J. Fareed

Laboratory assays and duplex scanning outcomes after symptomatic deep vein thrombosis: Preliminary results*

PURPOSEnThe purpose of this article was to assess a number of hematologic and fibrinolytic assays at the time of diagnosis of deep vein thrombosis (DVT) and at several intervals over a period of 6 months afterward and to correlate these results with the results of serial duplex scanning.nnnMETHODSnThirty-five patients (average age 61, range 18 to 82) with acute symptomatic DVT confirmed by duplex scanning were included. On diagnosis, blood was drawn, and plasma levels of tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor (PAI), D-dimer (DD), and tissue factor pathway inhibitor (TFPI) were determined. Duplex scanning and all laboratory assays were repeated 1 week, 1 month, 3 months, and 6 months thereafter.nnnRESULTSnThe rate of DVT complete resolution 6 months after diagnosis was 57%. Whereas plasma levels of PAI were similar throughout the 6-month follow-up period, t-PA increased significantly 1 week after diagnosis and decreased thereafter. Both DD and TFPI levels decreased significantly after diagnosis compared with presentation values. Comparing these assay levels between patients with complete resolution versus partial or no resolution, PAI levels were significantly higher during the first week in patients with poor outcome. Plasma levels of t-PA were higher in cases with good outcome, and DD levels were higher in patients with poor outcome. TFPI levels were similar in both outcome groups.nnnCONCLUSIONSnPatients with complete DVT resolution on duplex scanning at 6 months had significantly lower levels of PAI on presentation and after 1 week than did those with incomplete lysis. Although differences were not significant, t-PA levels were higher and DD lower in patients with good outcome. Our results suggest that certain plasma fibrinolytic assays might correlate with the outcome of DVT, as assessed by duplex ultrasonography.

Pharmacokinetics of enoxaparin in patients undergoing percutaneous coronary intervention with and without glycoprotein IIb/IIIa therapy.

The pharmacokinetic profile of enoxaparin was established in a substudy involving 1054 patients undergoing percutaneous coronary intervention. Patients enrolled in the National Investigators Collaborating on Enoxaparin 1 (NICE-1) trial received enoxaparin as a 1.0-mg/kg intravenous bolus. Patients enrolled in the NICE-4 trial received enoxaparin as a 0.75-mg/kg intravenous bolus followed by abciximab as a 0.25-mg/kg bolus and a 0.125-mcg/kg/min 12-hour infusion. Blood samples were collected at six time points over 12 hours and analyzed for plasma anti-Xa, anti-IIa, and Heptest (Haemachem Inc., St. Louis, MO) activity using specific and sensitive assay methods. Data were similar in both trials. Plasma anti-Xa, anti-IIa, and Heptest activity peaked shortly after the enoxaparin bolus and declined in parallel over the ensuing 12 hours. Area under the curve and peak activity were greatest for Heptest activity and least for anti-IIa activity. Values for clearance, volume of distribution, volume of distribution at steady state, and elimination rate constant were on the order of 10 mL/h/kg, 48 mL/kg, 45 mL/kg, and 0.22/h, respectively. These measures suggest that the use of abciximab in combination with enoxaparin during percutaneous coronary intervention is unlikely to affect the pharmacokinetics of enoxaparin.