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Kianian S, Scorsese G, Zabirowicz E, Poppers J. Perioperative Management of a Patient with Hemophilia C and Allergy to Fresh Frozen Plasma. Case Rep Anesthesiol 2023; 2023:8973346. [PMID: 37034885 PMCID: PMC10076113 DOI: 10.1155/2023/8973346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 02/21/2023] [Accepted: 02/28/2023] [Indexed: 03/31/2023] Open
Abstract
Hemophilia C is a rare bleeding disorder characterized by a deficiency in clotting factor XI (fXI) and has no standard of care for preoperative optimization before cardiac surgery. Normalization of fXI levels in patients with hemophilia C can be achieved with fresh frozen plasma (FFP), which sometimes results in allergic reactions. We present a case of a patient with hemophilia C requiring coronary artery bypass grafting surgery who developed an allergic reaction to FFP. Our report underscores the balance between thrombosis and bleeding risks when devising a perioperative plan for patients with hemophilia C.
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Anticoagulant therapy in patients with congenital FXI deficiency. Blood Adv 2021; 5:4083-4086. [PMID: 34597376 PMCID: PMC8945614 DOI: 10.1182/bloodadvances.2021005695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/10/2021] [Indexed: 11/25/2022] Open
Abstract
Bleeding risk of FXI deficiency on anticoagulation is unknown. We report 15 of 269 FXI-deficient subjects receiving VKA and/or DOACs. No major bleeding was observed for >1000 months of anticoagulation. Drug dose, monitoring and management were unaffected by FXI deficiency.
The bleeding phenotype of factor XI (FXI) deficiency is unpredictable. Bleeding is usually mild and mostly occurs after injury. Although FXI deficiency renders antithrombotic protection, some patients might eventually develop thrombosis or atrial fibrillation, requiring anticoagulant therapy. There is almost no evidence on the bleeding risk in this scenario. Our retrospective study of 269 white FXI-deficient subjects (1995-2021) identified 15 cases requiring anticoagulation. They harbored 8 different F11 variants, mainly in heterozygosis (1 case was homozygote), and had mild to moderate deficiency (FXI:C: 20% to 70%). Two subjects (13.3%) had bleeding history before anticoagulation. Atrial fibrillation was the main indication (12/15; 80%). Fourteen patients started therapy with vitamin K antagonists (VKA), but 4 subjects were on direct oral anticoagulants (DOACs) at the end of follow-up. Over >1000 months of anticoagulation, 2 mild bleeding episodes in 2 patients (13.3%, 95% confidence interval: 3.7% to 37.9%) were recorded. No major/fatal events were reported. “Pre-post” bleeding localization and severity did not change despite treatment. On VKA, drug dosing and management were also standard, unaltered by FXI deficiency. We provide the largest description of anticoagulant use in FXI deficiency, and the first cases receiving DOACs. Although further studies are needed, our observations suggest that moderate FXI deficiency does not interfere with anticoagulant management nor bleeding risk.
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Willmann S, Marostica E, Snelder N, Solms A, Jensen M, Lobmeyer M, Lensing AWA, Bethune C, Morgan E, Yu RZ, Wang Y, Jung SW, Geary R, Bhanot S. PK/PD modeling of FXI antisense oligonucleotides to bridge the dose-FXI activity relation from healthy volunteers to end-stage renal disease patients. CPT Pharmacometrics Syst Pharmacol 2021; 10:890-901. [PMID: 34085768 PMCID: PMC8376138 DOI: 10.1002/psp4.12663] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/13/2021] [Accepted: 05/14/2021] [Indexed: 12/17/2022] Open
Abstract
IONIS-FXIRX (BAY2306001) is an antisense oligonucleotide that inhibits the synthesis of coagulation factor XI (FXI) and has been investigated in healthy volunteers and patients with end-stage renal disease (ESRD). FXI-LICA (BAY2976217) shares the same RNA sequence as IONIS-FXIRX but contains a GalNAc-conjugation that facilitates asialoglycoprotein receptor (ASGPR)-mediated uptake into hepatocytes. FXI-LICA has been studied in healthy volunteers and is currently investigated in patients with ESRD on hemodialysis. We present a model-informed bridging approach that facilitates the extrapolation of the dose-exposure-FXI relationship from IONIS-FXIRX to FXI-LICA in patients with ESRD and, thus, supports the selection of FX-LICA doses being investigated in patients with ESRD. A two-compartment pharmacokinetic (PK) model, with mixed first- and zero-order subcutaneous absorption and first-order elimination, was combined with an indirect response model for the inhibitory effect on the FXI synthesis rate via an effect compartment. This PK/pharmacodynamic model adequately described the median trends, as well as the interindividual variabilities for plasma drug concentration and FXI activity in healthy volunteers of IONIS-FXIRX and FXI-LICA, and in patients with ESRD of IONIS-FXIRX . The model was then used to predict dose-dependent steady-state FXI activity following repeat once-monthly doses of FXI-LICA in a virtual ESRD patient population. Under the assumption of similar ASGPR expression in patients with ESRD and healthy volunteers, doses of 40 mg, 80 mg, and 120 mg FXI-LICA are expected to cover the target range of clinical interest for steady-state FXI activity in the phase IIb study of FXI-LICA in patients with ESRD undergoing hemodialysis.
