Frequency and Determinants of Thrombotic and Bleeding Complications in Ph Negative Myeloproliferative Neoplasms (MPN): The Role of Adamts-13 and VWF Activities in an Italian Cohort 0f 88 Well Characterized Patients

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3369-3369
Author(s):  
Augusto B. Federici ◽  
Maria C Carraro ◽  
Antonella Lattuada ◽  
Chiara Vanelli ◽  
Veronica Sciumbata ◽  
...  

Abstract Abstract 3369 Background: Patients with Ph-negative Myeloproliferative Neoplasms (MPN) such as Polycythemia Vera (PV), Essential Thrombocythemia (ET) and Primary Myelofibrosis (PMF) can be exposed during the course of these MPN to thrombotic and bleeding complications, with increased morbidity and mortality. Age, previous history of thrombosis, increased White Blood Cell (WBC) and Jak2 allele burden have been proposed as risk factors for Venous (VTE) and Arterial (ATE) thromboses while bleeding has been previously associated with abnormalities of the von Willebrand factor (VWF). Aims: To investigate any significant role of ADAMTS-13 and VWF activities in the thrombotic and bleeding complications observed in a small but well characterized cohort of MPN patients. Patients and Methods: 88 consecutive patients were diagnosed at the Hematology and Transfusion Medicine Division, L.SACCO University Hospital of Milan, according to WHO criteria. Patients signed an informed consent to participate in this clinical study with a protocol approved by local IRB and they showed MPN type (%), mean age (range), gender M/F and Jak2 positivity (%) as follows: PV[n=42 (48%), 68 (36–86), 18/24; 85.7%]; ET [n=34 (38%), 66 (30–93), 10/24, 61.7%]; PMF [n=12 (14%), 67 (37–88), 7/5, 58%]. Thrombotic and bleeding episodes were recorded and managed from the time of diagnosis and associated with the use of aspirin (ASA) and of other MPN therapies. Among additional lab parameters, plasmatic ADAMTS-13 and VWF activities were also measured at enrolment as endothelial/platelet marker. These activities were assayed with Technozym ADAMTS-13 activity (Technoclone GmbH, Austria), Innovance VWF-GPIb activity (Siemens AG, Germany) and HemosIL-VWF antigen (Instrumentation Laboratory, USA). Multimeric analyses were also tested using very sensitive intermediate SDS-agarose gel electrophoresis. Statistical analyses were performed by SPSS-17.2. Results: 59/88 (67%) patients did not show any thrombotic or bleeding complications during the 6-year follow-up. In these cases mean (range) values of VWF:GPIb and VWF:Ag were 104 (29–202) and 133 (52–288) U/dL while ADAMTS-13 was 102 (63–143). 20/88 (23%) cases showed at least one thrombotic event (13ATE/7VTE): AMI (6), STROKE (6), TIA (2), PE (1), DVT (7). Patients with thromboses showed relatively higher values VWF:GPIb and lower ADAMTS-13 and this was confirmed in multivariate analysis especially for ET [VWF:GPIb=135 (61–237) U/dL, p=0.004 and ADAMTS-13=89(62–134), p=0.009]. Major bleeding episodes mainly mucosal (5 gastrointestinal, 3 post-surgery, 1 severe menorrhagia) requiring blood transfusions or hysterectomy were observed in 9/88 (10%) patients. At the multivariate analysis, major bleedings were significantly associated with lower VWF:GPIb [68 (25–111) U/dL, p=0.022), lower VWF:Ag [93 (35–146) U/dL, p=0.016] and to the ASA intake (p=0.006). Most of these bleeders showed also a relative loss of the highest molecular weight multimers. Conclusions: Based on these observations, we confirm that thrombotic events in MPN may certainly have multiple risk factors: however, lower ADAMTS-13 and higher VWF activities might play a role as additional risk factors especially in ET. Conversely, lower levels of VWF with loss of the largest multimers are important risk factors for bleeding in MPN especially in patients treated with ASA. Disclosures: No relevant conflicts of interest to declare.

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1149-1149
Author(s):  
Jie Bai ◽  
Yuhui Zhang ◽  
Yingshao Wang ◽  
Guangshuai Teng ◽  
Yan Wang ◽  
...  

