Coronary vascular dysfunction is associated with adverse left ventricular filling in patients with angina but no obstructed coronary arteries

Angina with no obstructive coronary arteries is often due to coronary vascular dysfunction, which is increasingly described as a contributor and predictor of heart failure with preserved ejection fraction. We tested the hypothesis that coronary vascular dysfunction contributes to cardiac dysfunction. Sixty-eight participants with suspected coronary vascular dysfunction underwent LV pressure-volume assessment at rest and during isometric handgrip stress. Coronary function testing was performed by infusing standard doses of adenosine, acetylcholine, and nitroglycerine through a guiding catheter placed in the left main coronary artery, per established protocols. Of the participants studied, 12 had normal coronary vascular function while 56 had coronary vascular dysfunction. At rest, there were no differences between groups in any invasive pressure or volumetric measurement. With isometric handgrip, peak filling rate increased significantly in participants with normal coronary vascular function (0.56 ± 0.31 vs. 0.85 ± 0.68 1/s/mmHg) but remained unchanged in participants with coronary vascular dysfunction (0.51 ± 0.22 vs. 0.55 ± 0.43 1/s/mmHg; group x time interaction, p = 0.04). Moreover, left ventricular end-diastolic pressure decreased significantly with isometric handgrip in participants with normal coronary vascular function (12 ± 3 vs. 9 ± 4 mmHg) but increased in participants with coronary vascular dysfunction (14 ± 4 vs. 15 ± 6 mmHg; group x time interaction, p = 0.03). Coronary vascular dysfunction was associated with an impaired ability of the LV to adapt its filling during stress. Further work is needed to assess potential clinical significance.