Patients with myeloproliferative neoplasms and COVID-19 have increased rates of arterial thrombosis

Background

Both coronavirus disease‐2019 (COVID‐19) and myeloproliferative neoplasms (MPNs) are associated with systemic inflammation and risk of thrombosis. Risk of thrombosis in patients with COVID with and without MPNs has not been extensively studied.

Methods

Retrospective cohort study of 44 patients with MPNs and 1114 patients without MPNs positive for SARS‐COV‐2. Outcomes were arterial thrombosis (AT), venous thromboembolism (VTE), bleeding, and death. Time‐to‐event analysis was performed using competing risk regression model and Cox proportional hazards.

Results

AT occurred more frequently in patients with MPN (7% vs. 1%, p = 0.03). Rates of VTE (7% vs. 5%, p = 0.73), bleeding (7% vs. 2%, p = 0.06), and death (9% vs. 6%, p = 0.32) were similar. MPN patients were older and had more cardiovascular comorbidities. After time‐to‐event competing‐risk regression adjusting for age, MPN patients had higher risk of AT (subdivision hazards ratio 3.95, 95% CI 1.09–14.39) but not VTE, bleeding, or death.

Conclusions

Among patients with COVID‐19, MPN patients had higher risk of arterial thrombosis but not VTE, bleeding, and death compared with non‐MPN patients. Larger studies are needed to confirm our findings given the limited sample size.

Association of Thrombosis With Hypereosinophilic Syndrome in Patients With Genetic Alterations

IMPORTANCE

Hypereosinophilic syndromes (HESs) are a rare group of disorders that result in overproduction of eosinophils, leading to tissue damage. Thrombotic complications in HES and associated risk factors in this patient population have not been extensively studied.

OBJECTIVE

To investigate the rates of and risk factors associated with thrombotic events in patients with HES, including markers of clonal hematopoiesis as evidenced by molecular aberrations on next-generation sequencing.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study evaluated patients seen at Brigham and Women's Hospital and Harvard Medical School in Boston, Massachusetts, from January 1, 2015, to January 1, 2020. Patients who had hypereosinophilia with an absolute eosinophil count of 1500 cells/μL or greater on 2 separate occasions at least 1 month apart and who underwent genetic or molecular testing as part of their work-up were included. Patients with secondary eosinophilia were excluded.

MAIN OUTCOMES AND MEASURES

Symptomatic and asymptomatic arterial and venous thrombotic events after the diagnosis of HES and all-cause death.

RESULTS

A total of 71 patients (median age, 58 years [interquartile range (IQR), 43-67 years]; 36 women [51%]; 57 White patients [80%]) were included. Patients had a median follow-up time of 29 months (IQR, 19-49 months). Seventeen patients (24%) had 1 or more thrombotic events, including 11 venous thromboembolic events and 11 arterial thrombotic events (8 patients had ≥1 event and 3 patients had recurrent events). Patients with 1 or more thrombotic events had a higher median Eastern Cooperative Oncology Group performance status (median, 1 [IQR, 1-2] vs 0 [IQR, 0-1]; P = .002), had more frequent cardiac involvement (7 of 17 events [41%] vs 6 of 54 events [11%]; P = .01), more frequently received treatment (17 of 17 events [100%] vs 40 of 54 events [74%]; P = .02), and had more molecular aberrations on next-generation sequencing (12 of 17 [71%] vs 12 of 54 [26%]; P = .003) vs patients without thrombosis. After multivariable analysis, the presence of molecular aberration was associated with increased odds of thrombosis (adjusted odds ratio, 5.4; 95% CI, 1.1-27.7). Death occurred more frequently in patients with thrombotic events compared with those without (6 of 17 [35%] vs 2 of 54 [4%]; P = .002) and in patients with molecular aberrations compared with those without (6 of 24 [25%] vs 1 of 40 [3%]; P = .009), although only thrombotic events were significantly associated with increased odds of death after multivariable analysis.

CONCLUSIONS AND RELEVANCE

In this cohort study, thrombosis was common in patients with HES and was significantly associated with increased risk of death.