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Affiliation(s)
- Stefan Willmann
- Research & Development, PharmaceuticalsBayer AGWuppertal/BerlinGermany
| | - Eleonora Marostica
- Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics (LAP&P)LeidenThe Netherlands
| | - Nelleke Snelder
- Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics (LAP&P)LeidenThe Netherlands
| | - Alexander Solms
- Research & Development, PharmaceuticalsBayer AGWuppertal/BerlinGermany
| | - Markus Jensen
- Research & Development, PharmaceuticalsBayer AGWuppertal/BerlinGermany
| | | | | | | | - Erin Morgan
- Ionis Pharmaceuticals, IncCarlsbadCaliforniaUSA
| | - Rosie Z. Yu
- Ionis Pharmaceuticals, IncCarlsbadCaliforniaUSA
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Abstract
STUDY DESIGN Case report. OBJECTIVE To summarize the clinical manifestations and treatment of Factor XI deficiency in a patient with cervical spondylotic myelopathy. SUMMARY OF BACKGROUND DATA Factor XI deficiency is a rare genetic bleeding disorder caused by reduced levels and insufficient activity of a coagulation factor XI. It is claimed to be associated with prominent bleeding in case of trauma and surgery irrelevant to the FXI level. This is the first ever case of a patient with factor XI deficiency with cervical spondylotic myelopathy. METHODS A case was investigated retrospectively and the relevant literature was reviewed. RESULTS A 66-year-old man with a 2-months history of lack of finger dexterity and gait disturbance was referred to our department. He did not have a history of bleeding or coagulation disorder nor did his family. Magnetic resonance imaging (MRI) of the cervical spine revealed spinal canal stenosis at C3/4 to C5/6 and intramedullary hyperintensity at C3/4 on the :T2 weighted image (T2WI). Preoperative examination revealed no abnormal findings but a severe prolonged activated partial-thromboplastin time (APTT) of 139.8 seconds. Coagulation factor activity assay revealed severe deficiency of factor XI (<0.1%). In accordance with hematologist's recommendation, four units of fresh frozen plasma (FFP) were transfused on the day before surgery and APTT assayed early morning on the day of surgery was 70.5 seconds. An additional four units of FFP were transfused during the surgery and APTT was 60 seconds. The postoperative course was uneventful and the patient was discharged on the postoperative day 14. CONCLUSION Factor XI deficiency patients may develop excessive bleeding after trauma or surgery. Preoperative examination with prolonged APTT should be pursued until a diagnosis of is made. Under diagnosis of Factor XI deficiency, meticulous attentions are required for perioperative bleeding management including postoperative hematoma in spinal surgery.Level of Evidence: 5.
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5
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Hausman-Kedem M, Malinger G, Modai S, Kushner SA, Shiran SI, Ben-Sira L, Roth J, Constantini S, Fattal-Valevski A, Ben-Shachar S. Monogenic Causes of Apparently Idiopathic Perinatal Intracranial Hemorrhage. Ann Neurol 2021; 89:813-822. [PMID: 33527515 DOI: 10.1002/ana.26033] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Perinatal intracranial hemorrhage (pICH) is a rare event that occurs during the fetal/neonatal period with potentially devastating neurological outcome. However, the etiology of pICH is frequently hard to depict. We investigated the role of rare genetic variations in unexplained cases of pICH. METHODS We performed whole-exome sequencing (WES) in fetuses and term neonates with otherwise unexplained pICH and their parents. Variant causality was determined according to the American College of Medical Genetics and Genomics (ACMG) criteria, consistency between suggested genes and phenotypes, and mode of inheritance. RESULTS Twenty-six probands (25 families) were included in the study (9 with a prenatal diagnosis and 17 with a postnatal diagnosis). Intraventricular hemorrhage (IVH) was the most common type of hemorrhage (n = 16, 62%), followed by subpial (n = 4, 15%), subdural (n = 4, 15%), and parenchymal (n = 2, 8%) hemorrhage. Causative/likely causative variants were found in 4 subjects from 3 of the 25 families (12%) involving genes related to the brain microenvironment (COL4A1, COL4A2, and TREX-1). Additionally, potentially causative variants were detected in genes related to coagulation (GP1BA, F11, Von Willebrand factor [VWF], FGA, and F7; n = 4, 16%). A potential candidate gene for phenotypic expansion related to microtubular function (DNAH5) was identified in 1 case (4%). Fifty-five percent of the variants were inherited from an asymptomatic parent. Overall, these findings showed a monogenic cause for pICH in 12% to 32% of the families. INTERPRETATION Our findings reveal a clinically significant diagnostic yield of WES in apparently idiopathic pICH and support the use of WES in the evaluation of these cases. ANN NEUROL 2021;89:813-822.
