The effects of location and low-molecular-weight heparin administration on deep vein thrombosis outcomes in trauma patients.
BACKGROUND
Deep vein thrombosis (DVT) is common after trauma. Pulmonary embolism (PE) is a feared complication of DVT. Standard doses of low-molecular-weight heparin (LMWH) are commonly used to prevent and treat DVT and PE. There is variable bioavailability of LMWH with standard therapy. The traditional concept that below-knee DVT is associated with a lower risk of subsequent PE may result in less aggressive therapy. The purposes of this study were to assess the rates of PE in above-knee versus below-knee DVT and longitudinally evaluate outcomes of DVT treated with LMWH therapy.


METHODS
This was a retrospective review of patients at a university Level I trauma center during the years 2005 through 2010. Patients diagnosed with lower-extremity DVT were included in this study. Patients were classified by location of lower-extremity DVT and type of LMWH therapy received. All high-risk trauma patients were evaluated with weekly duplex Doppler ultrasonography. All duplex studies were reviewed for DVT resolution or improvement. Symptomatic patients were evaluated with computed tomographic angiography to rule out PE. Demographics, total length of hospital stay, length of intensive care unit stay, and Injury Severity Score (ISS) were collected.


RESULTS
Three-hundred eight trauma patients with lower-extremity DVT were included. More patients developed below-knee DVT (65.6%) compared with above-knee DVT (34.4%). Increased length of hospital stay, intensive care unit stay, and higher ISS were noted in patients with above-knee DVT. More patients had below-knee DVT in the prophylactic dosing group. With LMWH therapy, three PEs occurred in patients in the prophylactic dosing group with below-knee DVT, and no PEs occurred in the therapeutic treatment group. The incidence of PE between patients with below-knee DVT compared with above-knee DVT overall was not different (3.3% and 4.7%, p = 0.59). To assess DVT outcomes, 157 of the 308 patients had serial duplex studies following diagnosis of lower-extremity DVT. The number of patients receiving either therapeutic or prophylactic LMWH was similar (51% and 49%). There was no difference in rates of resolution or improvement between LMWH dosing groups or location of DVT.


CONCLUSIONS
In screened trauma patients, below-knee DVT is more common than above-knee DVT. There was no difference in the incidence of PE between groups. Standard prophylactic and therapeutic dosing of LMWH does not affect the rates of resolution or improvement of lower-extremity DVT. Rates of resolution and improvement of DVT is not dependent of location of lower-extremity DVT.


METHODS
Therapeutic study, level IV; epidemiologic study, level III.
Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Oregon Health and Science University, Portland, Oregon 97239-3098, USA.
Tim H
TH
Lee
Brock J
BJ
Alonzo
Jerome
J
Differding
Samantha J
SJ
Underwood
Greg
G
Hamilton
Igor
I
Kremenevskiy
Steve
S
McNamara
Martin A
MA
Schreiber
D000328:Adult; D000368:Aged; D017984:Enoxaparin / Q000627:therapeutic use; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000627:therapeutic use*; D006801:Humans; D015601:Injury Severity Score; D007866:Leg / Q000098:blood supply; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control; D012189:Retrospective Studies; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D020246:Venous Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D014947:Wounds and Injuries / Q000150:complications* / Q000188:drug therapy
D017984:Enoxaparin; D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight