Women suffer disproportionately than men from coronary heart disease in the small vessels (arterioles) compared to the large vessels (arteries). This results in delays in diagnosis, missed opportunities for treatment, and likely contributes to the increased death rate from coronary heart disease in women compared to men. Current testing for small vessel disease is invasive in the cardiac catheterization laboratory and is not performed routinely. Accordingly, women with this condition are routinely either falsely reassured, or misdiagnosed as another non-cardiac condition.

New imaging and noninvasive technology exists that may improve this situation. Measurement of endothelial function, using non-invasive tonometry testing can detect the abnormality most associated with coronary heart disease, endothelial dysfunction. Imaging techniques such as cardiac magnetic resonance imaging can now show the subendocardial layer of the heart, where the small vessel abnormality exists. These techniques have not been tested to determine if they can be used to diagnose and treat the small vessel coronary heart disease condition.

40 women undergoing coronary angiography with non-obstructive coronary artery disease will be enrolled. They will receive invasive provocative acetylcholine testing in the cardiac catheterization laboratory, followed by noninvasive PAT tonometry testing, and cardiac magnetic resonance testing. Correlation analyses will be analyzed with regard to the predictive value of the noninvasive testing for the outcome of small vessel disease by the invasive acetylcholine testing. The data from this study will be pilot data for a larger prospective study. These studies an important step toward better understanding, and safer diagnosis of the coronary heart disease that is prevalent in over 9 million American women today.