Class I | Class IIa | Class IIb | Class III | |
Level A | ||||
ACC | Sufficient evidence from multiple randomised trials or meta-analyses | Some conflicting evidence from multiple randomised trials or meta-analyses | Greater conflicting evidence from multiple randomised trials or meta-analyses | Sufficient evidence from multiple randomised trials or meta-analyses |
ESC | Evidence/general agreement of efficacy Data from multiple randomised trials or meta-analyses | Weight of evidence/opinion in favour of efficacy Data from multiple randomised trials or meta-analyses | Efficacy less well established by evidence/opinion Data from multiple randomised trials or meta-analyses | Evidence/agreement of non-efficacy or possible harm Data from multiple randomised trials or meta-analyses |
Level B | ||||
ACC | Evidence from single randomised trial or non-randomised studies | Some conflicting evidence from a single randomised trial or non-randomised studies | Greater conflicting evidence from a single randomised trial or non-randomised studies | Evidence from a single randomised trial or non-randomised studies |
ESC | Evidence/general agreement of efficacy Data from single randomised trial or large non-randomised studies | Weight of evidence/opinion in favour of efficacy Data from single randomised trial or large non-randomised studies | Efficacy less well established by evidence/opinion Data from single randomised trial or large non-randomised studies | Evidence/agreement of non-efficacy or possible harm Data from single randomised trial or large non-randomised studies |
Level C | ||||
ACC | Only expert opinion, case studies or SOC | Only diverging expert opinion, case studies or SOC | Only diverging expert opinion, case studies or SOC | Only expert opinion, case studies or SOC |
ESC | Evidence/general agreement of efficacy Consensus of experts and/or non-randomised studies | Weight of evidence/opinion in favour of efficacy Consensus of experts and/or non-randomised studies | Efficacy less well established by evidence/opinion Consensus of experts and/or non-randomised studies | Evidence/agreement of non-efficacy or possible harm Consensus of experts and/or non-randomised studies |
Recommendation | Is recommended/indicated | Can be useful/effective/beneficial or indicated | May be considered/reasonable | No Benefit/not recommended or potentially harmful |
ACC (American College of Cardiology), ESC (European Society of Cardiology); PCI (percutaneous coronary intervention); SOC (standard of care).