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Evaluation of Weight-Based Boluses of Unfractionated Heparin in the Obese Population: What Should be the Maximum Dose?
The current ACC/AHA guidelines for NSTEMI and UA recommend a maximum bolus dose of 4000 units for unfractionated heparin based on limited data. There continues to be questions on the appropriate dosing of heparin in the obese population.
To evaluate the weight-based boluses of UFH in obese patients diagnosed with venous thromboembolism (VTE) or acute coronary syndrome (ACS).
A retrospective review of medical records from January 2009 – August 2010 was conducted on obese patients (BMI > 30 kg/m2) who received UFH per VTE or ACS UFH infusion protocols for six hours or greater during hospitalization. Activated partial thromboplastin times (aPTT) six hours from the start of the infusion were assessed.
A total of 72 patients were included in the study. The average age of the patients was 57.4 ± 12.3 years and 75% were male. The average weight and BMI of the patients was 123.9 ± 24.5 kg and 39.6 ± 8.3 kg/m2 respectively. Twenty-seven patients received UFH boluses of 7500 units or less with 7 (30%) supratherapeutic aPTTs recorded. Forty-five patients received UFH boluses above 7500 units with 35 (78%) supratherapeutic aPTTs recorded.
Dosing therapeutic UFH based on actual body weight in obese patients leads to supratherapeutic aPTTs. Based on this APTT data we currently limit the bolus of heparin 7500 units on the ACS and VTE protocols.
|UFH infusion protocol||UFH boluses received by indication, n (%)||Average dose of UFH bolus, units ± SD||Supratherapeutic aPTT 6 hrs after UFH bolus, n|
|VTE||33||10,391 ± 2096||26 (78.8%)|
|ACS High-dose||11||8,112 ± 683||8 (78.8%)|
|ACS Low-dose||28||6,885 ± 2039||11 (28.6%)|
ACC Moderated Poster Contributions
McCormick Place South, Hall A
Sunday, March 25, 2012, 9:30 a.m.-10:30 a.m.
Session Title: Acute Coronary Syndromes: Therapy II
Abstract Category: 4. Acute Coronary Syndromes: Therapy
Presentation Number: 1159-593
- 2012 American College of Cardiology Foundation