Hematologic manifestations of SARS-CoV-2 infection and MIS-C in hospitalized children. Results of the PICNIC registry.

Introduction: Hematologic complications of SARS-CoV-2 infection are well described in hospitalized adults with correlation to adverse outcomes. Information published in children has been limited. Methods: An international multi-centered retrospective registry was established to collect data on the clinical manifestations of SARS-CoV-2 or multisystem inflammatory syndrome (MIS-C) in hospitalized children between February 1, 2020 – May 31, 2021. This sub-study focused on hematologic manifestations. Study variables included patient demographics, comorbidities, clinical presentation, course, laboratory parameters, management, and outcomes. Results: Nine hundred and eighty-five children were enrolled and 915 (93%) had clinical information available; 385 (42%) had symptomatic SARS-CoV-2 infection upon admission, 288 had MIS-C (31.4%) and 242 (26.4%) had alternate diagnosis with SARS-CoV-2 identified incidentally. During hospitalization, 10 children (1%) experienced a thrombotic event, 16 (1.7%) had hemorrhage and 2 (0.2%) had both thrombotic and hemorrhagic episodes. Significant prothrombotic comorbidities included congenital heart disease (p-value = 0.007), central venous catheter (p = 0.04) in children with primary SARS-CoV-2 infection; and obesity (p-value= 0.002), cytokine storm (p= 0.012) in those with MIS-C. Significant pro- hemorrhagic conditions included age > 10 years (p = 0.04), CVC (p= 0.03) in children with primary SARS-CoV-2infection; and thrombocytopenia (0.001), cytokine storm (0.02) in those with MIS-C. Eleven patients died (1.2 %) with no deaths attributed to thrombosis or hemorrhage Conclusion: Thrombotic and hemorrhagic complications are uncommon in children with SARS-CoV-2 infection and observed with underlying co-morbid conditions. Understanding the complete spectrum of hematologic complications in children with SARS-CoV-2 infection or MIS-C requires ongoing multi-center studies.

Splenic Infarction in a COVID-19 Patient without Respiratory Symptoms

High rates of thromboembolic events have been seen in cases of COVID-19. Here, we report a case of 23-year-old previously healthy female presented with left-sided abdominal pain associated with vomiting. The computed tomography scan showed multiple ill-defined wedge-shaped low attenuating areas of the spleen, suggesting splenic infarction. In the absence of other thromboembolic contributing factors, we believe this was a thromboembolic event in splenic circulation in relation to COVID-19 infection. Our case adds to the evidence of an arterial thrombotic event in a noncritical COVID-19 patient, emphasizing the importance of addressing thromboembolism diagnosis and management measures to avoid potentially deadly consequences.

Andexanet Alfa for Specific Anticoagulation Reversal in Patients with Acute Bleeding during Treatment with Edoxaban

Background Andexanet alfa (andexanet) is approved for specific anticoagulation reversal in patients with life-threatening or uncontrolled bleeding during treatment with rivaroxaban or apixaban. There is limited experience with andexanet in patients with acute bleeding on edoxaban. Methods Patients with acute major bleeding within 18 hours of edoxaban intake were prospectively enrolled. Patients received a bolus and 2-hour follow-on infusion of andexanet. The co-primary efficacy outcomes were change in antifactor Xa activity and the percentage of patients achieving excellent or good hemostasis, 12 hours after andexanet treatment. Efficacy was analyzed in patients with confirmed major bleeding and baseline antifactor Xa activity ≥40 ng/mL. Safety was analyzed in all patients. Results Thirty-six patients (mean age: 82 years, 61.1% male and 91.7% with atrial fibrillation) with acute major bleeding on edoxaban received andexanet. The primary site of bleeding was intracranial in 29 patients (80.6%). In the efficacy population (n = 28), median antifactor Xa activity decreased from 121.1 (interquartile range [IQR]: 70.3–202.4) ng/mL at baseline to 24.0 (IQR: 77.7–83.7) ng/mL at the end of andexanet bolus (median decrease: 68.9%, 95% confidence interval [CI]: 56.1–77.7%). Excellent or good hemostasis at 12 hours was achieved in 78.6% (95% CI: 59.0–91.7%) of patients. Within 30 days, four patients (11.1%) experienced a thrombotic event and four others (11.1%) died. Conclusion In patients with acute major bleeding on edoxaban, andexanet significantly decreased antifactor Xa activity. Hemostatic efficacy was similar to that observed in patients with bleeding on rivaroxaban or apixaban. Thrombotic events occurred at a rate expected in such patients.

