INTRODUCTION: Angiographically normal coronary arteries have concealed intimal thickening that importantly contribute to coronary arterial disease activity. Increased plasma levels of plasminogen activator inhibitor (PAI) are associated with myocardial infarction and atherosclerosis. However, it remains unclear whether the PAI contributes to vascular wall thickening detected by intravascular ultrasound (IVUS) in normal coronary angiogram. The aim of this study was to evaluate if the PAI activity contributes to the extent of atherosclerotic changes in angiographically normal coronary arteries using IVUS technique. MATERIALS AND METHODS: We studied 33 consecutive patients with normal coronary angiograms. These patients were divided into a high level of plasma PAI activity group (H-PAI; n=12) and a normal range of PAI activity group (N-PAI; n=21), according to the plasma PAI activity levels. RESULTS: The average of "percent intima+media area (%I+M area)" and "maximal intima+media (I+M) thickness" were significantly greater in the H-PAI group as compared with those in the N-PAI group (p<0.05). Minimal lumen diameter and lumen area were comparable between these groups. The plasma PAI activity level was the independent predictor of increase in maximal I+M thickness, in multiple regression analysis with the traditional risk factors as covariates. CONCLUSIONS: Thickened intima+media of angiographically normal coronary arteries were associated with high plasma level of PAI activity, independently of other traditional risk factors. PAI may contribute to the pathogenesis of coronary intimal thickening that might increase coronary arterial tone.
INTRODUCTION: Angiographically normal coronary arteries have concealed intimal thickening that importantly contribute to coronary arterial disease activity. Increased plasma levels of plasminogen activator inhibitor (PAI) are associated with myocardial infarction and atherosclerosis. However, it remains unclear whether the PAI contributes to vascular wall thickening detected by intravascular ultrasound (IVUS) in normal coronary angiogram. The aim of this study was to evaluate if the PAI activity contributes to the extent of atherosclerotic changes in angiographically normal coronary arteries using IVUS technique. MATERIALS AND METHODS: We studied 33 consecutive patients with normal coronary angiograms. These patients were divided into a high level of plasma PAI activity group (H-PAI; n=12) and a normal range of PAI activity group (N-PAI; n=21), according to the plasma PAI activity levels. RESULTS: The average of "percent intima+media area (%I+M area)" and "maximal intima+media (I+M) thickness" were significantly greater in the H-PAI group as compared with those in the N-PAI group (p<0.05). Minimal lumen diameter and lumen area were comparable between these groups. The plasma PAI activity level was the independent predictor of increase in maximal I+M thickness, in multiple regression analysis with the traditional risk factors as covariates. CONCLUSIONS: Thickened intima+media of angiographically normal coronary arteries were associated with high plasma level of PAI activity, independently of other traditional risk factors. PAI may contribute to the pathogenesis of coronary intimal thickening that might increase coronary arterial tone.