Once Weekly Subcutaneous Ports for the Administration of Anticoagulants

Once Weekly Subcutaneous Ports for the Administration of Anticoagulants - A Prospective Pharmacokinetic and Clinical Utilization Study

The purpose of this study is to ascertain whether subcutaneous ports are an effective and reliable way to administer the low molecular weight heparin (LMWH) enoxaparin to patients for the prevention or treatment of venous thromboembolism.

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.

low molecular weight heparin, enoxaparin, Lovenox, Insuflon, subcutaneous catheter, once or twice daily dosing of subcutaneous enoxaparin

All participants in the study will use the subcutaneous catheter twice for a period of one week each to inject the enoxaparin. For the remainder of the study the participants will inject subcutaneously.

Indwelling subcutaneous catheter indicated for subcutaneous infusion of medication by injection. Maximum lifespan: 7 days or 75 injections.

Blood levels taken from the first and last visits (when available) were combined to get an average. The anti-Xa test reports the low molecular weight heparin concentration in the blood.

Anti-Xa subcutaneous blood levels are displayed in percent difference to show normal fluctuations of anti-Xa levels without using the port. A percent difference is calculated by the current value has the previous value subtracted from it; this new number is divided by the absolute value of the previous value; then this new number is multiplied by 100. This allows each set of data to be compared to itself. Anti-Xa tests measure the concentration of low molecular weight heparin in the blood.

Comparing subcutaneous baseline (without port) anti-Xa levels with day one of using the port. A percent difference is calculated by the current value has the previous value subtracted from it; this new number is divided by the absolute value of the previous value; then this new number is multiplied by 100. This allows each set of data to be compared to itself. Anti-Xa tests measure the concentration of low molecular weight heparin in the blood.

Comparing anti-Xa levels from the first day of using the port and the last day of using the port. A percent difference is calculated by the current value has the previous value subtracted from it; this new number is divided by the absolute value of the previous value; then this new number is multiplied by 100. This allows each set of data to be compared to itself. Anti-Xa tests measure the concentration of low molecular weight heparin in the blood.

GFR was calculated from a creatinine blood level to establish a safe renal function that would validate anti-Xa levels. Low molecular weight heparin is primarily cleared from the body by the kidneys. Any condition that decreases kidney function can potentially decrease LMWH clearance, increasing its concentration in the blood and increasing the potential for excessive bleeding.

Inclusion Criteria: Subjects receiving once or twice daily dosing of therapeutic doses of subcutaneous Enoxaparin. Subject has been on the same dose of Enoxaparin for at least one week. Anticipated length of Enoxaparin treatment at least 4 weeks. Age ≥ 18 years. Subject demonstration of proper subcutaneous catheter care during one education session with the investigator. Exclusion Criteria: Chronic renal insufficiency with glomerular filtration rate < 30 mL/min. Pregnancy Venous thromboembolism within the last 4 weeks.

University of North Carolina at Chapel Hill School of Medicine; University of North Carolina Hospital, N.C. Memorial Hospital