AHA GUIDELINES Bundle (free trial)

Estimate of Certainty (precision) of Treatment Effect LEVEL A Multiple populations evaluated* ▪Sufficient evidence from multiple randomized trials or meta-analyses ▪Recommendation that procedure or treatment is useful/effective ▪Recommendation that procedure or treatment is useful/effective CLASS I Benefit >>> Risk Procedure/Treatment SHOULD be performed/ administered Data derived from multiple randomized clinical trials or meta-analyses LEVEL B Limited populations evaluated* Data derived from a single randomized trial or nonrandomized studies ▪Recommendation's usefulness/efficacy less well established ▪Greater conflicting evidence from multiple randomized trails or meta-analyses ▪Recommendation's usefulness/efficacy less well established Size of Treatment Effect CLASS IIa CLASS IIb Benefit >> Risk Benefit ≥ Risk Additional studies with Additional studies with broad objectives focused objectives needed needed; additional registry data would be IT IS REASONABLE helpful to perform procedure/ Procedure/Treatment administer treatment MAY BE CONSIDERED ▪Recommendation in favor of treatment or procedure being useful/effective ▪Some conflicting evidence from multiple randomized trials or meta-analyses ▪Recommendation in favor of treatment or procedure being useful/effective ▪Greater conflicting evidence from single ▪Some conflicting evidence randomized trial or nonrandomized studies from single randomized trial or nonrandomized studies ▪Recommendation in favor of ▪Recommendation's usefulness/efficacy less treatment or procedure being well established useful/effective CLASS III No Benefit or CLASS III Harm Procedure/ Test Treatment Not Helpful No Proven COR III: Benefit No benefit ▪Recommendation that procedure or treatment is not Excess Cost Harmful be useful/effective and may to COR III: harmful w/o Benefit   Patients Harm or Harmful ▪Sufficient evidence from multiple randomized trials of meta-analyses ▪Recommendation that procedure or treatment is not useful/effective and may be harmful ▪Evidence from single randomized trial or nonrandomized studies ▪Only expert opinion, case studies, or standard of care ▪Recommendation that procedure or treatment is not useful/effective and may be harmful ▪Only diverging expert opinion, case studies, or standard of care ▪Evidence from single randomized trial or nonrandomized studies ▪Recommendation that procedure or treatment is useful/effective ▪Only expert opinion, case studies, or standard of care is reasonable may/might be considered can be useful/effective/beneficial may/might be reasonable is probably recommended or indicated usefulness/effectiveness is unknown/unclear/uncertain or not well established ▪Only diverging expert opinion, case studies, or standard of care should is recommended is indication is useful/effective/beneficial COR III: No benefit is not recommended is not indicated should not be performed/ administered/other is not useful/beneficial/ effective LEVEL C Very limited populations evaluated* Only consensus opinion of experts, case studies, or standards of care Suggested phrases for writing recommendations: treatment/strategy a is probably recommended/indicated in preference to treatment B it is reasonable to choose treatment a over treatment B † * Data available from clinical trials or registries about the usefulness/efficacy in different subpopulations, such as sex, age, history of diabetes, history of prior myocardial infarction, history of heart failure, and prior aspirin use. 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. COR III: Harm potentially harmful causes harm associated with excess morbidity/mortality should not be performed/ administered/other Comparative effectiveness phrases†: treatment/strategy a is recommended/ indicated in preference to treatment B treatment a should be chosen 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. Although randomized trials are unavailable, there may be a very clear clinical consensus that a particular test or therapy is useful or effective.

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