Association of marked prolongation of prothrombin time-international normalized ratio with warfarin and endoscopic nasobiliary drainage for biliary fistula after left hemihepatectomy.

What Is Known And Objective: Vitamin K deficiency is known to cause impaired coagulation. We report a case of marked prolongation of the prothrombin time-international normalized ratio (PT-INR) associated with warfarin and vitamin K deficiency caused by endoscopic nasobiliary drainage (ENBD).

Case Presentation: Oral administration of warfarin was initiated in a 67-year-old man after left hemihepatectomy. He developed a biliary fistula after surgery that was treated by ENBD, which resulted in significant prolongation of the PT-INR.

What Is New And Conclusion: The effect of warfarin was enhanced in this patient due to reduced absorption of vitamin K as a result of external biliary drainage.