A new report shows a reduced mortality rate for coronary artery bypass graft surgeries performed around the state.

California's Office of Statewide Health Planning and Development (OSHPD) on Monday released the “California Report on Coronary Artery Bypass Graft Surgery, 2009 Hospital Data,” showing that hospital operative mortality declined 34 percent since 2003, the first year of mandated public reporting for the 119 state-licensed hospitals that performed isolated coronary artery bypass graft (CABG) surgery during 2009.

“The findings in this report, especially the continued decline in the mortality rate, reinforce the importance of making our healthcare system more transparent and improving consumer access to information on quality and performance,” said acting OSHPD Director Stephanie Clendenin.

Coronary artery bypass graft surgery takes arteries or veins from elsewhere in a patient’s body and grafts them onto the coronary artery to help relieve angina and improve blood supply.

The surgery can become necessary when arteries are narrowed due to atherosclerosis. A common condition, atherosclerosis results from a buildup on artery walls of substances like fat and cholesterol which create “plaques,” hardened structures that can block arteries, according to the U.S. National Library of Medicine.

The hospitals listed in the report do not include Sutter Lakeside Hospital in Lakeport or St. Helena Hospital Clearlake. However, several other regional hospitals serving Lake County residents are included, including North Bay and Bay Area facilities.

Performance ratings for hospitals are based on three risk-adjusted outcomes: operative mortality, operative stroke and, for the first time, hospital readmission.

Additionally, utilization of the internal mammary artery during CABG surgery is used as a measurement of surgical quality.

Hospital results for risk-adjusted mortality, risk-adjusted hospital readmission and internal mammary artery utilization are based only on 2009 data, while hospital results for risk-adjusted post-operative stroke are based on combined 2008 and 2009 data.

Regarding mortality rates, key findings in the report show there were 252 operative deaths among 13,260 isolated non-salvage CABG surgeries, and the operative mortality rate for isolated CABG surgery in California was 1.90 percent, down from 2.24 percent in 2008.

In addition, the report found significant variation – from 0 percent to 13.0 percent – in hospital operative mortality rates after adjusting for patients’ pre-operative health. Despite such variation, 116 of 119 hospitals (97%) performed at a rate that did not differ significantly from the statewide average.

The report showed that only one hospital, Scripps Memorial Hospital La Jolla, performed statistically significantly “better” than the state average in terms of risk-adjusted operative mortality, while Scripps Mercy Hospital and West Hills Regional Medical Center performed “worse” than the state average.

When it came to post-operative strokes, of the 27,217 patients who underwent isolated CABG surgery, 384 (1.41%) experienced a post-operative stroke, similar to the national rate of 1.4 percent reported by the National Society of Thoracic Surgeons.

There was wide variation in post-operative stroke rates among hospitals after adjusting for patients’ pre-operative health.

Hospital risk-adjusted stroke rates ranged from 0 percent to 8.87 percent, and 114 of 121 hospitals (94%) performed at a rate that did not differ significantly from the statewide average.

For the third report in a row, Alta Bates Summit Medical Center performed statistically “better” than the state average in terms of risk adjusted post-operative stroke rates. Also receiving high marks were St. Joseph’s Medical Center in Stockton and St. Bernardine Medical Center in San Bernardino.

There also were four hospitals that performed “worse” than the state average: Good Samaritan Hospital in San Jose, Bakersfield Memorial Hospital, Providence Tarzana Medical Center in Tarzana and Scripps Memorial Hospital in La Jolla.

As for hospital readmissions, of the 11,823 patients who underwent isolated CABG surgery and were discharged alive, 1,565 (13.2%) experienced a hospital readmission within 30 days of the surgery, the report found.

There was wide variation in the readmission rates among hospitals performing CABG surgery after adjusting for patients’ pre-operative conditions.

Hospital risk-adjusted re-admission rates ranged from 0 percent to 29.77 percent, and 117 of 119 hospitals (98%) performed at a rate that did not differ significantly from the statewide average.

One hospital, Queen of the Valley, performed “better” than the state average on hospital readmission, and one hospital, San Joaquin Community Hospital, performed “worse” than the state average.

The study showed that, overall, UC Davis Medical Center, Santa Rosa Memorial Hospital, St. Helena Hospital, Sutter Medical Center of Santa Rosa, UCSF Medical Center and Queen of the Valley all performed well in all three categories.