Safety and efficacy of low-molecular-weight heparins in prophylaxis of deep vein thrombosis in postoperative/ICU patients: A comparative study

BACKGROUND: Venous thromboembolism (VTE), although a very common problem in everyday clinical practice, remains asymptomatic in most cases. Clinical diagnosis helps identify those who are going to have thromboembolic episode. A combination of clinical scoring systems like Wells’ score and D-dimer assay provide a useful diagnostic tool. Trauma (surgical or accidental) and critically ill patients are found to have greatest risk. Enoxaparin and dalteparin are amongst the most common low-molecular-weight heparins (LMWHs) used for deep venous thrombosis (DVT) prophylaxis in such patients. AIM: The present study is designed to compare their role in preventing DVT in postoperative or critically ill patients and to determine their relative safety profiles. MATERIALS AND METHODS: The study included 36 critically ill adult patients. All the patients were allocated into three groups of 12 patients each. Group I patients received no prophylaxis, group II received inj. enoxaparin s/c 0.6-0.8 mg/kg twice daily, and group III received inj. dalteparin s/c 125-250 units/kg once daily. Routine investigations and coagulation profile were recorded on admission to intensive care unit (ICU) and at every third day thereafter. Patients were daily assessed for pretest probability of DVT using Wells’ scoring, and D-dimer test was done on the 7(th) day. Occurrence of any bleeding (visible or occult) was noted, and incidence of DVT was determined in each group using positive results of D-dimer test and the clinical assessment with Wells’ score. RESULTS: A significant difference in Wells’ score (P < 0.05) was found between groups I and III on day 5 and day 7. A lower, but insignificant difference in the incidence of DVT was found between the study and control groups. No significant difference in major bleeding or other side effects was found. Better hemodynamic status and arterial blood gases in the study groups may indirectly refer to absence of asymptomatic DVT or silent pulmonary embolism in this group. CONCLUSION: The present study suggests that LMWHs, namely, enoxaparin and dalteparin, provide effective means of preventing DVT in high-risk, critically ill or postoperative patients, without causing any significant increase in the risk of bleeding or other side effects. Dalteparin appears to be unaffected by low creatinine clearance as explained by its clearance by a non-saturable mechanism. Still, a more extensive study with larger population is needed to make the outcomes worthwhile.