PHOENIX-Using a scoring system aimed at assessing the risk of stroke in patients with atrial fibrillation may help doctors identify which patients undergoing lung surgery may develop the heart arrhythmia-a condition that can lead to longer hospital stays and other complications after surgery, researchers reported at the 52nd annual meeting of the Society of Thoracic Surgeons.

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In a poster presentation, Svetlana Kotova, MD, a Thoracic Surgeon at Providence Health Services, Portland, Ore., reported that 17.7 percent of patients who had higher scores on the CHADS₂ scale developed postoperative atrial fibrillation compared with 7.9 percent of patients with low CHADS₂ scores and 11.1 percent of patients with average scores. She noted that the difference was statistically significant (P<0.001).

"Postoperative atrial fibrillation affects 12.5 percent of patients undergoing lobectomy and is associated with prolonged hospital stay and decreased survival," Kotova reported. "CHADS₂, used clinically to predict stroke risk in patients with atrial fibrillation, has been shown to predict postoperative atrial fibrillation in patients undergoing heart surgery."

Now, she suggested, "use of available CHADS₂ can predict postoperative atrial fibrillation in patients undergoing elective lobectomy. It can be used to risk stratify patients and selectively institute prophylactic measures in those who are at the greatest risk, such as patients with score 2 or greater."

Study Methodology & Results

Kotova and colleagues accessed a prospective thoracic surgery clinical database and identified elective lobectomy patients who underwent surgery from 2005 through June 2014. The researchers excluded persons under the age of 18, people undergoing non-elective surgery, and those who had been diagnosed with pre-existing atrial fibrillation.

Two researchers explored patient characteristics among those who developed atrial fibrillation in the cohort, and those who were free of the arrhythmia after surgery.

Postoperative atrial fibrillation developed in 113 patients of 933 undergoing elective lobectomy with overall incidence of 12 percent for the entire group. Age-being over age 75-was the only significantly different preoperative characteristic between postoperative atrial fibrillation and no postoperative atrial fibrillation groups, while remaining morbidities such as diabetes, hypertension, and coronary artery disease were similar. Overall length of hospital stay was 6.4 days among the patients who did not have atrial fibrillation and was 10.4 days among those patients who did develop postoperative atrial fibrillation (P<0.0001).

The study showed that in-hospital was 1.1 percent among those people who did not have atrial fibrillation following the lung surgery, but was 5.3 percent among the patients who did have atrial fibrillation (P=0.0008). The 30-day mortality was 1.5 percent among patients without atrial fibrillation and 6.2 percent among patients who did have atrial fibrillation (P=0.001). Rate of intensive care unit readmission and new neurologic events were also significantly higher in the postoperative atrial fibrillation group.

The mean CHADS₂ score calculated preoperatively was significantly higher in patients with postoperative atrial fibrillation-a score of 1.5-compared to no postoperative atrial fibrillation, a score of 1.1 (P=0.0014). Overall, 31 percent of patients fell into the high risk group and 17.7 percent of this population were later diagnosed with post-operative atrial fibrillation.

Future Considerations

When commenting on the study, Stephen D. Cassivi, MD, a Thoracic Surgeon and Professor of Surgery at the Mayo Clinic, Rochester, Minn., said, "Having atrial fibrillation after lung or chest surgery is not uncommon. Depending upon the extent of the surgery, the risk increases. The risk of atrial fibrillation can range from 5 to 20 percent.

"The good news is that atrial fibrillation is usually self-limiting-the atrial fibrillation resolves on its own in 90 to 95 percent of patients in 4 to 6 weeks postoperatively," Cassivi continued. "But atrial fibrillation causes angst and a certain amount of risk to the patient, but it is usually well-tolerated. The key thing is to understand which patients will get it, and if we can identify the people who are likely to have it, we might be able to prevent it from happening."

Cassivi noted that the main concern about atrial fibrillation is the risk of stroke, which is the reason atrial fibrillation patients are assessed with the CHADS₂ scale. "When that scale was done it was aimed at patients who already had atrial fibrillation-not the postoperative type-but the garden variety atrial fibrillation. In this study the score was used to identify patients at risk of postoperative atrial fibrillation.

"This study adds to our knowledge base," he added. "It proved what could be considered intuitive, which is great. The difficulty is that we don't have a lot we can do with that score. I would hate to have this score keep people from the operating room because they would be at a high risk for atrial fibrillation.

"Atrial fibrillation is treatable, although it does increase the risk of complications, increased use of resources and length of stay," Cassivi concluded. "There are not lot of current interventions that can pre-operatively prevent atrial fibrillation in patients who are at high risk. It is clear that if someone is on a beta blocker, then you should not stop the beta blocker. If they are low in magnesium, it is known that magnesium should be supplemented. There is not a high level of evidence, but you could initiate amiodarone in patients who are considered at high risk. So there are options available."

Ed Susman is a contributing writer.