California has recently become the first state to report hospital data on rate of stroke in patients after coronary artery bypass graft (CABG) surgery, and the results show a wide variation among 121 hospitals.
The new measure comes in the state's regular hospital data report for 2007 on CABG mortality, which has been issued eight times since 2001 when the first report covered hospital performance for 1998-99.
Joe Parker, director of healthcare outcomes for the California Office of Statewide Health Planning and Development, which issued the report, says that stroke was included this time in the CABG data because better hospital practices can reduce the number of patients who develop the complication, a known risk factor in these procedures.
"We want to be selecting something over which there is a possibility of control and improvement by a hospital," he says. "Stroke was selected because it is an important negative outcome of CABG surgery, and one that has a huge impact on families of those who care for stroke victims, as well as on the patients."
Of the 121 hospitals in the state that perform bypass graft surgery, one hospital had the lowest rate of stroke complications, Alta Bates Summit Medical Center, Summit Campus, a 337-bed hospital in Oakland.
Parker says that he visited with Russell Stanten, MD, cardiothoracic surgeon at Alta Bates, to learn what the hospital does to prevent stroke in these patients. He says Stanten replied that the hospital screens each patient for carotid disease, "and if they find it they deal with it prior to the CABG surgery." Additionally, Alta Bates surgeons also make sure the patients have transesophageal echocardiograms performed intraoperatively.
Additionally, Junaid Khan, MD director of cardiovascular services at Alta Bates, says a crucial reason for the hospital's success is in making sure that every anesthesiologist on a CABG case is board certified in echocardiography. The hospital, which does about 800 open heart procedures a year—many of them CABG—also limits the number of anesthesiologists and others who are allowed to work on these patients only "to those who do a lot of them."
"You may have people who are doing 10 cardiac surgeries a year. Ours are doing 100 cardiac cases a year," Khan says. "We also work with the perfusionists to make sure they maintain adequate pressure,"
The state's report says that risk adjusted post-operative stroke rates for five hospitals were worse than average:
- Los Angeles County Harbor-UCLA Medical Center (4.17%)
- Tri-City Medical Center in Oceanside (3.97)
- Sharp Memorial Hospital in San Diego (3.15%)
- Memorial Medical Center of Modesto (2.63%)
- Sutter Memorial Hospital in Sacramento (2.43%)
In a letter to the state agency, Robert Adamson, MD, medical director of the cardiac transplant program at Sharp, says that in 2006, "we noted an unusual cluster of six strokes. Each case was individually reviewed and no trends or common causes could be identified," but "strongly influenced our results for the two-year period."
He says that in 2007, the incidence of stroke in this population was half that in 2006 and zero in 2008. "In view of this, we feel that the rating, while accurate in number, does not reflect our current performance in this area."
For Harbor-UCLA, Bassam Omari, MD, chief of the division of cardiothoracic Surgery, wrote the agency explaining that the hospital has discovered discrepancies in risk factors reported for its CABG patients, which "adversely affected our expected mortality and morbidity."
Other reasons for Harbor-UCLA's high rates, he wrote, dealt with the high number of Jehovah's Witnesses "whose beliefs preclude our ability to provide life-saving blood transfusions" and said the hospital failed to adequately count those patients who had a prior stroke, which put them at greater risk.
For bypass graft mortality without stroke, no hospital performed significantly better than the state average. But Enloe Medical Center in Sacramento, Los Angeles Co. Harbor—UCLA Medical Center, St. Joseph's Medical Center in Stockton and Valley Presbyterian Hospital in Van Nuys, performed significantly worse.
The California agency keeps the largest public outcomes database in the country and is an important source of comparative information for performance.
Other significant findings from the report include the following:
- Of the 30,379 patients who underwent isolated CABG surgery, 405 experienced a stroke in which symptoms lasted for 72 hours or longer, a rate of 1.33%, which is close to the national rate of 1.4% reported by the Society of Thoracic Surgeons.
- The operative mortality rate for CABG surgery in the state in 2007 was 2.35%, slightly higher than 2.2% for 2006, but much lower than in the prior three years 3.1%, 3.3% and 2.9%.
- There were 347 operative deaths among the 14,756 CABG surgeries during 2007.
This latest report also scored hospitals on their use of the internal mammary artery (IMA) during CABG procedures, a practice associated with better surgical outcomes but may take longer. Five hospitals had low rates of IMA usage, including Citrus Valley Medical Center in Covina, Dameron Hospital in Stockton, Lakewood Regional Medical Center in Lakewood, Suttter Medical Center in Santa Rosa and Tri-City Medical Center in Oceanside.
Parker says that use of the IMA in bypass graft surgery is longer lasting and is associated with lower mortality, but takes about 15 minutes longer to perform than traditional use of the radial artery or saphenous vein, and that may be why some surgeons fail to use it. In 2007, the state had a 93.7% IMA usage, a 4% increase since 2003.
With its next report the state hopes to add in comparative data on how many CABG patients go into renal failure and require post-operative dialysis, another complication. Renal failure occurs in between 1% and 2% of CABG cases, on average, he says.
Debby Rogers, vice president for Quality and Emergency Services for the California Hospital Association, says her organization is "pleased that they're issuing reports with more recent data." She noted that the reports indicate a distinct "through the years that care is improving" related to CABG mortality.