Basic Hemostatic Parameters in Patients with Long-Term Oral Anticoagulation Undergoing Cholecystectomy

Antiplatelet and Anticoagulant Medications Significantly Increase the Risk of Postoperative Hematoma: Review of over 4500 Thyroid and Parathyroid Procedures

PURPOSE

Antiplatelet and/or anticoagulant medication use is common. Abstinence a week before surgery may still result in altered hemostasis. The study aim was to report on perioperative antiplatelet and anticoagulant use in thyroidectomy and parathyroidectomy patients, and to determine the association with postoperative hematoma (POH) rates.

METHODS

Retrospective review of a prospective endocrine surgery database was performed. Procedure extent was defined as unilateral, bilateral, or extensive. Antiplatelets were categorized as none, 325 mg aspirin (ASA), <325 mg ASA, clopidogrel, or other. Anticoagulants were categorized as none, oral, or injectable.

RESULTS

A total of 4514 patients were identified. POH developed in 22 patients (0.5 %). Rates were similar between age, gender, and reoperative status. POH were seven times more common after thyroidectomy (0.8 vs. 0.1 %, p < 0.01). Unilateral procedures had lower POH rates than bilateral or extensive (0.1 vs. 0.9 vs. 0.8 %, p < 0.01). POH rates in patients receiving 325 mg ASA (0.8 %) or clopidogrel (2.2 %) were much higher than patients not receiving antiplatelets (0.5 %) or receiving <325 mg ASA (0.1 %, p = 0.04). Oral anticoagulants (2.2 %) and injectable anticoagulants (10.7 %) had much higher POH rates than patients not receiving anticoagulants (0.4 %, p < 0.01). Target organ, patient gender, procedure extent, antiplatelet use, and anticoagulant use were included on logistic regression to determine association with POH. Bilateral procedures, thyroidectomy, clopidogrel, oral, and injectable anticoagulants were all independently associated with POH.

CONCLUSIONS

POH occur more frequently after thyroidectomy and during bilateral procedures. Patients requiring clopidogrel or any anticoagulant coverage are at much higher risk for POH. These higher-risk patients should be considered for observation to ensure prompt POH recognition and intervention.

Study of Octaplex dosing accuracy: an in vitro analysis

Prothrombin complex concentrates (PCC) are recommended for urgent warfarin reversal. However, disagreement exists regarding the proper dosing strategy (i.e. fixed vs. weight-based). We measured the in vitro effect of PCC dosing on international normalised ratio (INR) and factor activity. Plasma from warfarin-anticoagulated patients with stable INRs was collected. PCC doses of 1,000, 2,000 and 3,000 IU were added to the samples, and INR and factor activity were analysed before and after PCC. Twenty-three of thirty subjects enrolled had complete data for analysis. INRs were below 1.5 in all samples post-1,000 IU, and decreased further with subsequent doses (p<0.001). Factors II, VII, and X increased with consecutive doses (p<0.01). Linear correlation was seen between INR and factors II, VII and X. Factor IX did not increase consistently nor show correlation with INR reversal. Weight-based dosing was then estimated; INRs were all <1.2 (0.9-1.2) and activity >0.50 IU for factors II, VII and X (0.96-1.52, 0.51-1.45 and 0.81-1.38, respectively). Factor IX did not uniformly correct above 0.50 IU (0.31-1.31). We confirm in vitro that 1,000 IU of Octaplex(®) is able to correct INR to <1.5 but factors were not uniformly >0.50 IU until 2,000 IU, and not >1.00 IU until 3,000 IU. This suggests that INR correction alone may not accurately reflect factor activity, and lends support for weight-based dosing.