High versus low fixed-dose four factor-prothrombin complex concentrate for warfarin reversal in patients with intracranial hemorrhage.

BACKGROUND: Four-factor prothrombin complex concentrate 4F-PCC is the standard of care for warfarin reversal in patients with major bleed or requiring urgent surgery. Although the 4F-PCC dose is weight and international normalized ratio (INR) based, for practical purposes, a fixed-dose approach has been explored, especially for rapid reversal. We report our experience using two different fixed-dose 4F-PCC for warfarin reversal in patients presenting with intracranial hemorrhage (ICH). STUDY DESIGN AND METHODS: We completed a retrospective chart review comparing high (4000 units) versus low (2000 units) dose 4F-PCC by evaluating patient characteristics, laboratory data, and pre-and post-4F-PCC brain imaging. RESULTS: There was no significant difference between patient characteristics or INR correction (≤1.5) between the two groups. Eighty percent (12/15) of patients who received the low dose 4F-PCC had either improved or stable brain imaging as compared to 88% (14/16) of patients who received the high dose PCC. When the eight patients (4 from each arm of the study) who required neurosurgery were excluded, only two patients in each arm had worse imaging after 4F-PCC. CONCLUSION: There was no significant difference between the INR correction and the brain imaging changes in patients with an ICH who received either the high or the low fixed-dose 4F-PCC for warfarin reversal.

Role of plasma exchange in stiff person syndrome.

OBJECTIVE: Stiff person syndrome (SPS) is commonly associated with antibodies directed against 65-kDa glutamic acid decarboxylase (GAD65). Therapeutic Plasma Exchange (TPE) has been used as an adjunct therapy in patients who do not respond well to conventional treatment, which includes immunosuppression therapies, anti-anxiety medications, muscle relaxants, anticonvulsants, and pain relievers. METHODS: We retrospectively analyzed the clinical data and outcomes of ten patients with the clinical diagnosis of anti-GAD65 positive SPS in which TPE was employed to improve symptoms refractory to conventional treatment during an eight-year period. RESULTS: TPE was initiated as complementary therapy in patients with worsening of symptoms characteristic of SPS. Six patients underwent chronic treatment with TPE following an initial course, of which the frequency of TPE was guided by the clinical response. Two patients only had transient improvements with further disease progression. Four patients developed a relapse of symptoms when the interval between procedures was increased. One of the four patients dependent on TPE had worsening of symptoms following complete cessation of TPE due to lack of insurance coverage. Four patients underwent only an acute hospitalized course of treatment with TPE; one demonstrated complete resolution of symptoms; one had a partial response; and two experienced no improvement. CONCLUSION: Our study supports previous reports that TPE may be beneficial for the management of patients with anti-GAD65 positive SPS, both for acute exacerbations and long-term maintenance, either as an adjunct therapy, or in lieu of treatment with disease modifying agents.

Susceptibility of Cardiac Troponin Assays to Biotin Interference.

OBJECTIVES: To investigate biotin interference on three cardiac troponin (cTn) assays and demonstrate a method to overcome biotin interference. METHODS: cTn levels were measured in (1) plasma from healthy volunteers on 10-mg daily biotin supplementation mixed with a plasma with known elevated troponin, (2) plasmas with known elevated cTn after mixing in reagent biotin to simulate supplementation, and (3) biotin-spiked plasma specimens pretreated with streptavidin-agarose beads. RESULTS: Daily biotin ingestion (10 mg) and studies simulating daily biotin use resulted in significant interference in the Gen5 cardiac troponin T (cTnT) assay; the contemporary Gen 4 cTnT and high-sensitivity cardiac troponin I (hs-cTnI) assays were unaffected. The biotin interference threshold was 31, 315, and more than 2,000 ng/mL for Gen5 cTnT, cTnT, and hs-cTnI assays, respectively. Streptavidin pretreatment blocked biotin interference in cTn assays. CONCLUSIONS: Biotin interference is possible at plasma concentrations achievable by ingestion of over-the-counter supplements that may lead to delayed or missed diagnosis of myocardial injury with the Gen5 cTnT assay.

Advantages of isovolemic hemodilution-red cell exchange therapy to prevent recurrent stroke in sickle cell anemia patients.

Chronic simple hypertransfusion (every 3 to 4 weeks) effectively prevents secondary stroke in children with sickle cell anemia but leads to iron overload despite chelation therapy. Conventional red blood cell exchange (C-RBCx) has advantages over simple transfusion: no net iron gain and less frequent hospital visits. However, C-RBCx requires more red blood cell units, an apheresis instrument and skilled personnel; it is also more expensive. We developed a modified procedure where isovolemic hemodilution precedes RBCx (IHD-RBCx) to decrease RBC units required and to increase the interval between procedures. Twenty patients underwent IHD-RBCx over a period of 7 years. IHD-RBCx required 11% fewer RBC units and increased inter-procedure interval from 37 to 53 days compared to C-RBCx. The median number of annual procedures decreased from 9.8 to 7.0 per patient, resulting in estimated savings of more than $4.5 million over 10 years for 20 patients while providing improved care. Five patients have discontinued chelation therapy; three while on C-RBCx and two while on IHD-RBCx. No adverse events occurred related to the isovolemic hemodilution phase and no patients had recurrent stroke. IHD-RBCx is a safe, efficient, and cost effective therapy for secondary prevention of stroke in patients with sickle cell anemia.