Point-of-care Measurement of the Antifibrinolytic Activity of Tranexamic Acid in Cardiac Surgery

Обзор

Tranexamic acid (TXA) is a widely used antifibrinolytic agent that can reduce postoperative blood loss and packed red blood cell transfusions during cardiac surgery. Previous (in-vivo) studies have measured TXA plasma concentration and associated clinical effect (e.g. blood loss). Patient blood management guidelines recommend the routine use of TXA in cardiac surgery, especially for procedures with a high risk of bleeding. A new point-of-care viscoelastic diagnostic assay (tissue plasminogen activator assay, TPA assay) allows for a rapid determination of antifibrinolytic activity in a patient in the operating room making TXA dose adjustment easily possible intraoperatively. Currently, there is no consensus on the dosing of TXA and different protocols are used. Recommendations for high doses (e.g. 30 mg/kg followed by 16 mg/kg per hour during cardiac surgery with 2 mg/kg added to extracorporeal circulation) alternate with recommendations for low doses (e.g., 10 mg/kg followed by 1 mg/kg per hour for 12 hours). Tranexamic acid administration increases the risk of postoperative seizure, a risk that appears to be dose dependant. A recent meta-analysis suggests that a single TXA bolus of 20 mg/kg is sufficient to reduce postoperative blood loss and packed red blood cell transfusion in patients undergoing aortocoronary bypass surgery. The calculations in the meta-analysis were, however, based on a simulation of blood concentrations of TXA by a pharmacokinetic model, so the results are subject to many uncertainties. The optimal TXA regimen for cardiac surgery, both in terms of efficacy and safety therefore remains uncertain and requires further investigation. This study was invented to determine the actual levels of tranexamic acid in vivo to observe antifibrinolytic activity during cardiac surgery up to 48 hours after termination of surgery. The risk category is evaluated as risk category A as the study is a clinical trial examining the effect of drugs that are already authorized for the clinical use.

Вмешательства

• Препарат Tranexamic acid bolus 20 mg/kg
  Bolus of tranexamic acid in the standard dose group
• Препарат Tranexamic acid bolus 10 mg/kg
  Bolus of tranexamic acid in the low dose group
• Препарат Tranexamic acid bolus 1 mg/kg
  Bolus of tranexamic acid in the low dose group (to add into the CPB prime)
• Препарат Tranexamic acid continuous infusion of 1 mg/kg/h in the low dose group
  Tranexamic acid continuous infusion during the procedure

Первичные конечные точки

• TPA test [Срок оценки: 48 hours after completion of surgery]

Вторичные конечные точки (1)

• Chromatography [Срок оценки: 48 hours after completion of surgery]

Критерии участия

Критерии включения

Eligible patients:

• Over 18 years old
• Elective surgery
• Written informed consent
• Patient planned for aortocoronary artery bypass graft surgery, aortic valve replacement or mitral valve surgery (or a combination of these procedures)
• Normal renal function
• No previous intake of anticoagulants except acetylsalicylic acid in the preoperative period

Критерии исключения

• Impaired renal function (eGFR < 30 ml/min.)
• History of seizure
• Pregnancy
• Inability to understand and sign the informed consent (e.g., language problems, dementia, psychological disorders)

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Открытое

Основная цель

Лечение

Центры проведения

Швейцария · 1 центр

• Dpt. Anesthesiology and pain Medicine — Bern

Идентификаторы

NCT: NCT06128330 · 2022-02070

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

Открыть это исследование на ClinicalTrials.gov ↗