PRS AAPS Oral Proofs 2016
Christopher J. Pannucci, MD, MS,* Brad Rockwell, MD,* Kory Fleming, MPH,* Maureen Ghanem, PharmD,* Arash Momeni, MD,† Jay Agarwal, MD*
From the *University of Utah, Salt Lake City, Utah; and †University of Pennsylvania, Philadelphia, Pa.
PURPOSE: Despite guideline-compliant enoxaparin prophylaxis, 1 in 25 highest risk patients has a VTE event. We examined the pharmacokinetics of standard enoxaparin doses in plastic surgery patients with an emphasis on total body surface area surgically injured (TBSI) as a predictor of enoxaparin metabolism.
METHODS: The Plastic Surgery Foundation funded this ongoing prospective interventional study, which recruited adult plastic surgery patients receiving postoperative enoxaparin (40 mg once daily). Steady-state peak and trough anti-Factor Xa (aFXa) levels, which marks enoxaparin effectiveness and safety, were drawn. Patients with out-of-range aFXa levels had real-time dose adjustment based on a written protocol.
RESULTS: Fifty-three patients have been recruited, and 39.6% had in-range peak aFXa levels. A total of 61.5% of patients had nondetectable aFXa 12 hour trough levels. Patients with increased TBSI were less likely to have in-range aFXa peak and trough levels. Among out-of-range patients who received dose adjustment, 58.3% achieved in-range peak aFXa levels.
CONCLUSIONS: Enoxaparin 40 mg once daily provides adequate prophylaxis in less than 40% of patients. A total of 61.5% of patients had nondetectable aFXa levels at 12 hours. Thus, the majority of patients are protected for less than 12 hours per day. Individualized TBSI-based enoxaparin dosing regimens and real-time aFXa monitoring deserve further study.