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Affiliation(s)
- Moran Hausman-Kedem
- Pediatric Neurology Institute, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gustavo Malinger
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Division of Obstetrics and Gynecology Ultrasound, Lis Maternity Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | | | - Steven A Kushner
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Shelly I Shiran
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Radiology Department, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Liat Ben-Sira
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Radiology Department, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Jonathan Roth
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Neurosurgery Department, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Shlomi Constantini
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Neurosurgery Department, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Aviva Fattal-Valevski
- Pediatric Neurology Institute, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shay Ben-Shachar
- Sackler Faulty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Schneider Children's Medical Center, Petah Tikva, Israel.,Clalit Research Institute, Ramat Gan, Israel
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6
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McCarthy ML, Ordway SM, Jones RM, Perkins JG. Successful perioperative management in a patient with factor XI deficiency. BMJ Case Rep 2018; 2018:bcr-2017-222434. [PMID: 29467123 DOI: 10.1136/bcr-2017-222434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Factor XI (FXI) deficiency is an autosomal disorder which manifests as bleeding of varying severity. While homozygotes typically experience more dramatic bleeding symptoms, heterozygotes may experience clinically significant bleeding following surgical procedures or trauma, and therefore the condition is not purely recessive. The clinical significance of FXI deficiency is complicated in that FXI levels do not correlate well with bleeding severity, and in fact the bleeding risk is variable even for an individual in response to different haemostatic challenges. We present the case of a 74-year-old man of Ashkenazi Jewish heritage with a family and personal history of bleeding during surgical procedures, who presented with excessive bleeding following total thyroidectomy. He was found to have a FXI level of 52% (low normal). Genetic testing revealed that he was heterozygous for the c.403G>T mutation. This case demonstrates successful work-up and perioperative management of a patient with FXI deficiency.
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Affiliation(s)
| | - Sarah M Ordway
- Internal Medicine, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Ryan M Jones
- Hematology-Oncology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Jeremy G Perkins
- Hematology-Oncology, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
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7
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David T, Kim YC, Ely LK, Rondon I, Gao H, O'Brien P, Bolt MW, Coyle AJ, Garcia JL, Flounders EA, Mikita T, Coughlin SR. Factor XIa-specific IgG and a reversal agent to probe factor XI function in thrombosis and hemostasis. Sci Transl Med 2017; 8:353ra112. [PMID: 27559095 DOI: 10.1126/scitranslmed.aaf4331] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 07/11/2016] [Indexed: 11/02/2022]
Abstract
Thrombosis is a major cause of morbidity and mortality. Current antithrombotic drugs are not ideal in that they must balance prevention of thrombosis against bleeding risk. Inhibition of coagulation factor XI (FXI) may offer an improvement over existing antithrombotic strategies by preventing some forms of thrombosis with lower bleeding risk. To permit exploration of this hypothesis in humans, we generated and characterized a series of human immunoglobulin Gs (IgGs) that blocked FXIa active-site function but did not bind FXI zymogen or other coagulation proteases. The most potent of these IgGs, C24 and DEF, inhibited clotting in whole human blood and prevented FeCl3-induced carotid artery occlusion in FXI-deficient mice reconstituted with human FXI and in thread-induced venous thrombosis in rabbits at clinically relevant doses. At doses substantially higher than those required for inhibition of intravascular thrombus formation in these models, DEF did not increase cuticle bleeding in rabbits or cause spontaneous bleeding in macaques over a 2-week study. Anticipating the desirability of a reversal agent, we also generated a human IgG that rapidly reversed DEF activity ex vivo in human plasma and in vivo in rabbits. Thus, an active site-directed FXIa-specific antibody can block thrombosis in animal models and, together with the reversal agent, may facilitate exploration of the roles of FXIa in human disease.
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Affiliation(s)
- Tovo David
- Cardiovascular Research Institute, University of California, San Francisco, Room SC452P, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3122, USA
| | - Yun Cheol Kim
- Centers for Therapeutic Innovation San Francisco, Pfizer Inc., 1700 Owens Street, San Francisco, CA 94158, USA
| | - Lauren K Ely
- Centers for Therapeutic Innovation San Francisco, Pfizer Inc., 1700 Owens Street, San Francisco, CA 94158, USA
| | - Isaac Rondon
- Centers for Therapeutic Innovation San Francisco, Pfizer Inc., 1700 Owens Street, San Francisco, CA 94158, USA
| | - Huilan Gao
- Centers for Therapeutic Innovation Boston, Pfizer Inc., 18th Floor, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Peter O'Brien
- Pharmacokinetics, Dynamics, and Metabolism Biotherapeutics and Translational Research, Pfizer Inc., 10724 Science Center Drive, San Diego, CA 92121, USA
| | - Michael W Bolt
- Drug Safety Research and Development, Pfizer Inc., 1 Burtt Road, Andover, MA 01810, USA
| | - Anthony J Coyle
- Centers for Therapeutic Innovation Boston, Pfizer Inc., 18th Floor, 3 Blackfan Circle, Boston, MA 02115, USA
| | - Jorge L Garcia
- PMI Preclinical, 1031 Bing Street, San Carlos, CA 94070, USA
| | | | - Thomas Mikita
- Centers for Therapeutic Innovation San Francisco, Pfizer Inc., 1700 Owens Street, San Francisco, CA 94158, USA.
| | - Shaun R Coughlin
- Cardiovascular Research Institute, University of California, San Francisco, Room SC452P, 555 Mission Bay Boulevard South, San Francisco, CA 94143-3122, USA.
