Several studies have examined the independent thromboprophylactic effectiveness of LMWH on the incidence of DVT and PE in acute SCI. Various forms of LMWH have been investigated including Enoxaparin, Dalteparin, and Tinzaparin.
Two studies compared the effectiveness of Enoxaparin versus Dalteparin in preventing VTEs. Chiou-Tan et al. (2003) conducted an RCT in which acute SCI individuals (<3 months post-SCI) were randomized to receive either 30 mg Enoxaparin every 12 hours or 5000 IU Dalteparin once daily. The authors found that 6% of individuals receiving Enoxaparin and 4% of individuals receiving Dalteparin developed DVTs (p=0.51); however, no individuals developed PE. A case control study conducted by Slavik et al. (2007) also compared the efficacy of Enoxaparin and Dalteparin. Individuals were studied within 72 hours post-SCI and received either 30 mg Enoxaparin twice daily or 5000 IU Dalteparin once daily. No significant difference regarding the incidence rate of DVT or PE was found between these groups, indicating equivalent prophylactic efficacy.
A case control study by Marciniak et al. (2012) compared the effect of Enoxaparin versus Tinzaparin on incidence of VTE events. All individuals were within 3 months of sustaining an SCI and were admitted to inpatient rehabilitation at a median of 15 days after injury. Individuals received either 5000 IU Enoxaparin, 4500 IU Tinzaparin (high-dose), or 3500 IU Tinzaparin (low-dose). The results revealed that individuals who received either Enoxaparin or the high dose of Tinzaparin had a significantly reduced risk of developing VTE complications compared with individuals receiving 3500 IU Tinzaparin. The authors indicated that uncontrolled factors may have affected this result, although these were not specified. The findings suggested an association between developing VTE and having had no prophylaxis prior to admission to inpatient rehabilitation, despite using prophylaxis after admission. Prophylaxis prior to admission may be protective of VTE, with no particular type of prophylaxis being significantly different in terms of protective efficacy.
A case control study by Hebbeler et al. (2004) compared two dosages of Enoxaparin. Individuals were within 2 months of sustaining SCI and received either 40 mg once daily or 30 mg twice daily of Enoxaparin. There were no significant differences found in DVT or PE incidence between groups and therefore the prophylactic efficacy of Enoxaparin was equivalent between the two dosages studied.
In a case series by Harris et al. (1996), individuals who were hospitalized for an average of 19 days following injury received 30 mg of Enoxaparin every 12 hours from admission. No individuals developed DVT in this study population. In a recent observational study, DiGiorgi et al. (2017) found that just 6.1% of their sample experienced a DVT and 4.1% a PE after 40 mg daily enoxaparin administration.
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.