Plasma Adsorption with the MTx.100 Column in Critically Ill COVID-19 Patients: A Prospective Study and Propensity Score Analysis.

BACKGROUND: Early in the COVID-19 pandemic, patients with severe disease admitted to the intensive care unit (ICU) had a high incidence of mortality. We aimed to investigate whether plasma adsorption with the MTx.100 Column could improve survival. METHODS: We performed a prospective, single-arm, multicenter, Emergency Use Authorization (EUA) trial in patients admitted to the ICU with severe COVID-19 who were worsening despite standard therapy. The primary outcome was all-cause mortality on day 28. Outcomes were analyzed using both a pre-specified performance goal (PG), and a propensity score-matched (PSM) analysis from the highest enrolling center, in which patients treated with the standard of care (SOC) plus the MTx.100 Column (n = 70) were compared to a contemporaneous cohort treated at the same center with SOC only (n = 244). FINDINGS: Between May 21, 2020, and November 2, 2021, 107 patients with severe COVID-19 (mean age 58.1) at 7 US centers were enrolled and had at least one plasma adsorption treatment initiated. All-cause mortality on day 28 was 37.4% (40/107), an improvement over the prespecified PG (88.1%, p < 0.0001). There were no serious adverse events attributable to the MTx.100 Column or plasmapheresis. Improvements in most metabolic and inflammatory markers were also noted. The PSM analysis showed that survival odds were three times higher for MTx.100 Column-treated patients (95% CI: 1.56-5.88) than for those treated with SOC only. INTERPRETATION: The MTx.100 Column treatment in severe COVID-19 resulted in a lower mortality than SOC by both pre-specified PG and PSM analysis. TRIAL REGISTRATION: clinicaltrials.gov (NCT04358003).

Vitamin K Antagonist Reversal for Urgent Surgery Using 4-Factor Prothrombin Complex Concentrates: A Randomized Clinical Trial.

Importance: Millions of people take vitamin K antagonists (VKAs). Some people who need urgent surgical procedures require rapid VKA reversal to prevent excessive intraoperative bleeding. Objective: To evaluate the hemostatic noninferiority of an investigational 4-factor prothrombin complex concentrate (4F-PCC) to a control 4F-PCC for rapid VKA reversal before urgent surgery. Design, Setting, and Participants: This phase 3, double-blind, noninferiority randomized clinical trial (LEX-209) was conducted in 24 hospitals in the US, Russia, Georgia, Belarus, Ukraine, and Romania from June 7, 2017, through November 8, 2021; the study was stopped in February 2022. Participants were adult patients taking VKA who had an international normalized ratio (INR) of 2 or higher and needed urgent surgery with a substantial bleeding risk (≥50 mL). Patients were randomized 1:1 to a single infusion of either the investigational 4F-PCC or the control 4F-PCC. Data analysis followed intention-to-treat and per-protocol approaches. Interventions: Single intravenous infusion was dosed by body weight and baseline INR. A dose of 25, 35, or 50 IU/kg of investigational 4F-PCC or control 4F-PCC was administered for baseline INR of 2 to less than 4, 4 to 6, or over 6, respectively. Main Outcome and Measure: The primary end point was hemostatic efficacy at surgery end. An independent adjudication board, blinded to the 4F-PCC treatment allocation, assessed hemostatic efficacy using an objective 4-point scale. Results: A total of 208 patients (median [range] age, 67.5 [31-92] years; 118 males [56.7%]) received the investigational (n = 105) or the control (n = 103) 4F-PCC. The median (range) dose was 25 (16-50) IU/kg in the investigational group and 25 (15-50) IU/kg in the control group, with a median (range) infusion time of 12 (8-50) minutes and 13 (7-30) minutes and a median (range) time from infusion to surgery start of 1.42 (0.25-15.25) hours and 1.50 (0.42-18.50) hours, respectively. Baseline median (range) INR was 3.05 (1.97-21.10) in the investigational group and 3.00 (2.00-11.30) in the control group. In the intention-to-treat analysis, the investigational 4F-PCC was noninferior to the control 4F-PCC, resulting in effective hemostasis in 94.3% of patients vs 94.2% of patients (proportion difference, 0.001; 95% CI, -0.080 to 0.082; P < .001), meeting the prespecified noninferiority margin of 0.15. An INR of 1.5 or lower at 30 minutes after infusion occurred in 78.1% of patients in the investigational group vs 71.8% of patients in the control group (proportion difference, 0.063; 95% CI, -0.056 to 0.181). Thrombotic events (2.9% vs 0%, respectively) and mortality (4.8% vs 1.0%, respectively) were no different than expected for 4F-PCC use. One patient in each treatment group discontinued due to adverse events (cardiac disorders unrelated to 4F-PCC). Conclusions and Relevance: This randomized clinical trial found that the investigational 4F-PCC was hemostatically noninferior to the control 4F-PCC for rapid VKA reversal in patients needing urgent surgery with considerable bleeding risk; the safety profile of these two 4F-PCCs was similar. These results support the investigational 4F-PCC as a therapeutic option for surgical patients requiring rapid VKA reversal. Trial Registration: ClinicalTrials.gov Identifier: NCT02740335.

