More than 27 million Americans undergo noncardiac surgery annually. Cardiac complications can be a major source of morbidity and mortality in the perioperative period.
The focus of the preoperative evaluation for patients with preexisting atrial fibrillation is to (1) assess rate and/or rhythm control; (2) identify patients with valvular disease or heart failure; (3) determine if prior thromboembolic events have occurred; and (4) take a thorough history of previous management plans employed when cessation of anticoagulation was required. A complete cardiovascular examination should be performed including review of the ECG and prior echocardiograms.
Because the thromboembolic rates are similar for paroxysmal, persistent, and permanent atrial fibrillation, recommendations for anticoagulation are generally the same. Prior factors that induced atrial fibrillation episodes, including whether it occurred with previous surgical procedures, should be elicited.
Preoperative management includes optimizing the heart rate. Adequacy of rate control should be individualized. AV nodal blockers are typically continued perioperatively, and a post-op plan should be made for continuing these agents, taking into account whether or not the patient is anticipated to be NPO. Management of patients receiving antiarrhythmic medications, such as sotalol, propafenone, and amiodarone, should generally include a discussion with the patient’s cardiologist.
Perioperative anticoagulation requires complex decision making. A plan for perioperative anticoagulation should be developed prior to surgery whenever possible. This plan should include anticipating the postoperative conditions affecting the resumption of anticoagulation.
The management of anticoagulation in patients undergoing surgical procedures is challenging because interrupting anticoagulation for a procedure transiently increases the risk of thromboembolism. At the same time, surgery and invasive procedures have associated bleeding risks that are increased by the anticoagulant(s) administered for thromboembolism prevention. If the patient bleeds from the procedure, their anticoagulant may need to be discontinued for a longer period, resulting in a longer period of increased thromboembolic risk. A balance between reducing the risk of thromboembolism and preventing excessive bleeding must be reached for each patient. One approach to decision making is outlined below:
- Estimate thromboembolic risk – A higher thromboembolic risk increases the importance of minimizing the interval without anticoagulation. We estimate thromboembolic risk for patients with atrial fibrillation based on age and comorbidities according to CHADS-VASC. For those with a recent deep vein thrombosis or pulmonary embolism, we estimate the risk based on the interval since diagnosis. If thromboembolic risk is transiently increased (eg, recent stroke, recent pulmonary embolism), we prefer to delay surgery until the risk returns to baseline, if possible. For patients with more than one condition that predisposes to thromboembolism, the condition with the highest thromboembolic risk takes precedence.
- Estimate bleeding risk – A higher bleeding risk confers a greater need for perioperative hemostasis, and hence a longer period of anticoagulant interruption. Bleeding risk is dominated by the type and urgency of surgery; some patient comorbidities also contribute. Procedures with a low bleeding risk (eg, dental extractions, minor skin surgery) often can be performed without interruption of anticoagulation.
- Determine the timing of anticoagulant interruption – The timing of anticoagulant interruption depends on the specific agent the patient is receiving. As examples, warfarin requires earlier discontinuation than the shorter-acting target-specific oral anticoagulants (ie. dabigatran, rivaroxaban, apixaban)
- Determine whether to use bridging anticoagulation – For patients receiving warfarin, the interval without an anticoagulant may be as long as five to six days due to the long half-life of warfarin and time to reach the therapeutic INR range. The use of heparin or low molecular weight (LMW) heparin to reduce the interval without anticoagulation (ie, bridging anticoagulation) may be appropriate for some patients, especially those who have a high thromboembolic risk.
REFERENCES
Coon WW, Willis PW 3rd. Recurrence of venous thromboembolism. Surgery 1973; 73:823.
About the Author:
Rishi G Anand, MD is board certified, and well published cardiovascular disease specialist and cardiac electrophysiologist. He serves as the Director of an Electrophysiology laboratory in Fort Lauderdale, Florida. He also serves as an author and Editorial board member for EP Lab Digest which is a nationwide publication. He serves an advisor to Medicare at the state level on health coverage policy matters. He has been nominated to serve as an expert advisor to the center for Medicare/Medicaid services (CMMS) Medicare Evidence Development and Coverage Advisory Committee (MEDCAC). MEDCAC is utilized by CMMS to supplement its own research and allow for additional expert and public input on coverage topics, including those that are highly complex or have a major potential impact on the health of beneficiaries and/or the Medicare program itself.
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