Clopidogrel resistance is common in patients undergoing vascular and coronary interventions

Objectives “Clopidogrel resistance,” also defined as heightened platelet reactivity (HPR) while on clopidogrel therapy, may lead to a sub-optimal antiplatelet effect and a potential thrombotic event. There is limited literature addressing the prevalence of HPR in a large cohort of patients receiving either coronary or endovascular interventions. Methods In a large integrated healthcare system, patients with a P2Y12 reaction units (PRU) test were identified. HPR was defined as a PRU ≥ 200 during clopidogrel therapy. Vascular and coronary interventions were identified utilizing CPT codes, HPR prevalence was calculated, and Fischer’s exact test was used to determine significance. Results From an initial cohort of 2,405,957 patients (October 2014 to January 2020), we identified 3301 patients with PRU tests administered. Of these, 1789 tests had a PRU ≥ 200 (HPR overall prevalence, 54%). We then identified 1195 patients who underwent either an endovascular or coronary procedure and had a PRU measurement. This corresponded to 935 coronary and 260 endovascular interventions. In the coronary cohort, the HPR prevalence was 54% (503/935). In the vascular cohort, the HPR prevalence was 53% (137/260); there was no difference between cohorts in HPR prevalence ( p = 0.78). Conclusion “Clopidogrel resistance” or HPR was found to be present in nearly half of patients with cardiovascular disease undergoing intervention. Our data suggest HPR is more common in the cardiovascular patient population than previously appreciated. Evaluating patients for HPR is both inexpensive ($25) and rapid (< 10 min). Future randomized studies are warranted to determine whether HPR has a clinically detectable effect on revascularization outcomes.

Comparison of Higher-Than-Standard to D-Dimer Driven Thromboprophylaxis in Hospitalized Patients With COVID-19

Introduction: Coronavirus disease 2019 is a global health threat often accompanied with coagulopathy. Despite use of thromboprophylaxis in this population, thrombotic event rates are high. Materials and methods: This was a multicenter, retrospective cohort study comparing the safety and effectiveness of thromboprophylaxis strategies at 2 institutions in hospitalized patients with coronavirus disease 2019. Regimen A utilized a higher-than-standard thromboprophylaxis dosage and Regimen B received full-dose anticoagulation for any D-dimer 3 mcg/mL or greater and prophylactic for less than 3 mcg/mL. The primary outcome compared the rate of thrombotic events between treatment groups. Secondary endpoints compared rates of major or clinically relevant non-major bleeding as well as the proportion of patients in each group experiencing thrombotic events within 30 days of discharge. Results: One-hundred fifty-three patients were included in the analysis, 64 receiving Regimen A and 89 receiving Regimen B. Seven (4.6%) thrombotic events occurred, 3 (4.7%) in patients receiving Regimen A, and 4 (4.5%) in Regimen B ( P = 1.0). Twelve patients (13.5%) receiving Regimen B had a bleeding event versus 2 (3.1%) in Regimen A ( P = .04), half of which were major in each group. All patients who bled in either treatment group were receiving mechanical ventilation, and 12 of 14 were receiving full-dose anticoagulation. One patient receiving Regimen A was readmitted with a pulmonary embolism. Conclusions: In this study, the thromboprophylactic regimen impacted bleeding, but no significant difference was seen with thrombotic outcomes. Almost all patients who experienced a bleed were mechanically ventilated and receiving full-dose anticoagulation. The use of full-dose anticoagulation should be cautioned in this population without an additional indication.

Safety and Efficacy of Intermediate- and Therapeutic-Dose Anticoagulation for Hospitalised Patients with COVID-19: A Systematic Review and Meta-Analysis

Background: COVID-19 patients are at high thrombotic risk. The safety and efficacy of different anticoagulation regimens in COVID-19 patients remain unclear. Methods: We searched for randomised controlled trials (RCTs) comparing intermediate- or therapeutic-dose anticoagulation to standard thromboprophylaxis in hospitalised patients with COVID-19 irrespective of disease severity. To assess efficacy and safety, we meta-analysed data for all-cause mortality, clinical status, thrombotic event or death, and major bleedings. Results: Eight RCTs, including 5580 patients, were identified, with two comparing intermediate- and six therapeutic-dose anticoagulation to standard thromboprophylaxis. Intermediate-dose anticoagulation may have little or no effect on any thrombotic event or death (RR 1.03, 95% CI 0.86–1.24), but may increase major bleedings (RR 1.48, 95% CI 0.53–4.15) in moderate to severe COVID-19 patients. Therapeutic-dose anticoagulation may decrease any thrombotic event or death in patients with moderate COVID-19 (RR 0.64, 95% CI 0.38–1.07), but may have little or no effect in patients with severe disease (RR 0.98, 95% CI 0.86–1.12). The risk of major bleedings may increase independent of disease severity (RR 1.78, 95% CI 1.15–2.74). Conclusions: Certainty of evidence is still low. Moderately affected COVID-19 patients may benefit from therapeutic-dose anticoagulation, but the risk for bleeding is increased.

