To compare the efficacy of low-dose unfractionated heparin (LDUH) and enoxaparin for the prevention of deep venous thrombosis (DVT) in the medical ICU.
This was a prospective, randomized double-blinded trial to compare LDUH 5000 BID with enoxaparin. Patients were screened with a bedside Doppler ultrasound of the lower extremities at 48-72 hours of ICU admission and again at 7 days. All patients, older than 18 years of age, admitted to the MICU at Georgetown University Hospital were eligible. Exclusion criteria included pregnancy; contraindication to anticoagulation (e.g. uncontrolled hypertension,hemorrhagic stroke in the past 3 months, active gastrointestinal bleeding); ongoing anticoagulant therapy; intolerance to heparin; platelet count <80,000/ml; international normalized ratio (INR) > 2.0. Written informed consent was obtained prior to randomization.The primary endpoint was the diagnosis of DVT by Dopplers or death.
From March 2003 to March 2004, 308 patients were screened. Thirty(9.75%) were enrolled. Two patients (6.7%), one in each study arm, were diagnosed with DVT by 72 hours; and one(3.3%)in the enoxaparin arm by 7 days.Patients were excluded for the following reasons: Active gastrointestinal bleeding: 59 (19%), intracranial hemorrhage: 18 (6%), hemorrhage from other sites (e.g. retroperitoneal): 4 (1%), already anticoagulated: 53 (17%), thrombocytopenia: 15 (5%), other coagulopathy: 27 (9%), acute renal failure and denied entry by treating physician: 19 (6%), Expected ICU stay <48 hours: 61 (20%), withdrawal of support within 48 hours of ICU admission: 4 (1%), patient or family declined enrollment: 14 (4.5%), miscellaneous (morbid obesity, aortic dissection, intolerance to heparin: 4 (1%).
Despite medical prophylaxis, 10% of MICU patients developed DVT. Almost half the patients (49%, excluding those with MICU length of stay <48 hours and those already on anticoagulation) had contraindications to medical thromboprophylaxis.
Incidence of DVT in the MICU remains high, despite medical prophylaxis. Therefore, for MICU patients, combined medical and mechanical thromboprophylaxis should be considered. Furthermore, a significant proportion of MICU patients have contraindications to medical thromboprophylaxis. For this patient population, routine screening Dopplers may be warranted.
Tunay Kuru, None.