2013 Spring Newer Oral Antithrombotics Adds Complexity to Bridging Strategies
Patients undergoing surgery at Cleveland Clinic typically receive preoperative evaluation at the Internal Medicine Preoperative Assessment, Consultant and Treatment (IMPACT) Center in Cleveland Clinic’s Medicine Institute. An important issue that must be addressed prior to procedures requiring interruption of anticoagulation, is how to “bridge” antithrombotic therapy before and/or after surgery.
And now, for patients with atrial fibrillation (a-fib) who are on anticoagulation therapy, there’s a new factor in the equation. “We are seeing more patients who are taking one of the newer oral agents - dabigatran, rivaroxaban or apixaban,” says Marcelo P. Villa-Forte Gomes, MD, vascular medicine specialist in the Department of Cardiovascular Medicine, Cleveland Clinic Heart & Vascular Institute. “The IMPACT Center often refers them to Vascular Medicine for individualized perioperative management. We also see many patients with venous thrombosis or who are hypercoagulable so that we can evaluate them preoperatively.”
Warfarin Bridging: Emerging Research
Traditionally, bridging strategies have involved moving patients from warfarin to heparin or a low molecular weight heparin (LMWH) such as enoxaparin or dalteparin. In patients at risk of thrombotic events, Cleveland Clinic specialists typically follow perioperative clinical guidelines from the American College of Chest Physicians and the American Heart Association/American College of Cardiology. Cleveland Clinic has also developed its own document, Cleveland Clinic Anticoagulation Management Program, which provides practical guidance for physicians and trainees.
Bridging is prescribed routinely in at least two-thirds of patients on warfarin therapy who need to undergo a surgical or invasive procedure.
Current Practice Focuses On:
- Evaluating patients preoperatively to determine if they are high or low risk for thromboembolic complications;
- Establishing a bridging strategy preoperatively for those who are at high risk, while bridging is often unnecessary for those who are low risk;
- Post-operatively, most patients—especially those at high risk—are bridged back to warfarin, while low-risk patients with afib may not require bridging.
Currently, most recommendations for bridging are based on the patient’s history and underlying indication for anticoagulation (i.e., afib, mechanical heart valve or venous thromboembolism). “Because large-scale randomized clinical trials are lacking, current guidelines provide recommendations based on limited data and expert opinion,” Dr. Gomes says. “But a multicenter trial called BRIDGE is currently under way to determine whether bridging anticoagulation is needed in patients with afib during warfarin interruption.”
Newer Oral Antithrombotics
Dabigatran, rivaroxaban and apixaban are so new that none of the major clinical guidelines that address oral anticoagulant bridging provide specific recommendations for perioperative management of patients who are taking them.
“These agents have a half-life of approximately 12 hours, so the recommendations for perioperative management should be quite different than those for warfarin,” he says. “No one knows the best way to manage these drugs prior to invasive procedures, and there are no clinical trial data to guide these decisions. This is a big challenge in day-to-day medical practice right now for many MDs. Physicians with patients on these medications should refer them to Vascular Medicine specialists preoperatively for recommendations.”
Unlike the INR monitoring available for warfarin, there is no monitoring test for newer oral anticoagulants. Additionally, the new oral anticoagulants do not have a reversal agent.
“If a patient is bleeding or coming in for surgery on these drugs, they cannot be reversed,” Dr. Gomes says. “So how and when to stop these drugs before surgery becomes incredibly important.”
To refer a patient to a vascular medicine specialist at Cleveland Clinic, please call toll-free 800.223.2273, ext. 44420, or contact us online.
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Call a Heart & Vascular Nurse locally 216.445.9288 or toll-free 866.289.6911.
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