the Efficacy and Safety of Prothrombin Complex Concentrate In Patients Requiring Urgent Reversal of Warfarin, A Retrospective Canadian Experience

Major bleeding remains the most frequent adverse effect of oral anticoagulant therapy. A rapid method of reversal is required for patients on warfarin who suffer acute bleeding or require emergency surgery. Octaplex is a prothrombin complex concentrate recently recommended for use by the National Advisory Committee for Blood and Blood Products of Canada (Canadian Blood Services) at a dose of 1000 IU of factor IX activity. It ensures rapid INR correction by providing vitamin K-dependent factors without a large volume load. The main goal of this study was to investigate both the efficacy and safety of Octaplex use in a tertiary care center in Quebec, Canada.

A retrospective review was conducted on the charts of patients who received Octaplex for urgent warfarin reversal between 1 January 2009 and 31 October 2009. Data collected included INRs pre and post Octaplex administration, and documentation of any adverse events.

We identified 146 occasions when Octaplex was administered for urgent INR reversal. A total of 118 patients were included in the study with a median age of 77. The three most frequent indications for Octaplex were: 1) gastrointestinal bleeding, 2) intracranial hemorrhage, and 3) pre-procedural INR reversal. The majority of patients (90.7%) were treated with Octaplex at a dose of 1000 IU of factor IX activity, with a range of 500 IU to 5000 IU. The average mean pre-and post INRs were 4.00 and 1.65, respectively. Overall, 89.8% (130/146) of patients corrected to an INR < 2.0, of which 51.5% (67/130) corrected to an INR < 1.5. Although 8.2% (12/146) of patients were considered to have a poor response (post INR > 2.1), these patients tended to have a higher mean pre-INR value (5.28 vs. 2.69) and still achieved important absolute drops in INR (range 1.1–9.3, mean 2.91). Only 4 patients (2.7%) did not experience a reversal of their INR. Seventeen patients received second doses of Octaplex, 70.6% (12/17) of whom achieved a post INR < 1.5 and 94.1% (16/17) achieved a post INR < 2.0. There were 8 reported thrombotic events amongst 118 patients: 3 myocardial infarctions, 3 DVTs, 1 ischemic limb and 1 intracardiac clot. All patients with these adverse events had other co-morbities that could have also contributed to these toxicities.

Octaplex is efficient and appears to be safe in the urgent reversal of INR in patients taking vitamin K antagonists.

No relevant conflicts of interest to declare.