• Measure and report plasma anti-Xa levels when administering LMWH by the standard of care subcutaneous injection and by a subcutaneous port. [ Time Frame: six data points over 1-3 months ] [ Designated as safety issue: Yes ]
  

• Compare plasma anti-Xa levels obtained after subcutaneous LMWH injection without port to anti-Xa levels obtained via subcutaneous port on day 7 [ Time Frame: over 1-4 weeks ] [ Designated as safety issue: Yes ]
  
• compare plasma anti-Xa levels obtained after subcutaneous LMWH injection without port to anti-Xa levels obtained via subcutaneous port on day 1 [ Time Frame: 1-4 weeks ] [ Designated as safety issue: Yes ]
  
• compare plasma anti-Xa levels obtained via subcutaneous port on day 1 to levels obtained on day 7 [ Time Frame: 7 days ] [ Designated as safety issue: Yes ]
  
• Describe subjects' usage and opinions about the port at the end of the pharmacokinetic study period and report the proportion of subjects who would consider using the port instead of subcutaneous injection in the future [ Time Frame: 1-3 months ] [ Designated as safety issue: No ]
  
• report the proportion of subjects who are routinely using the subcutaneous port 3-4 months after the end of the pharmacokinetic part of the study of all subjects still on LMWH at that time [ Time Frame: 1-6 months ] [ Designated as safety issue: No ]
  

Subcutaneous ports have recently been used to administer Low Molecular Weight Heparin (LMWH) to patients for the prevention or treatment of venous thromboembolism; however, no studies have been performed to evaluate the ports' reliability in delivering this type of drug. Hence, it is not known whether absorption of the drug is constant over the seven-day lifespan of the port. Although the use of subcutaneous ports is not currently the standard of care, health care providers are more frequently using this as an alternative method to direct injection of LMWH, particularly in pediatric patients.

The main advantage of subcutaneous ports is the decreased number of needle sticks when using the ports to administer the medication. However, it is possible that, due to potential repeated bleeding into the subcutaneous space at the port site or other factors, drug absorption may decrease over the seven day lifespan of the port, resulting in a decrease of plasma drug level. Subtherapeutic LMWH levels and, hence, ineffective anticoagulation may result. This study's aim is to determine if the current use of subcutaneous ports is a safe, effective and reliable way of administering LMWH for the purpose of anticoagulation.