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News Release

Heart Surgery Using Bypass Machine Leads To Better Recoveries

Color photo of Dr. Fred Grover, UC Denver School of Medicine

AURORA, Colo. – In the first conclusive study on the subject, patients who get coronary bypass surgery with the use of a heart lung bypass machine have better recoveries than patients who had the same procedure without the bypass machine. That’s according to a major study co-authored by Frederick L. Grover, MD, a cardiothoracic surgeon at the Denver Veterans Affairs Medical Center and chair of the department of surgery at University of Colorado Denver School of Medicine. The study was published November 5 in the New England Journal of Medicine.

Physicians at 18 Veterans Affairs medical centers, including the VA in Denver, found there was no difference in the early (30-day) combined outcomes of death and major complications. But by one year, about 10 percent of the 2,203 patients that had the off-pump procedure had died, had heart attacks or required repeat bypasses. That is compared to 7.4 percent of those who underwent operations using heart-lung machines. There was no difference in survival between the study groups up to 5 years after surgery. 

Researchers believed there would be fewer complications for patients who had bypass surgery without the heart lung machine. The findings were the opposite for the majority of the patients. “We thought those patients would end up doing better neurologically. Or they would get out of the hospital faster, but neither occurred,” said co-author Grover, who is also one of the principal investigators nationally. 

While most patients having coronary bypass surgery won’t have any special benefit from having off-pump surgery, a small number of patients may benefit because of their particular conditions and circumstances.

The study represents a cross section of surgical expertise that is probably more typical of national surgery than some single center reports from surgeons who have made this a major interest and have dedicated their career to it. 

The study lasted for seven years and cost $12 million. It was sponsored by the Cooperative Studies Program (CSP), a division of the US Department of Veterans Affairs that specializes in comparative effectiveness research.  This study involved several cardiothoracic surgeons, cardiologists, and nurse date managers at each of the 18 VA Medical Centers that participated, as well as the statistical support from the Perry Point VA Cooperative Studies Center in Maryland and the National Study Administrative Office here in Denver.

The University of Colorado Denver School of Medicine faculty work to advance science and improve care as the physicians, educators and scientists at University of Colorado Hospital, The Children’s Hospital, Denver Health, National Jewish Health, and the Denver Veterans Affairs Medical Center. Degrees offered by the UC Denver School of Medicine include doctor of medicine, doctor of physical therapy, and masters of physician assistant studies.  The School is part of the University of Colorado Denver, one of three campuses in the University of Colorado system. For additional news and information, please visit the UC Denver newsroom online.


Contact:  Erika Matich, 720.848.7852,

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