Warfarin dosing after bariatric surgery: a retrospective study of 10 patients previously stable on chronic warfarin therapy. Issue 2 (20th February 2014)

• Record Type: Journal Article
• Authors: Schullo‐Feulner, A. M.; Stoecker, Z.; Brown, G. A.; Schneider, J.; Jones, T. A.; Burnett, B.
• Is Part Of: Clinical obesity. Volume 4:Issue 2(2014)
• Page Start: 108
• Page End: 115
• Publication Date: 2014-02-20
• Subjects: Obesity -- Periodicals; Obesity -- Treatment -- Periodicals; 616.398005
• DOI: 10.1111/cob.12046
• Languages: English
• ISSNs: 1758-8103

Abstract

<abstract abstract-type="main"> <title>Summary</title> <sec id="cob12046-sec-1002" sec-type="section"> <p>Many changes associated with bariatric surgery have the potential to affect warfarin dosing; yet current literature includes little data describing this phenomenon. Investigating this relationship may allow for determination of post‐bariatric surgery warfarin dosing using stable pre‐operative dosing levels. A retrospective chart review was completed for 10 patients stabilized on chronic warfarin therapy who underwent bariatric surgery. Data collection consisted of the following: warfarin requirement in mg/week, time in target range (TTR), creatinine, liver function, diarrhoea, medication changes, diet, and signs of bleeding and/or thrombosis. Three study patients underwent laparoscopic adjustable gastric banding procedures and seven patients underwent Roux‐en‐Y gastric bypass. The average (standard deviation) weekly warfarin dose required in the immediate post‐operative interval was 64% (25%) of baseline dosing, corresponding to a TTR of 48%. At 6 months, patients required 85% (19%) of baseline weekly dosing, with TTR of 53.4%. At 1 year, dosing was 90% (16%) of baseline with TTR of 63.5%. Patients underwent medication changes as well as transient bouts of diarrhoea. Two patients suffered unspecified haemorrhages of the gastrointestinal tract (international normalized ratio [INR] = 2.3 and 9.8). This patient set demonstrated an initial drop in warfarin requirement, followed by escalating dosing trends that became more predictable as patients were farther out from procedure.</p> </sec> </abstract>