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8
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Factor XI gene variants in factor XI-deficient patients of Southern Italy: identification of a novel mutation and genotype-phenotype relationship. Hum Genome Var 2017; 4:17043. [PMID: 29138690 PMCID: PMC5678205 DOI: 10.1038/hgv.2017.43] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/27/2017] [Accepted: 08/02/2017] [Indexed: 11/12/2022] Open
Abstract
Congenital Factor XI (FXI) deficiency shows a high variability in clinical phenotype. To date, many allele variants have been shown to cause this bleeding disorder. However, the genotype–phenotype relationship is difficult to establish. This report provides insights into this bleeding disorder. Sixteen unrelated Italian index cases with congenital FXI deficiency and their relatives were investigated. After the identification of the deficiency, we obtained DNA from each subject and analyzed the FXI gene using direct sequencing. We identified 5 and 11 individuals with severe and moderate deficiency of FXI activity, respectively. Most patients (8/16) carried mutations in the Apple 2 domain and 4 patients showed c.403G>T (p.Glu135*; type II mutation). Four novel compound heterozygosities were identified. Bleeding symptoms were present in two severely deficient subjects carrying the combinations c.901T>C (p.Phe301Leu)/c.1556G>A (p.Trp519*) and c.943G>A (p.Glu315)/c.1556G>A (p.Trp519*), respectively. Bleeding episodes were also observed in the presence of a moderate deficiency in two individuals heterozygous for c.449C>T (p.Thr150Met) and c.1253G>T (p.Gly418Val), respectively. One novel mutation, c.1682C>A (p.Ala561Asp), was identified as potentially deleterious in an asymptomatic individual. We confirm an unclear prediction of phenotype from mutational data. The FXI levels should be coupled with FXI analysis for a more comprehensive prediction of the bleeding phenotype in FXI deficiency.
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9
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Wheeler AP, Gailani D. The Intrinsic Pathway of Coagulation as a Target for Antithrombotic Therapy. Hematol Oncol Clin North Am 2017; 30:1099-114. [PMID: 27637310 DOI: 10.1016/j.hoc.2016.05.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Plasma coagulation in the activated partial thromboplastin time assay is initiated by sequential activation of coagulation factors XII, XI, and IX. While this series of proteolytic reactions is not an accurate model for hemostasis in vivo, there is mounting evidence that factor XI and factor XII contribute to thrombosis, and that inhibiting them can produce an antithrombotic effect with a small effect on hemostasis. This article discusses the contributions of components of the intrinsic pathway to thrombosis in animal models and humans, and results of early clinical trials of drugs targeting factors IX, XI, and XII.
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Affiliation(s)
- Allison P Wheeler
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, C-3321A Medical Center North, 1161 21st Avenue, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University, 397 Preston Research Building, 2220 Pierce Ave, Nashville, TN 37232, USA.
| | - David Gailani
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, C-3321A Medical Center North, 1161 21st Avenue, Nashville, TN 37232, USA; Hematology/Oncology Division, Department of Medicine, Vanderbilt University, 777 Preston Research Building, 2220 Pierce Avenue, Nashville, TN 37232, USA
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10
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Abstract
Clotting factor abnormalities in children provide an interesting challenge to the medical care team. Understanding the diagnostic process and the medical management of children with factor abnormalities is crucial, as life-threatening complications can occur. This article will familiarize the reader with symptoms, laboratory testing, diagnosis, and treatment of hereditary coagulation factor abnormalities.
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Affiliation(s)
- Nicole Sevier
- Baylor College of Medicine, Texas Children's Cancer Center and Hematology Service, 6701 Fannin, suite 1400, MC 3-3320, Houston, TX 77030, USA.
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11
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ten Cate-Hoek AJ, Weitz JI, Gailani D, Meijer K, Philippou H, Bouman AC, Whitney Cheung Y, van Mens TE, Govers-Riemslag JW, Vries M, Bleker S, Biedermann JS, Stoof SCM, Buller HR. Theme 3: Non-invasive management of (recurrent) venous thromboembolism (VTE) and post thrombotic syndrome (PTS). Thromb Res 2016; 136 Suppl 1:S13-8. [PMID: 26387731 DOI: 10.1016/j.thromres.2015.07.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Arina J ten Cate-Hoek
- Maastricht University Medical Center, Laboratory for Clinical Thrombosis and Hemostasis, Cardiovascular Research Institute Maastricht (CARIM), Netherlands; Thrombosis Center, USA.