Differentiation of Patients with Symptomatic Low von Willebrand Factor from Those with Asymptomatic Low von Willebrand Factor

BACKGROUND

 Accurate diagnosis of symptomatic low von Willebrand factor (VWF) remains a major challenge in von Willebrand disease (VWD). However, present tests do not adequately take into account flow forces that, at very high shear rates, reveal a weakness in the VWF-platelet glycoprotein glycoprotein Ib bond in normal subjects. The degree of this weakness is greater in symptomatic, but not asymptomatic, low VWF.

OBJECTIVE

 The aim of this study is to distinguish patients with symptomatic low VWF (levels in the 30-50 IU/dL range) from those with asymptomatic low VWF and normal subjects.

METHODS

 We measured platelet adhesion (PA)/aggregation in our novel microfluidic flow system that permits real-time assessment of PA (surface coverage) and PA/aggregation (V, aggregate volume) using epifluorescence digital videomicroscopy in flowing noncitrated whole blood at 4,000 second^-1. Blood samples from 24 low VWF patients and 15 normal subjects were collected into plastic tubes containing 4 U/mL enoxaparin. MetaMorph software was used to quantify rates of PA and V increase.

RESULTS

 Rates of PA increase showed a bimodal distribution, with values for 16/24 patients (Group I) all below the 2.5th percentile of normal, and values for 8/24 patients (Group II) similar to controls. Bleeding scores (mean ± standard error) were 5.50 ± 0.45 versus 2.75 ± 0.45 (p = 0.00077), and 10 clinically significant bleeding events were observed in seven versus zero (p = 0.0295) Group I and Group II subjects, respectively.

CONCLUSION

 The present approach may offer a definitive means to distinguish symptomatic low VWF from either asymptomatic low VWF or normal controls.

Identification and characterization of novel mutations implicated in congenital fibrinogen disorders

INTRODUCTION

Fibrinogen is a complex molecule comprised of two sets of Aα, Bβ, and γ chains. Fibrinogen deficiencies can lead to the development of bleeding or thromboembolic events. The objective of this study was to perform DNA sequence analysis of patients with clinical fibrinogen abnormalities, and to perform genotype-phenotype correlations.

MATERIALS AND METHODS

DNA from 31 patients was sequenced to evaluate disease-causing mutations in the three fibrinogen genes: FGA,FGB, and FGG. Clinical data were extracted from medical records or from consultation with referring hematologists. Fibrinogen antigen and functional (Clauss method) assays, as well as reptilase time (RT) and thrombin time (TT) were obtained for each patient. Molecular modeling was used to simulate the functional impact of specific missense variants on the overall protein structure.

RESULTS

Seventeen mutations, including six novel mutations, were identified in the three fibrinogen genes. There was little correlation between genotype and phenotype. Molecular modeling predicted a substantial conformational change for a novel variant, FGG p.Ala289Asp, leading to a more rigid molecule in a region critical for polymerization and alignment of the fibrin monomers. This mutation is associated with both bleeding and clotting in the two affected individuals.

CONCLUSIONS

Robust genotype-phenotype correlations are difficult to establish for fibrinogen disorders. Molecular modeling might represent a valuable tool for understanding the function of certain missense fibrinogen mutations but those should be followed by functional studies. It is likely that genetic and environmental modifiers account for the incomplete penetrance and variable expressivity that characterize fibrinogen disorders.

Effects of red-cell storage duration on patients undergoing cardiac surgery

BACKGROUND

Some observational studies have reported that transfusion of red-cell units that have been stored for more than 2 to 3 weeks is associated with serious, even fatal, adverse events. Patients undergoing cardiac surgery may be especially vulnerable to the adverse effects of transfusion.

METHODS

We conducted a randomized trial at multiple sites from 2010 to 2014. Participants 12 years of age or older who were undergoing complex cardiac surgery and were likely to undergo transfusion of red cells were randomly assigned to receive leukocyte-reduced red cells stored for 10 days or less (shorter-term storage group) or for 21 days or more (longer-term storage group) for all intraoperative and postoperative transfusions. The primary outcome was the change in Multiple Organ Dysfunction Score (MODS; range, 0 to 24, with higher scores indicating more severe organ dysfunction) from the preoperative score to the highest composite score through day 7 or the time of death or discharge.