Introduction: Thrombosis is the most important risk factor affecting event-free survival and overall survival (OS) of patients with myeloproliferative neoplasms (MPNs). To explore the risk factors of thrombosis in patients with JAK2V617F-mutated MPN, a cohort of 1537 Chinese patients with JAK2V617F-mutated MPN was retrospectively analyzed for clinical characteristics, laboratory characteristics, cytogenetics, thromboembolism, disease progression and OS. Methods: The qualitative data were compared by the Chi-square test or Fisher's test, and continuous variables were compared with the Mann-Whitney U test or Kruskal-Wallis test. The Kaplan-Meier method and multivariate Cox analysis were used to study the risk factors of thrombosis in patients with JAK2V617F-mutated MPN. Results: Among the 1537 MPN patients, 931, 468 and 138 had polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), respectively. The median follow-up time was 7 years (range 1-47), and 12.8% of patients (197/1537) died during this period. A total of 16.8% (259/1399) of PV and ET patients had secondary myelofibrosis, and 2.5% (38/1537) of patients developed acute myeloid leukemia (AML). Thrombosis events occurred in 43.9% (675/1537) of patients, among which 91.4%(617/675) were arterial thrombosis and 16.6% (112/675) were venous thrombosis. The number of thrombosis events in PV, ET and PMF patients was 439 (47.2%), 197 (42.1%) and 39 (28.2%), respectively. The multivariate analysis indicated that age≥60 years old (P=0.003, HR=1.76, 95% CI[1.214, 2.552]), HCT≥48% (P=0.022, HR=1.635, 95% CI[1.073, 2.492]), at least one cardiovascular risk factor (P=0.024, HR=1.559, 95% CI[1.061,2.291]), a history of thrombosis (P<0.0001, HR=2.313, 95% CI[1.573,3.401]), and JAK2V617Fallele burden (V617F%) ≥50% (P=0.003, HR=1.804, 95% CI [1.221, 2.665]) are risk factors for thrombosis in JAK2V617F-mutated MPN. According to the results of the multivariate analysis, a risk model of thrombosis was established and comprised low-risk (0 points), intermediate-risk (1 points) and high-risk (≥2 points) groups, among which the incidence of thrombosis was 9.1%, 33.7% and 72.9%, respectively. Conclusions: The Chinese thrombosis risk model of JAK2V617F-mutated MPN established in this study suggests that elderly patients with a history of thrombosis should reduce V617F%, control HCT to less than 48% and mitigate cardiovascular risk factors, all of which are necessary measures to prevent thrombosis in patients with JAK2V617F-mutated MPN. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4937-4937
Author(s):  
Franca Radaelli ◽  
Stefania Bramanti ◽  
Mariangela Colombi ◽  
Alessandra Iurlo ◽  
Alberto Zanella

Abstract Essential thrombocythemia (ET) is a chronic myeloproliferative disorder characterized by peripheral thrombocytosis and abnormal proliferation of megakariocytes in the bone marrow. Even thought thrombosis is frequently associated to ET, the risk factors of this clinical complication are still controversial. The aim of this retrospective, single institution study was to investigate clinical and laboratory characteristics associated with the occurrence of thrombotic events, with the purpose of identifying subgroups of patients who could benefit from antiaggregant and/or cytostatic treatment. 306 consecutive ET patients (109 men and 197 females, median age 58 yr) diagnosed between January 1979 and December 2002 were included in the study. At the time of analysis, 196 patients were still alive with a median follow up of 96 months. The following variables were investigated for the association with thrombotic complications: age, platelet count, previous history of thrombotic events, time from diagnosis, treatment with antiaggregant/cytostatic drugs, and cardiovascular risk factors such as arterial hypertension, obesity, hypercolesterolemia, diabetes, cigarette smoking. At the time of last follow up, 46 patients (15%) experienced at least one thrombotic event. The occurrence of thrombotic events was observed in 26/64 (40.6%) patients with previous history of thrombosis and in 20/242 (8.3%) patients with no previous history of thrombosis (p&lt;0.0001 Fisher’s exact test, odd ratio 7.6). A significant difference between the two groups of patients was also confirmed when Kaplan Meier estimates of thrombosis-free survival were compared by log-rank test (p&lt;0.0001). By logistic regression, platelet number at diagnosis did not associate with occurrence of thrombosis in the whole patient population. When patients without previous history of thrombosis were stratified according to the number of cardiovascular risk factors (none vs one vs more than one), a significant correlation with occurrence of thrombotic events was observed (Mantel-Haenszel Chi-square 5.47, p&lt;0.05). This study confirms that history of thrombosis is strongly related with risk of further thrombotic events in patients with ET, whereas platelet number at diagnosis does not seem to represent a prognostic factor. In patients with no previous history of thrombosis, the presence of other cardiovascular risk factors has to be taken into account when establishing the therapeutic approach.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 211-211
Author(s):  
David A. Jacobsohn ◽  
Mukta Arora ◽  
John P. Klein ◽  
Joseph H. Antin ◽  
Brian J. Bolwell ◽  
...  

