Key Points
Invasive coronary function testing:
- identified a vasomotor disorder in 94% of patients.
- led to a change from pre-procedure diagnosis in 89% of patients; and
- led to a change in medical therapy following testing in 72% of patients
Ischemia with nonobstructive coronary arteries (INOCA) is increasingly recognized as a common and clinically significant condition, affecting up to 30–50% of patients undergoing coronary angiography. Despite its association with persistent symptoms, impaired quality of life, and increased long-term risk, uncertainty surrounding diagnostic yield and clinical utility has limited widespread adoption of invasive coronary function testing.
On March 28, 2026, the primary short-term results of DISCOVER INOCA (NCT05288361), a prospective multicenter registry of patients undergoing invasive coronary function testing, designed to address these gaps, were presented at the American College of Cardiology Scientific Sessions in New Orleans, LA.
A total of 500 patients with suspected ischemic heart disease undergoing clinically indicated coronary angiography and found to have nonobstructive coronary arteries were enrolled. Participants underwent a standardized assessment including invasive coronary angiography, acetylcholine testing, bolus thermodilution, and intravascular imaging. The study population was predominantly female (78%) with a mean age of 57 years and a high burden of cardiovascular risk factors. Patients presented with significant symptom burden, with the majority classified as CCS class II or III angina and demonstrating impaired baseline quality-of-life scores.
Following invasive coronary function testing, a physiologic diagnosis was established in nearly all patients. Vasospastic angina, coronary microvascular dysfunction, and mixed vasomotor disorders were the most frequently identified, with a high degree of overlap observed between phenotypes. Importantly, normal coronary physiology was identified in only 5.6% of patients, underscoring the limitations of angiography alone in this population.
The diagnostic impact of testing was substantial, with 89% of patients experiencing reclassification from their pre-procedure “empiric” diagnosis. This translated into clinical action, as 72% of patients had changes in their medical therapy following the procedure. At 30-day follow-up, significant improvements in angina-related health status, measured by Seattle Angina Questionnaire, were observed, particularly among patients with vasospastic angina and mixed vasomotor disease. However, patients with isolated microvascular dysfunction or normal physiology did not demonstrate the same degree of early symptomatic improvement, highlighting the heterogeneity of treatment response across INOCA phenotypes. Additional follow-up assessments are planned for 6 months, 12 months, and annually to 5 years.
Invasive coronary function testing was associated with a favorable safety profile. Procedural serious adverse events occurred in 1.4% of patients, while the 30-day major adverse cardiovascular event rate was 1.8%, including myocardial infarction and cardiovascular hospitalization.
Taken together, the registry provides prospective evidence that routine invasive coronary function testing yields high diagnostic clarity, frequently alters clinical management, and is associated with early improvements in patient-reported outcomes in a subset. These findings reinforce a shift toward mechanism-based evaluation and treatment in patients with ischemia or angina and nonobstructive coronary disease.
“In the primary results of DISCOVER-INOCA, we demonstrated that standardized invasive coronary function testing not only identifies a vasomotor disorder in the vast majority of patients, but also meaningfully changes diagnosis and management,” the investigators concluded. “These findings support broader adoption of comprehensive physiologic testing to guide targeted therapy in patients with INOCA.”