Relation between baseline plaque burden and subsequent remodelling of atherosclerotic left main coronary arteries: a serial intravascular ultrasound study with long-term (> or =12 months) follow-up.

Aims: Glagov's histopathological observation and non-serial intravascular ultrasound studies (IVUS) concluded that compensatory coronary remodelling diminishes as 40% atherosclerotic plaque burden is reached. We tested this hypothesis with serial IVUS.
Methods and Results: Serial IVUS examinations of 46 atherosclerotic non-stenotic left main stems (18+/-8 months apart) were analysed to assess the relation between baseline plaque burden (=plaque+media area/vessel area) vs. serial remodelling (=vessel area at baseline - at follow-up). There were 25 plaques with baseline plaque burden <40% (30.1+/-6.6%, group A) and 21 plaques with baseline plaque burden > or =40% (46.1+/-5.8%, group B). There was no relation between baseline plaque burden vs. subsequent changes in vessel area overall (r=0.07, P=0.7), for group A (r=0.03, P=0.6), and group B (r=0.01, P=0.8). The frequency of positive serial remodelling (vessel area increase) vs. negative or intermediate serial remodelling (no change or decrease) were similar in group A [17 (68%) vs. 8 (32%)] and group B lesions [18 (86%) vs. 3 (14%)] (P=0.2).
Conclusion: IVUS demonstrates that serial coronary remodelling is not related to baseline plaque burden. Lesions with baseline plaque burden <40% may subsequently show a lack of compensation or frank arterial shrinkage, whereas lesions with baseline plaque burden >40% may continue to develop compensatory enlargement.