Researchers examine factors in cardiac bypass patient survival rates

Risk factors that affect the long-term health of coronary artery bypass graft (CABG) surgery patients have been assessed and compiled by a team of Penn State College of Medicine researchers to address a lack of information for patients and doctors.

“When determining a treatment plan, patients and their doctors are interested in knowing short- and long-term prognoses following a particular treatment,” said Chuntao Wu, M.D., Ph.D., assistant professor of public health sciences. “Especially before undergoing major procedures such as coronary artery bypass graft surgery, it would be helpful if physicians can present an accurate picture before patients make informed consents. Our goal in this study was to obtain figures for this purpose.”

Using the New York State Cardiac Surgery Reporting System, researchers identified 8,597 patients who received CABG surgery in a six-month period in the year 2000. This database contains variables, including discharge status, patient demographics, pre-procedural risk factors, procedure related information and post-procedural complications. They then used the National Death Index and a statistical model they designed to determine the risk of death from 13 factors related to the surgery. They also created a simple risk score that can be used to predict long-term mortality after CABG surgery.

This study is unique in that it analyzed data from one, three, five, and seven years after surgery. Of the patients surveyed, 2,156 deaths occurred in the seven-year period. The one, three, five, and seven-year mortality rates were 6.2 percent, 11.2 percent, 17.6 percent and 24.2 percent, respectively.

Higher risk of mortality is associated with a number of factors including older age, extreme values of body mass index, left main coronary disease, a few comorbidities (cerebrovascular disease, peripheral arterial disease, congestive heart failure, malignant ventricular arrhythmia, chronic obstructive pulmonary disease, diabetes mellitus, and renal failure), and open heart surgery prior to CABG surgery.

The researchers published their findings in Circulation and had presented the research at the American Heart Association Scientific Sessions 2011.

“In the past, simple risk scores have been created mainly to predict procedural mortality after surgery, but there is also a need for scores that predict long-term mortality,” said Wu. “This information can be used by clinicians and patients when weighing the risk and benefit of certain procedures, in choosing treatment options for the management of severe coronary artery disease.”

This study was funded by the National Institutes of Health (NIH Grant: RC1HL099122), and its abstract was presented at the American Heart Association Scientific Sessions 2011 in Orlando, FL.

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Last Updated August 31, 2012