Abstract Abstract 211 The adverse impact of chronic GVHD (cGvHD) on health and quality of life is especially critical in children because of their longer life expectancy and problems impacting growth and development. Although risk-factors for developing cGvHD in children are reported, little is known about risk factors for non-relapse mortality (NRM) in children with cGvHD. Identification of predictors for mortality in children with cGvHD could permit risk-adapted therapy, help plan for clinical trials and assist in counseling. We performed a multivariate analysis using data from CIBMTR to identify transplant- and cGvHD-related risk factors for NRM and survival in a cohort of 1117 subjects aged 0–20 years, transplanted from related donors, unrelated donors (URD), or unrelated cord blood (UCB) in 1995–2004 for acute myelogenous leukemia (AML), acute lymphoid leukemia (ALL), chronic myelogenous leukemia (CML) or myelodysplastic syndrome (MDS). Median age was 12 years. Characteristics of cGvHD at diagnosis were: progressive onset (49%), total bilirubin >2 mg/dL (16%), thrombocytopenia (platelets <100 × 109/L, 32%) and Karnofsky/Lansky (KPS/L) score <80 (24%). Probabilities of NRM at 1, 3, and 5 years after diagnosis of cGvHD were 17% (95% CI: 14–19%), 22% (20-25%) and 24% (21-27%), respectively. Multivariate analysis indentified four factors significantly associated (p<0.01) with higher NRM: (1) HLA-partially-matched or -mismatched URD; (2) peripheral blood cell graft; (3) KPS/L <80 at cGVHD diagnosis; and (4) platelets <100 × 109/L at cGVHD diagnosis. Survival after diagnosis of cGVHD at 1-, 3- and 5-years was 75% (72-77%), 63% (60-66%), and 59% (56-62%). Factors significantly associated with worse survival were: (1) age >10 years; (2) transplant from an HLA-partially-matched or -mismatched URD; (3) advanced disease at transplant; (4) KPS/L <80; and (5) platelets <100 × 109/L. The cumulative incidence of NRM at 5 years was higher for children with KPS/L <80 (46%; CI: 40–52%) than for those with a higher KPS/L score (15%; CI: 12–18%; p<0.001). This translated to poorer survival of 42% (36-48%) vs. 66% (CI: 63–70%; p<0.001), respectively. 5 year cumulative incidence of NRM was also higher in children with platelets <100 × 109/L: 37% (32-43%) vs. 15% (CI: 12–18%; p<0.001). This also resulted in poorer survival (47%, CI: 42–52%; vs. 67%, CI: 63–71%; p<0.001). Cumulative incidence of discontinuation of systemic immune suppression (death and relapse treated as competing risks) at 1, 3 and 5 years after diagnosis of cGvHD were 22% (20-25%), 34% (31-37%), and 37% (34-40%). In conclusion, we identified several factors adversely correlated with NRM and survival children with cGvHD. The correlation between peripheral blood cell grafts and increased NRM without poorer survival may be explained by fewer relapses. This is the first large study elucidating factors affecting outcome after diagnosis of cGvHD in children. Our results may be useful for risk stratification.SurvivalNRMRelative Risk95% CIPRelative Risk95% CIPAge (baseline: 0–9 years)    10-191.321.091.600.005NSKPS/L (baseline: 80–100)<.001<.001    <801.891.522.34<.0013.012.293.96<.001    unknown1.341.001.780.051.641.122.430.015Platelets (x10e9/L) (baseline: ≥ 100)<.001<.001    <1001.631.322.01<0.0012.321.763.07<.001    Unknown1.330.991.780.061.731.182.520.005Donor (baseline: HLA-identical siblings)0.003<0.001    Other related1.681.132.520.0111.670.962.960.07    HLA-well-matchedunrelated1.401.021.940.041.250.801.960.33    Partially matched unrelated1.691.232.310.0011.941.282.940.002    Mismatched unrelated1.751.272.42<0.0012.311.493.59<0.001No data1.020.641.620.941.220.602.130.71Disease State (baseline: Early)<0.0010.005    Intermediate0.960.781.180.700.650.500.850.07    Advanced1.561.192.040.0010.920.631.350.68Graft (baseline: BM)0.002    BloodNS1.761.282.41<0.001    Cord BloodNS1.070.671.700.78NS=Not SignificantCumulative Incidence of NRM by Platelets and KPS/L at Diagnosis of cGvHDCumulative Incidence of NRM by Platelets and KPS/L at Diagnosis of cGvHDSurvival and Cumulative Incidence of Discontinuation of Immune SuppressionSurvival and Cumulative Incidence of Discontinuation of Immune Suppression Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4664-4664
Author(s):  
Philip LY Hui ◽  
Deborah J Cook ◽  
Wendy Lim ◽  
Graeme Fraser ◽  
Donald M. Arnold

