A new study led by Michigan Medicine has found that one in five older adults develops an infection within six months of undergoing heart surgery, with women significantly more likely to be affected. The research, published in The Journal of Thoracic and Cardiovascular Surgery, highlights persistent disparities in post-surgical outcomes and underscores the need for improved its prevention strategies.
The study examined thousands of Medicare patients who underwent coronary artery bypass grafting (CABG), commonly known as heart bypass surgery, or aortic valve replacement. Women were found to have a 60% greater likelihood of developing infections compared to men. The three most common infections were urinary tract infections (UTIs), pneumonia, and sepsis.
Racial Disparities in Post-Surgical Infections
Beyond gender differences, the study also identified racial disparities in its rates. Black patients had an overall rate of 28%, compared to 19.2% among white patients.
“Our investigations highlight persistent disparities in outcomes for patients undergoing cardiac surgery that will require multidisciplinary efforts to correct,” said J’undra N. Pegues, M.D., M.S., first author of the study and a research fellow in the Department of Cardiac Surgery at U-M Health.
The researchers noted that variations in hospital quality, access to care, and social determinants of health may contribute to these disparities. Hospitals with higher infection rates were also more likely to discharge patients to extended care or rehabilitation facilities, potentially increasing their risk of developing it later.
Longer Follow-Up Reveals Higher Infection Rates
Previous studies have reported lower post-surgical infection rates, but the researchers attribute their higher findings to a longer follow-up period of six months. Most national registries track it for only 30 days, potentially underestimating the true burden of post-surgical complications.
“Patients who have a heart bypass or valve replacement surgery are at risk for developing it that may come about over a longer period of time, such as UTIs and gastrointestinal infections,” said Donald Likosky, Ph.D., senior author of the study and Richard and Norma Sarns Research Professor of Cardiac Surgery at U-M Medical School.
Tracking it beyond the immediate post-surgical period is crucial, as some hospitals are better equipped than others to prevent complications. Infection rates varied by nearly 40% across hospitals included in the study, highlighting the need for targeted interventions at lower-performing facilities.
Strategies for Reducing Infection Risk
Researchers emphasized that collaborative efforts between hospitals and community health stakeholders could help lower its rates and improve patient outcomes. A statewide quality improvement initiative in Michigan between 2012 and 2017 successfully reduced the risk of pneumonia following heart surgery.
“Our study reinforces the importance of bringing together hospitals and community stakeholders to identify and subsequently implement potentially modifiable hospital and community practices to prevent postoperative infections,” said Syed Sikandar Raza, M.D., co-author of the study and a thoracic surgery resident at U-M Health.
The findings suggest that hospitals nationwide could benefit from adopting similar quality improvement strategies to address post-surgical infections and reduce disparities in patient care. As heart bypass and aortic valve replacement surgeries account for the majority of cardiac procedures in the U.S., ensuring better prevention protocols could have a significant impact on patient health and recovery.
Reference: Syed Sikandar Raza, Shiwei Zhou, Noah M. Barnett, Chiang-Hua Chang, Robert B. Hawkins, Raed Alnajjar, Alphonse DeLucia, Charles F. Schwartz, Michael P. Thompson, Thomas M. Braun, Eric N. Hammond, Jeremy Wolverton, Francis D. Pagani, Donald S. Likosky. Interhospital variability in 180-day infections following cardiac surgery. The Journal of Thoracic and Cardiovascular Surgery, 2025.