Stroke and Respiratory Failure: Mind the Shunt!

When stroke patients present with respiratory failure, the first thought that clinicians have is that it is probably related to aspiration pneumonia. However, other causes should be considered, such as intracardiac or intrapulmonary shunts, that could present with paradoxical embolism. Paradoxical embolism is a rare entity defined by the occurrence of a venous thrombotic event associated with a systemic arterial embolism. Frequently, paradoxical embolism presents with platypnoea-orthodeoxia syndrome. Platypnoea-orthodeoxia syndrome is uncommon and is characterized by dyspnoea and hypoxaemia induced by orthostatic position, where symptoms and oxygenation are relieved by recumbency. The authors report a case of a patient who presented with an ischaemic stroke and progression to platypnoea-orthodeoxia syndrome with documentation of simultaneous pulmonary embolism and pulmonary arteriovenous malformations.

High Risk of Venous Thrombosis Recurrence in Fully Anticoagulated Patient with Antithrombin Deficiency during COVID-19: A Case Report

Coagulation dysfunction is a serious issue in patients with Coronavirus disease-19 (COVID-19). With regard to recently published studies, a high number of patients with acute respiratory distress syndrome (ARDS) secondary to COVID-19 developed life-threatening thrombotic complications despite anticoagulation. We report a case of young woman with the type-II heparin-binding site (HBS) antithrombin (AT) deficiency (Budapest 3-homozygous), who developed acute deep vein thrombosis on two occasions due to COVID-19 infection in the course of stable anticoagulation with vitamin K antagonist. The first thrombotic event was observed during mild COVID-19 infection, while the second thrombotic event she developed 2 months after she was negative for severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2). Our case highlights the complexity of the treatment in this particular type of thrombophilia and the need for precaution even in mild forms of viral infection. In the treatment of acute thrombosis, AT-deficient patients may benefit from the use of AT concentrate along with low-molecular weight heparin (LMWH), while in cases of type II-HBS, AT supplementation is mandatory.

Near fatal stent thrombosis in an aneurysmatic RCX as first manifestation of heparin induced thrombocytopenia (HIT) without thrombocytopenia

Background Thrombosis resulting from heparin-induced thrombocytopenia (HIT) occurs in about 2% of patients without a significant decrease in platelet counts. We report on such a near fatal thrombotic event caused by coronary intervention. Case presentation A supposedly “completely healthy” 53-year-old patient was admitted to hospital with covered rupture of an aneurysm of the Aorta descendens. He was successfully operated on and underwent coronary angiography due to NSTEMI six days later. Immediately after intervention of a 90% RCX stenosis he developed ventricular flutter, was defibrillated, and re-angiography showed partial occlusion of the RCX stent. Lots of white thrombi could be retrieved by aspiration catheter and gave reason for a HIT without thrombocytopenia. The detection of platelet factor 4/heparin complex antibodies by immunoassay supported and the subsequent Heparin Induced Platelet Activation Assay proved this diagnosis. Conclusions The clinical event of an acute stent thrombosis should alarm the interventional team to the diagnosis of HIT even with a normal platelet count.

Transcriptomic-based clustering of advanced atherosclerotic plaques identifies subgroups of plaques with differential underlying biology that associate with clinical presentation

Histopathological studies have revealed key processes of atherosclerotic plaque thrombosis. However, the diversity and complexity of lesion types highlight the need for improved sub-phenotyping. We hypothesized that unbiased clustering of plaques based on gene expression results in an alternative categorization of late-stage atherosclerotic lesions. We analyzed the gene expression profiles of 654 advanced human carotid plaques. The unsupervised, transcriptome-driven clustering revealed five dominant plaque types. These novel plaque phenotypes associated with clinical presentation (p<0.001) and showed differences in cellular compositions. Validation in coronary segments showed that the molecular signature of these plaques was linked to coronary ischemia. One of the plaque types with most severe clinical symptoms pointed to both inflammatory and fibrotic cell lineages. This highlighted plaque phenotype showed high expression of genes involved in active inflammatory processes, neutrophil degranulation, matrix turnover, and metabolism. For clinical translation, we did a first promising attempt to identify circulating biomarkers that mark these newly identified plaque phenotypes. In conclusion, the definition of the plaque at risk for a thrombotic event can be fine-tuned by in-depth transcriptomic based phenotyping. These differential plaque phenotypes prove clinically relevant for both carotid and coronary artery plaques and point to differential underlying biology of symptomatic lesions.