Abstract Abstract 4664 Background: The epidemiology of thrombocytopenia in critically ill patients has not been well characterized. The objective of this study was to systematically review the prevalence, incidence, risk factors for, and consequences of thrombocytopenia among critically ill patients. Methods: We searched MEDLINE, EMBASE, the Cochrane Registry for controlled trials (until May 2010), and the Online Computer Library as well as bibliographies of relevant studies to identify investigations designed to examine the frequency, risk factors and/or outcomes associated with thrombocytopenia among patients admitted to the intensive care unit (ICU). We selected studies, abstracted data and assessed methodological quality in duplicate, independently. Heterogeneity of design and analysis precluded statistical pooling of results. Results: We identified 23 studies (12 prospective) enrolling 6,568 patients from medical, surgical, mixed, cardiac or trauma ICUs. Prevalent thrombocytopenia (on ICU admission) occurred in 8.3 – 67.6% of patients; incident thrombocytopenia (developing during the course of the ICU stay) occurred in 13.0 – 44.1% patients. High illness severity, organ dysfunction, sepsis and renal failure were common risk factors. Only 1 study using multivariate analysis examined whether thrombocytopenia was associated with major bleeding but found no association. Six out of 8 studies using multivariate analysis found that thrombocytopenia increased the risk of death. Conclusion: The frequency of thrombocytopenia during critical illness varies widely based on case mix and definition. Thrombocytopenia appears to increase the risk of death after adjustment for confounding factors. The association between thrombocytopenia and bleeding in the ICU has not been adequately examined. Although thrombocytopenia was associated with poor outcomes in most studies, randomized trials of platelet transfusions or other interventions aimed at increasing the platelet count are needed to determine whether improvement of thrombocytopenia can modify these risks. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 858-858
Author(s):  
Anindya Chatterjee ◽  
Joydeep Ghosh ◽  
Baskar Ramdas ◽  
Sasidhar Vemula ◽  
Holly Martin ◽  
...  

Abstract Abstract 858 Multiple genetic checks and balances regulate the complex process of hematopoiesis. Despite these measures, mutations in crucial regulatory genes are still known to occur, which in some cases results in abnormal hematopoiesis, including leukemogenesis and/or myeloproliferative neoplasms (MPN). An example of a mutated gene that contributes to leukemogenesis is the FMS- like tyrosine kinase 3 (Flt3) that encodes a receptor tyrosine kinase, which plays an essential role in normal hematopoiesis. Interestingly, Flt3 is one of the most frequently mutated genes (∼30%) in acute myeloid leukemia (AML). Although various pathways downstream of Flt3 activation that lead to leukemic transformation have been extensively studied, effective treatment options for Flt3ITD mediated leukemogenesis is still warranted. In this study we used genetic, pharmacological and biochemical approaches to identify a novel role of Focal adhesion kinase (FAK) in Flt3ITD induced leukemogenesis. We observed hyperactivation of FAK in Flt3ITD expressing human and mouse cell. Treatment with FAK specific small molecule inhibitors F-14 and Y-11, inhibited proliferation and induced cell death of Flt3ITD expressing cells. Similarly, treatment of primary AML patient samples (n=9) expressing Flt3ITD mutations with F-14 inhibited their proliferation. Consistently expression of a dominant negative domain of FAK (FRNK) inhibited hyperproliferation and induced death of Flt3ITD bearing cells. Further, low-density bone marrow (LDBM) cells derived from FAK−/− mice transduced with Flt3ITD showed significantly reduced growth compared to wild-type (WT) LDBM cells transduced with Flt3ITD. We also observed hyperactivation of Rac1 in Flt3ITD expressing cells downstream of FAK, which was downregulated upon treatment with FAK inhibitor F-14 and Y11. Moreover, expression of dominant negative Rac1N17, or treatment with Rac1 inhibitor NSC23766 inhibited hyperproliferation of ITD bearing cells. We next wanted to ascertain the underlying mechanism of FAK mediated activation of Rac1 in Flt3ITD expressing cells. Toward this end, we found RacGEF Tiam1 to be hyperactive in Flt3ITD expressing cells, which was downregulated upon pharmacological inhibition of FAK. A Tiam1-Rac1 complex was also co-immunoprecipitated from Flt3ITD bearing cells, and this association was perturbed upon pharmacological inhibition of FAK. While, Stat5 a key molecule in Flt3ITD mediated leukemic progression, is activated and recruited to the nucleus to express Stat5 responsive genes; however the mechanism of Stat5 translocation to the nucleus is unknown. We observed a novel mechanism involving FAK and Rac1GTPase, in regulating the nuclear translocation of active Stat5. Pharmacological inhibition of FAK and Rac1 resulted in reduced Rac1 and STAT5 translocation into the nucleus, indicating a role of FAK-Rac-STAT5 signaling in Flt3ITD induced leukemogenesis. More importantly, expression of Flt3ITD in Rac1−/− or FAK−/− LDBM cells, showed inhibition of Stat5 activation and its failure to translocate into the nucleus when compared to Flt3ITD expression in WT-LDBM cells. We also observed association between active Rac1 and active Stat5 in the nucleus and in whole cell lysates of Flt3ITD bearing cells, and also in human AML patient samples (n=3), which was attenuated upon pharmacological inhibition of FAK. To determine the effect of FAK inhibition in vivo on Flt3ITD induced MPN, syngeneic transplantation was performed, and mice were treated with vehicle or with FAK inhibitor F-14. While vehicle treated mice developed MPN within 30 days, mice treated with F-14 showed significant overall survival (*p<0.02) and over 50% F-14 treated mice survived till 60 days post transplantation. Inhibition of kinases, and other signaling molecules, that are deregulated in cancer is an exciting new therapeutic strategy. This study indicate an essential role of FAK and Rac1 molecules in Flt3ITD mediated proliferation, survival and leukemogenesis, and demonstrates a novel mechanistic role of FAK/Rac1 in translocating active Stat5 into the nucleus and regulates transformation. To our knowledge, this is also the first time a role of RacGEF Tiam1 is observed in Flt3ITD induced leukemogenesis. Overall, this study demonstrates inhibition of FAK and Rac1 as potentially novel targets, and provides an alternative approach in treating humans suffering from Flt3-ITD induced AML. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1606-1606
Author(s):  
Kayo Shirado Harada ◽  
Kazuhiko Ikeda ◽  
Kazuei Ogawa ◽  
Hideyoshi Noji ◽  
Hideo Kimura ◽  
...  

