Possible further reduction in coronary flow velocity reserve in angina pectoris patients after oral glucose loading

Previous studies have suggested an increase in myocardial oxygen demand as a cause of postprandial angina. The purpose of this study was to assess coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD) before and after glucose ingestion in patients with known significant LAD stenosis.

Fourteen patients with significant LAD stenosis and 20 subjects without LAD stenosis were enrolled. Transthoracic Doppler echocardiography was performed to measure the average peak diastolic coronary flow velocity (APDV) in the LAD at rest and during adenosine infusion. CFVR was calculated as APDV during adenosine infusion (APDVATP) divided by APDV at rest (APDVrest). APDVrest, APDVATP, and CFVR were assessed during fasting and 30, 60, and 120 min after a 75-g oral glucose loading.

In patients with LAD stenosis, APDVrest at 30 min after glucose loading was the highest at any time point. However, significant differences were not found in the APDVATP among time points in the patients or controls. Consequently, the CFVR in the patients was the lowest at 30 min after glucose loading (fasting, 1.77 ± 0.19; 30 min, 1.48 ± 0.16; 60 min, 1.69 ± 0.17; and 120 min, 1.76 ± 0.19; p < 0.01, ANOVA), as in the controls.

These findings suggested that the value of CFVR in the LAD was reduced after glucose loading. Myocardial risk area supplied by a stenosed coronary artery may be exposed to myocardial ischemia more frequently during oral glucose loading than during fasting in patients with significant coronary artery stenosis.