Score = 0, Grade I, very low risk, complication rate about 0.4%;

Score = 1, Grade II, low risk, complication rate about 0.9%;

Score = 2, Grade III, moderate risk, complication rate about 7%;

Score ≥ 3, Grade IV, high risk, complication rate higher than 11%.

Revised Cardiac Risk Index (Lee Criteria), mainly used for preoperative cardiovascular risk assessment in non-cardiac surgery.

Note: High-risk surgeries include abdominal aortic aneurysm or other vascular surgeries, thoracoabdominal surgeries, orthopedic surgeries.