Abstract 3783: Reverse Remodeling of Human Atherosclerotic Coronary Arteries During Disease Regression
Background: Compensatory enlargement of coronary arteries accomodates plaque burden during atherosclerosis initiation and progression. Lipid-lowering therapy has altered the natural history of coronary atherosclerosis but the arterial changes that occur during disease regression need to be clarified.
Methods: Intravascular ultrasound was performed at baseline and after approximately 18 months of treatment in 432 patients with coronary artery disease. Mean plaque, lumen and total vessel areas were computed in a 30-mm coronary segment of interest.
Results: Mean low-density lipoprotein (LDL) cholesterol was 92 mg/dl (2.4 mmol/l) and 88% of patients received statins. Overall, changes in plaque area and total vessel area were highly correlated (r=0.82, P<0.0001). Among the 227 patients who had plaque regression over the study course, mean plaque area decrease was −0.58±0.54 mm2, and changes in mean total vessel and lumen areas were −1.02±1.10 mm2 and −0.44±0.86 mm2 respectively. The reduction in mean plaque area correlated better with the change in mean total vessel area (r=0.64, P<0.0001) than with the change in mean lumen area (r=0.20, P=0.003). The relationship between plaque regression and decrease in total vessel area was significantly better (P=0.019) for patients with more than 40 percent atheroma area (r=0.72; P<0.0001) than those with 40 percent or less (r=0.48; P=0.0004).
Conclusion: Regression of atherosclerotic plaque with low LDL-cholesterol levels is generally accompanied by a reduction in total vessel size, without an increase in luminal dimensions. This reverse vascular remodeling may be responsible for the so-called “regression paradox”, whereby secondary prevention is associated with significant clinical benefits despite minimal improvement in lumen dimensions of coronary arteries.