New AATS Guidance for the Prevention and Management of Postop AF

September 24, 2014

BOSTON, MA — The American Association for Thoracic Surgery (AATS) has issued new guidelines to help prevent the development of atrial fibrillation (AF) during or after surgery as well as for the clinical management of patients in whom AF or atrial flutter does develop[1].

In addition, the guidelines provide direction for managing patients with preexisting AF undergoing thoracic surgery, noting that these patients are at high risk for stroke, heart failure, and other complications. Managing their antiarrhythmic medications and perioperative anticoagulation can pose a challenge, so a preoperative cardiology consultation can be useful in these patients, according to the experts.

"The truth is we can't tell you exactly why atrial fibrillation occurs, but it's very clear that if you operate on the heart or the lung—and it's probably worse for the lung—you get a very high incidence of postoperative atrial fibrillation," said task force chair Dr Gyorgy Frendl (Brigham and Women's Hospital, Boston, MA). "So surgeons in thoracic and cardiac surgery are very much on the lookout for it, trying to figure out why it's happening, if there's any way to prevent it, or if there's any way to reduce it. The answers are not very simple."

The AATS task force charged with drafting the new guidelines included cardiologists, electrophysiologists, intensivists, anesthesiologists, and thoracic and cardiac surgeons, as well as a clinical pharmacist. Their recommendations are published September 23, 2014 in the Journal of Thoracic and Cardiovascular Surgery.

How to Prevent AF After Surgery

Speaking with heartwire , Frendl said that patients who develop AF after surgery have longer stays in the intensive-care unit, longer stays in the hospital, and a more complicated and costlier recovery. Postoperative physical therapy is paramount in lung surgery—the goal is to get patients on their feet and walking to help gain back physical fitness—but AF delays this important piece of care.

In the new guidelines, the experts recommend that all patients taking beta-blockers before surgery should continue to take them in the postoperative period to prevent the onset of AF or flutter (class I, level of evidence A). Frendl said that following surgery, a patient's blood pressure can be significantly reduced, and this might lead some physicians to stop the drug, which would be wrong.

"If you are on beta-blockade for other reasons, the worst thing you could do would be to take it away," said Frendl. "In the immediate, postoperative setting, many of these patients have more marginal blood pressures. If they live at 120 or 140 mm Hg, for various reasons, they can settle around 100 mm Hg. There is a fear with beta-blockers that the blood pressure will go even lower."

Instead of stopping beta-blockade if low blood pressure occurs, Frendl said the AATS recommendation is to reduce the dose very significantly or to space the drug out over longer intervals.

Intravenous magnesium supplementation can also be considered to prevent postoperative AF if serum magnesium levels are low or if operators suspect total body magnesium is depleted (class IIb, level of evidence C). The guideline writers state that digoxin should not be used for AF prophylaxis, nor should catheter-based or surgical pulmonary vein isolation be performed at the time of surgery to prevent AF or flutter.

For AF or flutter prevention in patients at intermediate or high risk for developing perioperative/postoperative AF or flutter, such as those at advanced age, with hypertension, or prior history of AF, diltiazem may be considered in patients with preserved cardiac function who are not taking preoperative beta-blockers (class IIa, level of evidence B).

Amiodarone given postoperatively can be considered in patients undergoing certain procedures, such as pulmonary resection or esophagectomy. Frendl notes that amiodarone can be problematic because it carries pulmonary toxicity if taken long term and at higher doses.

"It can cause lung damage, and if I remove a lung, and you're left with a single lung, I'd be very concerned with prescribing amiodarone," said Frendl. He notes, however, that single-center studies suggest the drug can be used safely as long as the dose is low.

Atorvastatin can also be considered for AF prevention in statin-naive patients undergoing intermediate- or high-risk surgeries, but the evidence supporting it is weak (class IIb, level of evidence C).

The AF Patient Coming in for Surgery

For the patient with AF on long-term warfarin or one of the new oral anticoagulants, how long anticoagulation should be stopped, as well as the need for heparin bridging, depends on the patient's stroke risk, which is assessed using the CHA2DS2-VASc score. When undergoing surgery, anticoagulation can be stopped without anticoagulant bridging for patients with a CHA2DS2-VASc score of less than 2. In addition to heparin, enoxaparin can be considered as a short-acting bridge if the patient has a glomerular filtration rate >50%.

Regardless, if anticoagulation is stopped, the duration should be minimized, according to the AATS task force.

For the management of patients with perioperative/postoperative AF or flutter, Frendl told heartwire that treatment depends on hemodynamic stability. For patients who are hemodynamically stable, the primary treatment is rate control, with rhythm control as a secondary strategy. The rate-control strategy should aim to titrate medication to achieve a heart rate of 110 bpm. For those who are hemodynamically unstable, the aim is urgent restoration of sinus rhythm.

The new guidelines provide a range of drug recommendations for the medical management for patients with new-onset perioperative/postoperative AF or flutter as well as recommendations for direct-current cardioversion for stable patients.

Overall, Frendl said the incidence of perioperative or postoperative AF/atrial flutter depends on the type of surgery and patient characteristics. For example, the use of flexible bronchoscopy, which is done to assess the trachea, bronchi, and bronchioles, is considered a minor procedure and carries a low risk for AF (<5% incidence). More major procedures, such as lung transplantations and thoracoscopic lobectomy, which is done for lung cancer, carry a higher risk of perioperative/postoperative AF and flutter (>15% incidence).

For patient characteristics and comorbidities, individuals with hypertension, heart failure, a prior MI, obstructive sleep apnea, hyperthyroidism, left ventricular hypertrophy/increased left wall thickness, and vascular heart disease, as well as those who smoke, are obese or inactive, or drink excessively are all at higher risk for developing AF/atrial flutter.

To heartwire , Frendl differentiated perioperative/postoperative atrial fibrillation from the atrial fibrillation that develops outside the surgical setting. Atrial fibrillation after surgery tends to resolve within six to 12 weeks, making it more of a transient problem. If healing continues and the patient continues to recover from surgery, many patients can stop the medications used to manage their postoperative atrial fibrillation, he said.

Fendl has received consultant fees and grant support from EarlySense and grant support from AlloCure and AbbVie. Disclosures for the authors are listed here.

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