Alicia N. Blanco

Thrombosis: A major contributor to global disease burden

Thrombosis is a common pathology underlying ischemic heart disease, ischemic stroke, and venous thromboembolism (VTE). The Global Burden of Disease Study 2010 (GBD 2010) documented that ischemic heart disease and stroke collectively caused one in four deaths worldwide. GBD 2010 did not report data for VTE as a cause of death and disability. We performed a systematic review of the literature on the global disease burden due to VTE in low, middle and high income countries. Studies from Western Europe, North America, Australia, and Southern Latin America (Argentina) yielded consistent results with annual incidences ranging from 0.75 to 2.69 per 1,000 individuals in the population. The incidence increased to between 2 and 7 per 1,000 among those 70 years of age or more. Although the incidence is lower in individuals of Chinese and Korean ethnicity, their disease burden is not low because of population aging. VTE associated with hospitalization was the leading cause of disability-adjusted-life-years (DALYs) lost in low and middle income countries, and second in high income countries, responsible for more DALYs lost than nosocomial pneumonia, catheter-related blood stream infections, and adverse drug events. VTE causes a major burden of disease across low, middle, and high income countries. More detailed data on the global burden of VTE should be obtained to inform policy and resource allocation in health systems, and to evaluate if improved utilization of preventive measures will reduce the burden.

Thrombosis: A Major Contributor to Global Disease Burden

Thrombosis is a common pathology underlying ischemic heart disease, ischemic stroke, and venous thromboembolism (VTE). The Global Burden of Disease Study 2010 (GBD 2010) documented that ischemic heart disease and stroke collectively caused one in four deaths worldwide. GBD 2010 did not report data for VTE as a cause of death and disability. We performed a systematic review of the literature on the global disease burden due to VTE in low-, middle-, and high-income countries. Studies from Western Europe, North America, Australia, and Southern Latin America (Argentina) yielded consistent results with annual incidences ranging from 0.75 to 2.69 per 1,000 individuals in the population. The incidence increased to between 2 and 7 per 1,000 among those 70 years of age or more. Although the incidence is lower in individuals of Chinese and Korean ethnicity, their disease burden is not low because of population aging. VTE associated with hospitalization was the leading cause of disability-adjusted-life-years (DALYs) lost in low- and middle-income countries, and second in high-income countries, responsible for more DALYs lost than nosocomial pneumonia, catheter-related blood stream infections, and adverse drug events. VTE causes a major burden of disease across low-, middle-, and high-income countries. More detailed data on the global burden of VTE should be obtained to inform policy and resource allocation in health systems, and to evaluate if improved utilization of preventive measures will reduce the burden.

Biological and clinical response to desmopressin (DDAVP) in a retrospective cohort study of children with low von Willebrand factor levels and bleeding history.

The diagnosis and management of von Willebrand disease (VWD) in paediatrics is challenging. Our aim was to review patients characteristics related to biological and clinical response to DDAVP in children with low von Willebrand factor (VWF) levels and bleeding history from a single institution. We included a retrospective cohort of 221 children (median age 11 years; 137 females): 27 type 1 (VWF levels within 15-30 IU dL-1) and 194 possible type 1 (VWF levels within 31-49 IU dL-1). The DDAVP infusion-test was performed in 214/221 children, 93.4% of whom showed good response. Patients with type 1 were at higher risk of DDAVP-test failure: 9/26 (34.6%) vs. 18/188 (9.6%) with possible type 1 (RR 3.44, 1.75-6.79; p= 0.002, Fishers exact test). In 68 children, the clinical response to DDAVP was evaluated 87 times: i) to stop bleeding: menorrhagia (13), mucocutaneous (12), haemarthrosis (1); and ii) to prevent surgical bleeding: adenotonsillectomy (17), major (15) and minor surgery (10); and dental procedures (19). No major adverse events or bleeding were observed. The treatment was effective with one single dose of DDAVP in almost all patients, without antifibrinolytic or local therapy, except in a girl with severe haemorrhage during menarche who required replacement therapy. In conclusion, patients with VWD type 1 were at higher risk of no response to DDAVP infusion-test. In this series, one dose of DDAVP proved effective and safe for children with VWD. Since this is a safe, effective and affordable therapy, we consider that a wider use should be promoted, especially in developing countries.

Major haemorrhage related to surgery in patients with type 1 and possible type 1 von Willebrand disease

Patients with von Willebrand disease (VWD) frequently bleed under a challenge. The aim of our study was to identify predictive markers of perioperative major haemorrhage in type 1 (VWF:RCo = 15-30 IU dl(-1)) and possible type 1 (VWF:RCo = 31-49 IU dl(-1)) VWD patients. We recorded perioperative bleeding complications previous to diagnosis and laboratory parameters in 311 patients with 498 surgical procedures. The patients were grouped according to the absence (A) or presence (B) of perioperative major haemorrhages. Eighty-one patients (26%) and 87 surgical procedures (17.5%) presented major haemorrhages associated with surgeries. There was no difference between the percentage of type 1 and possible type 1 VWD patients who had major haemorrhages (32.6% and 24.8% respectively; p = ns). No difference in the prevalence of O blood group, age, gender, positive family history and laboratory test results (FVIII and VWF) was observed, independent of the haemorrhagic tendency. Bleeding after tooth extraction was the most frequent clinical feature observed in patients with perioperative major haemorrhages. The bleeding score and the number of bleeding sites (> or = 3) were not predictors of major haemorrhage associated with surgery. Caesarean section and adenotonsillectomy showed the highest frequency of major haemorrhages (24.6% and 22.3%, respectively). In conclusion, type 1 and possible type 1 VWD patients showed similar incidence of perioperative major haemorrhages. Laboratory tests and positive family history did not prove to be effective at predicting major haemorrhages in patients that had either type 1 or possible type 1 VWD. The history of bleeding after tooth extraction could define risk factors of major haemorrhage.