RESULTS

The median storage time of red-cell units provided to the 1098 participants who received red-cell transfusion was 7 days in the shorter-term storage group and 28 days in the longer-term storage group. The mean change in MODS was an increase of 8.5 and 8.7 points, respectively (95% confidence interval for the difference, -0.6 to 0.3; P=0.44). The 7-day mortality was 2.8% in the shorter-term storage group and 2.0% in the longer-term storage group (P=0.43); 28-day mortality was 4.4% and 5.3%, respectively (P=0.57). Adverse events did not differ significantly between groups except that hyperbilirubinemia was more common in the longer-term storage group.

CONCLUSIONS

The duration of red-cell storage was not associated with significant differences in the change in MODS. We did not find that the transfusion of red cells stored for 10 days or less was superior to the transfusion of red cells stored for 21 days or more among patients 12 years of age or older who were undergoing complex cardiac surgery. (Funded by the National Heart, Lung, and Blood Institute; RECESS ClinicalTrials.gov number, NCT00991341.).

Fibrinogen replacement therapy for congenital fibrinogen deficiency

This review of published studies was conducted to derive data on patients with congenital fibrinogen deficiency (CFD), including dosing of fibrinogen replacement therapy, outcome, and adverse events, either temporally related or distant to fibrinogen replacement, in order to assist clinicians in developing treatment plans for patients with CFD. A systematic review was performed of case reports identified by a MEDLINE search between 1961 and 2010. Eligible studies included subjects with a diagnosis of CFD who received fibrinogen replacement. An attempt was made to extract dose, frequency, duration, hemostatic efficacy and adverse events such as thrombosis or allergic reactions. Reported thrombotic events distant from fibrinogen replacement were also recorded. From 104 papers reviewed, a total of 50 cases were identified: afibrinogenemia (35), hypofibrinogenemia (6), and dysfibrinogenemia (9). Fibrinogen replacement therapy was generally effective in preventing or treating bleeding in doses adequate to achieve and maintain fibrinogen activity above 50-100 mg dL(-1) (non-surgical and obstetric use) or 100-200 mg dL(-1) (surgical prophylaxis). Increased fibrinogen clearance was observed with massive hemorrhage, major surgery, and advanced pregnancy. Obstetric outcomes were optimized when fibrinogen replacement was initiated prior to conception. Uncontrolled hemorrhage, allergic reactions and antibody formation were rare events. However, thromboses, both related and unrelated to fibrinogen replacement, occurred in 15 of 50 (30%) patients overall, and in eight of 12 (67%) adult non-obstetric patients with afibrinogenemia. Published fibrinogen replacement regimens are presented for 50 CFD patients. Fibrinogen replacement therapy requires careful monitoring of fibrinogen levels. Afibrinogenemia is associated with thromboembolic complications with or without treatment.

A confirmed case of agranulocytosis after use of cocaine contaminated with levamisole

More than 2 million Americans use cocaine each month (National Survey on Drug Use and Health, Department of Health and Human Services: Substance Abuse and Mental Health Services Administration (SAMHSA) & Office of Applied Studies (OAS), Rockville, MD 2007). Starting in early 2003, South American cocaine cartels began to add levamisole, a pharmaceutical agent, to bulk cocaine prior to shipment to the USA (Valentino and Fuentecilla 2005). A dramatic increase in the prevalence of levamisole in cocaine was noted in early 2008. By October, 30% of cocaine bricks analyzed by the United States Drug Enforcement Administration contained levamisole (Casale et al. 2008). Exposure to levamisole can cause agranulocytosis (Amery and Bruynseels 1992). We report the first confirmed case of agranulocytosis associated with consumption of levamisole-contaminated cocaine in the USA. A previously healthy adult male presented to the emergency department with 5 days of mouth pain. He admitted to chronic active ethanol and crack cocaine abuse. Laboratory studies revealed severe neutropenia, with an absolute neutrophil count of 19 cells/mm³ (normal = 1,500-8,000 cells/mm³). A urine screen for drugs of abuse was positive for cocaine metabolites and opiates. Evaluation of a peripheral blood smear showed leukopenia with severe absolute neutropenia. A bone marrow biopsy revealed recently injured bone marrow showing early recovery. While in the hospital, the patient had little spontaneous bone marrow recovery. He received granulocyte colony-stimulating factor with improvement in peripheral white blood cell counts. The residue in the patient's crack pipe contained 10% levamisole. Subsequently, levamisole was detected in the patient's urine. Levamisole-associated agranulocytosis should be considered in the diagnosis of patients who present with neutropenia and a history or evidence of cocaine use.

