GSTM1 and heart valve disorder: The guideline recommends RBC transfusion for:Hb <6.9 g/dl in patients without cardiac comorbidities.Hb <8.1 g/dl in patients with cardiac comorbidities (ischemic or valvular heart disease).Hb <9 g/dl in patients with recent acute myocardial infarction.Outside these limits, transfusion is only advised in the presence of specific anemia symptoms (angina, orthostatic hypotension, tachycardia)