Effect of acenocoumarine on the breast-fed infant

Apart from teratogenic phenomena and the potential risk of maternal or neonatal peripartum haemorrhage, the use of oral anticoagulants during pregnancy poses an additional hazard: the risk of transferring some anticoagulant activity to the nursing infant through breast milk. We analysed the coagulation status of seven full term breast-fed neonates whose mothers were under chronic anticoagulant therapy with acenocoumarine as thromboembolic prophylaxis following cardiac valve replacement. Prothrombin Times (PT) observed in neonates were significantly higher than the corresponding maternal values. Data were subsequently compared with those obtained from a control group comprising forty-two full term neonates nursed by non-anticoagulated mothers: coagulation profiles again showed no signs of any noticeable antivitamin K effect. Our results indicate that mothers given acenocoumarine at therapeutic doses may safely breast-feed their infants: anticoagulant activity in breast milk seems to be negligible as assessed by neonates PT.

Intraplatelet levels of vWF:Ag and fibrinogen in myeloproliferative disorders

Several platelet function abnormalities have been described in the myeloproliferative syndromes. We have measured the intraplatelet vWF:Ag and fibrinogen (FI) in the platelet lysates by Laurell technique in 11 patients with polycythemia vera (PV), 10 with essential thrombocythemia (ET), 14 with chronic myelocytic leukaemia (CML) and 3 with myelofibrosis (MF) and these results were correlated with platelet function abnormalities. Decreased intraplatelet levels of vWF:Ag and FI were found in all the patients with ET and MF, in 8 out of 11 PV and 3 out of 14 CML. A statistical significant correlation was observed between the intraplatelet levels of vWF:Ag and FI in the control group and in CML and PV, but no correlation was found in ET and MF. No correlation was observed between the plasmatic and the intraplatelet levels of vWF:Ag and FI in any group. Evidences of platelet activation (spontaneous platelet aggregation or circulating platelet aggregates) were observed in 40% of the cases with ET and PV, and all these cases had low intraplatelet levels of both antigens. None of the cases with MF had evidences of platelet activation and 2 out of 14 patients with CML had platelet activation. The deficiency of the dense bodies was less frequent than the depletion of the alpha granules (5 out of 11 PV, 4 out of 10 ET, 6 out of 14 CML and 2 out of 3 MF). The low intraplatelet contents of vWF: Ag and FI, more frequently observed in ET and PV, may be the result of platelet activation and in vivo release, but megakaryocyte dysfunction is more likely in myelofibrosis.

Antiphospholipid antibodies and hyperhomocysteinaemia in patients with vascular occlusive disease

Hyperhomocysteinemia (HHcy), lupus anticoagulant (LA) and anticardiolipin antibodies (ACA) are independent risk factors for thrombosis. Even though risks are cumulative, the clinical impact of the association is unknown. Preliminary data suggested that HHcy might be associated with transient LA and ACA, disappearing after lowering HHcy. We prospectively evaluated the association of HHcy and LA/ACA, the effect of lowering HHcy with folic acid in LA behavior, and the correlation of the initial dRVVT with LA behavior after folic acid in 210 patients with thrombosis and adverse pregnancy outcomes. Prevalence of HHcy among patients with LA/ACA was 40%. Thirty-one patients exhibited only HHcy (15%; Group 1), 106 (50%; Group 2) had only LA/ACA, while 73 (35%; Group 3) had both. After therapy, 63% and 64% of LA/ACA remained positive in Group 3 and 2, respectively. We observed a trend towards a more positive dRVVT in persistent LA after lowering HHcy. No differences in clinical presentation or in outcomes after two years of followup were observed among the groups. Even though the association of HHcy and LA/ACA is common in patients with thrombosis, it might have no prognostic implications if Hcy levels are lowered. Currently, no laboratory findings correlate with LA behavior, which is independent of homocysteine levels and vitamin treatment.

Diagnosis and management of von Willebrand disease in a single institution of Argentina.

Von Willebrand disease (VWD) is a bleeding disorder with variable clinical expression. In this article we describe types, clinical features, genetic testing when needed, genotype/phenotype relationships, and the response to desmopressin (DDAVP) testing, according to our experience. Our findings are possible type 1, 69.6%; type 1, 13.5%; severe type 1, 0 .35%; type 3, 0.55%; type 2A, 9.5%; probable 2B, 0.6%; type 2M, 2.5%; and probable type 2N, 3.4%. The most frequent symptoms are ecchymoses-hematomas and epistaxis, and, in females >over 13 years also menorrhagia. In pregnant patients, assessment of laboratory parameters in months 7 and 8 is recommended to plan the need for prophylaxis at term. DDAVP merits to be considered as the first-choice therapy, including pregnant women and children, and no patient showed significant unwanted effects. Because this is a safe, effective, and affordable therapy, we hope to encourage clinicians, mainly pediatricians and obstetricians, to a wider use of DDAVP, especially in developing countries. We also report two patients with prophylactic treatment.

Global public awareness about atrial fibrillation

Essentials Early recognition of atrial fibrillation helps in stroke prevention. Survey in 10 countries to assess public awareness of atrial fibrillation. Overall global awareness of atrial fibrillation was 48%. Less than 46% of participants were aware atrial fibrillation leads to stroke.

Prophylaxis during surgery in antithrombin III deficiency with low dose of concentrates.

Considering that there is not «in vivo» evidence of the minimum value of AT (antithrombin III) required to avoid a thrombotic episode, we report a patient who underwent a histerectomy with low dose of AT concentrates