Unstable Angina Braunwald Classification

Grade I	Initial, severe, or aggravated angina.	Occurred within 2 months prior to visit, no pain at rest. Occurs 3 or more times daily, or stable angina patients have more frequent or severe angina, lasting longer, or lower threshold for triggering physical activity.
Grade II	Subacute rest angina.	Experienced one or more episodes of rest angina within 1 month prior to visit, but no episodes within the last 48 hours.
Grade III	Acute rest angina.	One or more episodes of rest angina within the last 48 hours.

Class A	Secondary unstable angina.	Based on coronary artery stenosis, accompanied by diseases outside the coronary vascular bed that cause instability in the balance between myocardial oxygen supply and demand, exacerbating myocardial ischemia.
Class B	Primary unstable angina.	No factors outside the heart that can cause or worsen angina attacks, and the patient has not experienced a myocardial infarction within the past 2 weeks.
Class C	Unstable angina post-myocardial infarction.	Unstable angina diagnosed within 2 weeks after a confirmed myocardial infarction.