Endothelium-independent coronary vasodilatation in patients with single vessel ischemic heart disease and its relationship with coronary artery morphology.

Objective: Investigation of the endothelium-independent coronary vasoreactivity in a single stenosed coronary artery and its correlation with the type of coronary morphology.

Methods: Ninety patients with single vessel coronary artery disease were allocated into two groups: a control group of 34 patients with simple coronary stenosis and an experimental group of 56 patients with complex coronary stenosis (modified Ambrose classification). The reference lumen diameter in the proximal, medial and distal segments of a stenosed coronary artery was assessed at baseline and after the intracoronary administration of glyceryl trinitrate in selective coronarography.

Results: After administration of the drug the lumen was dilated in 71.48% of the segments while there was no dilation in the remaining 28.52%. The dilated segments were 82.74% in the complex stenosis group versus 52.94% in the control group (P < 0.001). The mean change of the reference lumen diameter in the complex stenosis patients was 0.52 +/- 0.59 mm versus 0.24 +/- 0.46 mm in the simple stenosis group (P < 0.001). The change in the segments with dilated lumen was 0.39 +/- 0.36 of the baseline value in the complex stenosis group versus 0.24 +/- 0.23 in the control group (P < 0.001).

Conclusions: The coronary arteries with single stenosis react to intracoronary glyceryl trinitrate primarily with endothelium-independent vasodilatation. In complex stenosis coronary arteries there are more dilated segments and greater increase of the baseline reference lumen diameter.