A lower fibrinogen threshold does not lead to increased bleeding risk in patients receiving therapeutic plasma exchange: A prospective single-center analysis.

BACKGROUND: Plasma exchange (PLEX) therapy is indicated for several disorders. The 5% albumin is often used as a sole replacement fluid during most PLEX. However, each 1.0 plasma volume exchange depletes coagulation factors by ~65%. Although most coagulation factors recover to hemostatic levels within 24 h post-PLEX, fibrinogen requires 48-72 h to recover. Fibrinogen is the key coagulation protein for hemostasis. Therefore, fibrinogen is often monitored during the acute course of PLEX, and plasma is supplemented to prevent bleeding if fibrinogen is <100 mg/dL. STUDY DESIGN AND METHODS: We conducted a prospective, single-center, observational study to evaluate bleeding risk in adults who received an acute course of PLEX with a fibrinogen level of 80-100 mg/dL without plasma supplementation during the procedure or before central venous catheter removal. The study group was compared to patients with plasma fibrinogen >100 mg/dL. RESULTS: Among the 275 patients who received 1406 PLEXes, 62 patients (23%) who underwent 323 PLEXes met the inclusion criteria, and only 2 (3%) patients had bleeding while on oral anticoagulants. In contrast, out of 275 patients, 143 (52%) with fibrinogen levels >100 mg/dL received 751 PLEX treatments, and bleeding occurred in 2 (1%) while on low-molecular-weight heparin. CONCLUSIONS: Our findings suggest that a pre-procedure fibrinogen threshold of 80-100 mg/dL without plasma supplementation does not increase bleeding risk unless patients were on anticoagulation.

Bortezomib in relapsed/refractory immune thrombotic thrombocytopenic purpura: A single-centre retrospective cohort and systematic literature review.

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening haematological condition. Initial treatment involves plasma exchange (PLEX), corticosteroids, caplacizumab and rituximab. In relapsed and refractory cases despite initial treatments, further immune-modulating therapy includes the proteasome inhibitor, bortezomib. Evidence for bortezomib in this setting is limited to case reports and case series. We report our experience and perform a systematic review of the literature. We identified 21 publications with 28 unique patients in addition to our cohort of eight patients treated with bortezomib. The median age of patients was 44 years (IQR: 27-53) and 69% female. They were usually in an initial, refractory presentation of iTTP where they had received PLEX, corticosteroids, rituximab and another line of therapy. After bortezomib administration, 72% of patients had a complete response, with 85% maintaining a durable response without relapse at the last follow-up.

Evaluation of the efficacy and safety of amustaline/glutathione pathogen-reduced RBCs in complex cardiac surgery: the Red Cell Pathogen Inactivation (ReCePI) study-protocol for a phase 3, randomized, controlled trial.