| | - Jeffrey I Weitz
- McMaster University and Thrombosis and Atherosclerosis Research Institute, Canada
| | - David Gailani
- Vanderbilt University, Department of Pathology, Microbiology and Immunology, Nashville, USA
| | - Karina Meijer
- University of Groningen, University Medical Center Groningen, Department of Hematology, Netherlands
| | - Helen Philippou
- University of Leeds, Division of Cardiovascular and Diabetes Research, The LIGHT Labs, Leeds, UK
| | - Annemieke C Bouman
- Maastricht University Medical Center, Laboratory for Clinical Thrombosis and Hemostasis, Cardiovascular Research Institute Maastricht (CARIM), Netherlands; Thrombosis Center, USA
| | - Y Whitney Cheung
- University of Amsterdam, Academic Medical Center, Department of Vascular Medicine, Netherlands
| | - Thijs E van Mens
- University of Amsterdam, Academic Medical Center, Department of Vascular Medicine, Netherlands
| | - Jose W Govers-Riemslag
- Maastricht University Medical Center, Laboratory for Clinical Thrombosis and Hemostasis, Cardiovascular Research Institute Maastricht (CARIM), Netherlands
| | - Minka Vries
- Maastricht University Medical Center, Laboratory for Clinical Thrombosis and Hemostasis, Cardiovascular Research Institute Maastricht (CARIM), Netherlands
| | - Suzanne Bleker
- University of Amsterdam, Academic Medical Center, Department of Vascular Medicine, Netherlands
| | - Jossi S Biedermann
- Erasmus University Medical Center, Rotterdam, Department of Hematology, Netherlands
| | - S Carina M Stoof
- Erasmus University Medical Center, Rotterdam, Department of Hematology, Netherlands
| | - Harry R Buller
- University of Amsterdam, Academic Medical Center, Department of Vascular Medicine, Netherlands
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12
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Preoperative management of factor XI deficiency with therapeutic plasma exchange: A case report and literature review. J Clin Apher 2015; 31:579-583. [DOI: 10.1002/jca.21442] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/24/2015] [Indexed: 11/07/2022]
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13
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Gailani D, Bane CE, Gruber A. Factor XI and contact activation as targets for antithrombotic therapy. J Thromb Haemost 2015; 13:1383-95. [PMID: 25976012 PMCID: PMC4516614 DOI: 10.1111/jth.13005] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/01/2015] [Indexed: 11/26/2022]
Abstract
The most commonly used anticoagulants produce therapeutic antithrombotic effects either by inhibiting thrombin or factor Xa (FXa) or by lowering the plasma levels of the precursors of these key enzymes, prothrombin and FX. These drugs do not distinguish between thrombin generation contributing to thrombosis from thrombin generation required for hemostasis. Thus, anticoagulants increase bleeding risk, and many patients who would benefit from therapy go untreated because of comorbidities that place them at unacceptable risk for hemorrhage. Studies in animals demonstrate that components of the plasma contact activation system contribute to experimentally induced thrombosis, despite playing little or no role in hemostasis. Attention has focused on FXII, the zymogen of a protease (FXIIa) that initiates contact activation when blood is exposed to foreign surfaces, and FXI, the zymogen of the protease FXIa, which links contact activation to the thrombin generation mechanism. In the case of FXI, epidemiologic data indicate this protein contributes to stroke and venous thromboembolism, and perhaps myocardial infarction, in humans. A phase 2 trial showing that reduction of FXI may be more effective than low molecular weight heparin at preventing venous thrombosis during knee replacement surgery provides proof of concept for the premise that an antithrombotic effect can be uncoupled from an anticoagulant effect in humans by targeting components of contact activation. Here, we review data on the role of FXI and FXII in thrombosis and results of preclinical and human trials for therapies targeting these proteins.
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Affiliation(s)
- David Gailani
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Charles E. Bane
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee, USA
| | - Andras Gruber
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR
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14
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Lammy S, Pessotto R. Factor XI deficiency: incidental diagnosis post coronary artery bypass graft. Scott Med J 2014; 59:e6-8. [DOI: 10.1177/0036933013519027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Severe Factor XI (FXI) deficiency is defined when the activated partial thromboplastin time is prolonged and its activation is <1–15 UdL−1 in plasma. It is inherited as an autosomal recessive trait but can be acquired. In severe deficiency the bleeding diathesis is normally injury related. This particularly occurs during surgical procedures and trauma involving tissues rich in fibrinolytic activators. Cardiopulmonary bypass induces transient abnormalities in haemostasis which can cause a postoperative bleeding diathesis. Once treated, it does not appear to be a contraindication to cardiac procedures. Conversely, acquired deficiencies are more insidious being incidentally diagnosed during routine laboratory investigations and might be triggered by an inhibitory agent. We present a case of an uncomplicated 12-month delayed diagnosis of Factor XI deficiency following coronary artery bypass grafting and sternal rewiring. The potential risks if undiagnosed and the uncharacteristic clinical history of our case are discussed.
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Affiliation(s)
- Simon Lammy
- CT1 Cardiothoracic Surgery, Department of Cardiothoracic Surgery, Royal Infirmary of Edinburgh, UK
- The Collaborative Research (CORE) Group, Australia
- Oxford University Clinical Academic Graduate School, John Radcliffe Hospital, UK
| | - Renzo Pessotto
- Consultant Cardiothoracic Surgeon, Department of Cardiothoracic Surgery, Royal Infirmary of Edinburgh, UK
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15
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Abstract
Inherited factor XI (FXI) deficiency, also called Hemophilia C, is an uncommon autosomal recessive disorder, which is associated with a variable bleeding tendency that usually manifests after trauma or surgery. This concise report reviews current knowledge regarding the pathogenesis, genetics, diagnosis, clinical manifestations and management of this inherited bleeding disorder.
