A new set of studies led by Michigan Medicine reveals that one in five older adults who undergo heart surgery develop an infection within six months after the procedure.
The research also shows that women are significantly more likely to experience these infections, along with racial disparities in outcomes. The findings are published in The Journal of Thoracic and Cardiovascular Surgery.
The studies focused on Medicare patients who had either coronary artery bypass grafting (CABG), commonly called heart bypass surgery, or aortic valve replacement. These two surgeries account for more than half of all heart procedures in Michigan, with CABG making up over 70% of heart surgeries nationwide.
Women were found to have 60% higher odds of getting a postoperative infection compared to men. The most common infections were urinary tract infections (UTIs), pneumonia, and sepsis. Black patients also had a higher overall infection rate at 28%, compared to 19.2% among white patients.
“These studies highlight persistent inequalities in health outcomes after cardiac surgery,” said Dr. J’undra Pegues, lead author of the infection disparities study and a research fellow in the Department of Cardiac Surgery at U-M Health. “Fixing these issues will require teamwork across different parts of the healthcare system.”
One of the studies looked at hospital data across Michigan and found that 21.2% of older patients developed an infection within six months of surgery. Pneumonia and UTIs made up nearly 17% of these infections. The infection rates varied widely—by as much as 40%—depending on the hospital.
Dr. Pegues pointed out that it’s important to track infections over a longer period, as some hospitals have more resources to prevent infections, while some patients face greater health risks due to social and economic challenges.
Previous studies showed lower infection rates, but those studies typically only followed patients for 30 days after surgery. The new research followed patients for six months, which allowed the team to catch more infections, including those that develop later, such as gastrointestinal or urinary infections.
“Surveillance beyond the first month is key,” said Dr. Donald Likosky, senior author of both studies and a professor of cardiac surgery at the University of Michigan. “Many registries do not capture these longer-term complications, which leads to underestimating the true burden of infections.”
Dr. Charles Schwartz, chair of the Department of Surgery at Trinity Health Oakland and a co-author, agreed: “The current systems fail to track many infections, which is why studies like this are so important.”
The studies also showed that patients treated at lower-performing hospitals, where higher infection rates are expected, were more likely to be discharged to extended care or rehab facilities. Other factors, such as diabetes, high blood pressure, and cancer, may also increase the risk of developing infections after surgery.
Dr. Francis Pagani, co-author of both studies, emphasized the need for long-term infection monitoring and preventive care, especially for high-risk patients. He noted that age-related health conditions can contribute to the delayed infections observed in the study.
Efforts to reduce infection rates through collaboration are showing promise. Between 2012 and 2017, a statewide quality improvement program helped several hospitals lower their pneumonia rates through targeted strategies.
“These results highlight the value of hospitals working together with communities to improve patient outcomes,” said Dr. Syed Sikandar Raza, first author and thoracic surgery resident at U-M Health. “By sharing effective practices and focusing on prevention, we can help reduce the number of infections after heart surgery.”
If you care about heart health, please read studies about a new cause of heart rhythm disorders and eating just one cup of nitrate-rich vegetables daily can reduce heart disease risk.
For more information about heart health, please read studies about blood thinners that may not prevent stroke in people with heartbeat problems and this diabetes drug may protect heart health in older veterans.
The study is published in The Journal of Thoracic and Cardiovascular Surgery.
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