Abstract
Activated protein C (APC) is a naturally occurring anticoagulant that interacts
with factor V and VIII to inhibit the clotting cascade. The prevalence of APC
resistance among Korean patients with deep vein thrombosis is ill defined. The
aim of the present study was to investigate the prevalence of APC resistance and
factor V Leiden mutation in Korean patients with deep vein thrombosis. The
presence of factor V Leiden mutation was determined in 49 patients who visited
Asan Medical Center. APC ratio was performed in 33 individuals from the above 49
patients. Three patients were excluded from the analysis because their baseline
aPTT was prolonged. Resistance to APC was diagnosed when the APC ratio was below
2.55. APC resistance was documented in 8 individuals, representing 27% (8/30) of
the patients on whom APC resistance test was performed. The 2 patients, who
showed APC resistance, were positive for lupus anticoagulant. None of the 49
patients demonstrated factor V Leiden mutation. These findings indicate that
factor V Leiden mutation is rare and APC resistance is less prevalent in Korean
patients with deep vein thrombosis than in Caucasians. APC resistance not caused
by factor V Leiden mutation may be a risk factor for deep vein thrombosis in
this population.