Unstable angina

This code represents a severe form of angina pectoris characterized by new onset, increasing frequency or intensity of chest pain, or angina at rest. It indicates an acute coronary syndrome where myocardial ischemia is present but without evidence of myocardial necrosis. This condition signifies an impending myocardial infarction and requires urgent medical attention.

Use this code when documentation clearly states "unstable angina" or describes symptoms consistent with it, such as crescendo angina, rest angina, or new-onset severe angina. Supporting documentation often includes ECG changes (e.g., ST depression, T-wave inversion) without elevated cardiac biomarkers, and a clinical assessment indicating high risk for acute coronary events.

• Do not use this code if myocardial infarction (MI) is confirmed; instead, code the appropriate MI (e.g., I21.x).
• Always review documentation for specific types of angina (e.g., exertional, Prinzmetal's) to ensure the most specific code is selected.
• Sequence this code as the primary diagnosis when it is the reason for the encounter, especially in acute care settings.