Abstract Myeloproliferative Neoplasms (MPNs) are characterized by clonal proliferative hematopoiesis with increased mature blood cells. The signal-activating mutations such as JAK2V617F increase blood cells, but it remains uncertain how an abnormal hematopoietic cell clone expands in MPNs. We have recently showed that overexpression of the high mobility group AT-hook 2 (HMGA2) causes proliferative hematopoiesis with providing a clonal growth advantage to hematopoietic cells in mice (Ikeda et al, Blood, 2011), suggesting the possibility that HMGA2 contributes to the pathogenesis of MPNs. However, since only a few studies have evaluated expression of HMGA2 mRNA in patients with MPNs, the role of HMGA2 in the pathogenesis of MPNs is yet unclear. MPNs also show mutations in epigenetic modifiers involving DNA methylation such as polycomb group genes (PcG) and aberrant expressions of micro RNAs (miRNA) that negatively regulate expressions of targeted genes. Interestingly, deficiency in either PcG-related BMI1 (Oguro et al, J Exp Med, 2012) or let-7-family miRNA (Mayr et al, Science, 2007) causes deregulation of HMGA2 expression, leading to its oncogenic activity in part by negatively regulating tumor suppressor p16. Thus, in this study, to clarify the role of HMGA2 in MPNs, we investigated expression of HMGA2 mRNA in peripheral granulocytes of 56 patients with MPNs including 23 polycythemia vera (PV), 26 essential thrombocythemia (ET) and 7 primary myelofibrosis (PMF) along with clinical findings, JAK2V617F allele burden, expressions of BMI1 mRNA and let-7-family miRNAs, and promoter methylation of p16. Quantitative RT-PCR (qPCR) showed significantly higher expression of HMGA2 mRNA relative to internal control HPRT1 mRNA in PMF (mean ± SD; 31.7 ± 42.8, p<0.01), but not PV (15.7 ± 53.2) or ET (2.14 ± 7.70), compared with 12 healthy volunteers (HV; 0.431 ± 0.366). In addition, deregulated HMGA2 expression (>1.2), which was determined as relative expression level above mean + 2SD of HMGA2 mRNA in 12 HV, was most frequently detected in patients with PMF [7/7 (100%)] (p<0.01), compared with PV [5/23 (21.7%)] and ET [6/26 (23.1%)]. We also found a significant positive correlation in expression levels of HMGA2 mRNA with serum LDH values (r=0.531, p<0.01) rather than JAK2V617F allele burden (r=0.25, p=0.08). These data suggested that expression of HMGA2 mRNA independently correlated with disease phenotype and status in MPNs. We next explored the cause of deregulated expression of HMGA2 mRNA and found lower expression of let-7a (0.19 ± 0.13 vs. 0.42 ± 0.39, p=0.04) and -7c (0.57 ± 0.60 vs. 1.14 ± 0.94, p=0.06) rather than -7b (p=0.2) by qPCR, in patients with deregulated expression of HMGA2 mRNA compared with other patients. However, HMGA2-involved chromosomal abnormality in 12q13-15 was not detected in any patient, and there was no difference in expression of BMI1 mRNA between patients with deregulated expression of HMGA2 mRNA and other patients. Thus, decreased expression of let-7 miRNAs might contribute to deregulated expression of HMGA2 mRNA in MPNs. Finally, we investigated correlation of deregulated expression of HMGA2 mRNA with promoter methylation of p16. Methylation-specific PCR assay detected promoter methylation of p16 in 17/56 (30.4%) patients with MPNs. Strikingly, patients with deregulated expression of HMGA2 mRNA significantly more often showed promoter methylation of p16 compared with other patients [10/18 (55.6%) vs. 7/38 (18.4%), p<0.01]. Furthermore, patients with promoter methylation of p16 showed higher expression levels of HMGA2 mRNA than patients without the methylation, especially in patients with PMF (2.33 ± 0.90 vs. 70.9 ± 38.3, p=0.01). In conclusion, deregulated expression of HMGA2 in association with decreased expression of let-7 miRNAs may play a crucial role in the pathogenesis of MPNs possibly through p16. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2369-2369
Author(s):  
Ashish V Chintakuntlawar ◽  
Jennifer Guenther ◽  
Rajiv K Pruthi ◽  
John A. Heit ◽  
Mrinal M. Patnaik

