DVT Prophylaxis - Drug Comparison

CPG Venous Thromboembolism, 2013

• Low  molecular  weight  heparins  have  become  the  standard  first  line thromboprophylactic  agents.
• Although  relatively  costly,  LMWHs  have  been  widely  used  for prophylaxis owing  to  their  cost ­effectiveness. 
• Studies  comparing  LMWH  (once or twice daily) with UFH have shown that LMWH is more effective than UFH in  preventing  thrombosis  without  increasing  the  risk  of  bleeding
• LMWheparin is less likely to produce haematomas at injection site,heparin induced  thrombocytopenia/ thrombosis (HITT) and osteoporosis than UFH.
• Unfractionated  heparin  is  no  longer the  preferred first  line  agent  as  it   requires  complex  labor intensive administration,  monitoring and   dose  adjustment. 

Uptodate

• Meta-analysis of 36 randomized trials of a mixed population of hospitalized medical patients that included those at low and high risk for VTE. Both UFH and LMW heparin reduced the risk of DVT without any effect on mortality. When compared with UFH, use of LMW heparin was associated with a lower risk of DVT but no difference was reported between the two agents in the risk of bleeding or thrombocytopenia.
• Another meta-analysis of 16 randomized studies reported similar results in a population of over 34,000 medical patients. Both UFH and LMW heparin reduced the risk of DVT (odds ratio [OR] 0.38; 95% CI 0.29-0.51) as well as symptomatic and fatal PE (OR 0.65; 95% CI 0.42-1) with no effect on mortality and thrombocytopenia. However, an increase in major hemorrhage was reported with use of heparin (OR 1.81; 95% CI 1.1-2.98). Compared to UFH, LMW heparin was associated with a reduced risk of DVT (OR 0.77, 95% CI 0.62-0.96) and lower rates of major bleeding (OR 0.43, 95% CI 0.22-0.83).

Selection of method of prophylaxis 

• Selecting a method of thromboprophylaxis is dependent upon many factors including the nature of the acute medical illness, the risk of hemorrhage and thrombosis, preferences and values of the patient, institutional policy, and cost.
• Although thromboprophylaxis is typically individualized, our approach in hospitalized medical patients is outlined in the sections below. These suggestions apply to hospitalized medical patients regardless of whether or not they are receiving aspirin or statins on admission.

Low risk patients 

• For most patients hospitalized with an acute medical illness and who are without obvious risk factors for VTE (eg, young patients admitted for a 12 hour observation following an episode of syncope from hypoglycemia), pharmacologic thromboprophylaxis is not warranted. Options for this low risk group include early ambulation with or without mechanical methods of thromboprophylaxis.

Moderate risk patients 

• For most patients hospitalized with an acute medical illness, who have at least one risk factor for VTE and do not have an increased risk of bleeding, we recommend the use of pharmacologic thromboprophylaxis rather than mechanical methods or no prophylaxis.
• Low molecular weight heparin is generally the preferred anticoagulant based upon randomized trials that suggest it is superior for preventing DVT.
• For those with renal failure (creatinine clearance <30 mL/min) or for those in whom cost is an issue, unfractionated heparin (UFH) is a reasonable alternative to LMW heparin.

High risk patients 

• For most patients hospitalized with an acute medical illness who are considered to be at high risk for VTE (eg, critically-ill, cancer, stroke) and at low risk of bleeding, we recommend the use of pharmacologic thromboprophylaxis rather than mechanical methods or no prophylaxis.
•  In general, we prefer low molecular weight (LMW) heparin rather than other anticoagulants but UFH is an alternative in those with renal failure or in whom cost is an issue

Reference : 

1. CPG Malaysia Treatment & Prevention of Venous Thromboembolism, 2013

2. Uptodate