Acetylcholine versus cold pressor testing for evaluation of coronary endothelial function.

Area of Science:

• Cardiology
• Vascular Biology
• Diagnostic Testing

Background:

• Intracoronary acetylcholine (IC-Ach) assesses coronary endothelial function but is often impractical.
• Cold pressor testing (CPT) is a simpler alternative for endothelial function and perfusion imaging.
• CPT has not been evaluated in symptomatic women with non-obstructive coronary artery disease (CAD) and suspected coronary microvascular dysfunction (CMD).

Purpose of the Study:

• To evaluate the utility of CPT in assessing coronary endothelial function in women with suspected CMD.
• To compare the effects of CPT and IC-Ach on coronary artery diameter and blood flow in this patient group.

Main Methods:

• 163 women with suspected CMD and no obstructive CAD underwent coronary reactivity testing.
• Doppler flow wire assessed coronary artery diameter and coronary blood flow (CBF) in the left anterior descending artery.
• Measurements were taken at baseline, during IC-Ach infusion, and during CPT.

Main Results:

• Coronary artery diameter changes with IC-Ach and CPT were moderately correlated (r=0.59, P<0.001).
• The correlation was stronger in subjects with normal endothelial response to IC-Ach.
• CPT increased rate pressure product, while IC-Ach did not significantly alter it.

Conclusions:

• CPT shows moderate correlation with IC-Ach for coronary diameter changes in women with suspected CMD.
• CPT may be useful, especially in patients with normal endothelial function.
• CPT is not a substitute for IC-Ach in diagnosing coronary endothelial dysfunction.