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Affiliation(s)
- Massimo Franchini
- Servizio di Immunoematologia e Trasfusione - Centro Emofilia, Azienda Ospedaliera di Verona, Italy
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16
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Yamagishi T, Ochi N, Yamane H, Fukazawa T, Wada H, Takigawa N. Successful treatment of a lung cancer patient with factor XI deficiency. Haemophilia 2013; 19:e367-9. [PMID: 23992470 DOI: 10.1111/hae.12260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2013] [Indexed: 11/28/2022]
Affiliation(s)
- T Yamagishi
- Department of General Internal Medicine 4, Kawasaki Medical School, Okayama, Japan
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18
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Inhibition of factor XI activation attenuates inflammation and coagulopathy while improving the survival of mouse polymicrobial sepsis. Blood 2012; 119:4762-8. [PMID: 22442348 DOI: 10.1182/blood-2011-10-386185] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Severe bacterial sepsis often leads to a systemic procoagulant and proinflammatory condition that can manifest as disseminated intravascular coagulation, septic shock, and multiple organ failure. Because activation of the contact proteases factor XII (FXII), prekallikrein, and factor XI (FXI) can trigger coagulation and inflammatory responses, the contact factors have been considered potential targets for the treatment of sepsis. However, the pathogenic role of contact activation in severe infections has not been well defined. We therefore investigated whether an anticoagulant antibody (14E11) that selectively inhibits prothrombotic FXI activation by activated FXII (FXIIa) modifies the course of bowel perforation-induced peritoneal sepsis in mice. Early anticoagulation with 14E11 suppressed systemic thrombin- antithrombin complex formation, IL-6, and TNF-α levels, and reduced platelet consumption in the circulation and deposition in the blood vessels. Treatment with 14E11 within 12 hours after bowel perforation significantly improved survival compared with vehicle treatment, and the saturating dose did not increase tail bleeding. These data suggest that severe polymicrobial abdominal infection induces prothrombotic FXI activation, to the detriment of the host. Systemic anticoagulation by inhibiting FXI activation or FXIIa procoagulant activity during sepsis may therefore limit the development of disseminated intravascular coagulation without increasing bleeding risks.
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Histidine-rich glycoprotein binds factor XIIa with high affinity and inhibits contact-initiated coagulation. Blood 2011; 117:4134-41. [DOI: 10.1182/blood-2010-07-290551] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Histidine-rich glycoprotein (HRG) circulates in plasma at a concentration of 2μM and binds plasminogen, fibrinogen, and thrombospondin. Despite these interactions, the physiologic role of HRG is unknown. Previous studies have shown that mice and humans deficient in HRG have shortened plasma clotting times. To better understand this phenomenon, we examined the effect of HRG on clotting tests. HRG prolongs the activated partial thromboplastin time in a concentration-dependent fashion but has no effect on tissue factor–induced clotting, localizing its effect to the contact pathway. Plasma immunodepleted of HRG exhibits a shortened activated partial thromboplastin time that is restored to baseline with HRG replenishment. To explore how HRG affects the contact pathway, we examined its binding to factors XII, XIIa, XI, and XIa. HRG binds factor XIIa with high affinity, an interaction that is enhanced in the presence of Zn2+, but does not bind factors XII, XI, or XIa. In addition, HRG inhibits autoactivation of factor XII and factor XIIa–mediated activation of factor XI. These results suggest that, by binding to factor XIIa, HRG modulates the intrinsic pathway of coagulation, particularly in the vicinity of a thrombus where platelet release of HRG and Zn2+ will promote this interaction.
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Módolo NSP, de Azevedo VLF, Santos PSS, Rosa ML, Corvino DR, Alves LJSC. Anesthetic strategy for cesarean section in a patient with factor XI deficiency. Case report. Rev Bras Anestesiol 2010; 60:176-80, 102-4. [PMID: 20485963 DOI: 10.1016/s0034-7094(10)70023-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Accepted: 12/24/2009] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Factor XI deficiency is a rare hematologic disorder. Hemophilia C (factor XI deficiency) affects both genders and it is usually asymptomatic, manifesting only as postoperative hemorrhage. It is an autosomal recessive, homozygous or heterozygous, disorder, and its severity depends on the levels of factor XI. The objective of this report was to present the anesthetic strategy in a patient with hemophilia C. CASE REPORT This is a 32 years old female, gravida 1/para 0, on the 39th week of pregnancy, scheduled for elective cesarean section. Physical and laboratorial exams did not show any abnormalities. According to the recommendations of the hematologist, on the day of the procedure, the patient was given promethazine, 25 mg, hydrocortisone, 500 mg, due to prior transfusion reaction, and plasma, 10 mL x kg(-1) for a total of 700 mL. Two hours later, the patient underwent subarachnoid block under routine monitoring. Ringer's lactate, 2000 mL, was administered for hydration. The anesthetic-surgical procedure proceeded without intercurrences. Postoperatively, the patient was doing well when, on the 3rd PO day, fresh frozen plasma (FFP), 10 mL x kg(-1), was administered to prevent late postoperative bleeding. CONCLUSIONS The objective of this report was to present the anesthetic protocol for patients with hemophilia C and to alert for the need of investigation in patients with a history of postoperative bleeding, when a coagulation study should e be done before any invasive procedure and, in the case of prolonged aPTT, one should investigate the presence of factor XI deficiency.
