Warfarin users prone to coagulopathy in first 30 days after hospital discharge from gastric bypass

Obes Surg. 2013 Oct;23(10):1515-9. doi: 10.1007/s11695-013-0972-5.


Background: Lehigh Valley Health Network (LVHN), a nonprofit tertiary care facility in Allentown, Pennsylvania, is an accredited American College of Surgeons Bariatric Surgery Center Network (ACSBSCN) Level 1 site performing 400+ bariatric procedures annually. Bariatric data submission began in April 2008. Complication review revealed that approximately 17 % of patients on chronic anticoagulation (warfarin) therapy preoperatively were readmitted with supratherapeutic international normalized ratios (INRs), postsurgical bleeding, anastomotic ulcer, or other intraluminal hemorrhage. Opinion level recommendations have been published regarding the adjustment of warfarin dosages post-bariatric procedures with no widespread consensus. Case series have been published detailing perioperative hemorrhage risk for bariatric patients on preoperative anticoagulation. Little data of post-discharge hemorrhage rates have been published. With increasing numbers of bariatric surgical procedures performed annually, there is a potential for developing serious coagulopathic complications in those patients who resume their anticoagulation therapy postoperatively.

Methods: Retrospective review of LVHN data from the ACSBSCN database was analyzed for 30-day readmissions due to documented extra- or intraluminal hemorrhage with INR and coagulopathy. Follow-up INR and warfarin doses were collected up to 6 months postoperatively.

Results: Over a 3-year period, 38 patients undergoing bariatric procedures were identified as being on preoperative warfarin therapy. Six of 38 developed hemorrhage within 30 days. Two patients presented beyond 30 days with bleeding. Supratherapeutic INR was present in five of six readmitted patients. Mean INR was 5.8. Warfarin sensitivity was present in a statistically significant higher number of patients within 30 days of surgery. After 30 days, a resistance to warfarin was demonstrated.

Conclusions: Bariatric surgery patients taking warfarin are prone to coagulopathy in the early post-op period requiring vigilant monitoring to prevent supratherapeutic INR and corresponding risk of hemorrhage.

MeSH terms

  • Adult
  • Anticoagulants / administration & dosage*
  • Anticoagulants / adverse effects*
  • Drug Administration Schedule
  • Female
  • Gastric Bypass*
  • Hemorrhage / chemically induced*
  • Hemorrhage / epidemiology
  • Hemorrhage / prevention & control
  • Humans
  • International Normalized Ratio
  • Male
  • Middle Aged
  • Obesity, Morbid / complications
  • Obesity, Morbid / epidemiology
  • Obesity, Morbid / surgery*
  • Outcome Assessment, Health Care
  • Patient Discharge / statistics & numerical data
  • Patient Readmission / statistics & numerical data
  • Pennsylvania / epidemiology
  • Retrospective Studies
  • Risk Factors
  • Time Factors
  • Warfarin / administration & dosage*
  • Warfarin / adverse effects*


  • Anticoagulants
  • Warfarin