BACKGROUND: Red blood cell (RBC) transfusion is a critical supportive therapy in cardiovascular surgery (CVS). Donor selection and testing have reduced the risk of transfusion-transmitted infections; however, risks remain from bacteria, emerging viruses, pathogens for which testing is not performed and from residual donor leukocytes. Amustaline (S-303)/glutathione (GSH) treatment pathogen reduction technology is designed to inactivate a broad spectrum of infectious agents and leukocytes in RBC concentrates. The ReCePI study is a Phase 3 clinical trial designed to evaluate the efficacy and safety of pathogen-reduced RBCs transfused for acute anemia in CVS compared to conventional RBCs, and to assess the clinical significance of treatment-emergent RBC antibodies. METHODS: ReCePI is a prospective, multicenter, randomized, double-blinded, active-controlled, parallel-design, non-inferiority study. Eligible subjects will be randomized up to 7 days before surgery to receive either leukoreduced Test (pathogen reduced) or Control (conventional) RBCs from surgery up to day 7 post-surgery. The primary efficacy endpoint is the proportion of patients transfused with at least one study transfusion with an acute kidney injury (AKI) diagnosis defined as any increased serum creatinine (sCr) level ≥ 0.3 mg/dL (or 26.5 µmol/L) from pre-surgery baseline within 48 ± 4 h of the end of surgery. The primary safety endpoints are the proportion of patients with any treatment-emergent adverse events (TEAEs) related to study RBC transfusion through 28 days, and the proportion of patients with treatment-emergent antibodies with confirmed specificity to pathogen-reduced RBCs through 75 days after the last study transfusion. With ≥ 292 evaluable, transfused patients (> 146 per arm), the study has 80% power to demonstrate non-inferiority, defined as a Test group AKI incidence increase of no more than 50% of the Control group rate, assuming a Control incidence of 30%. DISCUSSION: RBCs are transfused to prevent tissue hypoxia caused by surgery-induced bleeding and anemia. AKI is a sensitive indicator of renal hypoxia and a novel endpoint for assessing RBC efficacy. The ReCePI study is intended to demonstrate the non-inferiority of pathogen-reduced RBCs to conventional RBCs in the support of renal tissue oxygenation due to acute anemia and to characterize the incidence of treatment-related antibodies to RBCs.

Acute Chest Syndrome in Sickle Cell Disease.

Acute chest syndrome (ACS) is the leading cause of mortality among individuals with sickle cell disease (SCD) accounting for 25% of all deaths. The etiologies and clinical manifestations of ACS are variable among children and adults, with a lack of clear risk stratification guidelines for the practicing clinician. In addition, the management of ACS is based on limited evidence and is currently guided primarily by expert opinion. This manuscript reviews the pathophysiology, risk factors, and current management strategies for ACS through a review of published data on this subject between 1988 and 2022. Blood transfusion is often used as a therapeutic intervention for ACS to increase blood's oxygen-carrying capacity and reduce complications by reducing hemoglobin S (HbS) percentage, based on the very low quality of the evidence about its efficacy. The benefit of RBC transfusion for ACS has been described in case series and observational studies, but randomized studies comparing simple transfusion vs. exchange transfusions for ACS are lacking. In this review, we conclude that the development of clinical and laboratory risk stratification is necessary to further study an optimal management strategy for individuals with ACS to avoid transfusion-related complications while minimizing mortality.

Hemoglobin S target of <50% as compared to 30% in chronic red cell exchange for secondary stroke prevention in sickle cell disease.

