Prevalence, clinical characteristics, and outcomes of patients with non-obstructive coronary arteries undergoing emergent coronary angiography for suspected STEMI

A proportion of patients undergoing emergent coronary angiography for suspected ST-segment elevation myocardial infarction (STEMI) present with non-obstructive coronary arteries ("white caths"). Data on their prevalence, etiology, and outcomes in contemporary practice remain limited.

To describe the prevalence, clinical characteristics, final diagnoses, and 1-year outcomes of patients with non-obstructive coronary arteries following emergent coronary angiography for suspected STEMI.

We retrospectively analyzed 405 consecutive patients who underwent emergent coronary angiography for suspected STEMI at our center. Patients were classified as having obstructive (≥50% stenosis) or non-obstructive coronary arteries. Demographics, final diagnosis, and 1-year mortality were compared using Mann–Whitney U and chi-square tests, as appropriate.

Among 405 patients, 38 (9.4%) had non-obstructive coronary arteries. There were no significant differences in female prevalence (36.6% vs. 27.0%; p = 0.203) or age (median 62 vs. 64 years; p = 0.109). Final diagnoses among "white cath" patients included vasospasm (18.4%), MINOCA (13.2%), acute myocarditis (13.2%), non-cardiac chest pain (10.5%), acute pericarditis (7.8%), early repolarization (7.8%), Takotsubo syndrome (7.8%), aortic valvulopathy (5.0%), dilated cardiomyopathy (5.0%), acute aortic syndrome (5.0%), hypertrophic cardiomyopathy (2.6%), left bundle branch block (2.6%), and other causes. One-year mortality was significantly higher in the "white cath" group (15.8% vs. 6.1%; p < 0.001).

In this cohort, approximately 9% of patients undergoing emergent coronary angiography for suspected STEMI had non-obstructive coronary arteries. Despite similar baseline characteristics, these patients exhibited higher 1-year mortality. This unexpectedly high mortality likely reflects a selection bias inherent to the activation of emergent catheterization protocols, underscoring the need for refined triage criteria, diagnostic approaches and management strategies in this heterogeneous population.