Sex Differences in Coronary Pathophysiology

This is a research study evaluating possible causes of chest pain (or an anginal equivalent, such as fatigue resulting in a decrease in exercise tolerance, shortness of breath, or back, shoulder, neck, or jaw pain) in people with no evidence of significant coronary artery disease on their coronary angiogram (pictures of the blood vessels in the heart). The purpose of the research study is to determine if there is diffuse atherosclerosis (plaque) not appreciated by angiography, or if the coronary endothelium (lining of the blood vessels in the heart) and/or microcirculation (small vessels in the heart that are not easily seen with an angiogram) are not functioning properly in those who have chest pain (or an anginal equivalent), but normal coronary arteries on angiography. Specifically, we are interested if these findings are more common in women than men.

Women are more likely than men to have chest pain suggestive of angina but normal-appearing coronary arteries on angiography, which ultimately imparts a significant morbidity/mortality and economic burden. Recent evidence suggests that women commonly have endothelial and microcirculatory dysfunction, as well as diffusely distributed atherosclerosis--disorders that can cause chest pain, but will not be seen on angiography. This presents an intriguing basis for pathophysiologic differences between women and men, but there are no studies that actually compare the presence of such findings in women with that of men. The objective of this research project is to determine if the incidence of such pathophysiologic differences is truly higher in women than it is in men.

We hope to determine if there is a higher incidence of diffuse atherosclerotic plaque, endothelial dysfunction, and/or microcirculatory dysfunction in women compared with men. If this sex difference exists, it has significant implications for how we should be testing and treating women with chest pain but angiographically normal coronary arteries.

Eligibility Criteria:
Inclusion Criteria:

1. Patient referred for elective coronary angiography because of a reasonable clinical suspicion of coronary ischemia.
2. Presence of angina or an anginal equivalent (including chest, back, shoulder, arm, neck, jaw discomfort, or shortness of breath brought on by physical exertion, emotional stress, or certain times of day/month).

Exclusion Criteria:1) Asymptomatic (such as a pre-op cath)

2) Status-post heart transplant

3) Status-post coronary artery bypass grafting

4) Age \<18

5) Renal insufficiency (creatinine \>1.5)

6) Presence of an acute coronary syndrome (STEMI or NSTEMI), Tako-tsubo, an abnormal ejection fraction (EF\<55%), cardiogenic shock, or recent VT/VF

7) Presence of another likely explanation of chest pain, such as pulmonary hypertension or aortic stenosis

8) History of adverse reaction to any of the medications being used (acetylcholine, nitroglycerin, adenosine, or heparin)

9) Currently taking vasoactive medication (such as nitroglycerin)

10) Inability to provide an informed consent, including an inability to speak, read, or understand English, Spanish, Chinese, Farsi, Japanese, Korean, Russian, or Vietnamese

11) A hearing impairment that won't allow for a typical verbal conversation or a visual impairment that won't allow for reading of the written consent

12) Participation in another study (with the exception of the Stanford Gene-PAD study)

13) A potentially vulnerable subject (including minors, pregnant women, economically and educationally disadvantaged, decisionally impaired, and homeless people)