Invasive Evaluation of Patients with Angina in the Absence of Obstructive Coronary Artery Disease
Background—More than 20% of patients presenting to the cardiac catheterization laboratory with angina have no angiographic evidence of coronary artery disease (CAD). Despite a "normal" angiogram, these patients often have persistent symptoms, recurrent hospitalizations, a poor functional status, and adverse cardiovascular outcomes, without a clear diagnosis.
Methods and Results—In 139 patients with angina in the absence of obstructive CAD (no diameter stenosis >50%), endothelial function was assessed, the index of microcirculatory resistance (IMR), coronary flow reserve (CFR), and fractional flow reserve (FFR) were measured, and intravascular ultrasound (IVUS) was performed. There were no complications. The average age was 54.0±11.4 years and 107 (77%) were women. All patients had at least some evidence of atherosclerosis based on IVUS examination of the LAD. Endothelial dysfunction (a decrease in luminal diameter of >20% after intracoronary acetylcholine) was present in 61 patients (44%). Microvascular impairment (an IMR ≥25) was present in 29 patients (21%). Seven patients (5%) had an FFR ≤0.80. A myocardial bridge was present in 70 patients (58%). Overall, only 32 patients (23%) had no coronary explanation for their angina, with normal endothelial function, normal coronary physiologic assessment, and no myocardial bridging.
Conclusions—The majority of patients with angina in the absence of obstructive CAD have occult coronary abnormalities. A comprehensive invasive assessment of these patients at the time of coronary angiography can be performed safely and provides important diagnostic information which may affect treatment and outcomes.
- Non-ostructive coronary artery disease
- Index of microcirculatory resistance
- chest pain
- fractional flow reserve
- endothelial dysfunction
- myocardial bridging
- Received August 4, 2014.
- Revision received December 23, 2014.
- Accepted January 16, 2015.