Disclosures: Mori reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
December 31, 2020
2 min read

CABG, surgical AVR may be safe despite flu season severity, duration

Disclosures: Mori reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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CABG or surgical AVR procedures may be safe to perform even in the worst of influenza seasons, according to research published in JAMA Network Open.

“Among older adults who underwent elective coronary and aortic valve operations during influenza seasons, there were no consistent associations between the severity of the influenza season and the risk of mortality or readmission,” Makoto Mori, MD, surgery resident at the Center for Outcomes Research and Evaluation at the Yale-New Haven Hospital, and colleagues wrote. “For CABG procedures, increasing seasonal severity may be associated with a slightly higher risk of 30-day mortality.”

Woman with flu
Source: Adobe Stock

Using Medicare fee-for-service inpatient claims data, researchers identified 313,159 individuals who underwent CABG (median age, 73 years; 71% men) and 135,550 who underwent surgical AVR (median age, 76 years; 61% men) during influenza seasons (November 1 to March 31) between 2003 and 2017.

“Patients recovering from a major operation are increasingly susceptible to respiratory complications, but whether undergoing operations during more severe influenza seasons is associated with a higher risk of respiratory complications remains unknown,” the researchers wrote.

The duration and severity of influenza seasons were defined as mild, moderate and severe based on rates of influenza-associated hospitalizations and deaths related to pneumonia or influenza according to CDC statistics.

Of the influenza seasons studied, six were mild, five were moderate and four were severe.

“Because elective procedures may be postponed to mitigate the potential risk, we evaluated associations between the severity of influenza seasons and the risks of mortality and hospital readmissions after elective coronary artery bypass grafting (CABG) and surgical aortic valve replacement,” the researchers wrote.

Outcomes of interest included in-hospital and 30-day mortality and all-cause and pneumonia-related 30-day readmissions.

Researchers observed that patients who underwent CABG during moderate (OR = 1.06; 95% CI, 1.01-1.11) and severe (OR = 1.06; 95% CI, 1.01-1.12) influenza seasons experienced greater risks for 30-day mortality compared with patients who had procedures during mild seasons (P = .03).

Among patients who underwent surgical AVR, 30-day mortality risk was not significantly higher during moderate (OR = 1.03; 95% CI, 0.96-1.1) or severe (OR = 1.01; 95% CI, 0.94-1.06) influenza seasons compared with mild seasons (P = .66).

Moreover, risk for all-cause readmission risk was not significantly greater in CABG or surgical AVR performed during moderate (OR for CABG = 0.99; 95% CI, 0.97-1.01; OR for surgical AVR = 0.99; 95% CI, 0.96-1.02) or severe influenza seasons (OR for CABG = 0.92; 95% CI, 0.9-0.95; OR for surgical AVR = 0.93; 95% CI, 0.9-0.96) compared with mild influenza seasons.

“Our large sample suggests that it is safe to perform elective major operations regardless of the severity of influenza seasons,” the researchers wrote.