Five studies have been found which examined LMWH alone, or compared different dosages or types of LMWHs.
In examining the LMWH enoxaparin, Harris et al. (1996) performed a case series with 105 subjects (66 with SCI). All patients received 30 mg of enoxaparin s/c q12h beginning at the time of admission. Patients scheduled for surgery withheld anticoagulation therapy on the morning of the operation, resumed 24 hours later, and continued until the patients’ discharge. No patient developed clinical or ultrasound evidence of a DVT.
The optimal dose of enoxaparin has not been established to date. Hebbeler et al. (2004) compared two dosing regimens of enoxaparin (40 mg daily or 30 mg twice daily) among 129 acute SCI patients. Symptomatic thromboembolism did not differ between the two groups with DVT occurring in only one patient in each group. Furthermore, there was no difference in bleeding complications between the two groups.
Since there are many new LMWHs available, studies have compared their efficacy. One RCT (Chiou-Tan et al. 2001) and one case control study (Slavik et al. 2007) compared acute SCI patients who received enoxaparin (30-40 mg s/c q12h) to those who received dalteparin (2000-5000 IU s/c daily). There were no significant group differences between the two groups in terms of incidence and location of DVTs or bleeding complications. A third study by Marciniak et al. (2012) compared enoxaparin to two different doses of tinzaparin (4500 IU and 3500 IU). After controlling for multiple variables they reported no differences in DVT incidence between the LMWHs.
One systematic review evaluated the ideal time for initiating DVT treatment with LMWH. Christie et al. (2011) concluded that LMWH prophylaxis for DVT should be administered within 72 hours post SCI. However, this conclusion should be interpreted with caution, as it was based on a single, small (N=5) systematic review.
There is level 4 evidence (from one case control study; Hebbeler et al. 2004) that 40 mg daily enoxaparin is no more effective than 30 mg twice daily enoxaparin in reducing the incidence of deep venous thrombosis or bleeding complications when used prophylactically.
There is level 1b evidence (from one RCT and one case control study; Chiou-Tan et al. 2003; Slavik et al. 2007) that enoxaparin is no more effective than dalteparin in reducing the risk of deep venous thrombosis or bleeding complications although enoxaparin is more expensive.
There is level 3 evidence (from one case control study; Marciniak et al. 2012) that enoxaparin is no more effective than tinzaparin in reducing the risk of deep venous thrombosis or bleeding complications.
There appears to be no difference between enoxaparin and dalteparin, or enoxaparin and tinzaparin, in reducing the risk of venous thrombosis post-SCI.