Abstract Introduction Hereditary antithrombin (AT) deficiency is an autosomal dominant thrombophilia. It is classified into type 1 (quantitative) or type 2 (qualitative) deficiency based on the AT antigen and activity levels (Haemophilia 2008:14; 1229). The goal of this study was to correlate clinical phenotype with AT molecular defects. Methods After IRB approval, patients with a diagnosis of hereditary AT deficiency established at the Mayo Clinic, Rochester, were identified from the clinical database (1997-2012). AT activity was assayed by a chromogenic Factor Xa assay and AT antigen level was assayed by latex immunoassay. Peripheral blood leukocyte genomic DNA was extracted using standard methods. PCR-amplification and ABI BigDye Terminator cycle sequencing kit was performed for all SERPINC1 exons, intronic splicing regions and the 3’UTR. SERPINC1 sequence was analyzed using Mutation Surveyor software (SoftGenetics). Clinical data were obtained from patient interview and medical record review. An event was defined as an episode of venous thromboembolism (VTE), including deep vein thrombosis and/or pulmonary embolism; arterial thrombosis, including cerebrovascular event and/or myocardial infarction, and an obstetric event, including miscarriages and/or spontaneous abortions. Statistical analysis was performed with SAS 9.1.3 (SAS Institute Inc. Cary, NC). Results Of 30 patients with hereditary AT deficiency; sequence data was available on 22. Twenty-nine (97%) patients were white, and 19 (63%) were females. Six patients (20%) were smokers and 9 (30%) had a body mass index of >30. Based on the AT activity and antigen levels, 18 (81%) had type 1 AT deficiency, while the remainder had type 2. Eleven patients were heterozygous for six novel (all type 1) mutations. One patient was also a homozygous carrier for the Factor V Leiden mutation. The median age at first thrombotic event was 24.4 years (range, 16.2-70.7), and the median age at diagnosis of AT deficiency was 40.7 years (range, 17.8-76). Both, the median ages at first thrombotic event and at diagnosis were comparable in type 1 versus type 2 AT deficiency patients (P=0.52 and 0.97 respectively). Thirteen patients (43%) had unprovoked thrombotic events. Majority had VTE (n=21, 70%), which included one patient each with splanchnic venous thrombosis, and cerebral venous sinus thrombosis. At last follow up, twenty-one patients (70%) were on chronic anticoagulation [17 (81%) were on warfarin, 2 (9.5%) on enoxaparin and 2 (9.5%) were on rivaroxaban]. Median number of events was 1 (range 0-7). Four patients (19%) had bleeding complications from anticoagulation. Only one death was noted in the cohort and cause of death could not be determined. Conclusions Type 1 hereditary AT deficiency is the most clinically prevalent subtype in practice. Of the patients who developed thrombosis; clinical characteristics did not differ between type 1 and type 2 AT deficiency. We report 6 novel mutations in patients with hereditary AT deficiency. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2391-2391
Author(s):  
Harold J. Leraas ◽  
Jina Kim ◽  
Zhifei Sun ◽  
Uttara P. Nag ◽  
Brian D. Ezekian ◽  
...  