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Vasileiadis I, El-Ali M, Nanas S, Kolias S, Zacharatos P, Christopoulou-Cokkinou V, Kotanidou A. First diagnosis of factor XI deficiency in a patient with subarachnoid haemorrhage. Blood Coagul Fibrinolysis 2009; 20:309-13. [PMID: 19367158 DOI: 10.1097/mbc.0b013e328329e485] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Aneurismal subarachnoid haemorrhage (SAH) is a devastating event affecting patients at a fairly young age and accounting for significant morbidity and mortality. Although there is progress concerning diagnostic methods and treatment, this case report might add interesting data to the current understanding of this disease and its clinical management with respect to circumstantial deficiency of the coagulation factor XI (FXI). In this report, we present a unique case of aneurismal SAH in a patient with underlying coagulation FXI deficiency which was incidentally identified after patient's admission, as routine blood tests revealed increased activated partial thromboplastin time. Despite early successful treatment with coiling, the patient had a second episode of SAH a few months after his discharge, due to aneurysm revascularization and rupture. Molecular analysis and identification of new mutations were performed. We describe management of SAH with respect to a coexisting bleeding disorder; also testing of patient's family members for FXI deficiency and decisions about screening for intracranial aneurysm are described. Late complications of SAH are - among others - aneurysm revascularization and rebleeding. Although FXI deficiency could be considered an exacerbating factor, it cannot be definitely implicated.
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Affiliation(s)
- Ioannis Vasileiadis
- First Department of Pulmonary and Critical Care Medicine, Medical School, Evaggelismos Hospital, National and Kapodistrian University of Athens, Athens, Greece
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The use of desmopressin in congenital factor XI deficiency: a systematic review. Ann Hematol 2009; 88:931-5. [DOI: 10.1007/s00277-009-0792-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 07/06/2009] [Indexed: 10/20/2022]
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Pepino F, Granchamp P, Odin I, Decroisette E, Nathan N. [Labour epidural analgesia for a woman with a factor XI deficiency: an illconsidered risk?]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2008; 28:86-90. [PMID: 19101109 DOI: 10.1016/j.annfar.2008.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Accepted: 10/03/2008] [Indexed: 11/18/2022]
Abstract
Inherited bleeding disorders contraindicate epidural analgesia because of the risk of epidural haematoma. However, there is no consensus about a minimal rate of factor XI required for its performance. We report here a case of epidural analgesia in a pregnant woman with a moderate and symptomatic factor XI deficiency, despite this theoretical contraindication. Indeed, the factor XI deficiency results in a haemorrhagic risk which is variable and not easily foreseeable. Nevertheless, no neurological after-effect or excessive bleeding occurred although no specific prophylaxis had been performed.
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Affiliation(s)
- F Pepino
- Service d'anesthésie-réanimation, hôpital de mère et de l'enfant, 8, avenue Dominique-Larrey, 87042 Limoges cedex, France.
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Martin-Salces M, Jimenez-Yuste V, Alvarez MT, Quintana M, Hernandez-Navarro F. Review: Factor XI Deficiency: Review and Management in Pregnant Women. Clin Appl Thromb Hemost 2008; 16:209-13. [DOI: 10.1177/1076029608327864] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Factor XI deficiency is a rare disease found predominantly in Ashkenazi Jews. There is a poor correlation between factor XI level and bleeding in patients with factor XI deficiency. Individuals with severe factor XI deficiency are usually at risk of excessive bleeding after surgery and injury, particularly when trauma involves tissues rich in fibrinolytic activity. Women with partial or severe deficiency are at risk of excessive uterine bleeding during labor. The unpredictable nature of factor XI deficiency complicates management during pregnancy and delivery. This review gives an overview of the management of pregnant women with factor XI deficiency.
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Affiliation(s)
- Monica Martin-Salces
- Haemophilia Unit, Haematology Department, Hospital Universitario La Paz, Madrid, Spain,
| | - Victor Jimenez-Yuste
- Haemophilia Unit, Haematology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Maria Teresa Alvarez
- Haemophilia Unit, Haematology Department, Hospital Universitario La Paz, Madrid, Spain
| | - Manuel Quintana
- Haemophilia Unit, Haematology Department, Hospital Universitario La Paz, Madrid, Spain
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Abstract
Factor IX is a key component of the plasma system that forms a fibrin clot at a site of vascular injury. Activation of factor IX by factor XIa is required in certain situations to prevent bleeding from premature clot degradation. Factor XIa is a coagulation protease comprised of two identical subunits. The biochemical and physiologic implications of this unusual structural feature are being actively investigated. Congenital factor XI deficiency causes a mild-to-moderate bleeding disorder, with hemorrhage typically involving the oral/nasal cavities and the urinary tract. Current treatment recommendations take this tissue-specific bleeding pattern into account and target factor replacement to certain types of procedures and clinical situations. Results from animal models and human population studies indicate that factor XI contributes to thromboembolic disease. This protease may therefore be a legitimate therapeutic target.
