Previous reports have shown that high-risk patients undergoing heart bypass surgery do best when the surgeon and hospital have considerable experience with this operation. Now, new research suggests that this finding applies to low-risk patients too.

“Numerous reports have shown that higher hospital volumes are related to better (bypass surgery) outcomes,” lead author Dr. Chuntao Wu, from the State University of New York at Albany, told AMN Health. “Recently, however, people have suggested that this volume-outcome relationship may not hold for low-risk patients.”

The study, which is reported in the American Heart Association’s journal Circulation, involved more than 57,000 patients who underwent bypass surgery in New York between 1997 and 1999. The patients were classified as low- or moderate-to-high risk depending on whether their predicted risk of death, while hospitalized, fell below or above 2 percent, respectively.

Regardless of the assigned risk group, the risk of death fell as the annual number of cases performed by the surgeon and the hospital increased.

The lowest risk of death was seen when the operation was performed by high-volume surgeons at a high-volume hospital. Treatment under these conditions reduced the risk of death for low-risk patients by 48 percent.

Given the choice between a high-volume surgeon at a low-volume hospital or the opposite scenario, the results favored the former option, Wu said. “This suggests that surgeon volume matters more, but the mortality difference was not statistically significant,” he added.

When asked if the findings suggest that all bypass surgery patients should be referred to high-volume hospitals, Wu said that for logistical reasons, the solution “is not that simple.” Instead, he said further research “should try to determine why high-volume centers are doing better and then apply their processes to other hospitals.”

SOURCE: Circulation, August 9th rapid access issue, 2004.