Lupus Anticoagulant Testing in Patients Receiving Rivaroxaban or Apixaban for the Treatment of Venous Thromboembolism
Notice bibliographique
Résumé
Abstract Background. Lupus Anticoagulant (LA) testing is often performed in order to determine the cause of idiopathic venous thromboembolism (VTE) as well as the duration of therapy. The timing of the testing is often problematic. Acutely, many patients have received LMWH which often will interfere with test results. LA testing in patients on warfarin is technically feasible and current guidelines have established procedures for this situation. In contrast direct anti-Xa inhibitors such as apixaban and rivaroxaban can cause false positive results if residual anti-Xa inhibition is present. In general, prior to performing a thrombophilia screen, anticoagulants must be held in order to produce valid results. The duration of this varies with different anticoagulants. Some groups have advised that apixaban and rivaroxaban should be held for 2-3 days prior to testing. This overcomes the half-life of both agents. However, to date there have not been adequate studies to validate this approach, and no standardized approach has been proposed. At our centre we require patients to withhold apixaban or rivaroxaban on the day prior to and the day of LA testing. We aimed to determine the adequacy of this approach. Methods. We reviewed consecutive patients with VTE treated with rivaroxaban or apixaban and who required LA screening. . LA testing was requested at least 3 months after the initial VTE diagnosis. Patients were asked to hold the anticoagulant the day prior to and the day of LA testing (last dose taken at least 48 hours prior to testing). Plasma was collected in 3.2% citrate tubes and LA testing was done using dilute Russell viper's venom time and LA-sensitive activated partial thromboplastin time, according to the guidelines of the International Society on Thrombosis and Haemostasis. Plasma aliquots were frozen at -20 Celsius for further testing and apixaban or rivaroxaban plasma levels were measured by liquid chromatography-tandem mass spectrometry. Results. We included 21 patients (13 women). The mean age at VTE diagnosis was 57 years. Twelve patients had a pulmonary embolism (PE), 10 deep vein thrombosis (DVT), and 1 both a PE and DVT. Sixteen (76.2%) of the 21 patients received rivaroxaban, the rest apixaban. The mean apixaban level was 17.3 ng/ml (range 11.4 to 28.9). The mean rivaroxaban level was 11.7 ng/ml (range 8 to 27.8). All of these levels were consistent with being below trough levels for acute VTE treatment. All patients were negative for LA screening and there were no technical issues with performing the LA tests. Conclusion. Our results suggest that holding rivaroxaban or apixaban both the day prior to and the day of testing allows for a valid assessment of LA. This is supported by the low measured levels of both rivaroxaban and apixaban and the lack of technical issues with the LA testing. Disclosures Lazo-Langner: Bayer: Honoraria; Pfizer: Honoraria; Daiichi Sankyo: Research Funding. Louzada:Pfizer: Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Bayer: Honoraria. Kovacs:Daiichi Sankyo Pharma: Research Funding; Bayer: Honoraria, Research Funding; LEO Pharma: Honoraria; Pfizer: Honoraria, Research Funding.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,003 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».