Studies meeting the 10 criteria of risk of bias: A: peer-reviewed publications; B: temperature control; C: random assignment of treatments or controls; D: model-blind induction; E: blinded assessment of outcomes; F: use of anesthetics without significant intrinsic cardioprotective effects; G: appropriate animal models (elderly, diabetic, or hypertensive); H: sample size calculation; I: compliance with animal welfare regulations; J: potential conflict-of-interest statements.