How does coronary angioplasty affect progression of undilated atherosclerotic lesions?

To evaluate the effects of coronary angioplasty on the progression or regression of atherosclerotic lesions in arterial segments not dilated, we retrospectively compared angiograms obtained before and after the procedure from 252 consecutive patients referred for catheterization at least one month after successful angioplasty. Progression and regression rates were similar in dilated and undilated arteries. The appearance of new lesions was more common in dilated arteries. Lesion progression and the appearance of new lesions were more common and lesion regression was less common in dilated arteries with restenosis than in undilated or dilated arteries without restenosis. Mechanical trauma during angioplasty might accelerate progression and the appearance of new lesions, whereas normalization of blood flow rate and pattern, especially in arteries without restenosis, might lessen the rate of progression and the appearance of new lesions.