New Guideline Aims to Standardize Anticoagulation During Cardiopulmonary Bypass

A consortium of thoracic surgeons, anesthesiologists, and perfusionists has released a guideline that attempts to describe best practices for the use of anticoagulation during cardiopulmonary bypass.

Heparin remains the gold standard, but the lack of any concise guidance in this area since cardiopulmonary bypass was developed in the 1960s has resulted in substantial variation in practice in terms of dosing, monitoring, reversal, and use of heparin alternatives in patients with contraindications, according to lead author Linda Shore-Lesserson, MD (North Shore University Hospital, Manhasset, NY).

The new guideline—crafted by the Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiologists, and the American Society of ExtraCorporeal Technology and published online January 19, 2018, ahead of print in the Annals of Thoracic Surgery, Anesthesia & Analgesia, and the Journal of ExtraCorporeal Technology—was based on a review of 96 highly cited studies and consolidates evidence in the field.

“I would hope this would be educating and that the majority of clinicians who practice these procedures every day or every week would have a little more understanding of the science and the data that have led up to the practice that they currently have,” Shore-Lesserson told TCTMD. “The second outcome I would hope for would be some more standardization in the field, some more agreement in the calculation of the heparin dose and the desired levels of anticoagulation that are considered therapeutic and safe for our patients.”

The authors make recommendations in three main areas:

• Optimal heparin dosing and monitoring
• Heparin contraindications and use of alternative drugs like bivalirudin, IV antiplatelets, and argatroban
• Reversal of anticoagulation, typically with the gold standard protamine

The largest section of the guideline is probably the one dealing with monitoring of anticoagulation levels, a topic that has been a source of controversy and anxiety for clinicians who worry about maintaining a level sufficient to prevent the formation of clots in the circuit outside the patient’s body, Shore-Lesserson said.

She said controversy stems from the fact that there are new technologies used for monitoring and there aren’t enough data in this area. Moreover, she added, there is not enough incentive for manufacturers to conduct the large-scale trials that are needed to establish best practices. Activated clotting time (ACT) is the gold standard for monitoring, but it’s unclear whether various devices for measuring ACT perform similarly because those studies have not been done.

“We really have quite a crude test to monitor such an important concept like anticoagulation,” Shore-Lesserson said. “I think it’s important that clinicians understand that the activated clotting time is really just a guide, it’s not a threshold that’s absolute. It’s a guide to indicate that our patient is responding to heparin, and . . . that is a message that we really tried to impart in the guideline.”

Another potential area of controversy in the guideline, Shore-Lesserson said, involves use of alternatives to heparin because of a lack of familiarity with the options.

“Many clinicians are not comfortable with the alternative anticoagulants to heparin,” she said. “To have to use an alternate anticoagulation strategy in patients who cannot receive heparin is stressful for these clinicians, and we hope that this document will help guide in these decisions.”