KDIGO Clinical Practice Guideline for Acute Kidney Injury
How to decide to use anticoagulation: Recommendations and Rationale

• 5.3.1: In a patient with AKI requiring RRT, base the decision to use anticoagulation for RRT on assessment of the patient’s potential risks and benefits from anticoagulation (see Figure 17). (Not Graded)
  • 5.3.1.1: We recommend using anticoagulation during RRT in AKI if a patient does not have an increased bleeding risk or impaired coagulation and is not already receiving systemic anticoagulation. (1B)

Rationale

The goal of anticoagulation with RRT is to prevent clotting of the filter and/or reduction in membrane permeability, and thus to achieve adequate RRT and to prevent blood loss in the clotted filter. These benefits have to be weighed against the risk of bleeding, and economic issues, such as workload and costs.

Patients with impaired coagulation (e.g., thrombocytopenia, or prolonged prothrombin time or activated partial thromboplastin time [aPTT]), due to underlying diseases such as liver failure or dilution coagulopathy, may not benefit from additional anticoagulation for RRT. In two recent large trials 50–60% of AKI patients requiring RRT were treated without anticoagulant.^562,563 While filter performance was not assessed, adequate CRRT filter survival without anticoagulation has mostly been described in patients with coagulopathies.^572-575 However, no specific cut-off points have been determined for platelet count, aPTT, International Normalized Ratio, fibrinogen, or other coagulation factors that would indicate the possibility to perform RRT without anticoagulation. On the other hand, prolonged clotting times can also point to a consumptive coagulopathy based on the presence of an activated coagulation. In these patients, frequent filter clotting will occur and necessitate a switch to some form of anticoagulation.⁵⁷⁶

In patients that are treated without anticoagulation, special attention is required to non-anticoagulant strategies to prolong filter survival. These include a good functioning vascular access, the reduction of blood viscosity and hemoconcentration by saline flushes, predilution, high blood flow rates, diffusive treatment, the reduction of blood-air contact in the bubble trap, and assuring prompt reaction to alarms.^577,578

Many patients with AKI require systemic anticoagulation for their underlying diseases (e.g., artificial heart valve, acute coronary syndrome, atrial fibrillation). It is evident that, in most instances, these patients will not require additional anticoagulation for RRT; however, this should be assessed on a case-by-case basis.