VWF and myocardial infarction: Patients with non-O compared to O blood group have more myocardial necrosis, larger myocardial infarct size and reduced pre-procedural thrombolysis in myocardial infarction (TIMI) flow of coronary, accounting for the higher level of von Willebrand factor (VWF) and factor VIII in non-O blood groups, especially in A and B blood groups [16, 17, 21].