Estrogen acutely abolishes abnormal cold-induced coronary constriction in men

Area of Science:

• Cardiology
• Endocrinology
• Vascular Biology

Background:

• Ambient cold exposure can trigger myocardial ischemia via coronary artery constriction and reduced coronary blood flow.
• Estrogen possesses vasoactive properties that may mitigate abnormal coronary constriction in a sex-independent manner.

Purpose of the Study:

• To investigate whether estrogen can acutely abolish abnormal coronary responses to cold exposure in men.

Main Methods:

• A randomized, double-blinded, placebo-controlled clinical trial was conducted in a cardiac catheterization laboratory.
• Men with abnormal coronary artery constriction in response to a cold pressor test (CPT) received either intravenous conjugated estrogens (1.25 mg) or a placebo.
• Coronary cross-sectional area (CSA) and coronary blood flow were measured before and after intervention during CPT.

Main Results:

• In men receiving estrogen, a repeat CPT after intervention showed a 16.3% increase in CSA and a 54.9% increase in coronary blood flow (p < 0.01).
• Estrogen intervention significantly altered CSA and coronary flow responses to CPT compared to pre-intervention levels (p < 0.01).
• The placebo group showed no significant changes in CSA or coronary flow responses to CPT.

Conclusions:

• Conjugated estrogens acutely abolish abnormal coronary constriction in men in response to cold stimuli.
• Estrogen administration improves coronary blood flow during cold exposure in men.
• These findings indicate that estrogen favorably modulates coronary vasoreactivity in men.