Background: As endothelial dysfunction can be responsible for myocardial ischemia even in the absence of significant coronary lesions, we aimed to assess the correlation between endothelium-dependent vasomotor function and inducible ischemia late after successful coronary angioplasty.
Methods: In 30 patients without angiographic restenosis or coronary disease progression, coronary endothelial function was determined by acetylcholine infusion 6 months after elective single-vessel stenting of the left coronary artery. Acetylcholine-induced diameter changes were assessed in the proximal and distal segments of both the stented and the contralateral vessels by means of quantitative coronary angiography. A maximal workload ergometric test was also performed prior to endothelial function testing.
Results: Acetylcholine induced significant vasoconstrictive responses in the distal but not in the proximal segments of both the stented (-11 +/- 7% versus baseline; p < .01) and the contralateral vessels (-11 +/- 6%; p < .01), which were significantly correlated (R = .48; p < .05) and were completely reverted by nitroglycerine. Inducible ischemia was the only predictive factor for distal vasoconstriction in the stented vessel (p < .01) but not in the contralateral vessel (p = .06). Patients with minor signs of ischemia at the ergometric test showed a greater vasoconstriction than those with a completely normal test (-16 +/- 7% versus -7 +/- 6%; p< .01).
Conclusions: Exercise-induced ischemia late after successful percutaneous coronary intervention is related to distal coronary endothelial dysfunction.