PB1431 - Acquired von Willebrand syndrome in essential thrombocythemia patients referred to special coagulation laboratory of Iranian Blood Transfusion Organization (IBTO)

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Co-Author(s)

AR

Ali Rajabi

PhD of Hematology and Blood Banking
Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
Tehran, Tehran, Iran
MA

Minoo Ahmadinejad

Head of reference coagulation laboratory at Iranian Blood Transfusion Organization
Iranian Blood Transfusion Organization and the High Institute for Research and Education
Tehran, Tehran, Iran
SE

Sakineh Ebrahimi

MD, Hematologist
Departmant of oncology, Loghman Hakim hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Tehran, Tehran, Iran
MM

Mahsa Mojtabavi Naeini

BS of Chemistry
Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
Tehran, Tehran, Iran
SR

Sara Riahi

PhD of Microbiology
Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
Tehran, Tehran, Iran
RS

Roshanak Shamriz

PhD of Molecular Medicine
Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
Tehran, Tehran, Iran

Presenting Author(s)

PE

Peyman Eshghi

Professor
Pediatric Congenital Hematologic Disorders Research Center, Research Institute for Children’s Health, Shahid Beheshti University of Medical Sciences
Tehran, Tehran, Iran

Background: Although acquired von Willebrand syndrome (AVWS) is rare, most cases are frequently underdiagnosed or misunderestimated. The disease is due to the quantitative or qualitative defects in von Willebrand factor (vWF) secondary to other medical conditions such as myeloproliferative neoplasms including essential thrombocythemia (ET). ET has a complicated condition of both thrombotic and hemorrhagic events. Aspirin will be prescribed for the prevention of thrombosis, but patients with extreme thrombocytosis (platelet counts >1000×109/L) and a ristocetin cofactor activity (RCo) < 30%, should not receive aspirin because of an excessive risk of bleeding.

Aims: We aimed to report cases of AVWS in ET patients who were referred to our laboratory during the last decade.

Methods: Three patients with diagnosed ET and the possibility of AVWS were referred to the reference coagulation laboratory of IBTO for coagulation testing during the last decade. All three cases were referred in the last six months. Standard von Willebrand panel coagulation tests were done and ISTH-BAT was used for the assessment of bleeding scores.

Results: We describe three AVWS cases with ET, two females with 28 and 42 and one male with 49 years old. All patients had extreme thrombocytosis with no significant history of bleeding events. Laboratory results are shown in Table 1.

Conclusion(s): During the last decade, we have only three cases referred for the evaluation of AVWS and all were ET patients. It seems that there is much more than the world underestimation of the disease in our country. Raising awareness of practicing physicians about the need for this experience and conduction of facilities in specialized coagulation laboratories would be helpful for avoiding missing the AVWS cases.