Coronary artery bypass operations for elderly patients in California, 2003 to 2008

Background: Coronary artery bypass grafting (CABG) is no longer rare for elderly patients. This study evaluates operative mortality and the effects of off-pump CABG (OPCAB) on mortality for elderly Californians between 2003 and 2008.

Methods: All isolated CABGs in California for 2003 to 2008 were classified into cohorts by age: (1) younger than 75, (2) 75 to 84, and (3) 85 or older. Multivariable logistic regression models were developed for operative mortality. Trend analyses for observed and predicted mortality, and observed-to-expected mortality ratios were performed. The "recycled predictions" method was used to assess the effect of OPCAB on operative mortality.

Results: Among 101,710 isolated CABGs between 2003 and 2008, 22.0% were in cohort 2 and 2.3% were in cohort 3. Predicted mortality was unchanged for cohorts 2 and 3 (all p > 0.05), but observed-to-expected mortality ratios declined from 0.958 to 0.633 for cohort 2 (p = 0.021) and from 1.027 to 0.965 for cohort 3 (p = 0.168). The proportion of OPCAB for patients aged 75 years or older increased from 25.0% to 29.1% between 2003 and 2008. The adjusted odds ratio for operative mortality for OPCAB in patients aged 75 years or older was 0.752 (95% confidence interval, 0.650 to 0.871; p < 0.001) compared with on-pump CABG for the same age cohort.

Conclusions: In California, overall predicted mortality was unchanged for elderly patients between 2003 and 2008, but operative mortality significantly decreased for patients aged 75 to 84. Improvement for CABG patients aged 85 years or older was insignificant. The increase in the number of OPCAB patients was associated with decreased mortality for elderly patients.