QI can help tackle post-bypass infections

Women have greater likelihood of death

A study published in the "Archives of Internal Medicine"1 reveals a new opportunity for quality managers to have an impact in an area where disease/complications may be preventable and/or treatable: bypass surgery.

The study, conducted by the University of Michigan (U-M) Health System, was undertaken to gain better understanding of a long-puzzling fact: That women who have heart bypass surgery are far more likely than their male counterparts to die within days or weeks of their operation. This gender gap means many "extra" female deaths among the 270,000 Americans who have bypass surgery each year.

The study suggests that the answer to the mystery may lie with infections, regardless of their location in the body. In fact, it found that 96% of the gender difference in death risk within 100 days of coronary artery bypass surgery may be explained by differences in infection. The researchers used hospital and post-hospital data from 9,218 Michigan residents who had bypass surgery in a 15-month period. All were Medicare beneficiaries age 65 years or older. In all, about 12% of patients in the study who had infections during their hospital stay died before leaving the hospital, compared with 4% of those without infections. And when the researchers looked at who had died in the first 30 and 100 days after their operation, those who had had an infection in the hospital were still far more likely to die.

As for the gender differential, "We found that 16% of women patients had an infection, compared with 10% of men, " notes Mary A.M. Rogers, PhD, MS, Research Director of U-M’s Patient Safety Enhancement Program, a faculty member in the General Medicine division of the U-M Department of Internal Medicine, and the study’s lead author. Rogers had been working with Sanjay Saint, MD, MPH, director of the Patient Safety Enhancement Program and associate professor of general medicine at the U-M and the VA, on projects related to urinary tract infections among hospitalized patients with catheters. At the same time, she was working with heart-care quality researchers Brahmajee Nallamothu, MD, MPH, and Catherine Kim, MD, MPH, to examine differences among women and men in heart disease and care.

"Many studies have shown women have increased risk [of post-bypass infection]," notes Rogers. "Overall, what we found is pretty well consistent with those studies; a recent article suggested an even greater [likelihood of infection] when you look at younger women."

The big difference in this paper, she continues, is that her team looked at all infections. "In other studies, they tended to look at the surgical site, or the sternum, or the leg [where veins had been removed]," she observes. "We were looking at infection more as comorbidity."

Why the gap?

In the study, women were more likely than men to have infections of the urinary, respiratory, and digestive tracts. Women were also more likely than men to have skin and post-operative infections.

Is there a physiological reason for the difference between the genders?

"For one thing, women are more likely to have diabetes than men, and we know it is recommended that the patient maintain normal blood glucose control, which helps eliminate sepsis," Rogers offers. "And, we know that in general women are more likely to have immune-related disorders than men, so women on immunosuppressive medicines are also more likely to have infections."

Nevertheless, the apparent "gender gap" is only half the story. "When we looked closer, we found that there were two underlying relationships here: a greater prevalence of infection in women, and a higher mortality once infected for men," notes Rogers.

In other words, there are strong reasons for quality managers to focus their attention on minimizing post-bypass infections — regardless of the gender of the patient.

Prevention a joint responsibility

While there is much quality managers can do to target the prevention of these post-bypass infections, some of the responsibility must be borne by the patients, say Rogers and her co-authors. For example, elderly Americans should keep up-to-date with their yearly influenza vaccination and, every five years, be vaccinated against bacterial pneumonia; both vaccinations could be life-saving.

"Respiratory infections are prevalent in this population," notes Rogers, "And they tend to be deadly. At present, only two-thirds of the elderly get their influenza vaccine, and only half are on schedule for their pneumonia vaccinations."

Speaking of vaccinations, Rogers notes the recent CDC guidance which indicated that only 40% of health care workers receive their annual flu vaccinations.

"In my opinion, [flu vaccinations] should be part of patient care," she asserts. "You do not want to transmit the flu to someone who is in the hospital already."

Appropriate use of antibiotics also is important in patients undergoing bypass surgery. In fact, current national guidelines (American College of Cardiology and American Heart Association) for bypass surgery call for patients to receive antibiotics an hour before their operation begins and to stay on them for at least a day afterward; yet, Rogers points out, this occurs only 55% of the time.2

"That certainly could be improved," she states. "In general, because infection control procedures at every hospital are very specific by type of patient, infection, and how organisms are transmitted, we don’t know at this time whether one particular recommendation would have an impact, but in general it’s more a case of getting the guidelines implemented on a daily basis."

While in the hospital, the authors recommend, bypass patients should heed their doctors’ advice to get up and start walking the hospital floor after their operation, because staying in bed for long periods of time may encourage respiratory infections. Compliance, says Rogers, can be enhanced by vigilant monitoring by nurses.

Frequent hand-washing by patients and their hospital caregivers also is clearly a recommended procedure, and patients might also consider asking friends and family members who have colds to send their wishes by phone or computer instead of visiting.

While it would fall to the patient to make these calls, "The provider can raise the issue with the patient and tell them, for example, If you have family members coming to visit you, remind them that if they are sick or have a respiratory infection they should just wait until they are better to come visit,’" Rogers advises.


  1. Rogers MAM, Langa KM, Kim C, Nallamothu BK, McMahon LF, Jr., Malani PN, Fries BE, Kaufman SR, and Saint S. Contribution of Infection to Increased Mortality in Women After Cardiac Surgery. Arch Intern Med. 2006; 166: 437-443.
  2. Bratzler DW, Houck PM, Richards C, Steele L, Dellinger EP, Fry DE, Wright C, Ma A, Carr K, and Red L. Use of Antimicrobial Prophylaxis for Major Surgery: Baseline Results From the National Surgical Infection Prevention Project. Arch Surg. 2005; 140:174-182).

For more information, contact: Mary A.M. Rogers, PhD, MS, Research Director, Patient Safety Enhancement Program, Division of General Medicine, Department of Internal Medicine, University of Michigan, 300 North Ingalls, Suite 7E07, Ann Arbor, MI 48109-0429. Phone: (734) 647-8851. FAX: (734) 936-8944. Email: maryroge@umich.edu.