- Patients without significant and adequate reduction or relief of angina in spite of treatment with at least two functional classes of chronic anti-angina medication at the maximally tolerated dose. Functional classes of anti-angina medications include β-blockers, calcium channel blockers, nitrates, and metabolic modulators (i.e. ranolazine). Participants must have been on a stable anti-angina medication regimen for at least 4 weeks before signing the informed consent form.