A Prospective Multicenter U.S. Registry to Define Coronary Vasomotor Disorders in Ischemia With Nonobstructive Coronary Arteries
About the Registry
The DISCOVER INOCA Registry was designed to address a critical gap in cardiovascular medicine: millions of patients undergo cardiac catheterization each year but are found to have nonobstructive coronary arteries — yet continue to experience chest pain, shortness of breath, and reduced quality of life.
By performing comprehensive invasive coronary function testing across nine U.S. centers, DISCOVER INOCA provides the first large U.S. dataset to define the mechanisms, diagnostic yield, safety, and clinical impact of standardized coronary function testing in patients with INOCA.
The Disease
Ischemia with nonobstructive coronary arteries (INOCA) affects an estimated 3–4 million patients per year in the U.S. — yet many remain undiagnosed or are incorrectly reassured. INOCA encompasses several distinct physiologic disorders of the coronary circulation.
Impaired function of the small coronary vessels resulting in reduced coronary flow reserve (CFR <2.5) or elevated microvascular resistance (IMR ≥25). Present as a primary or mixed diagnosis in 44.6% of DISCOVER INOCA participants.
Sudden tightening of coronary vessels triggered by acetylcholine provocation testing. Epicardial vasospasm or microvascular spasm identified in 63.8% of DISCOVER INOCA participants — often overlooked without formal testing.
Myocardial bridging detected in 33% by angiography and 44% by intravascular imaging. Endothelial dysfunction identified in 32% of participants — frequently unrecognized without formal provocation testing.
Study Protocol
Every DISCOVER INOCA participant underwent a standardized, protocol-driven evaluation including acetylcholine vasoreactivity testing, bolus thermodilution physiology, and intravascular imaging — performed consistently across all nine U.S. centers.
Primary Short-Term Results · ACC.26 · March 2026
Presented at the American College of Cardiology Scientific Sessions (ACC.26) and submitted for publication. Results from 500 enrolled participants with adjudicated 30-day follow-up.
Cumulative endotypes: CMD (incl. mixed) 44.6% · VSA (incl. mixed) 63.8% · Endothelial dysfunction 32% · Symptomatic myocardial bridging 17%
Participating Centers
| Institution | Investigator | N (%) |
|---|---|---|
| Yale University New Haven, CT | Shah | 176 (35%) |
| Northeast Georgia Medical Center Gainesville, GA | Toleva, G. Henry | 86 (17%) |
| The Christ Hospital Cincinnati, OH | T. Henry | 82 (16%) |
| Stanford University Medical Center Palo Alto, CA | Tremmel | 70 (14%) |
| NYU Langone Health New York, NY | Smilowitz | 30 (6%) |
| Columbia University Irving Medical Center New York, NY | Sardar, Prasad | 25 (5%) |
| NY-Presbyterian Brooklyn Methodist Brooklyn, NY | Kobayashi | 15 (3%) |
| UCLA Medical Center Los Angeles, CA | Parikh | 14 (3%) |
| Thomas Jefferson University Hospital Philadelphia, PA | Savage | 5 (1%) |
Scientific Contributions
In memory of Dr. Amir Lerman, M.D. (Mayo Clinic, 1957–2026), whose pioneering work transformed our understanding of ischemic heart disease and endothelial function. The investigators of DISCOVER INOCA dedicate this study to his vision and enduring scientific legacy. Read his tribute →
Leadership
Yale Cardiovascular Research Group
Yale University School of Medicine
New Haven, Connecticut
Investigator-initiated research grant to Yale University from Abbott Vascular. The funding source was not involved in study design or implementation.
Cody Pietras — Executive Director
Kyna Henrici — Project Manager
Dr. Nida Latif — Call Center Director
Miranda Moore — Statistician
Dr. Ecaterina Cristea — Core Lab Director
Get In Touch
For questions about DISCOVER INOCA, patient participation, media inquiries, or research collaboration, please reach out to our study team at Yale University.
Find a Participating Site →The registry is currently in the follow-up phase. Contact the nearest site investigator for questions about long-term follow-up participation.