['Left main coronary artery (LMCA) disease influences survival; however, the predictors of LMCA changes over time are incompletely understood.', 'Paired intravascular ultrasound (IVUS) and core laboratory analyses were performed in a standardized fashion in 207 subjects (mean +/- SD age 58 +/- 10 years, 80% men). The average follow-up duration was 18 months (range 12-24 months). The IVUS measurements were first obtained at the smallest lumen area and the largest plaque area at follow-up and the corresponding positions in the LMCA were then measured at baseline.', 'The LMCA percentage of atheroma area at baseline was 38.2% +/- 11.8%, and 133 patients (64%) experienced an increase in percentage of atheroma area. Change in lumen area correlated positively with change in total vessel area (R = 0.85, P < .0001) and negatively with change in percentage of atheroma area (R = -0.58, P < .0001). Change in plaque area correlated well with change in total vessel area (R = 0.64, P < .0001) but only weakly with change in lumen area (r = 0.14, P = .039). Although LMCA length correlated negatively with baseline lumen area and total vessel area, it did not correlate with their changes over time. On multivariable analyses, current smoking predicted an increase in percentage of atheroma area (P = .0013) and plaque area (P = .0041). Height negatively predicted change in percentage of atheroma area (P = .001).'] Is remodeling a more important determinant of lumen size than atheroma burden in left main coronary artery disease?