Caterpillar plot demonstrating all 1,880 operations ranked by intrinsic cardiac risk. Horizontal reference line represents odds ratio of 1.0. Values greater than 1.0 represent higher than average risk for perioperative adverse cardiac events, whereas values less than 1.0 represent lower than average risk for perioperative adverse cardiac events. Vertical reference lines represent cut points used to classify operations as low, intermediate, and high intrinsic cardiac risks. 95% CIs are omitted for clarity.