Urokinase versus recombinant tissue plasminogen activator in thrombosed central venous catheters: a double-blinded, randomized trial.

Fifty dysfunctional central venous catheters proven radiographically to be occluded by thrombus were blindly randomized to be injected with either 2 mg recombinant tissue plasminogen activator (t-PA) or 10,000 units of urokinase (UK) and allowed to incubate for 2 h. A second dose was allowed if catheter function was not restored with the first injection. Repeat radiograph contrast injection was done when catheter function was restored or after 2 doses of study drug were administered, whichever occurred first. Thirteen of 22 catheters randomized to UK had full function restored compared to 25 of 28 randomized to t-PA (p = 0.013). Radiographic contrast injection showed 7 catheters randomized to UK had complete resolution of the thrombus compared to 17 randomized to t-PA (p = 0.042). Four catheters randomized to UK had complete resolution of the thrombus after a single dose compared to 13 randomized to t-PA (p = 0.036). A novel dose of 2 mg of t-PA restored catheter function more reliably and dissolved thrombi faster than twice the standard, FDA-approved dose of UK.

Protein C deficiency following hematopoietic stem cell transplantation: optimization of intravenous vitamin K dose.

Patients undergoing hematopoietic stem cell transplantation (HSCT) are dependent on i.v. vitamin K supplementation to prevent deficiency. Vitamin K deficiency may contribute to the development of a hypercoagulable state by limiting hepatic synthesis of fully functional carboxylated anticoagulant protein C (PC). The ratio of PC antigen (CAg) to PC measured in a clot-based functional assay (CFx) reflects the degree to which PC is carboxylated. The 133 patients undergoing HSCT received vitamin K 10 mg per week (low dose, 101 patients) or 5 mg per day (high dose, 32 patients) i.v. as their sole exogenous source of vitamin K. CAg and CFx were assayed before HSCT preparative regimen and again 14 days later. CAg and CFx fell significantly in both groups from day 0 to day 14 but there were no differences between the low-dose and high-dose vitamin K groups. For both groups, CAg correlated strongly with CFx at day 14 (p = 0.0001). At day 14, the CAg/CFx ratio for the low-dose group was significantly greater than for the high-dose group (1.26 +/- 0.4 vs 1.09 +/- 0.1, p < 0.0002), suggesting that low-dose patients had a higher proportion of incompletely carboxylated PC. The CAg/CFx ratio at day 14 correlated with serum albumin for the high-dose group (p = 0.05), but not the low-dose group (p = 0.09), suggesting that the change in ratio in the low-dose group was not simply due to a lack of protein synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of antithrombin concentrate during autologous hematopoietic stem cell transplantation.

Antithrombin is a naturally-occurring anticoagulant protein. Congenital deficiency of this protein predisposes to thrombotic complications. Acquired deficiency of antithrombin occurs in a variety of clinical circumstances, including hematopoietic stem cell transplantation (HSCT), and is associated with multiorgan failure and death in these situations. Normalization of antithrombin levels by infusion of concentrates of this protein has been found to be beneficial in many of these situations, but has not been routinely used in HSCT. Before antithrombin concentrates can be widely recommended in HSCT, its pharmacokinetics at various phases of the transplant process must be defined to allow estimation of the proper dose and dosing interval. To this end, the recovery and half-life of antithrombin concentrate was determined prior to and 7, 14 and 28 days after beginning the preparative regimen in nine patients with lymphoma undergoing HSCT. The recovery of the infused material was constant during the transplant hospitalization, averaging 2.0% per unit/kg. The half-life, however, dropped significantly during the latter half of the transplant procedure. The half-lives pre-chemotherapy and on day 7 were similar and averaged 20.4 h. On days 14 and 21 the the half-lives were significantly lower at 12.2 and 15.5 h, respectively. The drop in half-life during the transplant process will require antithrombin concentrate to be given more frequently during this time to maintain constant antithrombin levels.

Are clinical signs accurate indicators of the cause of central venous catheter occlusion?

BACKGROUND: Two hundred dysfunctional central venous catheters used for total parenteral nutrition and administration of cancer chemotherapy were radiographically examined in order to objectively identify thrombotic occlusions as the cause of catheter dysfunction. METHODS: Outcomes of radiographic dye injections were compared with factors such as the inability to aspirate blood or to infuse fluids, catheter type, and duration of catheter placement. RESULTS: Catheter type and duration of placement were not significant factors for predicting the type of dysfunction. Failure to withdraw blood was associated with 96% of the thrombosed catheters; this was also associated with 65% of the catheters with nonthrombotic dysfunctions. Once the cause of catheter occlusion was correctly identified, 90% of the catheters were restored to normal function. CONCLUSIONS: Inability to withdraw blood from a catheter does not necessarily mean it is occluded by thrombus. Mechanical complications account for a significant portion of dysfunctional catheters.

Double-lumen inferior vena cava catheters for peripheral stem cell apheresis and transplantations.

No previously published studies have described double-lumen hemodialysis/apheresis catheters for use with continuous-flow apheresis collection of peripheral stem cell (PSC). We prospectively evaluated experiences with these catheters during both PSC collection and transplantation. Because of previously-described successful experiences with single-lumen apheresis catheters placed in the inferior vena cava, all catheters evaluated in this study were placed in this anatomic location. Our experience demonstrated high rates of thrombotic occlusion (65%) and catheter-related infections (15%). This method of access should not be considered optimal in its present state of use. Further investigation into preferred catheter design, anatomic location, and thrombosis prophylaxis during continuous-flow apheresis is warranted.

Multiple organ dysfunction syndrome in bone marrow transplantation.

OBJECTIVE: To define the frequency and outcome of organ dysfunction in bone marrow transplantation (BMT) and to determine if patients with organ dysfunction have lower levels of protein C (PC) and/or antithrombin III (ATIII) than those without organ dysfunction. DESIGN: Inception cohort of patients undergoing BMT, followed for 28 days, until hospital dismissal, or until death. SETTING: Bone marrow transplant department of a university hospital. PATIENTS: A total of 199 consecutive patients admitted for BMT. INTERVENTIONS: Standard supportive care was given to all patients. MAIN OUTCOME MEASURES: Definitions of organ dysfunction were arrived at prior to beginning the study. They include pulmonary, central nervous system (CNS), hepatic, and renal dysfunction. Protein C and ATIII levels were measured prior to beginning the preparative regimen and weekly thereafter. RESULTS: Single organ dysfunction, manifesting as pulmonary, CNS, or hepatic dysfunction, occurred in 93 (48.5%) of the 199 patients and was a strong predictor of multiple organ dysfunction syndrome (MODS) and death. Death occurred in 14 (7.0%) of the patients. Cause of death was precisely identified in only four patients. Low levels of either PC or ATIII were associated with death and pulmonary, CNS, and hepatic dysfunction. Multivariate analysis showed ATIII and PC levels were associated with single organ dysfunction independent of the type of transplant, the type of preparative regimen, and the presence of bacteremia. CONCLUSIONS: Single organ dysfunction during BMT is a marker for a systemic abnormality that has a high likelihood of progressing to MODS, similar to that seen in other critically ill patient populations. MODS is the leading cause of death in series of BMT patients. Low levels of ATIII and PC are markers of and may be involved in the pathogenesis of MODS in BMT.