[Autoimmune acquired factor V deficiency developing after thoracic aortic aneurysm repair].

Area of Science:

• Hematology
• Immunology

Background:

• Acquired factor V deficiency is a rare bleeding disorder.
• It is caused by autoantibodies against factor V, leading to reduced activity and bleeding.
• This condition is occasionally linked to surgery, transfusions, or antibiotic use.

Purpose of the Study:

• To report a case of acquired factor V deficiency in an elderly patient following thoracic aortic aneurysm repair.
• To discuss the diagnostic challenges and implications of this rare disorder.

Main Methods:

• Case report of an 81-year-old male.
• Postoperative monitoring of coagulation parameters (PT, APTT).
• Factor V activity assays and inhibitor detection.
• Cross-mixing tests to differentiate antibody types.

Main Results:

• The patient developed markedly prolonged PT and APTT post-surgery despite no bleeding.
• Factor V activity was <3% with a detectable factor V inhibitor.
• Cross-mixing tests suggested both neutralizing and clearance-facilitating antibodies.

Conclusions:

• Acquired factor V deficiency should be considered in postoperative coagulopathy with unexplained prolonged PT and APTT.
• Cross-mixing tests require careful interpretation due to potential clearance-facilitating antibodies.
• Effective treatments include immunosuppression and management of bleeding episodes.