BACKGROUND: Sickle cell disease (SCD) patients with a history of stroke are encouraged to receive chronic red blood cell exchange (RBCx) for stroke prevention. The American Society of Hematology guideline published in 2020 recommends an HbS target of <30%. However, this approach necessitates more frequent RBCx and more RBC units. UT Southwestern has devised a chronic exchange protocol that elevates the HbS target to <50% in patients with a low risk of stroke. STUDY DESIGN: This retrospective chart review study reviewed the medical records of patients receiving chronic RBCx with a target of HbS <50% over the past 10-year period to assess the safety of maintaining higher HbS targets in SCD patients with a low risk of cerebrovascular accidents (CVA). RESULTS: Among 49 SCD patients in the chronic RBCx program for secondary stroke prevention, 33 patients were maintained on an HbS target of <50% (average measured: 35.4%) for the duration of RBCx program enrollment (median 93.0 months, 95% CI, 83-99). Stroke or transient ischemic attack (TIA) clearly attributable to changing target HbS had not been identified among the 33 study subjects. Seven patients experienced conversion between the HbS targets of <50% and <30% HbS target. Significant reductions were observed in the frequency of RBCx and usage of blood volume in four of them. CONCLUSION: The findings suggest that liberalizing the HbS target could confer clinical flexibility without increasing the risk of CVA in a selective population. Further studies to fully evaluate the potential benefits of this approach are indicated.

A case of hyperhemolysis syndrome in sickle cell disease and concomitant COVID-19.

BACKGROUND: Hyperhemolysis syndrome (HHS) is an uncommon transfusion reaction described in several hematologic disorders, including sickle cell disease (SCD). HHS is characterized by a decline in hemoglobin (Hb) values below pre-transfusion levels following transfusion of red blood cells (RBCs), coupled with laboratory markers consistent with hemolysis. The proposed pathophysiologic mechanisms underlying HHS include increased phosphatidylserine expression, macrophage activation, and complement dysregulation. Many pathophysiologic mechanisms thought to contribute to HHS have been similarly described in cases of severe COVID-19. CASE REPORT: A 28-year-old male with a history of HbSS presented with shortness of breath, right-sided chest pain, and a two-day history of fever. Polymerase chain reaction (PCR) detected SARS-CoV-2 infection with the omicron variant. The patient required an RBC transfusion (pre-transfusion hemoglobin [Hb]5.8 g/dL) with an immediate post-transfusion Hb of 6.3 g/dL. However, Hb rapidly declined to 1.7 g/dL, and lactate dehydrogenase (LDH) rose to 8701 u/L. The absolute reticulocyte count of 538 × 109/L correspondingly fell to 29 × 109/L. Despite additional RBC transfusions and initiation of immunosuppressive therapy, he expired on Day 9(D9). CONCLUSION: Given the similarities in their proposed pathophysiology, patients with SCD and concomitant SARS-CoV-2 infection may be predisposed to developing HHS.

Clinical Relevance of Preclinical and Clinical Studies of Four-Factor Prothrombin Complex Concentrate for Treatment of Bleeding Related to Direct Oral Anticoagulants.

Direct oral anticoagulants (DOACs) are widely used for the prevention and treatment of venous thromboembolism and stroke. When emergency reversal of DOAC-related anticoagulation is required, specific DOAC reversal agents are recommended, including idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. However, specific reversal agents are not always available, andexanet alfa has not been approved for urgent surgery, and clinicians need to know the patient's anticoagulant medication before administering these treatments. Four-factor prothrombin complex concentrates (4F-PCCs) are recognized as nonspecific, alternative hemostatic agents for treatment of DOAC-related bleeding. Evidence from preclinical and clinical studies shows that they may reduce the anticoagulant effects of DOACs and may help control DOAC-related bleeding. However, randomized controlled trials are lacking, and most data are from retrospective or single-arm prospective studies in bleeding associated with activated factor X inhibitors. There are no clinical data showing the efficacy of 4F-PCC for the treatment of bleeding in dabigatran-treated patients. This review focuses on the current evidence of 4F-PCC use in controlling bleeding associated with DOACs and provides an expert opinion on the relevance of these data for clinical practice. The current treatment landscape, unmet needs, and future directions are also discussed.

Thrombotic thrombocytopenic purpura in caplacizumab era - An individualized approach.