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Affiliation(s)
- Stephen B Smith
- Department of Pathology, Vanderbilt University, 777 Preston Research Building, 2220 Pierce Ave, Nashville, TN 37232-6307, USA
| | - David Gailani
- Division of Hematology/Oncology, Vanderbilt University, 777 Preston Research Building, 2220 Pierce Avenue, Nashville, TN 37232-6307, USA, Tel.: +1 615 936 1505, Fax: +1 615 936 3853,
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Souabni L, Meddeb N, Ajlani H, Ben Romdhane N, Sellami S. Hemarthrosis revealing congenital factor XI deficiency. Joint Bone Spine 2008; 75:348-9. [DOI: 10.1016/j.jbspin.2007.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2007] [Accepted: 06/06/2007] [Indexed: 11/28/2022]
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Modelling the effect of amplification pathway factors on thrombin generation: A comparison of hemophilias. Transfus Apher Sci 2008; 38:41-7. [DOI: 10.1016/j.transci.2007.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Avci Z, Malbora B, Gokdemir M, Ozkan S, Ozbek N. Successful use of recombinant factor VIIa (NovoSeven) during cardiac surgery in a pediatric patient with congenital factor XI deficiency. Pediatr Cardiol 2008; 29:220-2. [PMID: 17885783 DOI: 10.1007/s00246-007-9081-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/13/2007] [Accepted: 06/26/2007] [Indexed: 10/22/2022]
Abstract
We report our experience with the use of recombinant activated factor VII (rFVIIa) during cardiac surgery in a 4.5-year-old boy with severe congenital FXI deficiency and a congenital heart disease. After weaning the patient from cardiopulmonary bypass, the first intravenous dose of rFVIIa (90 microg/kg) was administered. This same dosage was repeated eight more times, at 2- to 4-hour intervals postoperatively. There was no bleeding during and after surgery. rFVIIa treatment may be used successfully in children with severe FXI deficiency in major operations such as open heart surgery.
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Affiliation(s)
- Zekai Avci
- Department of Pediatric Hematology, Baskent University Faculty of Medicine, 6. Cadde, No: 72/3, 06490 Bahcelievler, Ankara, Turkey.
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Sucker C, Sabel M, Stummer W, Zotz RB, Scharf RE, Gerhardt A. Recombinant Factor VIIa for the Prophylaxis of Perioperative Hemorrhage in a Patient With Congenital Factor XI Deficiency Undergoing Brain Tumor Neurosurgery. Clin Appl Thromb Hemost 2007; 14:472-5. [DOI: 10.1177/1076029607305119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The authors report on the first successful use of recombinant activated factor VII for the prophylaxis of bleeding during brain tumor neurosurgery in a patient suffering from inherited factor XI deficiency. Using the agent, surgery was performed without any bleeding complications. In this setting, off-label use of recombinant activated factor VII appears to be a promising alternative for patients suffering from this rare hemostatic defect with hitherto limited therapeutic options.
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Affiliation(s)
- Christoph Sucker
- Department of Hemostasis and Transfusion Medicine, Heinrich Heine University Medical Center, Dusseldorf, Germany
| | - Michael Sabel
- Department of Neurosurgery Heinrich Heine University Medical Center, Dusseldorf, Germany
| | - Walter Stummer
- Department of Neurosurgery, Heinrich Heine University Medical Center, Dusseldorf, Germany
| | - Rainer B. Zotz
- Department of Hemostasis and Transfusion Medicine, Heinrich Heine University Medical Center, Dusseldorf, Germany
| | - Ruediger E. Scharf
- Department of Hemostasis and Transfusion Medicine, Heinrich Heine University Medical Center, Dusseldorf, Germany
| | - Andrea Gerhardt
- Department of Hemostasis and Transfusion Medicine, Heinrich Heine University Medical Center, Dusseldorf, Germany, -duesseldorf.de
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Bozzao C, Rimoldi V, Asselta R, Landau M, Ghiotto R, Tenchini ML, De Cristofaro R, Castaman G, Duga S. A novel factor XI missense mutation (Val371Ile) in the activation loop is responsible for a case of mild type II factor XI deficiency. FEBS J 2007; 274:6128-38. [DOI: 10.1111/j.1742-4658.2007.06134.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Keuren JFW, Keuren JFW, Magdeleyns EJP, Govers-Riemslag JWP, Lindhout T, Curvers J. Effects of storage-induced platelet microparticles on the initiation and propagation phase of blood coagulation. Br J Haematol 2006; 134:307-13. [PMID: 16848773 DOI: 10.1111/j.1365-2141.2006.06167.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Platelets shed microparticles, which support haemostasis via adherence to the damaged vasculature and by promoting blood coagulation. We investigated mechanisms through which storage-induced microparticles might support blood coagulation. Flow cytometry was used to determine microparticle number, cellular origin and surface expression of tissue factor (TF), procoagulant phosphatidylserine (PtdSer) and glycoprotein (GP) Ib-alpha. The influence of microparticles on initiation and propagation of coagulation were examined in activated factor X (factor Xa; FXa) and thrombin generation assays and compared with that of synthetic phospholipids. About 75% of microparticles were platelet derived and their number significantly increased during storage of platelet concentrates. About 10% of the microparticles expressed functionally active TF, as measured in a FXa generation assay. However, TF-driven thrombin generation was only found in plasma in which tissue factor pathway inhibitor (TFPI) was neutralised, suggesting that microparticle-associated TF in platelet concentrates is of minor importance. Furthermore, 60% of all microparticles expressed PtdSer. In comparison with synthetic procoagulant phospholipids, the maximal rate of thrombin formation in TF-activated plasma was 15-fold higher when platelet-free plasma was titrated with microparticles. This difference could be attributed to the ability of microparticles to propagate thrombin generation by thrombin-activated FXI. Collectively, our findings indicate a role of microparticles in supporting haemostasis by enhancement of the propagation phase of blood coagulation.
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