Using data reported to the CABG Outcomes Public Reporting Program, the investigators applied a complex formula of 25 variables to estimate preoperative risk for each patient, based on the number and severity of risk factors, including age, race, body mass index, and existing medical conditions and physiologic measures. Under this formula, the calculated predicted risk of death from CABG in 2003 and 2006 improved but was not statistically different (3.06 percent and 3.05 percent, respectively). Overall death rates from the procedure did improve significantly - from 2.90 percent in 2003 and 2.22 percent in 2006.

According to J. Nilas Young, chief of cardiothoracic surgery at UC Davis and one of the study authors, reasons for the improvement in the death rate can be attributed to advances in surgical techniques along with improved anesthesiology, preoperative and postoperative care.

"There were several new approaches to bypass surgery and technologies introduced in the study timeframe - and even through today - that help improve outcomes for patients," said Young.

Another study outcome showed that the number of CABG procedures decreased significantly among California nonfederal hospitals and surgeons between 2003 and 2006, from 21,276 to 15,647. Caseload reductions were found regardless of performance ranking - a trend Li attributes to the ongoing transition to the use of stents, which can be inserted earlier in the disease process to widen arterial pathways without surgery.

"This study bears very good news for patients," said Li. "It indicates that access to medical care has not decreased, patients have more options and CABG has become an even safer procedure."

Source: University of California - Davis - Health System