Thrombotic thrombocytopenic purpura (TTP) is a rare disease characterized by a severe deficiency (< 10 % activity) of ADAMTS13 enzyme due to an autoantibody (aTTP) or genetic defect leading to congenital TTP (cTTP). The management of aTTP has evolved over the last 30 years, beginning with plasma exchange (PLEX) being the standard of care, leading to gradual aggressive immunosuppression therapies to manage exacerbations and relapses. Although PLEX had reversed the mortality from > 90 % to < 10-20 %, early deaths do occur in severe aTTP, especially when there is a delay in diagnosis and/or PLEX initiation. There is growing evidence that aTTP is often associated with the long-term neuropsychiatric sequela, probably associated with brain damage caused by microthromboses. Recently, a disease-modifying agent, caplacizumab, a potent nanobody that inhibits the interaction between the A1 domain of von Willebrand factor with GPIb on platelets, was approved by various agencies for the treatment of aTTP. Two clinical trials showed its efficacy in rapidly correcting platelet counts and preventing exacerbations because caplacizumab was continued for 30 days post-PLEX, irrespective of ADAMTS13 recovery. However, caplacizumab was associated with higher and unusual bleeding side effects compared to the placebo due to a severe acquired von Willebrand syndrome that persisted for the duration of therapy. Because of its longer half-life coupled with early aggressive rituximab therapy, it is prudent to use caplacizumab judiciously to avoid serious bleeds and to reduce costs. This manuscript provides a rational approach for using caplacizumab, an important disease-modifying agent.

INR and vitamin K-dependent factor levels after vitamin K antagonist reversal with 4F-PCC or plasma.

Restoration of the international normalized ratio (INR) to values <1.5 is commonly targeted to achieve hemostasis in patients with major bleeding or undergoing urgent surgery who are treated using vitamin K antagonists (VKAs). However, the relationship between corrected INR and vitamin K-dependent factor (VKDF) levels for hemostasis is uncertain. We aim to examine the impact of 4-factor prothrombin complex concentrate (4F-PCC) or plasma on INR correction and VKDF restoration and evaluate the relationship between INR values and VKDF levels in patients with acute major bleeding or patients requiring an urgent surgical procedure. Adult patients treated with VKA with an elevated INR (≥2.0 within 3 hours before study treatment) who received 4F-PCC or plasma after major bleeding or before an urgent surgery or invasive procedure were included in this retrospective analysis of data from 2 prospective phase 3b randomized controlled trials. Of the 370 patients included in this analysis, 185 received 4F-PCC, and 185 received plasma. In the 4F-PCC group, 159 of 185 (85.9%) had an INR ≤1.5 at 30 minutes after the end of infusion compared with only 72 of 184 (39.1%) in the plasma group. After 4F-PCC treatment, all VKDF levels exceeded 50% activity regardless of the postinfusion INR value. However, after plasma administration, mean activity levels for factors II and X were <50% at all time points assessed within 3 hours after starting the infusion, regardless of the postinfusion INR value. This retrospective analysis demonstrated that treatment with 4F-PCC among patients treated with VKA rapidly restores VKDFs to hemostatic levels irrespective of the postinfusion INR value, whereas treatment with plasma does not.

Red blood cells as glucose carriers to the human brain: Modulation of cerebral activity by erythrocyte exchange transfusion in Glut1 deficiency (G1D).

Red blood cells circulating through the brain are briefly but closely apposed to the capillary endothelium. We hypothesized that this contact provides a nearly direct pathway for metabolic substrate transfer to neural cells that complements the better characterized plasma to endothelium transfer. While brain function is considered independent of normal fluctuations in blood glucose concentration, this is not borne out by persons with glucose transporter I (GLUT1) deficiency (G1D). In them, encephalopathy is often ameliorated by meal or carbohydrate administration, and this enabled us to test our hypothesis: Since red blood cells contain glucose, and since the red cells of G1D individuals are also deficient in GLUT1, replacing them with normal donor cells via exchange transfusion could augment erythrocyte to neural cell glucose transport via mass action in the setting of unaltered erythrocyte count or plasma glucose abundance. This motivated us to perform red blood cell exchange in 3 G1D persons. There were rapid, favorable and unprecedented changes in cognitive, electroencephalographic and quality-of-life measures. The hypothesized transfer mechanism was further substantiated by in vitro measurement of direct erythrocyte to endothelial cell glucose flux. The results also indicate that the adult intellect is capable of significant enhancement without deliberate practice. ClinicalTrials.gov registration: NCT04137692 https://clinicaltrials.gov/ct2/show/NCT04137692.

