Men with nonobstructive coronary disease have higher burden of ischemic heart disease detected by cardiopulmonary exercise test

Background

Nonobstructive coronary artery disease (NOCAD), characterized by the presence of myocardial ischemic symptoms and signs without obstructive coronaries, is a common clinical condition, but it is less well understood. Few studies have analyzed the gender differences in inducible myocardial ischemia assessed by cardiopulmonary exercise test (CPET) in NOCAD.

Methods

We conducted a study of 289 NOCAD patients (mean age 60, 56% women) with ischemic symptoms and confirmed ⫹50% coronaries stenoses by coronary angiography who underwent symptom-limited CPET. We assessed ischemic response using predicted % peak VO₂, O₂ pulse trajectory, and exercise ECG test.

Results

Men with NOCAD had significantly lower predicted % peak VO₂ (62% vs. 73%), higher proportions of flattening pattern (16% vs. 2%), and downward patterns of O₂ pulse trajectory (2% vs. 0%) (p < .0001) compared with women. In contrast, women with NOCAD had a higher prevalence of shallow patterns of O₂ pulse trajectory (21% vs. 6%, p < .0001). Men with NOCAD had a higher risk ischemic profile (medium risk: 63% vs. 54%, high risk: 18% vs. 4%, p < .0001). After adjustment, men with NOCAD had significantly lower predicted % peak VO₂ (β −27.4, 95% CI −30.74 to −24.07), higher risk for abnormal O₂ pulse trajectories (OR 4.21, 95% CI 1.93 to 9.19), and myocardial ischemia risk per CPET parameters (OR 3.14, 95% CI 1.78 to 5.54) (p < .0001).

Conclusion

Men with NOCAD had a higher risk profile for ischemic heart disease per CPET. Therefore, they should receive rigorous management and follow-up to prevent cardiovascular events.