Objectives: The purpose of this study was to evaluate the extent of atherosclerotic changes in angiographically normal coronary arteries using intravascular ultrasound (IVUS) technique in patients with coronary spastic angina.
Background: Nitric oxide activity was shown to be decreased in coronary arteries of patients with coronary spastic angina (CSA). Decrease in nitric oxide causes arterial intimal hyperplasia or thickening. However, it remains unclear whether intimal thickening is diffusely present in coronary arteries of patients with CSA.
Methods: The IVUS study was performed in 26 patients with CSA and with normal coronary angiograms and in 31 control subjects in whom age and gender was matched with those in patients with CSA.
Results: Compared with control subjects, patients with CSA had significantly larger percent intima + media area (%I + M area), intima + media area and maximal intima + media thickness in all of proximal, middle and distal segments (p<0.01, respectively). Lumen area was comparable between these groups. The presence of spasm was the most powerful independent predictor of increase in percent intima + media area, in multiple-regression analysis with the traditional risk factors as covariates.
Conclusions: Intimal thickening existed entirely in a coronary artery in patients with CSA and with normal angiograms, independently of other traditional risk factors. The diffuse intimal thickening in the spasm coronary arteries is intimately related with coronary spasm.