Translation suppression underlies the restrained COVID-19 mRNA vaccine response in the high-risk immunocompromised group.

Background: Immunocompromised (IC) patients show diminished immune response to COVID-19 mRNA vaccines (Co-mV). To date, there is no 'empirical' evidence to link the perturbation of translation, a rate-limiting step for mRNA vaccine efficiency (VE), to the dampened response of Co-mV. Materials and methods: Impact of immunosuppressants (ISs), tacrolimus (T), mycophenolate (M), rapamycin/sirolimus (S), and their combinations on Pfizer Co-mV translation were determined by the Spike (Sp) protein expression following Co-mV transfection in HEK293 cells. In vivo impact of ISs on SARS-CoV-2 spike specific antigen (SpAg) and associated antibody levels (IgGSp) in serum were assessed in Balb/c mice after two doses (2D) of the Pfizer vaccine. Spike Ag and IgGSp levels were assessed in 259 IC patients and 50 healthy controls (HC) who received 2D of Pfizer or Moderna Co-mV as well as in 67 immunosuppressed solid organ transplant (SOT) patients and 843 non-transplanted (NT) subjects following three doses (3D) of Co-mV. Higher Co-mV concentrations and transient drug holidays were evaluated. Results: We observed significantly lower IgGSP response in IC patients (p<0.0001) compared to their matched controls in 2D and 3D Co-mV groups. IC patients on M or S showed a profound dampening of IgGSP response relative to those that were not on these drugs. M and S, when used individually or in combination, significantly attenuated the Co-mV-induced Sp expression, whereas T did not exert significant influence. Sirolimus combo pretreatment in vivo significantly attenuated the Co-mV induced IgMSp and IgGSp production, which correlated with a decreasing trend in the early levels (after day 1) of Co-mV induced Sp immunogen levels. Neither higher Co-mV concentrations (6µg) nor withholding S for 1-day could overcome the inhibition of Sp protein levels. Interestingly, 3-days S holiday or using T alone rescued Sp levels in vitro. Conclusions: This is the first study to demonstrate that ISs, sirolimus and mycophenolate inhibited Co-mV-induced Sp protein synthesis via translation repression. Selective use of tacrolimus or drug holiday of sirolimus can be a potential means to rescue translation-dependent Sp protein production. These findings lay a strong foundation for guiding future studies aimed at improving Co-mV responses in high-risk IC patients.

Successful use of lenalidomide to treat refractory acquired von Willebrand disease associated with monoclonal gammopathy.

Acquired von Willebrand syndrome (AVWS) is a rare hematologic disorder characterized by quantitative or qualitative defects of von Willebrand factor (vWF), a protein crucial for normal hemostasis. AVWS has been described in association with several pathologic entities with varied mechanisms. Among these, lymphoproliferative disorders are the most common, with monoclonal gammopathy of undetermined significance (MGUS) being the most frequently reported. AVWS in this setting is commonly associated with the development of bleeding that is clinically challenging to manage due to accelerated clearance of vWF, limiting the utility of many conventional treatment modalities such as DDAVP or vWF/FVIII. We report a case of a 43-year-old male who was sent to our institution for new-onset easy bruising and laboratories concerning for von Willebrand disease (vWD). Further diagnostic workup revealed evidence of an IgG monoclonal gammopathy and findings suggestive of vWF inhibition. Ultimately, he was found to have monoclonal gammopathy of clinical significance (MGCS)-associated AVWS refractory to conventional treatment but responsive to lenalidomide and dexamethasone. This case suggests that lenalidomide may be suitable for patients with AVWS secondary to MGCS.

Utilization of emicizumab in acquired hemophilia A: A case report.

