Class I: Disabling stable angina pectoris (CCS III-IV) despite medical therapy or high-risk criteria on clinical assessment / noninvasive testing or unexplained heart failure or survivors of cardiac arrest or severe ventricular arrhythmias or angina in conjunction with signs of heart failure or heart failure eci or early recurrence of angina after PCI/ CABG or pre cardiac valve surgery (♂: >35 yrs, ♀: >50 yrs.).
Class I!a: Inconclusive or conflicting results after noninvasive stress testing or unable to undergo noninvasive testing (disability, illness, or morbid obesity) or reevaluation of performed procedures (main stem PCI, high restenosis risk).
Class III: Risk of CAG outweighs the benefit (significant comorbidity) or mild angina (CCS class I or II) responding well to medical therapy. Always use common sense!