ACC GUIDELINES Bundle (free trial)

20 Size of Treatment Effect Size of Treatment Effect CLASS I Benefit >>> Risk Procedure/Treatment SHOULD be performed/ administered CLASS IIa Benefit >> Risk Additional studies with focused objectives needed IT IS REASONABLE to perform procedure/ administer treatment CLASS IIb Benefit ≥ Risk Additional studies with broad objectives needed; additional registry data would be helpful Procedure/Treatment MAY BE CONSIDERED CLASS III No Benefit or CLASS III Harm LEVEL A Multiple populations evaluated a Data derived from multiple randomized clinical trials or meta- analyses ▪Recommendation that procedure or treatment is useful/effective ▪Sufficient evidence from multiple randomized trials or meta-analyses ▪Recommendation in favor of treatment or procedure being useful/effective ▪Some conflicting evidence from multiple randomized trials or meta-analyses ▪Recommendation's usefulness/ efficacy less well established ▪Greater conflicting evidence from multiple randomized trials or meta- analyses ▪Recommendation that procedure or treatment is not useful/effective and may be harmful ▪Sufficient evidence from multiple randomized trials of meta-analyses LEVEL B Limited populations evaluated a Data derived from a single randomized trial or nonrandomized studies ▪Recommendation that procedure or treatment is useful/effective ▪Evidence from single randomized trial or nonrandomized studies ▪Recommendation in favor of treatment or procedure being useful/effective ▪Some conflicting evidence from single randomized trial or nonrandomized studies ▪Recommendation's usefulness/ efficacy less well established ▪Greater conflicting evidence from single randomized trial or nonrandomized studies ▪Recommendation that procedure or treatment is not useful/effective and may be harmful ▪Evidence from single randomized trial or nonrandomized studies LEVEL C Very limited populations evaluated a Only consensus opinion of experts, case studies, or standard of care ▪Recommendation that procedure or treatment is useful/effective ▪Only expert opinion, case studies, or standard of care ▪Recommendation in favor of treatment or procedure being useful/effective ▪Only diverging expert opinion, case studies, or standard of care ▪Recommendation's usefulness/ efficacy less well established ▪Only diverging expert opinion, case studies, or standard of care ▪Recommendation that procedure or treatment is not useful/effective and may be harmful ▪Only expert opinion, case studies, or standard of care Suggested phrases for writing recommendations: should is recommended is indicated is useful/effective/ beneficial is reasonable can be useful/effective/ beneficial is probably recommended or indicated may/might be considered may/might be reasonable usefulness/effectiveness is unknown/ unclear/uncertain or not well established COR III: No Benefit is not recommended is not indicated should not be performed/ administered/other is not useful/ beneficial/effective COR III: Harm potentially harmful causes harm associated with excess morbidity/mortality should not be performed/ administered/other Comparative effectiveness phrases b : treatment/strateg y A is recommended/ indicated in preference to treatment B treatment A should be chosen over treatment B treatment/strategy A is probably recommended/ indicated in preference to treatment B it is reasonable to choose treatment A over treatment B A recommendation with Level of Evidence B or C does not imply that the recommendation is weak. Many important clinical questions addressed in the guidelines do not lend themselves to clinical trials. Even when randomized trials are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective. a Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as sex, age, history of diabetes, history of prior MI, history of HF, and prior aspirin use. b For comparative-effectiveness recommendations (Class I and IIa; Level of Evidence A and B only), studies that support the use of comparator verbs should involve direct comparisons of the treatments or strategies being evaluated. Estimate of Certainty (Precision) of Treatment Effect Applying Classification of Recommendations and Level of Evidence

• Cover