VWF and aortic stenosis: Acquired von Willebrand syndrome is a rare disorder that occurs due to lymphoproliferative (e.g., chronic lymphocytic leukemia), myeloproliferative (e.g., thrombocythemia), cardiovascular (e.g., aortic stenosis) and immunological disorders (e.g., hypothyroidism), which provoke the qualitative and quantitative deficiency of vWF [44].