic stroke did not differ significantly among the three groups. Conclusions: Starting DOACs within a mean of 7 days after stroke appeared to be safe. Randomized controlled studies are needed to establish the added efficacy of starting anticoagulation early after stroke. [ABSTRACT FROM AUTHOR]

There is limited evidence on the outcomes and safety of mechanical thrombectomy (MT) among patients with acute ischemic stroke (AIS) in the context of cardiac diseases. Our study reviews MT in AIS within the context of cardiac diseases, aiming to identify existing and emerging needs and gaps. PubMed and Scopus were searched until December 31, 2023, using a combination of cardiological diseases and "mechanical thrombectomy" or "endovascular treatment" as keywords. Study design included case reports/series, observational studies, randomized clinical trials, and meta-analyses/systematic reviews. We identified 943 articles, of which 130 were included in the review. Results were categorized according to the cardiac conditions. MT shows significant benefits in patients with atrial fibrillation (n=139) but lacks data for stroke occurring after percutaneous coronary intervention (n=2) or transcatheter aortic valve implantation (n=5). MT is beneficial in AIS attributable to infective endocarditis (n=34), although functional benefit may be limited. Controversy surrounds the functional outcomes and mortality of patients with AIS with heart failure undergoing MT (n=11). Despite technical challenges, MT appears feasible in aortic dissection cases (n=4), and in patients with left ventricular assist device or total artificial heart (n=10). Data on AIS attributable to congenital heart disease (n=4) primarily focus on pediatric cases requiring technical modifications. Treatment outcomes of MT in patients with cardiac tumors (n=8) vary because of clot consistency differences. After cardiac surgery stroke, MT may improve outcomes with early intervention (n=13). Available data outline the feasibility of MT in patients with AIS attributable to large-vessel occlusion in the context of cardiac diseases.

Background: Ischemic strokes in orally anticoagulated patients pose challenges for acute management and secondary prevention but the characteristics of these strokes are poorly understood. We examined the clinical and imaging features, the presumed underlying etiology and the subsequent antithrombotic management., Methods: We analyzed a consecutive series of patients enrolled into the EIDASAF study, a single center, observational study of ischemic stroke patients with a diagnosis atrial fibrillation (AF) prior to the index event who had been admitted to the Hyperacute Stroke Unit of Imperial College London between 2010 and 2017. We compared patients with oral anticoagulation therapy prior admission (OAC prior ) with those without anticoagulation (OAC naive ). Brain imaging was analyzed centrally., Results: 763 patients were included in the analysis. 481 (63%) were OAC naive while 282 (37%) were OAC prior . Patients with OAC prior were younger, more often had a previous history of stroke or transient ischemic attack (TIA), and more often suffered from hypertension and diabetes. In OAC naive, patients, large and deep middle cerebral artery infarcts occurred more often than in OAC prior patients. The groups differed significantly in the distribution of competing etiologies underlying their stroke. At discharge, OAC prior more frequently were (re)-anticoagulated compared to OAC naive patients. Within the OAC prior group, patients with recurrent strokes did not differ from those with a first stroke regarding clinical characteristics and pattern of cerebral infarction but they were less frequently anticoagulated., Conclusions: Ischemic strokes on OAC represent a significant proportion of AF-related strokes. There is an unmet need to better understand the causes underlying these strokes and to optimize the medical management., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Coronavirus disease 19 (COVID-19) is considered a multisystemic disease. Several studies have reported persistent symptoms or late-onset complications after acute COVID-19, including post-COVID-19 hematological disorders. COVID-19-induced coagulopathy, an immunothrombotic state, has been linked to thromboembolic and hemorrhagic events. Late-onset thrombocytopenia related to immune system dysregulation has also been reported as a rare manifestation post COVID-19. Close monitoring of laboratory dynamics is considered essential to identify timely abnormal values that need further investigation, providing supportive care whenever indicated. The role of hematologists is essential in terms of the multidisciplinary approach of long COVID-19. This review summarizes all the available evidence on post-acute COVID-19 hematological complications., (© 2021 Wiley Periodicals LLC.)

Background Available evidence supports an association between atrial high-rate episode (AHRE) burden and thromboembolic risk, but the necessary extent and duration of AHREs to increase the thromboembolic risk remain to be defined. The aim of this systematic review and meta-analysis was to identify the thromboembolic risk associated with various AHRE thresholds. Methods and Results We searched PubMed and Scopus until January 9, 2020, for literature reporting AHRE duration and thromboembolic risk in patients with implantable electronic devices. The outcome assessed was stroke or systemic embolism. Risk estimates were reported as hazard ratio (HR) or relative risk alongside 95% CIs. We used the Paule-Mandel estimator, and heterogeneity was calculated with I 2 index. Among 27 studies including 61 919 patients, 23 studies reported rates according to the duration of the longest AHRE and 4 studies reported rates according to the cumulative day-level AHRE duration. In patients with cardiac implantable devices, AHREs lasting ≥30 seconds significantly increased the risk of stroke or systemic embolism (HR, 4.41; 95% CI, 2.32-8.39; I 2 , 5.5%), which remained consistent for the thresholds of 5 minutes and 6 and 24 hours. Patients with previous stroke or transient ischemic attack and AHREs lasting ≥2 minutes had a marginally increased risk of recurrent stroke or transient ischemic attack. The risk of stroke or systemic embolism was higher in patients with cumulative AHRE ≥24 hours compared with those of shorter duration or no AHRE (HR, 1.25; 95% CI, 1.04-1.52; I 2 , 0%). Conclusions This systematic review and meta-analysis suggests that single AHRE episodes ≥30 seconds and cumulative AHRE duration ≥24 hours are associated with increased risk of stroke or systemic embolism.