A Disease Management Protocol for Outpatient Perioperative Bridge Therapy with Enoxaparin in Patients Requiring Temporary Interruption of Long-Term Oral Anticoagulation

STUDY OBJECTIVE

Traditional perioperative bridge therapy for patients receiving long-term oral anticoagulation involves weight-adjusted intravenous unfractionated heparin (UFH) in the perioperative period during temporary discontinuation of the oral anticoagulant. We sought to determine whether an alternate strategy of outpatient-based perioperative disease management with low-molecular-weight heparin (LMWH) as bridge therapy provides the potential for cost savings.

DESIGN

Retrospective review of all clinic notes from an anticoagulation clinic.

SETTING

An integrated, staff-model health maintenance organization.

PATIENTS

Patients receiving long-term warfarin therapy from January 1998-March 2002 who received perioperative bridge therapy with the LMWH enoxaparin 1 mg/kg twice/day subcutaneously

MEASUREMENTS AND MAIN RESULTS

A total of 126 bridge therapy encounters in 84 patients receiving LMWH as perioperative bridge therapy were identified, with 48 of those encounters involving patients with at least one mechanical heart valve. A total of 1108 hospital bed days were saved. Based on 1996 cost estimates, the total approximate cost savings for the 4.25 years of the outpatient bridge therapy program was dollars 903,020. No thrombotic events were reported. Three major hemorrhagic events that required discontinuation of LMWH were reported.

CONCLUSION

Outpatient-based disease management protocols and the LMWH enoxaparin as bridge therapy during temporary discontinuation of warfarin for an elective surgical procedure resulted in cost savings of approximately dollars 212,475/year in an integrated health maintenance organization. In addition, this strategy appears both safe and effective.

Right atrial tunnel to the left atrial appendage: a danger during balloon septostomy

Right atrial tunnel to the left atrial appendage is a very rare anomaly not previously described. Per se, it has no physiological significance but is a source of potential disaster during balloon atrial septostomy. The precise anatomy is demonstrated and ways are proposed to avoid tearing the atrial wall during therapeutic cardiac catheterization.

The nuclear poly(A) binding protein, PABP2, forms an oligomeric particle covering the length of the poly(A) tail

The mammalian nuclear poly(A) binding protein, PABP2, controls the length of the newly synthesized poly(A) tail on messenger RNAs. To gain a better understanding of the mechanism of length control, we have investigated the structure of the PABP2.poly(A) complex. Electron microscopy and scanning force microscopy studies reveal that PABP2, when bound to poly(A), forms both linear filaments and discrete-sized, compact, oligomeric particles. The maximum diameter of the filament is 7 nm; the maximum diameter of the particle is 21(+/-2) nm. Maximum particle size is realized when the PABP2. poly(A) complex is formed with poly(A) molecules 200-300 nt long, which corresponds to the average length of the newly synthesized poly(A) tail in vitro and in vivo. The equilibrium between filaments and particles is highly sensitive to ionic strength; filaments are favored at low ionic strength, while particles predominate at moderate to high ionic strength. Nitrocellulose filter binding and gel mobility shift assays indicate that the PABP2.poly(A) particle formed on A(300) is not significantly more stable than complexes formed with smaller species of poly(A). These results are discussed in the context of the proposed functions for PABP2.