Manuel Moreno-Hernández

Activated protein C resistance and factor V Leiden in Mexico.

A common cause of hereditary thrombophilia is activated protein C resistance (APCR), and most cases result from factor V Leiden mutation. An APCR phenotype without association with factor V Leiden has been described. This transversal, observational, nonrandomized study evaluated these 2 phenomena in healthy indigenous and mestizo Mexican subjects (n = 4345), including 600 Mexican natives. No indigenous subjects had APCR, but 82 mestizo subjects did. After retesting, 50 subjects had a negative test. The remaining 32 subjects had factor V Leiden, giving a 0.85% prevalence of factor V Leiden in the mestizo Mexican population. Only 31% of APCR carriers had factor V Leiden. These results show a very low prevalence of APCR and factor V Leiden in Mexico. Except for factor V Leiden, there are no other mutations in the factor V gene responsible for the APCR phenotype. Acquired APCR is nearly twice as prevalent as the inherited variant.

von Willebrand's disease in Mexico: a pilot study

von Willebrands disease (VWD) is the most commonly inherited bleeding disorder. For a long time, it has been said that VWD was absent in some countries due to ethnical differences. Information about the prevalence of VWD in Mexico remains unclear, owing largely to poor awareness and diagnosis of the disease. The aim of this study was to objectively diagnose VWD in a cohort of highly selected Mexican patients with a chronic history of bleeding. Mexican Mestizos were recruited between July 2010 and August 2011. Included were 133 adult and paediatric patients with a high suspicion of VWD. Fifty‐three were diagnosed with VWD: 47 (88.7%) with type 1 VWD, four (7.5%) with type 2a VWD and two (3.8%) with type 3 VWD. Mean age for female patients was 19.5 years (range 3–44 years) and 18.5 years (range 4–63 years) for male patients. Mean age at start of bleeding symptoms was 8.8 years (range 1–61). The most frequent clinical symptoms were epistaxis (84.9%), ecchymosis (79.2%), haematomas (71.7%), gum bleeds (62.3%) and petechia (50.9%). Severe transoperative or postoperative bleeding was found in 17 patients (32.1%). Twenty‐six women at childbearing age had a history of abnormal gynaecological bleeding. Our results clearly demonstrate the presence of VWD in Mexican and underscore the importance of a more detailed description of VWD. Efforts to increase the awareness and diagnosis of VWD could help in better identification of patients with bleeding disorders and lead to early, appropriate management with safe and efficacious therapies such as desmopressin and plasma concentrates.

Impact of Classical Risk Factors for Arterial or Venous Thrombosis in Patients With Antiphospholipid Syndrome

There are classical risk factors associated with arterial thrombosis (AT) or venous thromboembolic disease (VTD). However, less is known about these risk factors and AT or VTD episodes in patients with antiphospholipid syndrome (APS). Our aim was to elucidate whether APS-related thrombotic episodes are associated with the same risk factors as the non-APS population. We gathered demographics, medical history, complications, and causes of death associated with the risk factors for AT or VTD in patients with APS. We analyzed 677 thrombotic events in 386 patients. Type 2 diabetes mellitus and grade 3 obesity were associated with VTD instead of AT. There were no significant differences between the groups for almost all laboratory tests analyzed, although lupus anticoagulant was significantly higher in the VTD group. We suggest that thrombosis in APS is due to the APS itself and that the risks factors for AT or VTD do not have a main role. Our findings may have an ethnical background. Therefore, it may be difficult to elaborate predictive thrombotic clinical scores applicable to patients with different ethnical background.

Effects of the contraceptive skin patch and subdermal contraceptive implant on markers of endothelial cell activation and inflammation

Changes in blood coagulation factors may partially explain the association between hormonal contraceptives and thrombosis. Therefore, the likely effects of the contraceptive skin patch and subdermal contraceptive implant on levels of inflammatory markers and endothelial activation were analyzed. This was an observational, prospective, longitudinal, nonrandomized study composed of 80 women between 18 and 35 years of age who made the decision to use the contraceptive skin patch or subdermal contraceptive implant. vascular cell adhesion molecule‐1 (VCAM‐1), endothelial cell leukocyte adhesion molecule‐1 (ELAM‐1), von Willebrand factor (VWF), and plasminogen activator inhibitor type 1(PAI‐1) as well as high‐sensitivity C‐reactive protein (hsCRP) were assayed before and after 4 months of use of the contraceptive method. VCAM‐1, VWF, and PAI‐1 remained unchanged in the contraceptive skin patch group; however, a significant increase in hsCRP (0.29–0.50 mg/dL; P =.012) and a significant decrease in ELAM‐1 (44–25 ng/mL; P =.022) were observed. A significant diminution in VCAM‐1 (463–362 ng/mL; P =.022) was also found in the subdermal contraceptive implant group. Our results strongly suggest that these contraceptive methods do not induce endothelial activation after 4 months of use. Increase in hsCRP levels was unrelated to changes in markers of endothelial activation.