Vascular remodelling after cardiac transplantation: a 3-year serial intravascular ultrasound study.

AIMS: To assess the time-course of intimal hyperplasia and vascular remodelling, and their relative contributions on luminal narrowing in transplant coronary artery disease (TCAD) by a 3-year serial intravascular ultrasound (IVUS) study. METHODS AND RESULTS: Serial IVUS examinations were performed in 90 cardiac transplant recipients at 1.4+/-0.6 months after transplantation and again annually thereafter for 3 years. From 90 arteries, 304 sites were matched from baseline to the third year post-transplant. Based on the change in external elastic membrane (EEM) area +/-10% at 1 year, 304 sites were divided into three groups: sites with no remodelling (52%); early constrictive remodelling (26%); and early compensatory enlargement (22%). Greater intimal growth was seen at 1 year in sites with early compensatory enlargement, whereas there was no change in intimal area in sites with early constrictive remodelling. Over 3 years, the cumulative lumen loss was greater in sites with early constrictive remodelling than in sites with early compensatory enlargement or no remodelling (P<0.001). When luminal narrowing occurred for each annual interval, the contribution from the decrease in EEM area was greater than that due to intimal thickening (P<0.001). CONCLUSION: During the first 3 years post-transplant, the largest intimal growth occurs in the first year, mostly in sites with early compensatory enlargement. The contribution to luminal loss in TCAD is greater from constrictive remodelling than from intimal hyperplasia. The type of remodelling pattern that occurs in transplanted coronary arteries within the first year post-transplant may be a predictor of the progression of luminal narrowing during subsequent years.