Table 4. Mortality Rates by Volume Center Activity (NACSA Cohort)
FrequencyObserved Mortality (%)Unadjusted OR (95% CI)Adjusted OR (95% CI)
Activity tertilea
Low‐volume (latest 3 years' activity)130810.6ReferenceReference
Medium‐volume (latest 3 years' activity)21599.50.89 (0.71, 1.12)0.80 (0.62, 1.02)
High‐volume (latest 3 years' activity)45918.80.82 (0.67, 1.00)0.76 (0.60, 0.95)
Activity tertilea
Low‐volume (6 years' activity)142411.1ReferenceReference
Medium‐volume (6 years' activity)23539.50.84 (0.68, 1.05)0.83 (0.66, 1.05)
High‐volume (6 years' activity)42818.60.75 (0.62, 0.91)0.71 (0.57, 0.88)
  • NACSA indicates National Adult Cardiac Surgery audit; OR, odds ratio.

  • a Adjusted for preoperative comorbidities, operative risk factors, and most distal aortic segment.