Compensatory enlargement of human coronary arteries during progression of atherosclerosis is unrelated to atheroma burden: Serial intravascular ultrasound observations from the REVERSAL trial

Aims: On the basis of the evidence from autopsy studies, it is accepted that compensatory enlargement (remodelling) of coronary arteries during progression of atherosclerosis diminishes once atheroma burden (cross-sectional area stenosis) reaches ∼40%. Our aim was to evaluate whether atheroma burden is a limiting factor for coronary arterial remodelling using in vivo serial intravascular ultrasound (IVUS). Methods and results: From the cohort of the Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) trial, we identified 210 focal coronary lesions at baseline IVUS. Of these, 128 lesions that had an increase in atheroma area at the 18-month follow-up IVUS were included in the analysis. Lesions were matched at baseline and follow-up. The increase in external elastic membrane (EEM) area for each mm² increase in atheroma area was not significantly different in lesions with <40 and ≥40% atheroma burden at baseline (1.62 vs. 1.28 mm², P=0.30). There were no correlations between atheroma burden at baseline and change in EEM (r=0.02, P=0.86) or change in lumen (r=0.04, P=0.64) areas. Conclusion: Assessment of coronary arterial remodelling by serial IVUS revealed that compensatory remodelling is not limited by atheroma burden. Atheroma burden is not a determinant of arterial enlargement during the progression of atherosclerosis.