BACKGROUND: Acquired Hemophilia A (AHA) is a rare autoimmune disorder associated with the development of autoantibodies against factor VIII (FVIII). Although obtaining hemostatic control through the use of recombinant factor VIIa, activated prothrombin complex concentrate and recombinant porcine FVIII are cornerstones in the clinical management of AHA, these therapies have several disadvantages, including a higher risk for the development of thromboembolic events, unpredictable efficacy and short half-lives. While emicizumab has been FDA licensed for use in bleeding prophylaxis for patients with Congenital Hemophilia A (CHA) with and without inhibitors, it has not been approved for use in AHA, with only a few reports describing its use in this context. CASE REPORT: We report our experience with the use of emicizumab in an 83-year old male with AHA, complicated by the onset of atrial fibrillation following admission, drug-induced thrombocytopenia, infectious complications, and the identification of a low-grade lymphoproliferative disorder, in which emicizumab prophylaxis was used for bleeding prophylaxis in the context of persistently elevated inhibitor titers without evidence of thrombotic events or thrombotic microangiopathy.

Multiplex Fragment Analysis for Flexible Detection of All SARS-CoV-2 Variants of Concern.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to emerge, and effective tracking requires rapid return of results. Surveillance of variants is typically performed by whole genome sequencing (WGS), which can be financially prohibitive and requires specialized equipment and bioinformatic expertise. Genotyping approaches are rapid methods for monitoring SARS-CoV-2 variants but require continuous adaptation. Fragment analysis may represent an approach for improved SARS-CoV-2 variant detection. METHODS: A multiplex fragment analysis approach (CoVarScan) was validated using PCR targeting variants by size and fluorescent color. Eight SARS-CoV-2 mutational hot spots in variants of concern (VOCs) were targeted. Three primer pairs (recurrently deleted region [RDR] 1, RDR2, and RDR3-4) flank RDRs in the S-gene. Three allele-specific primers target recurrent spike receptor binding domain mutants. Lastly, 2 primer pairs target recurrent deletions or insertions in ORF1A and ORF8. Fragments were resolved and analyzed by capillary electrophoresis (ABI 3730XL), and mutational signatures were compared to WGS results. RESULTS: We validated CoVarScan using 3544 clinical respiratory specimens. The assay exhibited 96% sensitivity and 99% specificity compared to WGS. The limit of detection for the core targets (RDR1, RDR2, and ORF1A) was 5 copies/reaction. Variants were identified in 95% of samples with cycle threshold (CT) <30 and 75% of samples with a CT 34 to 35. Assay design was frozen April 2021, but all subsequent VOCs have been detected including Delta (n = 2820), Mu, (n = 6), Lambda (n = 6), and Omicron (n = 309). Genotyping results are available in as little as 4 h. CONCLUSIONS: Multiplex fragment analysis is adaptable and rapid and has similar accuracy to WGS to classify SARS-CoV-2 variants.

High versus low fixed-dose four factor-prothrombin complex concentrate for warfarin reversal in patients with intracranial hemorrhage.

BACKGROUND: Four-factor prothrombin complex concentrate 4F-PCC is the standard of care for warfarin reversal in patients with major bleed or requiring urgent surgery. Although the 4F-PCC dose is weight and international normalized ratio (INR) based, for practical purposes, a fixed-dose approach has been explored, especially for rapid reversal. We report our experience using two different fixed-dose 4F-PCC for warfarin reversal in patients presenting with intracranial hemorrhage (ICH). STUDY DESIGN AND METHODS: We completed a retrospective chart review comparing high (4000 units) versus low (2000 units) dose 4F-PCC by evaluating patient characteristics, laboratory data, and pre-and post-4F-PCC brain imaging. RESULTS: There was no significant difference between patient characteristics or INR correction (≤1.5) between the two groups. Eighty percent (12/15) of patients who received the low dose 4F-PCC had either improved or stable brain imaging as compared to 88% (14/16) of patients who received the high dose PCC. When the eight patients (4 from each arm of the study) who required neurosurgery were excluded, only two patients in each arm had worse imaging after 4F-PCC. CONCLUSION: There was no significant difference between the INR correction and the brain imaging changes in patients with an ICH who received either the high or the low fixed-dose 4F-PCC for warfarin reversal.