Natural History of Patients With Ischemia and No Obstructive Coronary Artery Disease: The CIAO-ISCHEMIA Study.

BACKGROUND

Ischemia with no obstructive coronary artery disease (INOCA) is common and has an adverse prognosis. We set out to describe the natural history of symptoms and ischemia in INOCA.

METHODS

CIAO-ISCHEMIA (Changes in Ischemia and Angina over One Year in ISCHEMIA Trial Screen Failures With INOCA) was an international cohort study conducted from 2014 to 2019 involving angina assessments (Seattle Angina Questionnaire) and stress echocardiograms 1 year apart. This was an ancillary study that included patients with a history of angina who were not randomly assigned in the ISCHEMIA trial. Stress-induced wall motion abnormalities were determined by an echocardiographic core laboratory blinded to symptoms, coronary artery disease status, and test timing. Medical therapy was at the discretion of treating physicians. The primary outcome was the correlation between the changes in the Seattle Angina Questionnaire angina frequency score and changes in echocardiographic ischemia. We also analyzed predictors of 1-year changes in both angina and ischemia, and we compared CIAO participants with ISCHEMIA participants with obstructive coronary artery disease who had stress echocardiography before enrollment, as CIAO participants did.

RESULTS

INOCA participants in CIAO were more often female (66% of 208 versus 26% of 865 ISCHEMIA participants with obstructive coronary artery disease,

CONCLUSIONS

Improvement in ischemia and angina were common in INOCA but not correlated. Our INOCA cohort had a degree of inducible wall motion abnormalities similar to concurrently enrolled ISCHEMIA participants with obstructive coronary artery disease. Our results highlight the complex nature of INOCA pathophysiology and the multifactorial nature of angina. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02347215.