RESUMEN
Von Willebrand disease (VWD) is the most common inherited bleeding disorder and is divided into three types, namely type 1, type 2 (2A, 2B, 2M, 2N), and type 3. We report a case of a 24-year-old Caucasian woman with a rare variety of type 2M VWD. Her von Willebrand factor versus antigen ratio was 0.44 (normal ratio is greater than 0.7) . She was asymptomatic and hence not treated but followed up regularly. VWD is not life-threatening when treated timely.
RESUMEN
Bombay blood group or Oh phenotype is a rare autosomal recessive phenotype within the ABO blood grouping system. It occurs due to a mutation in the H gene that produces H antigen on red blood cells (RBCs). Individuals with two mutant H genes lack H antigen on RBCs and have anti-H antibodies in serum. At the time of blood grouping, this blood group mimics O blood group but it shows incompatibility with O group blood during cross matching. Several studies have reported an association of decreased von Willebrand factor (VWF) levels in plasma with ABO blood groups. Here we report a case of a 19-year-old male, who was labelled as Bombay phenotype and later found to have markedly reduced plasma VWF levels.
RESUMEN
Increased plasma levels of von Willebrand factor antigen (vWF:Ag) are associated with high risk of coronary artery disease. The effect of statin therapy on vWF:Ag levels remains uncertain. Therefore the aim of this meta-analysis was to evaluate the effect of statin therapy on vWF:Ag Levels. A systematic multiple-database search was carried out to identify randomized controlled trials (RCTs) that investigated the effect of statins on plasma vWF:Ag levels. Random-effect meta-analysis of 21 treatment arms revealed a significant decrease in plasma vWF:Ag levels following statin therapy (SMD: -0.54, 95 %CI: -0.87, -0.21, p=0.001). In subgroup analyses, the greatest effect was observed with simvastatin (SMD: -1.54, 95 %CI: -2.92, -0.17, p=0.028) and pravastatin (SMD: -0.61, 95 %CI: -1.18, -0.04, p=0.035), but not with fluvastatin (SMD: -0.34, 95 %CI: -0.69, 0.02, p=0.065), atorvastatin (SMD: -0.23, 95 %CI: -0.57, 0.11, p=0.179) and rosuvastatin (SMD: -0.20, 95 % CI: -0.71, 0.30, p=0.431). The lowering effect of statins on plasma vWF:Ag levels was greater in the subset of studies lasting ≥ 12 weeks (SMD: -0.70, 95 %CI: -1.19, -0.22, p=0.005) compared with that of studies lasting < 12 weeks (SMD: -0.34, 95 %CI: -0.67, 0.003, p=0.052). Finally, low-intensity statin therapy was not associated with a significant reduction in vWF:Ag levels (SMD: -0.28, 95 %CI: -0.82, 0.27, p=0.320), but a significant effect was observed in high-intensity statin trials (SMD: -0.66, 95 %CI: -1.07, -0.24, p=0.002). This meta-analysis of available RCTs demonstrates a significant reduction in plasma vWF:Ag levels following statin therapy.