Abstract Background: Venous thromboembolism (VTE) is an uncommon but clinically significant postoperative complication in children. Incidence of VTE in pediatric patients ranges from 34-58 per 10,000 hospitalized children1. Due to rarity of these events, there is limited information about the factors predisposing children to VTE after surgery. We queried a national surgical database to identify risks and outcomes associated with VTE in pediatric surgical patients. Methods: The National Surgical Quality Improvement Program-Pediatric (NSQIP) is a prospectively collected database that records pediatric surgical information, surgical approaches, and 30 day patient outcomes. The database was queried for the years 2012-2013 to identify pediatric patients (age < 18) who had received surgical intervention and were diagnosed with postoperative VTE. Because of their separate coding in NSQIP, we defined VTE as including venous thromboembolism, or pulmonary embolism (PE) diagnosed radiographically within 30 days of operation. To reduce non-random differences between patients we used propensity scores based on age, sex, race, BMI, and ASA classification to match patients in a 1:2 ratio using the nearest neighbor method. Using univariate and multivariate analysis, we identified preoperative risk factors associated with VTE. Results: In total, 130 patients were identified who developed VTE postoperatively (VTE n=122, PE n=7, BOTH PE + VTE n= 1) from this database of 114,395 patients. There were 104 patients with VTE that also had complete entries and were subsequently analyzed in this study. Surgical specialties treating patients in this analysis included cardiothoracic surgery, general surgery, neurosurgery, orthopedic surgery, otolaryngology, plastic surgery, and urology. Eighty-one unique operative CPT codes were identified for patients with VTE. Patients who developed VTE had increased operative time, anesthesia time, and total length of stay (all p < 0.001). Multivariate analysis demonstrated that pneumonia (odds ratio [OR] 1.73, 95% confidence interval [CI] 1.3 - 2.29), Central Line Associated Bloodstream Infection (CLABSI) (OR 1.69, 95% CI 1.18 - 2.42), sepsis (OR 1.47, 95% CI 1.18 - 1.82), septic shock (OR 1.36, 95% CI 1.06 - 1.75), and current solid or hematologic malignancy or active treatment of malignancy (OR 1.30, 95% CI 1.08 - 1.58) were all statistically significant risk factors associated with development of VTE (all p < 0.05). Conclusions: Postoperative VTE risk is significantly increased in children with malignancy or severe infections. Further research is needed to understand the mechanism between malignancy, systemic inflammation, and VTE risk in children. These findings may help to identify patients in need of prophylactic treatment in order to reduce postoperative thrombotic risk in pediatric patients. References: 1. Raffini L, Huang YS, Witmer C, Feudtner C. Dramatic increase in venous thromboembolism in children's hospitals in the United States from 2001 to 2007. Pediatrics. 2009;124(4):1001-1008. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1100-1100
Author(s):  
Mario Von Depka ◽  
Carsten Detering ◽  
Stefanie Döpke ◽  
Mahnaz Ekhlasi-Hundrieser

