The Coronary Vasomotion Disorders International Study Group (COVADIS) criteria determine whether an individual meets the diagnostic criteria for vasospastic angina through an evaluation of three key aspects: nitrate-responsive angina, transient ischemic electrocardiogram (ECG) changes, and coronary artery spasm.

The evaluator chooses one description from each of these three categories:

- **Nitrate-responsive Angina**: 
  - Rest angina, often occurring between night and early morning
  - Marked diurnal variation in exercise tolerance, where tolerance is reduced in the morning
  - Hyperventilation triggers an episode
  - Episodes are suppressed by calcium channel blockers but not by beta-blockers

- **Transient Ischemic ECG Changes** (during spontaneous episodes, observed in at least two contiguous leads):
  - ST-segment elevation of 0.1 mV or more
  - ST-segment depression of 0.1 mV or more
  - Presence of new negative U waves

- **Coronary Artery Spasm**:
  - A transient total or subtotal coronary artery occlusion with more than 90% constriction
  - Occurrence of angina and ischemic ECG changes either spontaneously or in reaction to a provocative stimulus, such as acetylcholine, ergot, or hyperventilation

For a diagnosis of vasospastic angina, the assessment requires:
- One or more aspects from nitrate-responsive angina to be true.
- One or more ECG changes to be observed.
- Both coronary artery spasm criteria to be met.

If all these checks pass—meaning there is at least one confirmed symptom from nitrate-responsive angina and transient ischemic ECG changes, alongside both indicators for coronary artery spasm—the diagnostic criteria are considered to be met. If any of these condition checks fail, the diagnostic criteria are not met.

The interpretation is straightforward: presence of all necessary criteria combinations confirms a diagnosis of vasospastic angina; otherwise, the criteria are not satisfied.

The Coronary Vasomotion Disorders International Study Group diagnostic criteria for vasospastic angina, also known as the COVADIS criteria, is a clinical tool designed for the diagnosis of vasospastic angina. This condition, characterized by coronary artery spasm leading to transient myocardial ischemia, can be challenging to diagnose due to its variable presentation and the need for provocative testing.

The COVADIS criteria incorporate three main components: nitrate-responsive angina, transient ischemic electrocardiogram changes, and evidence of coronary artery spasm. Nitrate-responsive angina is identified by rest angina, particularly between night and early morning, marked diurnal variation in exercise tolerance with reduced tolerance in the morning, the ability of hyperventilation to precipitate an episode, and the suppression of episodes by calcium channel blockers but not beta-blockers. Transient ischemic electrocardiogram changes are identified by ST-segment elevation or depression of at least 0.1 mV or the appearance of new negative U waves. Evidence of coronary artery spasm is determined by transient total or subtotal coronary artery occlusion, with angina and ischemic electrocardiogram changes either spontaneously or in response to a provocative stimulus such as acetylcholine, ergot, or hyperventilation.

The diagnostic criteria are met if there is evidence of nitrate-responsive angina, transient ischemic electrocardiogram changes, and coronary artery spasm. The criteria are not met if these conditions are not fulfilled. This diagnostic tool aids clinicians in identifying patients with vasospastic angina, enabling appropriate management and treatment of this condition.

Coronary Vasomotion Disorders International Study Group diagnostic criteria for vasospastic angina (COVADIS criteria)