Apixaban versus Aspirin for Embolic Stroke of Undetermined Source

Apixaban versus Aspirin for Embolic StrokeIn a trial of 352 patients with embolic stroke of undetermined source, 5 mg of apixaban administered twice daily was compared with 100 mg of aspirin administered once daily for the prevention of recurrent ischemic strokes. At 12 months, 13.6% of patients given apixaban had new ischemic lesions on magnetic resonance imaging compared with 16.0% of patients given aspirin, and the rates of clinically relevant bleeding were also comparable.

Resumption of Antiplatelet Therapy after Major Bleeding

Major bleeding is a common threat in patients requiring antiplatelet therapy. Timing and intensity with regard to resumption of antiplatelet therapy represent a major challenge in clinical practice. Knowledge of the patient's bleeding risk, defining transient/treatable and permanent/untreatable risk factors for bleeding, and weighing these against thrombotic risk are key to successful prevention of major adverse events. Shared decision-making involving various disciplines is essential to determine the optimal strategy. The present article addresses clinically relevant questions focusing on the most life-threatening or frequently occurring bleeding events, such as intracranial hemorrhage and gastrointestinal bleeding, and discusses the evidence for antiplatelet therapy resumption using individual risk assessment in high-risk cardiovascular disease patients.

[Acquired immune thrombocytopenia: An update on aspects of diagnosis and management relevant for intensive care medicine]

Acquired thrombocytopenias represent a group of bleeding diseases, which can be mediated by immune or non-immune factors. Acquired immune thrombocytopenia (AITP) leads to an accelerated decrease in platelet count by platelet reactive antibodies arising from several mechanisms. In AITP, autoantibodies, alloantibodies or drug-dependent antibodies are usually targeting platelet surface glycoproteins. The consequence of this is a significant decrease in the number of circulating platelets, leading to clinic pathological disorders including immune thrombocytopenia, heparin-induced thrombocytopenia or drug-induced thrombocytopenia, respectively. The aforementioned disorders are characterized by a severe reduction in platelet count (< 20 × 10⁹/l), which is, with the exception of HIT, associated with high bleeding risk. In this review we provide current insight into recent achievements regarding diagnosis and management of AITP.

Autoimmune Heparin-Induced Thrombocytopenia after Transcatheter Aortic Valve Implantation: Successful Treatment with Adjunct High-Dose Intravenous Immunoglobulin

We describe a rare case of autoimmune heparin-induced thrombocytopenia after transcatheter aortic valve implantation in which antibodies against platelet factor 4/heparin have led to platelet activation even after heparin cessation, causing a delayed drop in platelet count to below 20 × 10 ⁹ /L. Most interestingly, platelet count rapidly improved after intravenous immunoglobulin treatment and no new thromboembolic complications were observed with further anticoagulation with rivaroxaban.

Dysregulated IER3 Expression is Associated with Enhanced Apoptosis in Titin-Based Dilated Cardiomyopathy

Apoptosis (type I programmed cell death) of cardiomyocytes is a major process that plays a role in the progression of heart failure. The early response gene IER3 regulates apoptosis in a wide variety of cells and organs. However, its role in heart failure is largely unknown. Here, we investigate the role of IER3 in an inducible heart failure mouse model. Heart failure was induced in a mouse model that imitates a human titin truncation mutation we found in a patient with dilated cardiomyopathy (DCM). Transferase dUTP nick end labeling (TUNEL) and ssDNA stainings showed induction of apoptosis in titin-deficient cardiomyocytes during heart failure development, while IER3 response was dysregulated. Chromatin immunoprecipitation and knock-down experiments revealed that IER3 proteins target the promotors of anti-apoptotic genes and act as an anti-apoptotic factor in cardiomyocytes. Its expression is blunted during heart failure development in a titin-deficient mouse model. Targeting the IER3 pathway to reduce cardiac apoptosis might be an effective therapeutic strategy to combat heart failure.

Biophysical properties of mutant KCNQ1 S277L channels linked to hereditary long QT syndrome with phenotypic variability

Hereditary long QT syndrome (LQTS) is associated with ventricular torsade de pointes tachyarrhythmias and sudden cardiac death. Mutations in a cardiac voltage-gated potassium channel, KCNQ1, induce the most frequent variant of LQTS. We identified a KCNQ1 missense mutation, KCNQ1 S277L, in a patient presenting with recurrent syncope triggered by emotional stress (QTc=528ms). This mutation is located in the conserved S5 transmembrane region of the KCNQ1 channel. Using in vitro electrophysiological testing in the Xenopus oocyte expression system, the S277L mutation was found to be non-functional and to suppress wild type currents in dominant-negative fashion in the presence and in the absence of the regulatory ß-subunit, KCNE1. In addition, expression of S277L and wild type KCNQ1 with KCNE1 resulted in a shift of the voltage-dependence of activation by -8.7mV compared to wild type I(Ks), indicating co-assembly of mutant and wild type subunits. The electrophysiological phenotype corresponds well with the severe clinical phenotype of the index patient. However, investigation of family members revealed three patients that exhibit asymptomatic QT interval prolongation (QTc=493-518ms). In conclusion, this study emphasizes the value of biophysical testing to provide mechanistic evidence for pathogenicity of ion channel mutations identified in LQTS patients. The inconsistent association of the KCNQ1 S277L mutation with the clinical presentation suggests that additional genetic, epigenetic, or environmental factors play a role in defining the individual clinical LQTS phenotype.