Abstract Objectives: von Willebrand disease (VWD) is the most common hereditary bleeding disorder. This study reviews the management of perioperative anticoagulation in patients with VWD undergoing surgical procedures. Risk factors for VTE with von Willebrand factor (VWF) concentrate use are older age, previous VTE, obesity, surgery, hormone replacement therapy use, antifibrinolytic therapy use and high post infusion FVIII levels. Currently, there are few data from randomized clinical trials assessing efficacy and possible complications of perioperative VTE prophylaxis in VWD patients. Methods: A total number of 116 surgeries were performed (minor: n=64 and major: n=52) in this retrospective, single-centre study. They were divided into groups of perioperative non-anticoagulation (n=54) and perioperative anticoagulation (n=62), who all received coagulation factor concentrate (CFC). Sub-analyses were done according to the type of concentrate used. Anticoagulation was performed using different low molecular weight heparins (LMWH) according to standard protocols or body-weight adapted doses in patients with either elevated body-mass-index or additional thrombosis risk factors. Blood samples had been collected pre- and post-surgery (up to 21 days) to analyse PT, aPTT, PFA, and trough levels of FVIII coagulant activity (FVIII:C), VWF activity (VWF:GPIbM) and antigen (VWF:Ag), respectively. Furthermore, the median doses of CFC/kg and the median total number of infusions were calculated. The rates of clinically overt thrombosis as well as bleeding were assessed during the post-operative phase. Results: The majority of patients suffered from VWD type 1 (104), 9 patients with type 2A, 2 with type 2M and 1 with type 3 VWD. Humate-P (H) was used in 55 patients and 61 patients received Wilate (W). Using W, we found parallel curves for FVIII:C, VWF-antigen and VWF:GPIbM, respectively. Using H, less concordance between VWF:Ag and VWF:GPIbM was visible and FVIII:C tends to increase between D3 to D10 in spite of decreasing VWF:Ag and VWF:GPIbM. This observation was visible in minor as well as major surgical procedures. LMWH (Enoxaparin, Nadroparin and Certaparin) were used in doses between 30 and 100 mg/injection (mean 46.0 ± 18.5 mg/injection) and a mean of 32.2 ± 24.6 injections in total (range: 8-112). In one patient a significant haematoma occurred (1/116; 0.9%), also one thrombotic event was documented in a different patient (1/116; 0.9%). Conclusion: Using standard dose LMWH in patients with no overt increased thrombosis risk as well as body-weight-adapted LMWH in high risk patients seem to be safe and effective in VWD patients receiving coagulation factor concentrate perioperatively. However, prospective randomized comparative studies are required to determine the optimal indication as well as type of anticoagulation according to the CFC treatment regimen in this setting. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 216-216
Author(s):  
Chanté L Richardson ◽  
Valerie M Schrott ◽  
Claudette M St. Croix ◽  
Yinna Wang ◽  
Catherine G Corey ◽  
...  

Abstract Iron and erythropoietin (Epo) are intimately linked regulators of erythropoiesis. Moderate iron restriction suppresses erythropoiesis at the Epo-dependent, CFU-E stage, without induction of apoptosis and without suppression of other hematopoietic cell lineages. Iron modulates Epo bioactivity in patients with iron deficiency anemia (IDA) and patients with anemia of chronic disease and inflammation (ACDI). To conserve iron when supplies are low, this erythroid iron restriction response reduces iron consumption by suppressing erythropoiesis. The erythroid iron sensor is unknown. Aconitases are multifunctional iron-sulfur cluster proteins localized in the cytosol (Aco1) and mitochondria (Aco2) that convert citrate into isocitrate. We have shown that iron restriction inhibits Aco2 enzymatic activity leading to suppression of erythropoiesis in vitro, and these effects are reversed by isocitrate. Isocitrate corrects IDA in mice and ACDI in rats (Bullock GC, et al. Blood. 2010;116:97-108; Richardson CL, et al. J Clin Invest. 2013 Aug 1;123(8):3614-3623). Iron restriction also alters the cross-talk between transferrin receptor and Epo receptor signaling pathways. These results suggest that Aco2 is an iron-responsive regulator of erythropoiesis. We are investigating the downstream molecular signaling mechanisms by which iron restriction induced-inactivation of Aco2 suppresses erythropoiesis. Our novel preliminary data show that mitochondrial oxidative metabolism rates change over time during erythropoiesis and that iron restriction reduces erythroid mitochondrial metabolism 4 to 7-fold compared to iron replete controls. This iron restriction induced change in respiration is associated with a significant, 1.5 to 3-fold, increase in mitochondrial superoxide production without a corresponding increase in hydrogen peroxide. Importantly, these mitochondrial alterations are reproduced by direct inhibition of aconitase with fluoroacetate (FA) and are not due to changes in mitochondrial number. Further, isocitrate reverses the effects of iron restriction or aconitase inhibition on mitochondrial metabolism and attenuates superoxide production. Based on these data and the known role of reactive oxygen species (superoxide/hydrogen peroxide) in Epo signaling, we propose the overarching hypothesis that iron restriction inhibits mitochondrial aconitase which, in turn, alters erythroid mitochondrial metabolism and ROS signaling resulting in suppression of erythropoiesis (Figure 1). We show for the first time bioenergetics profiles from iron restricted and iron replete primary human erythroid progenitor cells undergoing erythropoiesis. We also show that moderate levels of iron restriction cause mitochondrial dysfunction and alterations in mitochondrial ROS in differentiating erythroid progenitors. The clinical relevance of this project lies in its potential for the development of new iron-free agonists and antagonists of red blood cell production. Agonists may benefit patients with anemia due to iron deficiency or chronic inflammation and antagonists may benefit patients with myeloproliferative neoplasms. Figure 1: Proposed mechanism of iron-dependent regulation of erythropoiesis Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


Sign in / Sign up

Export Citation Format

Share Document