title: Successful use of rivaroxaban in postoperative deep vein thrombosis of the lower limb following instability with warfarin: a case report.
abstract: BACKGROUND
  Evidence from clinical trials shows rivaroxaban to be effective for the treatment of deep vein thrombosis. Switching to rivaroxaban following failure of indirect anticoagulants in deep vein thrombosis has not been demonstrated in a real-life setting.
  
  
  METHODS
  A 43-year-old white woman was switched from warfarin to rivaroxaban for the treatment of thrombosis of her right common femoral vein after saphenectomy. The reason for the switch was due to the instability of anti-coagulation therapy with vitamin K antagonists over a period of 3 months during which she did not reach the "therapeutic range" of prothrombin time-international normalized ratio. The ineffectiveness of the conventional oral anticoagulant was confirmed by persistence of moderate-high values of fibrin D dimers (780 ng/ml) and by residual vein thrombosis at an ultrasound examination. Objectively, her right leg appeared to be still edematous and warm and pain was elicited by deep palpation. Rivaroxaban was administered after warfarin discontinuation (prothrombin time-international normalized ratio = 1.43) at a dosage of 15 mg every 12 hours for 3 weeks, followed by 20 mg once daily for 3 months. After this period, her objective symptoms significantly improved, with reduction of edema of her lower limb and pain relief. Her fibrin D dimer values returned to normal (210 ng/ml). An ultrasound showed recanalization of the obstructed venous segment.
  
  
  CONCLUSIONS
  In this case report, a switch to rivaroxaban from warfarin was shown to be effective and safe for the treatment of postoperative deep vein thrombosis, whereas standard oral anticoagulation therapy, which required dose adjustments over a period of 3 months, was not able to stabilize the therapeutic range of prothrombin time-international normalized ratio nor improve our patient's outcome.
authors.affiliation: Department of Internal Medicine Hospital, Hemophilia and Rare Coagulopathies Centre, "I. Veris Delli Ponti", 73020, Scorrano, Azienda Sanitaria Locale di Lecce, Italy. marioschiavoni@gmail.com.
authors.forename: Mario
authors.initials: M
authors.lastname: Schiavoni
authors.affiliation: Department of Internal Medicine Hospital, Hemophilia and Rare Coagulopathies Centre, "I. Veris Delli Ponti", 73020, Scorrano, Azienda Sanitaria Locale di Lecce, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Coluccia
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D011183:Postoperative Complications / Q000188:drug therapy*; D000069552:Rivaroxaban / Q000627:therapeutic use*; D016896:Treatment Outcome; D020246:Venous Thrombosis / Q000188:drug therapy*; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D000069552:Rivaroxaban
keywords: Case report; Postoperative deep venous thrombosis; Rivaroxaban; Warfarin